I have a HP3335A. I started to experiment problems as cpu freeze and leveling errors and I found microscopic cracks on power supply board also I removed the transistors and found an anormal slope on characteristic curves (this is thermal deterioration). Replaced the transistors and re-soldered the complete board, Also I removed the capacitors for test , these was ok . Cleaned the contacts and mounted again. After that work, instrument started to work like never. It??s very very flat, let me show you the results. I attached the response curves I measured. X Avis is logarithmic starting @1 MHz , and Y Axis is in dB relative to 1 MHz. I used 3 different methods to measure.?
Regards,?
Ing. Patricio A. Greco
Taller Aeronáutico de Reparación 1B-349
Organización de Mantenimiento?Aeronáutico de la Defensa OMAD-001
Laboratorio de Calibración ISO 17025?AREA: RF/MW?
Gral. Martín Rodríguez 2159
San Miguel (1663)
Buenos Aires
T: +5411-4455-2557
F: +5411-4032-0072
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Taking the assemblies loose is almost essential to troubleshooting the supply boards, but very important: You have to install a jumper to reconnect the ground - the boards are grounded through one of the brackets (the one to the bottom of the chassis if I remember correctly) and will be disconnected when it it taken loose.
Hal
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Taking the assemblies loose is almost essential to troubleshooting the supply boards, but very important: You have to install a jumper to reconnect the ground - the boards are grounded through one of the brackets (the one to the bottom of the chassis if I remember correctly) and will be disconnected when it it taken loose.
Hal
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Re: VNA Calibration - Port Impedance - a late life ponder
Hi Dan Port1 and port 2 of a VNA has an input impedance deviating from pure 50 ohm by nature, High quality VNA might deviate only slightly. When you ?do a full two port calibration on a commercial VNA you are performing a full 12 term error correction (if isolation is included else 10 term error correction) The 12 term error correction allow the VNA to compensate for these impedance deviation of port1 and port 2 and thus the VNA now is simulated to have perfect 50 output/input impedance on the two ports, and running a sweep right after calibration you should se return loss of some 70dB or even more theoretical up to ?infinitum. As you have a thru adaptor included then thru adaptor reduces the return loss measurement because the port 1 and port 2 is SOL calibrated at the end of two test cables and now the thru adaptor inserted which has a nonperfect Z0 and has insertion loss which influencing the measurements. Normally the thru adaptor is assumed to be perfect lossless. If you have a calibration kit with identical male and female LC coefficient (like the HP 85033C) then try to SOL calibrate and use a e.g. female on port1 and a male on port2 and define the delay for the thru to 0ps then you eliminate the effect of a thru adaptor, as now ideally no loss and no delay is used during thru calibration. Then you get the ultimate return loss shown just after calibration. It all depends on if your VNA is a full two port device. VNA’s like NanoVNA and the many derivatives does not allow 12 term error correction and has only 5/6 term error correction. What type of VNA are you using. Kind regards Kurt ????? ? ? Hello Group -
My whole life I have been calibrating VNAs and then verifying the cal by connecting Through, and looking for very good RL and IL across the band.
I'll set up my confusion / question this way: let's say I have two VNAs that are perfectly calibrated. Now I take port 1 of VNA A and connect it to port 1 of VNA B.
What I am doing is measuring VNA B's actual impedance on port 1. Which is not going to be perfect - or necessarily close to it.
The "true" impedance of any VNA port is not as good as you measure after a cal with a through.
Why is that?
After a perfect cal, with a perfect through, S11 and S22 should be showing the actual "true" impedance of the other port (port 1 is looking at Port 2, and vice-versa.
Can someone tell me what is wrong with my thinking on this? I must be wrong... but I don't know why.
Thanks in advance -
Dan
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Radu -
The power supply comes out in two pieces - the "front" board separates from the caps+PCB (connected together with cables). It is not too hard and it is actually hard to mix the cables up, but good pictures is always a good idea.
There is a spring loaded release screw accessible (from the top as I remember) that you need to find to release the capacitor band and associated PCB.
