Re: "ADDITIONAL STANDARDS ARE NEEDED" when using E-Cal
Bruce, Steffan,
I think you are forgetting that there is another verification you can perform - completely remove the ECal module and connect the test ports together and verify the error in the calibration is close to 0.00dB across the frequency range.? That is your error ;-)? ? You can also confirm the phase starts at on the right side of the smith chart for the open port as one would even in manual calibration.
Answering your question the signalling on the DB25 uses the same protocol, in fact the first board is the same between the low and high band modules.? The primary difference is the low band uses 7 switch signals to the lower board and the high band module uses a total of 16.
Analog voltages to the PIN switches are different with the low band using 0 and -12V whereas the high band unit uses +5 and +24V for its pin switches, so the final driver board is completely different between the 2 bands.
The digital interface controlls access to the EEPROM which contains the measurement data, and a way of enabling any of the 7 (or 16) switches in the RF path.
I did open my 85097 (which I use on my 8753ES analyzer) but haven't reverse engineered it other than a conceptual understanding of it taking the signals from the parallel port and using a control line (or maybe register) to multiplex between the A and B ports.?
Following onto answer Steffan's questions,
1.? Yes recalibration this should be possible.?? The contents of the EEPROM are simply the actual S1P measurements for each PIN switch combination, so its a matter of taking a full measurement (on a mechanical calibrated VNA) against each of the PIN switch combinations to get a set of known values.? Note there are only a few standard combinations used? which have been chosen by the design engineers who have a better understanding of the phase delays along the transmission line required for best calibration.
2.? As per #1 above, because you know the complex impedance of the ECal port the VNA will measure the impedance it sees and will de-embed to solve the 12-term matrix for calibration (or 3-6 terms depending on the calibration type selected).???? Instead of a short, open or 50R in the solution matrix we use the known values for the ECal.
It should be noted that the ECal is never a perfect thru, open or short at any time of the electronic calibration.? From memory the short is a few ohms but to "hammer it home" the following 2 PIN's are also energized to ensure there is a stronger reflections.
For successful calibration there must be a ~180deg reversal observed at each frequency (perhaps 90 deg - I know quarter wave is required for unknown through).? This can be easily achieved in the high band cal with the length of transmission line.? For the low band? module there is also a PIN switch halfway through which simulates a open to create a larger phase reversal.
If you have ever used a sliding load during calibration then you will know what I mean by 90 degree observations to get a solid calibration point.
This 180deg requirement is also what sets the lower frequency limit of 45MHz for our units.? As noted in Joels book more modern ECals use a GASFET switch which allow for a more traditional SOLT standard at lower frequencies.
The Arduino board I built is able to reprogram the EEPROM but I haven't added that into the code.? The datasheet wasn't an easy read at the time! ?? After dumping the contents I found the ECals to be better than what I can achieve mechanically, so if I re-calibrate mine it would be a step backwards. ? Given I don't posses a 4 receiver VNA and lower grade test cables my calibrations will always be inferior.
Finally I believe there must be a version of firmware for the 85060C which supports the calibration process.? This is based on the references in the dumped EEPROM data.? Maybe its hidden in the current version somewhere.? If anyone is able to get a copy it would be greatly appreciated.
--
Wayne
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Re: HP-8753E Power Cycles at Start Up
Burt:
Probably will end up doing that. I had a spare SMPS for the rig, and that is doing the job for now. I have the A15 open and on my desk. When I get back to the office on Monday, I will start looking at the filter capacitors.?
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On Aug 28, 2022, at 12:54 AM, Burt K6OQK <biwa@...> wrote:
?Rich,
I have cured a lot of weird problems by fixing the obvious things first.? I suspect that if you were to re-cap the power supply module you would be pleased.? That's been my experience in 90% of the symptoms you describe.
Burt, K6OQK
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Re: "ADDITIONAL STANDARDS ARE NEEDED" when using E-Cal
Hello,
Hope not being too far off topic with two questions.
1. If the ECal module drifts, wouldn't one solution be to simply re-characterize it? I believe this is standard procedure on the newer ones (more or less) whenever one wants to use a configuration different from factory setup.
It would be interesting if anyone with a known 'broken' performance could test writing to Flash and see if at least the communication works.
2. Although the format of the 85062 is not too complicated (reading out content and comparing with measurements seems to give a good match), the actual data stored doesn't make enough sense to be used on its own. Does anyone know the details of how the calibration is performed? As Wayne pointed out, it is likely some kind of hybrid TRL/TRM version, but does anyone know the details? The app notes I have seen don't go too deep into details...
Regards,
? Staffan
PS. I noticed the document regarding 85062-60006 I uploaded earlier wasn't the latest version so I added thT. Don't know if I can or should delete the previous???
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Re: HP-8753E Power Cycles at Start Up
Rich,
I will second Paul's suggestion. I had an HP3586B that developed strange problems.? The big Molex connector between the power transformer and the mother board looked fine... until I turned it over.? The bottom side was black.? I replaced the connector by hard wiring directly from the transformer to the motherboard.? In my case I put about a foot of service loop in a coil tucked between the transformer and the motherboard.? My 3586B has been working flawlessly since doing that; about 10 years ago.
Burt, K6OQK
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Re: HP-8753E Power Cycles at Start Up
Rich,
I have cured a lot of weird problems by fixing the obvious things first.? I suspect that if you were to re-cap the power supply module you would be pleased.? That's been my experience in 90% of the symptoms you describe.
Burt, K6OQK
|
Re: HP-8753E Power Cycles at Start Up
Hi Peter:
There was one thing I negated to mention. I am not sure if it was from a temperature DELTA caused from opening the enclosure/chassis or not, but I did reseat the molex connector which attaches to the Motherboard. While this allowed me to get through the boot sequence but, all kinds of strange errors started to appear. The one most seen was related to the source not being found (forget the exact text).?
I have seen a very similar problem in a Tektronix 2400 (2440) series scope PSU. The problem was on the secondary side of the SMPS, and was caused by a high precision current sense resistor drifting out of tolerance. This caused the scope to recycle much in the same manner as I described with my 8753E. These resistors were there to sense an overcurrent condition, and shutdown the scope in order to save it. That one took me forever to figure out, because I did not realize the tolerances needed to be so tight, and with a normal hand held DMM everything looked OK. I needed to see another decimal or two, if memory serves me.
I looked briefly in the Post Regulator assembly, and I did not see any such resistors. The caps looked ok (physically speaking), as in they had not spewed their guts, or swelled based on my physical inspection of them.?
As I stated, I am going to look for ripple, as that would tell me a lot.?
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Show quoted text
On Aug 27, 2022, at 8:06 PM, peter bunge <bunge.pjp@...> wrote:
? I am sending my repair log private. This same thing happened in Sept 2019. For those interested this is a summary ¡¤????????
At
turn on all the front panel displays flash on and off continuously.
¡¤????????
On
the rear of the instrument the top red LED flashes in time to the fan surges
and the bottom green LED stays on. The A15 pre-regulator is probably OK.
¡¤????????
All
green LEDs on A8 are flashing. There is probably something loading one of the
power supplies.
¡¤????????
?Pull A9, A10, A11, A12 and the power supplies
are OK. Start putting them back one at a time.
¡¤????????
OK
until A9 is replaced and the problem returns. A9 capacitors all seem OK but A9
drives the display. Pulling the connector on the display driver board (molex
connector) removes the problem. Everything pointed to the Newscope LCD but various tests running it on a separate power supply were inconclusive. Conclusion:
It is
unlikely that the LCD display was the actual problem. There may have been a
marginal overload somewhere in the 8753B and the LCD current pushed the total
past the trip point.
The
problem could also have been that the trip point setting had shifted for some
reason to a level that tripped when the LCD was finally connected. The LCD only draws current from the +5v power
supply so this is where to look if the problem returns. A test
load was made to replace the Newscope9 if the problem re-appears.
It will
draw 100mA more than the Newscope 9 from both the +5v and +15v supplies and can
be easily modified.
I will report back here when I find the problem. Peter
On Sat, Aug 27, 2022 at 7:38 PM Rich Miller via <av8torrich= [email protected]> wrote: Hi Peter:
When I get a few moments to take a look with a scope I will. This problem seems very much temperature related. My plan is to let it run for a good couple of hours, and then probe the A15W1 Feedthrough points on the SMPS.?
My only concern is, I may not see a lot of ripple with the SMPS unloaded. I have had two cases in various instruments where the switcher fooled me like this. It was not until I loaded it down did I begin to see a lot of ripple.? ? Rich; I would be interested?in what you find. I plan on putting my 8753 on a variac to run with lower voltage. If it was a failing reservoir?capacitor in the pre-regulator this should show it up. The other thing to check is to 'scope the ripple on the pre-regulator. Keep me informed. Peter. On Sat, Aug 27, 2022 at 7:16 PM Rich Miller via <av8torrich= [email protected]> wrote: Peter:
I have it back and running. It was the A8 board, despite the service manual pointing to the post regulator board. I replaced the SMPS, and I am back in business. I opened the SMPS, and did not find anything out of the ordinary. I may plug this in, leave it sit for a few hours, and then begin probing the output.? ?Hi Peter:
Have an update for you. The fault started again. If you follow the troubleshooting guide on Section 5-8 - Page 271 it would leave you to believe I have a post regulator problem (A8).? Swapped A8 out, and the problem precise. When I unplug A15W1 from the post regulator, the problem disappears. Being that I have a known good post regulator board to swap out, I think the problem is the A15 Pre Regulator (SMPS). Getting ready to swap that out and see what happens. ? ? Rich; I think this is a case of "nothing works Thursday". It happens sometimes and maybe this only applied to 8753s. The electronics Gods work in mysterious ways. I read the manual and it says surging is the post regulator circuit sensing an overcurrent and shutting down the power supply repeatedly to protect it. Maybe a cap reforming after months of non use? I had disconnected the S-Param Test set and thought it may have been the culprit but reconnecting it made no difference. It still works. Peter On Sat, Aug 27, 2022 at 2:02 PM Rich Miller via <av8torrich= [email protected]> wrote: LOL - I just got to my office with a replacement PSU, and Post Regulator Board. This was an hour drive.?
?Turned on the VNA, and its fine now. This maybe temp related, so I am going to run some more measurements and wait for the fault to manifest once again. A little annoyed, but such is life I suppose.
I was in the middle of an important measurement when this happened yesterday, so I am going to take it while I can. I will keep you updated, as I learn more. Rich ? I took the cover off and everything works. I have no idea what the problem was. This unit had a manufacturer's fault on it for 30+ years. The problem showed up once and fixed itself after re-seating?boards but I could not confirm what fixed it. Two years later the fault re-appeared and it was these two bad solder joints. It is not the problem this time because they were re-soldered and the symptoms are different anyway. So the fan was surging and it would not start up. I will 'scope the filter caps before putting the cover back on. How are you making out with yours? My HP8753B suddenly started doing this surging with all the front lights on (I will have to re-check that statement but it is what I remember). This was several weeks ago and I have not had time to check it. If you start on yours take the top lid off and look at the row of lights on the power supply board. They should be green if OK and red to indicate a bad power supply (I'm going from memory so anyone correct me if I am wrong). Check the?power supplies with a good digital meter BUT DO NOT ADJUST ANY, especially if they are marginally off,?you do not want an additional fault of your own doing. Check each one with a 'scope and I would not be surprised if you find high ripple on one or more in which case replace the bad capacitor.? The manual will tell you what they should look like. Also there is?a start up sequence for the?CPU row of red lights. Check the manual. The fans are special on these?and are?controlled by a circuit. The VNA will not turn on if the?fan is bad and it?must be replaced by the correct one. I will be starting on mine next week, possibly Monday. I have family visiting right now. Peter.
On Fri, Aug 26, 2022 at 7:35 PM Rich Miller via <av8torrich= [email protected]> wrote: All:
My HP-8753E started demonstrating what I believe is a PSU related fault. When I switch the VNA on, it attempts to boot up, but before it can, I hear the fan stop, and then turn back on, and the VNA attempts a start again. This cycle goes on forever at this point.
I have taken a close look at the spare PSU, and there are no fuses externally. I also note there is a Voltage Regulator Board. I am wondering if anyone has had this issue, and was it the PSU itself or the Regulator Board?
My thinking is if this was a hard fault in the PSU something would have self destructed, or blown a component/fuse internal to the PSU. That being said, I have never seen the inside of the PSU to know if there is some sort of soft restart, or a fuse which should blow.