Its actually easiest to connect wires to all the test points and then put the PS back together as it is somewhat difficult to run the PS outside the chassis. I use lengths of wire wrap wire to extend the test points.
Cheers!
Bruce
Cheers!
Bruce
Quoting Radu Bogdan Dicher <vondicher@...>:
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Thank you. I figured out that error, but I still can't figure out how to
access the measurement points. I enclose some pics. Unless the PS PCB
slides out somehow, I cannot yet figure out how to access those points.
Not wanting to sound lazy, but I really hate terrible engineering of
servicing. Jury's still out on whether it's me not having read the entire
service manual (closely enough), or whether they did a bad job at making
these very serviceable.
Radu.
On Fri, Sep 16, 2022 at 7:34 PM tmillermdems <tmiller11147@...>
wrote:
There is an error in the manual. A16 is actually A15, the pass transistor
assembly. C1, C3, CR1, and CR2 are just below the J2 and J3 connectors.
Regards
On 9/16/2022 9:00 PM, Radu Bogdan Dicher wrote:
Working on this unit, with a non-working display, and other lights on
there not making much sense. I didn't even really try to output a signal
and see if it's there.
PS a high profile suspect, obviously. All raw DC supplies look OK, all
regulated supplies are low by almost about 30%. Smoking gun that is.
So, I am working through the troubleshooting steps for Group F (p.8-F-1).
If regulated supplies are off, and unregulated are OK, step two says to
check A16 voltage doubler. This is supposedly done by measuring 55V between
R1/CR2 and R2/CR4.
Has anyone in the history of the 3335A been able to reach the points where
measuring this is feasible? I've been bending my probes and self to figure
how am I supposed to perform this measurement. Has anyone done this
recently enough to recall, or versed in this unit to tell me how the heck
am I supposed to measure this unreachable potential differential?
Thank you,
Radu.
[image: width=]
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Virus-free.www.avast.com
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<#m_2761576008215403673_m_9007556647973482003_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
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You have done the first thing, take some good pictures. Now just
unplug those cables and see if you can get to those two parts to
attach some test clips. I would guess those caps have dried out if
the 55 volts is low.
You should be able to pull the whole assembly out for service.
Probable screwed down somehow. I don't have one of those units to
explore.
Good luck,
Regards
On 9/16/2022 11:24 PM, Radu Bogdan
Dicher wrote:
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Show quoted text
Thank
you. I figured out that error, but I still can't figure out
how to access the measurement points. I enclose some pics.
Unless the PS PCB slides out somehow, I cannot yet figure out
how to access those points.?
Not
wanting to sound lazy, but I really hate
terrible?engineering of servicing. Jury's still out on
whether it's me not having read the entire service manual
(closely enough), or whether they did a bad job at making
these very serviceable.?
Radu.?
There is an error in the manual. A16 is actually A15, the
pass transistor assembly.? C1, C3, CR1, and CR2 are just
below the J2 and J3 connectors.
Regards
On 9/16/2022 9:00 PM, Radu Bogdan Dicher wrote:
Working on this unit, with a
non-working display, and other lights on there not making
much sense. I didn't even really try to output a signal
and see if it's there.?
PS a high profile suspect, obviously. All raw DC supplies
look OK, all regulated supplies are low by almost about
30%. Smoking gun that is.?
So, I am working through the troubleshooting steps for
Group F (p.8-F-1). If regulated supplies are off, and
unregulated are OK, step two says to check A16 voltage
doubler. This is supposedly done by measuring 55V between
R1/CR2 and R2/CR4.?
Has anyone in the history of the 3335A been able to reach
the points where measuring this is feasible? I've been
bending my probes and self to figure how am I supposed to
perform this measurement. Has anyone done this recently
enough to recall, or versed in this unit to tell me how
the heck am I supposed to measure this unreachable
potential differential?
Thank you,
Radu.?
|
Thank you. I figured out that error, but I still can't figure out how to access the measurement points. I enclose some pics. Unless the PS PCB slides out somehow, I cannot yet figure out how to access those points.?
Not wanting to sound lazy, but I really hate terrible?engineering of servicing. Jury's still out on whether it's me not having read the entire service manual (closely enough), or whether they did a bad job at making these very serviceable.?
Radu.?
There is an error in the manual. A16 is actually A15, the pass
transistor assembly.? C1, C3, CR1, and CR2 are just below the J2
and J3 connectors.
Regards
On 9/16/2022 9:00 PM, Radu Bogdan
Dicher wrote:
Working on this unit, with a non-working display, and other lights
on there not making much sense. I didn't even really try to output
a signal and see if it's there.?
PS a high profile suspect, obviously. All raw DC supplies look OK,
all regulated supplies are low by almost about 30%. Smoking gun
that is.?
So, I am working through the troubleshooting steps for Group F
(p.8-F-1). If regulated supplies are off, and unregulated are OK,
step two says to check A16 voltage doubler. This is supposedly
done by measuring 55V between R1/CR2 and R2/CR4.?
Has anyone in the history of the 3335A been able to reach the
points where measuring this is feasible? I've been bending my
probes and self to figure how am I supposed to perform this
measurement. Has anyone done this recently enough to recall, or
versed in this unit to tell me how the heck am I supposed to
measure this unreachable potential differential?
Thank you,
Radu.?
|
There is an error in the manual. A16 is actually A15, the pass
transistor assembly.? C1, C3, CR1, and CR2 are just below the J2
and J3 connectors.
Regards
On 9/16/2022 9:00 PM, Radu Bogdan
Dicher wrote:
Working on this unit, with a non-working display, and other lights
on there not making much sense. I didn't even really try to output
a signal and see if it's there.?
PS a high profile suspect, obviously. All raw DC supplies look OK,
all regulated supplies are low by almost about 30%. Smoking gun
that is.?
So, I am working through the troubleshooting steps for Group F
(p.8-F-1). If regulated supplies are off, and unregulated are OK,
step two says to check A16 voltage doubler. This is supposedly
done by measuring 55V between R1/CR2 and R2/CR4.?
Has anyone in the history of the 3335A been able to reach the
points where measuring this is feasible? I've been bending my
probes and self to figure how am I supposed to perform this
measurement. Has anyone done this recently enough to recall, or
versed in this unit to tell me how the heck am I supposed to
measure this unreachable potential differential?
Thank you,
Radu.?
|
Radu -
Its been "awhile" , but s I recall, there is a cap across the 55V supply that is easier to access - look at the schematic diagram and see if you can get to it.
Cheers!
Bruce
Quoting Radu Bogdan Dicher <vondicher@...>:
toggle quoted message
Show quoted text
Working on this unit, with a non-working display, and other lights on there not making much sense. I didn't even really try to output a signal and see if it's there.
PS a high profile suspect, obviously. All raw DC supplies look OK, all regulated supplies are low by almost about 30%. Smoking gun that is.
So, I am working through the troubleshooting steps for Group F (p.8-F-1). If regulated supplies are off, and unregulated are OK, step two says to check A16 voltage doubler. This is supposedly done by measuring 55V between R1/CR2 and R2/CR4.
Has anyone in the history of the 3335A been able to reach the points where measuring this is feasible? I've been bending my probes and self to figure how am I supposed to perform this measurement. Has anyone done this recently enough to recall, or versed in this unit to tell me how the heck am I supposed to measure this unreachable potential differential?
Thank you,
Radu.
|
Working on this unit, with a non-working display, and other lights on there not making much sense. I didn't even really try to output a signal and see if it's there.?
PS a high profile suspect, obviously. All raw DC supplies look OK, all regulated supplies are low by almost about 30%. Smoking gun that is.?
So, I am working through the troubleshooting steps for Group F (p.8-F-1). If regulated supplies are off, and unregulated are OK, step two says to check A16 voltage doubler. This is supposedly done by measuring 55V between R1/CR2 and R2/CR4.?
Has anyone in the history of the 3335A been able to reach the points where measuring this is feasible? I've been bending my probes and self to figure how am I supposed to perform this measurement. Has anyone done this recently enough to recall, or versed in this unit to tell me how the heck am I supposed to measure this unreachable potential differential?