I would also be curious if there is some other protection feature in the 8753E which would cause it to power cycle like I describe above?
Thanks in advance!
Rich
|
Re: HP-8753E Power Cycles at Start Up
I am sending my repair log private. This same thing happened in Sept 2019. For those interested this is a summary ¡¤????????
At
turn on all the front panel displays flash on and off continuously.
¡¤????????
On
the rear of the instrument the top red LED flashes in time to the fan surges
and the bottom green LED stays on. The A15 pre-regulator is probably OK.
¡¤????????
All
green LEDs on A8 are flashing. There is probably something loading one of the
power supplies.
¡¤????????
?Pull A9, A10, A11, A12 and the power supplies
are OK. Start putting them back one at a time.
¡¤????????
OK
until A9 is replaced and the problem returns. A9 capacitors all seem OK but A9
drives the display. Pulling the connector on the display driver board (molex
connector) removes the problem. Everything pointed to the Newscope LCD but various tests running it on a separate power supply were inconclusive. Conclusion:
It is
unlikely that the LCD display was the actual problem. There may have been a
marginal overload somewhere in the 8753B and the LCD current pushed the total
past the trip point.
The
problem could also have been that the trip point setting had shifted for some
reason to a level that tripped when the LCD was finally connected. The LCD only draws current from the +5v power
supply so this is where to look if the problem returns. A test
load was made to replace the Newscope9 if the problem re-appears.
It will
draw 100mA more than the Newscope 9 from both the +5v and +15v supplies and can
be easily modified.
I will report back here when I find the problem. Peter
On Sat, Aug 27, 2022 at 7:38 PM Rich Miller via <av8torrich= [email protected]> wrote: Hi Peter:
When I get a few moments to take a look with a scope I will. This problem seems very much temperature related. My plan is to let it run for a good couple of hours, and then probe the A15W1 Feedthrough points on the SMPS.?
My only concern is, I may not see a lot of ripple with the SMPS unloaded. I have had two cases in various instruments where the switcher fooled me like this. It was not until I loaded it down did I begin to see a lot of ripple.? ? Rich; I would be interested?in what you find. I plan on putting my 8753 on a variac to run with lower voltage. If it was a failing reservoir?capacitor in the pre-regulator this should show it up. The other thing to check is to 'scope the ripple on the pre-regulator. Keep me informed. Peter. On Sat, Aug 27, 2022 at 7:16 PM Rich Miller via <av8torrich= [email protected]> wrote: Peter:
I have it back and running. It was the A8 board, despite the service manual pointing to the post regulator board. I replaced the SMPS, and I am back in business. I opened the SMPS, and did not find anything out of the ordinary. I may plug this in, leave it sit for a few hours, and then begin probing the output.? ?Hi Peter:
Have an update for you. The fault started again. If you follow the troubleshooting guide on Section 5-8 - Page 271 it would leave you to believe I have a post regulator problem (A8).? Swapped A8 out, and the problem precise. When I unplug A15W1 from the post regulator, the problem disappears. Being that I have a known good post regulator board to swap out, I think the problem is the A15 Pre Regulator (SMPS). Getting ready to swap that out and see what happens. ? ? Rich; I think this is a case of "nothing works Thursday". It happens sometimes and maybe this only applied to 8753s. The electronics Gods work in mysterious ways. I read the manual and it says surging is the post regulator circuit sensing an overcurrent and shutting down the power supply repeatedly to protect it. Maybe a cap reforming after months of non use? I had disconnected the S-Param Test set and thought it may have been the culprit but reconnecting it made no difference. It still works. Peter On Sat, Aug 27, 2022 at 2:02 PM Rich Miller via <av8torrich= [email protected]> wrote: LOL - I just got to my office with a replacement PSU, and Post Regulator Board. This was an hour drive.?
?Turned on the VNA, and its fine now. This maybe temp related, so I am going to run some more measurements and wait for the fault to manifest once again. A little annoyed, but such is life I suppose.
I was in the middle of an important measurement when this happened yesterday, so I am going to take it while I can. I will keep you updated, as I learn more. Rich ? I took the cover off and everything works. I have no idea what the problem was. This unit had a manufacturer's fault on it for 30+ years. The problem showed up once and fixed itself after re-seating?boards but I could not confirm what fixed it. Two years later the fault re-appeared and it was these two bad solder joints. It is not the problem this time because they were re-soldered and the symptoms are different anyway. So the fan was surging and it would not start up. I will 'scope the filter caps before putting the cover back on. How are you making out with yours? My HP8753B suddenly started doing this surging with all the front lights on (I will have to re-check that statement but it is what I remember). This was several weeks ago and I have not had time to check it. If you start on yours take the top lid off and look at the row of lights on the power supply board. They should be green if OK and red to indicate a bad power supply (I'm going from memory so anyone correct me if I am wrong). Check the?power supplies with a good digital meter BUT DO NOT ADJUST ANY, especially if they are marginally off,?you do not want an additional fault of your own doing. Check each one with a 'scope and I would not be surprised if you find high ripple on one or more in which case replace the bad capacitor.? The manual will tell you what they should look like. Also there is?a start up sequence for the?CPU row of red lights. Check the manual. The fans are special on these?and are?controlled by a circuit. The VNA will not turn on if the?fan is bad and it?must be replaced by the correct one. I will be starting on mine next week, possibly Monday. I have family visiting right now. Peter.
On Fri, Aug 26, 2022 at 7:35 PM Rich Miller via <av8torrich= [email protected]> wrote: All:
My HP-8753E started demonstrating what I believe is a PSU related fault. When I switch the VNA on, it attempts to boot up, but before it can, I hear the fan stop, and then turn back on, and the VNA attempts a start again. This cycle goes on forever at this point.
I have taken a close look at the spare PSU, and there are no fuses externally. I also note there is a Voltage Regulator Board. I am wondering if anyone has had this issue, and was it the PSU itself or the Regulator Board?
My thinking is if this was a hard fault in the PSU something would have self destructed, or blown a component/fuse internal to the PSU. That being said, I have never seen the inside of the PSU to know if there is some sort of soft restart, or a fuse which should blow.
I would also be curious if there is some other protection feature in the 8753E which would cause it to power cycle like I describe above?
Thanks in advance!
Rich
|
Re: HP-8753E Power Cycles at Start Up
Hi Peter:
When I get a few moments to take a look with a scope I will. This problem seems very much temperature related. My plan is to let it run for a good couple of hours, and then probe the A15W1 Feedthrough points on the SMPS.?
My only concern is, I may not see a lot of ripple with the SMPS unloaded. I have had two cases in various instruments where the switcher fooled me like this. It was not until I loaded it down did I begin to see a lot of ripple.?
toggle quoted message
Show quoted text
On Aug 27, 2022, at 7:22 PM, peter bunge <bunge.pjp@...> wrote:
? Rich; I would be interested?in what you find. I plan on putting my 8753 on a variac to run with lower voltage. If it was a failing reservoir?capacitor in the pre-regulator this should show it up. The other thing to check is to 'scope the ripple on the pre-regulator. Keep me informed. Peter. On Sat, Aug 27, 2022 at 7:16 PM Rich Miller via <av8torrich= [email protected]> wrote: Peter:
I have it back and running. It was the A8 board, despite the service manual pointing to the post regulator board. I replaced the SMPS, and I am back in business. I opened the SMPS, and did not find anything out of the ordinary. I may plug this in, leave it sit for a few hours, and then begin probing the output.? ?Hi Peter:
Have an update for you. The fault started again. If you follow the troubleshooting guide on Section 5-8 - Page 271 it would leave you to believe I have a post regulator problem (A8).? Swapped A8 out, and the problem precise. When I unplug A15W1 from the post regulator, the problem disappears. Being that I have a known good post regulator board to swap out, I think the problem is the A15 Pre Regulator (SMPS). Getting ready to swap that out and see what happens. ? ? Rich; I think this is a case of "nothing works Thursday". It happens sometimes and maybe this only applied to 8753s. The electronics Gods work in mysterious ways. I read the manual and it says surging is the post regulator circuit sensing an overcurrent and shutting down the power supply repeatedly to protect it. Maybe a cap reforming after months of non use? I had disconnected the S-Param Test set and thought it may have been the culprit but reconnecting it made no difference. It still works. Peter On Sat, Aug 27, 2022 at 2:02 PM Rich Miller via <av8torrich= [email protected]> wrote: LOL - I just got to my office with a replacement PSU, and Post Regulator Board. This was an hour drive.?
?Turned on the VNA, and its fine now. This maybe temp related, so I am going to run some more measurements and wait for the fault to manifest once again. A little annoyed, but such is life I suppose.
I was in the middle of an important measurement when this happened yesterday, so I am going to take it while I can. I will keep you updated, as I learn more. Rich ? I took the cover off and everything works. I have no idea what the problem was. This unit had a manufacturer's fault on it for 30+ years. The problem showed up once and fixed itself after re-seating?boards but I could not confirm what fixed it. Two years later the fault re-appeared and it was these two bad solder joints. It is not the problem this time because they were re-soldered and the symptoms are different anyway. So the fan was surging and it would not start up. I will 'scope the filter caps before putting the cover back on. How are you making out with yours? My HP8753B suddenly started doing this surging with all the front lights on (I will have to re-check that statement but it is what I remember). This was several weeks ago and I have not had time to check it. If you start on yours take the top lid off and look at the row of lights on the power supply board. They should be green if OK and red to indicate a bad power supply (I'm going from memory so anyone correct me if I am wrong). Check the?power supplies with a good digital meter BUT DO NOT ADJUST ANY, especially if they are marginally off,?you do not want an additional fault of your own doing. Check each one with a 'scope and I would not be surprised if you find high ripple on one or more in which case replace the bad capacitor.? The manual will tell you what they should look like. Also there is?a start up sequence for the?CPU row of red lights. Check the manual. The fans are special on these?and are?controlled by a circuit. The VNA will not turn on if the?fan is bad and it?must be replaced by the correct one. I will be starting on mine next week, possibly Monday. I have family visiting right now. Peter.
On Fri, Aug 26, 2022 at 7:35 PM Rich Miller via <av8torrich= [email protected]> wrote: All:
My HP-8753E started demonstrating what I believe is a PSU related fault. When I switch the VNA on, it attempts to boot up, but before it can, I hear the fan stop, and then turn back on, and the VNA attempts a start again. This cycle goes on forever at this point.
I have taken a close look at the spare PSU, and there are no fuses externally. I also note there is a Voltage Regulator Board. I am wondering if anyone has had this issue, and was it the PSU itself or the Regulator Board?
My thinking is if this was a hard fault in the PSU something would have self destructed, or blown a component/fuse internal to the PSU. That being said, I have never seen the inside of the PSU to know if there is some sort of soft restart, or a fuse which should blow.
I would also be curious if there is some other protection feature in the 8753E which would cause it to power cycle like I describe above?
Thanks in advance!
Rich
|
Re: HP-8753E Power Cycles at Start Up
Rich; I would be interested?in what you find. I plan on putting my 8753 on a variac to run with lower voltage. If it was a failing reservoir?capacitor in the pre-regulator this should show it up. The other thing to check is to 'scope the ripple on the pre-regulator. Keep me informed. Peter.
On Sat, Aug 27, 2022 at 7:16 PM Rich Miller via <av8torrich= [email protected]> wrote: Peter:
I have it back and running. It was the A8 board, despite the service manual pointing to the post regulator board. I replaced the SMPS, and I am back in business. I opened the SMPS, and did not find anything out of the ordinary. I may plug this in, leave it sit for a few hours, and then begin probing the output.? ?Hi Peter:
Have an update for you. The fault started again. If you follow the troubleshooting guide on Section 5-8 - Page 271 it would leave you to believe I have a post regulator problem (A8).? Swapped A8 out, and the problem precise. When I unplug A15W1 from the post regulator, the problem disappears. Being that I have a known good post regulator board to swap out, I think the problem is the A15 Pre Regulator (SMPS). Getting ready to swap that out and see what happens. ? ? Rich; I think this is a case of "nothing works Thursday". It happens sometimes and maybe this only applied to 8753s. The electronics Gods work in mysterious ways. I read the manual and it says surging is the post regulator circuit sensing an overcurrent and shutting down the power supply repeatedly to protect it. Maybe a cap reforming after months of non use? I had disconnected the S-Param Test set and thought it may have been the culprit but reconnecting it made no difference. It still works. Peter On Sat, Aug 27, 2022 at 2:02 PM Rich Miller via <av8torrich= [email protected]> wrote: LOL - I just got to my office with a replacement PSU, and Post Regulator Board. This was an hour drive.?