Thank you,
Radu.?
|
Re: VNA Calibration - Port Impedance - a late life ponder
Dan,
If you want to measure the impedance of port 2, do a one-port calibration (at the end of the cable) of port 1.? Then connect the cable to port 2.
A full 2 port calibration is not what you want for this, as it attempts to remove the errors due to port mismatches, and will do the math to measure the characteristics of the DUT connected between port 1 and port 2.? It can tell if your DUT is just a zero length connection by looking at all 4 S parameters and using them to correct for the imperfect termination at port 2.? If the VNA sees just a port 1 connection, it sees that S12 and S21 are zero and does not apply all the corrections.? That is why a good 50 ohm load under test looks the same as the full 2 port connection direct to port 2 even though port 2 is really not necessarily a very good 50 ohm match.
As I attempted to explain before, the full 2 port calibration is used when you want to measure the characteristics of? two-port Device Under Test.
--John Gord
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On Fri, Sep 16, 2022 at 04:27 AM, dan.meeks222@... wrote:
I may not have been clear with my question. I am not using two VNAs to measure each other - I realize that may not actually be practical. That was my way of setting up the question. IF I used one to measure the other, it would show some "real" port impedance (not ideal). But if I use the same VNA and measure port 2 with port 1, I get a very different result (after cal of course). This is my ponder.
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Hi, "Sven Schnelle" <svens@...> writes: "Sven Schnelle" <svens@...> writes:
So if the YTM current is not parked correctly the YIG sphere will interfere with the Band 0 passband. This should be
fairly straightforward to check by measuring the coil voltage around 4GHz and confirming it parks at a similar location
when a Band 0 frequency is selected. I think i measured ~2.3V above the coil, but don't know what the voltage
required to tune it to 4GHz is. I'll check this evening, thanks!
A mismatched YTF interfering would also explain why the dip is at ~2.2Ghz,
and after that the output level increases again...
I did another test now: unsolder the tuning coils from the PCB and
connect it to voltage source. Moving current from 0 to 50mA (i think
i've read 15mA/GHz in the Service manual) didn't change the level
of the output. I've found the SYTM now used and ordered two. Lets
see whether at least one of them works. If it works, i'm selling
the other one - guess i'll find someone who needs one. Good news - got the SYTM's and swapped them. The first one seems to be broken, Band 0 is ok, but in the other bands level is constantly declining and there are lot of harmonics. Adjusting SRD or YTF current doesn't help. The other one i ordered seems to be ok, output level is in a +/- 1dB Band, above 20Ghz in +/- 2dB. I'm happy that i have now a working 8340A. The only thing left todo is repairing the well-known HP button spring problem.
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Re: VNA Calibration - Port Impedance - a late life ponder
I may not have been clear with my question. I am not using two VNAs to measure each other What are you measuring? IF I used one to measure the other, What does it mean? Are you comparing one vs the other one? But if I use the same VNA and measure port 2 with port 1, I get a very different result (after cal of course). Means that are measuring port 2 so let me say you are measuring S11 connecting port 1 to port 2. So means that using the first VNA you are measuring S11 connecting port 1 of the first VNA to port 2 of the second VNA… Gianni ? Da: [email protected] [mailto:[email protected]] Per conto di dan.meeks222@...
Inviato: venerdì 16 settembre 2022 13:28
A: [email protected]
Oggetto: Re: [HP-Agilent-Keysight-equipment] VNA Calibration - Port Impedance - a late life ponder ? I may not have been clear with my question. I am not using two VNAs to measure each other - I realize that may not actually be practical. That was my way of setting up the question. IF I used one to measure the other, it would show some "real" port impedance (not ideal). But if I use the same VNA and measure port 2 with port 1, I get a very different result (after cal of course). This is my ponder.
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Re: VNA Calibration - Port Impedance - a late life ponder
I may not have been clear with my question. I am not using two VNAs to measure each other - I realize that may not actually be practical. That was my way of setting up the question. IF I used one to measure the other, it would show some "real" port impedance (not ideal). But if I use the same VNA and measure port 2 with port 1, I get a very different result (after cal of course). This is my ponder.