?Turned on the VNA, and its fine now. This maybe temp related, so I am going to run some more measurements and wait for the fault to manifest once again. A little annoyed, but such is life I suppose.
I was in the middle of an important measurement when this happened yesterday, so I am going to take it while I can. I will keep you updated, as I learn more. Rich ? I took the cover off and everything works. I have no idea what the problem was. This unit had a manufacturer's fault on it for 30+ years. The problem showed up once and fixed itself after re-seating?boards but I could not confirm what fixed it. Two years later the fault re-appeared and it was these two bad solder joints. It is not the problem this time because they were re-soldered and the symptoms are different anyway. So the fan was surging and it would not start up. I will 'scope the filter caps before putting the cover back on. How are you making out with yours? My HP8753B suddenly started doing this surging with all the front lights on (I will have to re-check that statement but it is what I remember). This was several weeks ago and I have not had time to check it. If you start on yours take the top lid off and look at the row of lights on the power supply board. They should be green if OK and red to indicate a bad power supply (I'm going from memory so anyone correct me if I am wrong). Check the?power supplies with a good digital meter BUT DO NOT ADJUST ANY, especially if they are marginally off,?you do not want an additional fault of your own doing. Check each one with a 'scope and I would not be surprised if you find high ripple on one or more in which case replace the bad capacitor.? The manual will tell you what they should look like. Also there is?a start up sequence for the?CPU row of red lights. Check the manual. The fans are special on these?and are?controlled by a circuit. The VNA will not turn on if the?fan is bad and it?must be replaced by the correct one. I will be starting on mine next week, possibly Monday. I have family visiting right now. Peter.
On Fri, Aug 26, 2022 at 7:35 PM Rich Miller via <av8torrich= [email protected]> wrote: All:
My HP-8753E started demonstrating what I believe is a PSU related fault. When I switch the VNA on, it attempts to boot up, but before it can, I hear the fan stop, and then turn back on, and the VNA attempts a start again. This cycle goes on forever at this point.
I have taken a close look at the spare PSU, and there are no fuses externally. I also note there is a Voltage Regulator Board. I am wondering if anyone has had this issue, and was it the PSU itself or the Regulator Board?
My thinking is if this was a hard fault in the PSU something would have self destructed, or blown a component/fuse internal to the PSU. That being said, I have never seen the inside of the PSU to know if there is some sort of soft restart, or a fuse which should blow.
I would also be curious if there is some other protection feature in the 8753E which would cause it to power cycle like I describe above?
Thanks in advance!
Rich
|
Re: HP-8753E Power Cycles at Start Up
Peter:
I have it back and running. It was the A8 board, despite the service manual pointing to the post regulator board. I replaced the SMPS, and I am back in business. I opened the SMPS, and did not find anything out of the ordinary. I may plug this in, leave it sit for a few hours, and then begin probing the output.?
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On Aug 27, 2022, at 3:30 PM, Richard Miller <av8torrich@...> wrote:
? Hi Peter:
Have an update for you. The fault started again. If you follow the troubleshooting guide on Section 5-8 - Page 271 it would leave you to believe I have a post regulator problem (A8).? Swapped A8 out, and the problem precise. When I unplug A15W1 from the post regulator, the problem disappears. Being that I have a known good post regulator board to swap out, I think the problem is the A15 Pre Regulator (SMPS). Getting ready to swap that out and see what happens. ? On Aug 27, 2022, at 2:44 PM, peter bunge <bunge.pjp@...> wrote:
? Rich; I think this is a case of "nothing works Thursday". It happens sometimes and maybe this only applied to 8753s. The electronics Gods work in mysterious ways. I read the manual and it says surging is the post regulator circuit sensing an overcurrent and shutting down the power supply repeatedly to protect it. Maybe a cap reforming after months of non use? I had disconnected the S-Param Test set and thought it may have been the culprit but reconnecting it made no difference. It still works. Peter On Sat, Aug 27, 2022 at 2:02 PM Rich Miller via <av8torrich= [email protected]> wrote: LOL - I just got to my office with a replacement PSU, and Post Regulator Board. This was an hour drive.?
?Turned on the VNA, and its fine now. This maybe temp related, so I am going to run some more measurements and wait for the fault to manifest once again. A little annoyed, but such is life I suppose.
I was in the middle of an important measurement when this happened yesterday, so I am going to take it while I can. I will keep you updated, as I learn more. Rich ? I took the cover off and everything works. I have no idea what the problem was. This unit had a manufacturer's fault on it for 30+ years. The problem showed up once and fixed itself after re-seating?boards but I could not confirm what fixed it. Two years later the fault re-appeared and it was these two bad solder joints. It is not the problem this time because they were re-soldered and the symptoms are different anyway. So the fan was surging and it would not start up. I will 'scope the filter caps before putting the cover back on. How are you making out with yours? My HP8753B suddenly started doing this surging with all the front lights on (I will have to re-check that statement but it is what I remember). This was several weeks ago and I have not had time to check it. If you start on yours take the top lid off and look at the row of lights on the power supply board. They should be green if OK and red to indicate a bad power supply (I'm going from memory so anyone correct me if I am wrong). Check the?power supplies with a good digital meter BUT DO NOT ADJUST ANY, especially if they are marginally off,?you do not want an additional fault of your own doing. Check each one with a 'scope and I would not be surprised if you find high ripple on one or more in which case replace the bad capacitor.? The manual will tell you what they should look like. Also there is?a start up sequence for the?CPU row of red lights. Check the manual. The fans are special on these?and are?controlled by a circuit. The VNA will not turn on if the?fan is bad and it?must be replaced by the correct one. I will be starting on mine next week, possibly Monday. I have family visiting right now. Peter.
On Fri, Aug 26, 2022 at 7:35 PM Rich Miller via <av8torrich= [email protected]> wrote: All:
My HP-8753E started demonstrating what I believe is a PSU related fault. When I switch the VNA on, it attempts to boot up, but before it can, I hear the fan stop, and then turn back on, and the VNA attempts a start again. This cycle goes on forever at this point.
I have taken a close look at the spare PSU, and there are no fuses externally. I also note there is a Voltage Regulator Board. I am wondering if anyone has had this issue, and was it the PSU itself or the Regulator Board?
My thinking is if this was a hard fault in the PSU something would have self destructed, or blown a component/fuse internal to the PSU. That being said, I have never seen the inside of the PSU to know if there is some sort of soft restart, or a fuse which should blow.
I would also be curious if there is some other protection feature in the 8753E which would cause it to power cycle like I describe above?
Thanks in advance!
Rich
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Re: PNA Cal Kit Editor software
I may have it - I'm out of my lab at present but when I get home I'll take a look and let you know
Cheers!
Bruce
Quoting "Dr. David Kirkby, Kirkby Microwave Ltd" <drkirkby@...>:
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Does anyone have a copy of the calibration kit editor software that is part of the PNA firmware? It used to be around as a standalone program on the very useful na.support.keysight.com subdomain, but it seems that is being removed.
I'm not looking for the older software that worked with instruments like the 8753 - I'm looking for the newer software that works with the PNAs.
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PNA Cal Kit Editor software
Does anyone have a copy of the calibration kit editor software that is part of the PNA firmware? It used to be around as a standalone program on the very useful na.support.keysight.com subdomain, but it seems that is being removed.
I'm not looking for the older software that worked with instruments like the 8753 - I'm looking for the newer software that works with the PNAs.
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Re: I bought a working HP3400A, however it doesn't.
It sounds to me like you should, and you both should be well on your way.? Radu.?
On Sat, Aug 27, 2022 at 10:38 AM Mikek < amdx@...> wrote: >I think the seller did a perfectly?good job at owning up to that, and honestly, kudos to both<
?That reminds me, he did follow through with negotiating when he was made aware of the condition.
I need to leave him a positive feedback.
??????????????????????????????????????? Mike
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Re: HP-8753E Power Cycles at Start Up
Hi Peter:
Have an update for you. The fault started again. If you follow the troubleshooting guide on Section 5-8 - Page 271 it would leave you to believe I have a post regulator problem (A8).? Swapped A8 out, and the problem precise. When I unplug A15W1 from the post regulator, the problem disappears. Being that I have a known good post regulator board to swap out, I think the problem is the A15 Pre Regulator (SMPS). Getting ready to swap that out and see what happens. ?
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On Aug 27, 2022, at 2:44 PM, peter bunge <bunge.pjp@...> wrote:
? Rich; I think this is a case of "nothing works Thursday". It happens sometimes and maybe this only applied to 8753s. The electronics Gods work in mysterious ways. I read the manual and it says surging is the post regulator circuit sensing an overcurrent and shutting down the power supply repeatedly to protect it. Maybe a cap reforming after months of non use? I had disconnected the S-Param Test set and thought it may have been the culprit but reconnecting it made no difference. It still works. Peter On Sat, Aug 27, 2022 at 2:02 PM Rich Miller via <av8torrich= [email protected]> wrote: LOL - I just got to my office with a replacement PSU, and Post Regulator Board. This was an hour drive.?
?Turned on the VNA, and its fine now. This maybe temp related, so I am going to run some more measurements and wait for the fault to manifest once again. A little annoyed, but such is life I suppose.
I was in the middle of an important measurement when this happened yesterday, so I am going to take it while I can. I will keep you updated, as I learn more. Rich ? I took the cover off and everything works. I have no idea what the problem was. This unit had a manufacturer's fault on it for 30+ years. The problem showed up once and fixed itself after re-seating?boards but I could not confirm what fixed it. Two years later the fault re-appeared and it was these two bad solder joints. It is not the problem this time because they were re-soldered and the symptoms are different anyway. So the fan was surging and it would not start up. I will 'scope the filter caps before putting the cover back on. How are you making out with yours? My HP8753B suddenly started doing this surging with all the front lights on (I will have to re-check that statement but it is what I remember). This was several weeks ago and I have not had time to check it. If you start on yours take the top lid off and look at the row of lights on the power supply board. They should be green if OK and red to indicate a bad power supply (I'm going from memory so anyone correct me if I am wrong). Check the?power supplies with a good digital meter BUT DO NOT ADJUST ANY, especially if they are marginally off,?you do not want an additional fault of your own doing. Check each one with a 'scope and I would not be surprised if you find high ripple on one or more in which case replace the bad capacitor.? The manual will tell you what they should look like. Also there is?a start up sequence for the?CPU row of red lights. Check the manual. The fans are special on these?and are?controlled by a circuit. The VNA will not turn on if the?fan is bad and it?must be replaced by the correct one. I will be starting on mine next week, possibly Monday. I have family visiting right now. Peter.
On Fri, Aug 26, 2022 at 7:35 PM Rich Miller via <av8torrich= [email protected]> wrote: All:
My HP-8753E started demonstrating what I believe is a PSU related fault. When I switch the VNA on, it attempts to boot up, but before it can, I hear the fan stop, and then turn back on, and the VNA attempts a start again. This cycle goes on forever at this point.
I have taken a close look at the spare PSU, and there are no fuses externally. I also note there is a Voltage Regulator Board. I am wondering if anyone has had this issue, and was it the PSU itself or the Regulator Board?
My thinking is if this was a hard fault in the PSU something would have self destructed, or blown a component/fuse internal to the PSU. That being said, I have never seen the inside of the PSU to know if there is some sort of soft restart, or a fuse which should blow.
I would also be curious if there is some other protection feature in the 8753E which would cause it to power cycle like I describe above?
Thanks in advance!
Rich
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Re: "ADDITIONAL STANDARDS ARE NEEDED" when using E-Cal
Wayne, Dan -
Two comments:
1) Confidence check on the Ecal is exactly that but NOT verification. The reason is that both the Ecal and confidence check features share elements that could change with age. BUT, a good confidence check should really make you feel good :-)
I am in the process of converting the data from my verification kit from tape to disk. Wayne - once I get it done, I will do yours if you wish. Note- What I will NOT do is reclaim the tape cartridge. There is quite a bit of data on how to that online. I'm willing to risk my tape but not willing to be responsible for destroying your tape :-)
2) Since the processor is some version of X86, that strengthens the likelihood that the software for the 85097 is closely related to the software on the 85060. Which makes it less understandable why the 85062 (45M-26G) would work with my 85097 but not with the 85060). If I had an 85060, I might be inclined to do some tracing of the interface conversation to see what is going on. (Sometime In the future - really busy right now)
WAYNE QUESTION:
One of your previous comments seemed to indicate that the electrical interface or interface protocol was different between the 45M-2G 85062 and the 1-26.5G 85062A. Is this true? I would expect not - I was always thinking about connect a logic analyzer and a GPIB capture device to my 85097 and try to map the conversations between the 95097-8510 and 85097-85062 into something understandable. But you have essentially done 1/2 that so I'm less inclined to do that now. But I would be interested if you had discovered any difference between the communication protocols of the 1-26G and 45M-2G85062s.
Quoting Wayne ZL2BKC <w.knowles@...>:
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I'm also in agreement that ECals can be trusted.? I have 5 and they are all bang on against there own verification data to better than 0.05dB and only a few deg phase out to 20GHz which is better than I can achieve with my mechanical kits.? Since the verification data in the module never changes calibration can always be trusted as long as it matches post calibration.
Most certainly re-calibration will be required if any of the connectors are replaced, in fact its easy to confirm if the specs have changed.
In fact Joel Dunsmore says in his book (page 153) "Since the fist introduction, the quality, capability and convenience of Ecal has been greatly enhanced and now its use may exceed that of the mechanical calibration kits"
Bruce, It has been a year or two since I opened my 85060C but I recall it has an embedded PC with a 80286 processor and a Cyrix co-processor (apparently it has some math homework to do!).? I'm not sure if it runs DOS or not, but the files on the firmware diskette cant run from a DOS environment
--
Wayne
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Re: HP-8753E Power Cycles at Start Up
Rich; I think this is a case of "nothing works Thursday". It happens sometimes and maybe this only applied to 8753s. The electronics Gods work in mysterious ways. I read the manual and it says surging is the post regulator circuit sensing an overcurrent and shutting down the power supply repeatedly to protect it. Maybe a cap reforming after months of non use? I had disconnected the S-Param Test set and thought it may have been the culprit but reconnecting it made no difference. It still works. Peter
On Sat, Aug 27, 2022 at 2:02 PM Rich Miller via <av8torrich= [email protected]> wrote: LOL - I just got to my office with a replacement PSU, and Post Regulator Board. This was an hour drive.?
?Turned on the VNA, and its fine now. This maybe temp related, so I am going to run some more measurements and wait for the fault to manifest once again. A little annoyed, but such is life I suppose.
I was in the middle of an important measurement when this happened yesterday, so I am going to take it while I can. I will keep you updated, as I learn more. Rich ? I took the cover off and everything works. I have no idea what the problem was. This unit had a manufacturer's fault on it for 30+ years. The problem showed up once and fixed itself after re-seating?boards but I could not confirm what fixed it. Two years later the fault re-appeared and it was these two bad solder joints. It is not the problem this time because they were re-soldered and the symptoms are different anyway. So the fan was surging and it would not start up. I will 'scope the filter caps before putting the cover back on. How are you making out with yours? My HP8753B suddenly started doing this surging with all the front lights on (I will have to re-check that statement but it is what I remember). This was several weeks ago and I have not had time to check it. If you start on yours take the top lid off and look at the row of lights on the power supply board. They should be green if OK and red to indicate a bad power supply (I'm going from memory so anyone correct me if I am wrong). Check the?power supplies with a good digital meter BUT DO NOT ADJUST ANY, especially if they are marginally off,?you do not want an additional fault of your own doing. Check each one with a 'scope and I would not be surprised if you find high ripple on one or more in which case replace the bad capacitor.? The manual will tell you what they should look like. Also there is?a start up sequence for the?CPU row of red lights. Check the manual. The fans are special on these?and are?controlled by a circuit. The VNA will not turn on if the?fan is bad and it?must be replaced by the correct one. I will be starting on mine next week, possibly Monday. I have family visiting right now. Peter.
On Fri, Aug 26, 2022 at 7:35 PM Rich Miller via <av8torrich= [email protected]> wrote: All:
My HP-8753E started demonstrating what I believe is a PSU related fault. When I switch the VNA on, it attempts to boot up, but before it can, I hear the fan stop, and then turn back on, and the VNA attempts a start again. This cycle goes on forever at this point.
I have taken a close look at the spare PSU, and there are no fuses externally. I also note there is a Voltage Regulator Board. I am wondering if anyone has had this issue, and was it the PSU itself or the Regulator Board?
My thinking is if this was a hard fault in the PSU something would have self destructed, or blown a component/fuse internal to the PSU. That being said, I have never seen the inside of the PSU to know if there is some sort of soft restart, or a fuse which should blow.
I would also be curious if there is some other protection feature in the 8753E which would cause it to power cycle like I describe above?
Thanks in advance!
Rich
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Re: HP-8753E Power Cycles at Start Up
LOL - I just got to my office with a replacement PSU, and Post Regulator Board. This was an hour drive.?
?Turned on the VNA, and its fine now. This maybe temp related, so I am going to run some more measurements and wait for the fault to manifest once again. A little annoyed, but such is life I suppose.
I was in the middle of an important measurement when this happened yesterday, so I am going to take it while I can. I will keep you updated, as I learn more. Rich
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On Aug 27, 2022, at 12:53 PM, peter bunge <bunge.pjp@...> wrote:
? I took the cover off and everything works. I have no idea what the problem was. This unit had a manufacturer's fault on it for 30+ years. The problem showed up once and fixed itself after re-seating?boards but I could not confirm what fixed it. Two years later the fault re-appeared and it was these two bad solder joints. It is not the problem this time because they were re-soldered and the symptoms are different anyway. So the fan was surging and it would not start up. I will 'scope the filter caps before putting the cover back on. How are you making out with yours? My HP8753B suddenly started doing this surging with all the front lights on (I will have to re-check that statement but it is what I remember). This was several weeks ago and I have not had time to check it. If you start on yours take the top lid off and look at the row of lights on the power supply board. They should be green if OK and red to indicate a bad power supply (I'm going from memory so anyone correct me if I am wrong). Check the?power supplies with a good digital meter BUT DO NOT ADJUST ANY, especially if they are marginally off,?you do not want an additional fault of your own doing. Check each one with a 'scope and I would not be surprised if you find high ripple on one or more in which case replace the bad capacitor.? The manual will tell you what they should look like. Also there is?a start up sequence for the?CPU row of red lights. Check the manual. The fans are special on these?and are?controlled by a circuit. The VNA will not turn on if the?fan is bad and it?must be replaced by the correct one. I will be starting on mine next week, possibly Monday. I have family visiting right now. Peter.
On Fri, Aug 26, 2022 at 7:35 PM Rich Miller via <av8torrich= [email protected]> wrote: All:
My HP-8753E started demonstrating what I believe is a PSU related fault. When I switch the VNA on, it attempts to boot up, but before it can, I hear the fan stop, and then turn back on, and the VNA attempts a start again. This cycle goes on forever at this point.
I have taken a close look at the spare PSU, and there are no fuses externally. I also note there is a Voltage Regulator Board. I am wondering if anyone has had this issue, and was it the PSU itself or the Regulator Board?
My thinking is if this was a hard fault in the PSU something would have self destructed, or blown a component/fuse internal to the PSU. That being said, I have never seen the inside of the PSU to know if there is some sort of soft restart, or a fuse which should blow.
I would also be curious if there is some other protection feature in the 8753E which would cause it to power cycle like I describe above?
Thanks in advance!
Rich
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Re: I bought a working HP3400A, however it doesn't.
>I think the seller did a perfectly?good job at owning up to that, and honestly, kudos to both<
?That reminds me, he did follow through with negotiating when he was made aware of the condition.
I need to leave him a positive feedback.
??????????????????????????????????????? Mike
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Re: HP-8753E Power Cycles at Start Up
I took the cover off and everything works. I have no idea what the problem was. This unit had a manufacturer's fault on it for 30+ years. The problem showed up once and fixed itself after re-seating?boards but I could not confirm what fixed it. Two years later the fault re-appeared and it was these two bad solder joints. It is not the problem this time because they were re-soldered and the symptoms are different anyway. So the fan was surging and it would not start up. I will 'scope the filter caps before putting the cover back on. How are you making out with yours?
My HP8753B suddenly started doing this surging with all the front lights on (I will have to re-check that statement but it is what I remember). This was several weeks ago and I have not had time to check it. If you start on yours take the top lid off and look at the row of lights on the power supply board. They should be green if OK and red to indicate a bad power supply (I'm going from memory so anyone correct me if I am wrong). Check the?power supplies with a good digital meter BUT DO NOT ADJUST ANY, especially if they are marginally off,?you do not want an additional fault of your own doing. Check each one with a 'scope and I would not be surprised if you find high ripple on one or more in which case replace the bad capacitor.? The manual will tell you what they should look like. Also there is?a start up sequence for the?CPU row of red lights. Check the manual. The fans are special on these?and are?controlled by a circuit. The VNA will not turn on if the?fan is bad and it?must be replaced by the correct one. I will be starting on mine next week, possibly Monday. I have family visiting right now. Peter.
On Fri, Aug 26, 2022 at 7:35 PM Rich Miller via <av8torrich= [email protected]> wrote: All:
My HP-8753E started demonstrating what I believe is a PSU related fault. When I switch the VNA on, it attempts to boot up, but before it can, I hear the fan stop, and then turn back on, and the VNA attempts a start again. This cycle goes on forever at this point.
I have taken a close look at the spare PSU, and there are no fuses externally. I also note there is a Voltage Regulator Board. I am wondering if anyone has had this issue, and was it the PSU itself or the Regulator Board?
My thinking is if this was a hard fault in the PSU something would have self destructed, or blown a component/fuse internal to the PSU. That being said, I have never seen the inside of the PSU to know if there is some sort of soft restart, or a fuse which should blow.
I would also be curious if there is some other protection feature in the 8753E which would cause it to power cycle like I describe above?
Thanks in advance!
Rich
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Re: I bought a working HP3400A, however it doesn't.
From my collection of facts of this transaction, the seller has misrepresented the item offered for sale.?
I can't imagine a circumstance where cleaning the switching contacts (which fixed the issue observed) can have anything to do with "damage in transit," or other such things that are outside a seller's purview or control. I mean, a really, really sizable?stretch at best,?though,?frankly, not a chance. Simply put, he didn't diligently check the exact?condition of the item for sale before candidly posting. I think the seller did a perfectly?good job at owning up to that, and honestly, kudos to both - I don't think anyone did anything?out of bounds here. Good communication throughout, agreement reached ultimately. One hopes all transactions go this way.?
Accusing the seller, or the buyer, of anything outrageous?in what has been described is disingenuous. I've been a seller where I had no capacity?to check any and all functions?of a complicated unit I've sold. To the best of my ability, I've represented the condition of the unit, but as others described, it's honestly a gamble. With old units, it's not impossible?for some "time bound" event to be essentially rushed by such abusive treatment as shipping is (given the age of some of these things). Accepting there's a gamble involved in that, I think all sellers should expect to have to negotiate through some loss of revenue just to keep a buyer happy,?at least occasionally. Buyers absolutely should expect something presented as "used" to work as designed across all?functions (because eBay has it set at that level). They'll be on the other end of things - and appreciate it - when they're buying something. It is as simple as that, and eBay is just following expectations common in transactional exchanges occurring in mature commercial markets such as the US and others.?
Radu.?
On Sat, Aug 27, 2022 at 8:55 AM Craig Petersen < n7uqa91@...> wrote: As with ALL of my eBay purchases I expect my purchase to be a "roll of the dice". Even if the seller has tested the device I still take it with a grain of salt. Many sellers buy these things at auction and don't know how to test them properly or only test them to a "power on" condition. I recently purchased a HP 3437A volt meter that was sold as working, functions as intended, was owned by a HP engineer. However on bench testing I discovered that the volt meter section did not work and was showing a constant over voltage condition. It turned out that all that was wrong with it was a bad filter capacitor in the voltage doubler circuit. This is one of the reasons why I'll pay a premium on some instruments that have been fully tested by companies like BRL Test, Select Test and others. That way you know the instrument was checked, repaired and or aligned and is guaranteed to work properly.?
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Burt K6OQK
Dr. David Kirkby, Kirkby Microwave Ltd