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Re: HP6060B Electronic Load - Need Binding Posts/Rack Mount Kit
I have a suggestion for a way to approach the rear connector usability problem. I like to have my 175W Kikusui electronic load ready to use. It is located on my bench about 18 inches up from the working surface. What I did was get two approximately three foot lengths of 8-gauge stranded wire and added sense wires to each. I used a bunch of short pieces of shrink-wrap to hold the sense wires to the load wires, then used a few shrink-wrap pieces to hold the two load wires together leaving about 8 inches free toward the clip end. I terminated, with heavy copper connectors, the load connections, and used heavy alligator clips on the business ends. I soldered some 14-gauge solid copper wire inside the clips from the wire attachment end to the teeth end to help reduce resistance in the clips themselves.? The cable is always ready for use and it always uses the sense wires, since any reasonable length of heavy wire will have some annoying voltage drop. This setup really works great, the voltage reading and calculated wattage readings are significantly more accurate.
Looking at the 6060B, I would have expected HP to have dedicated connectors on the front or rear for sense wires since this load is probably only marginally accurate for voltage/wattage measurement without them for the loads it is built for.? If you are really going to use this load for 150W or more, you may want to go to 6-gauge stranded wire.? Also for ease of use, you may want to solder copper ferrules on the ends of the cable before putting them in the connectors if you will be removing and replacing the wires regularly.
I believe I got my wire out of an extension cord for 240V 30A power connection to a telco equipment rack.
--
T. Gerbic
Central California
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Re: HP6060B Electronic Load - Need Binding Posts/Rack Mount Kit
Hello Eric, I will contact you off-list. Thank you for the offer, I hope the postage will not be a deal breaker.
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Re: 8660C restoration attempt
Ruben -
Good job on the fan - with proper cleaning, almost any fan can be restored.
When you start on the PLL, be sure to try to access the drive from the various PLLs (main chassis, and 2 in the opt 100) separately so you know where to start rather than "shotgunning" it.
That service plug in would be helpful. I'd considering offering $75 and see what happens.
Cheers!
Bruce
Quoting RubenRubio <rubenrb2019@...>:
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Antonio -
Thanks, that is an interesting proposition. I’ll take your word, maybe in the near future need some parts. Have you plugins? Which?
Today I’ve checked the rectifiers, all bridges are ok, and the filter caps don’t have physical leaks, but measuring capacitance with DMM shows all of them have more than the specified. In my opinion that denotes high ESR (I haven’t ESR meter, but DMM base it’s measure of capacitance in time of charge). I decided to substitute all of them with good modern nichicon caps in a reversible way, to see if the ripple improves.
As you can see in the photos attached, the power supply main board suffered corrosion and someone did some repair on that. I’ve read here that this issue is common in 8660.
On the other hand, I just make service of the fan. All parts cleaned and new white lithium grease applied. Such a fun task, don’t think to get that far disassembling the bearings, but so easy to remove them, washers and circlips. Better to clean every bit of old grease with pure degreaser.
Next step, buy those new caps and try them :D
Regards
Ruben
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Re: 8660C restoration attempt
Antonio -
Thanks, that is an interesting proposition. I’ll take your word, maybe in the near future need some parts. Have you plugins? Which?
Today I’ve checked the rectifiers, all bridges are ok, and the filter caps don’t have physical leaks, but measuring capacitance with DMM shows all of them have more than the specified. In my opinion that denotes high ESR (I haven’t ESR meter, but DMM base it’s measure of capacitance in time of charge). I decided to substitute all of them with good modern nichicon caps in a reversible way, to see if the ripple improves.
As you can see in the photos attached, the power supply main board suffered corrosion and someone did some repair on that. I’ve read here that this issue is common in 8660.?
On the other hand, I just make service of the fan. All parts cleaned and new white lithium grease applied. Such a fun task, don’t think to get that far disassembling the bearings, but so easy to remove them, washers and circlips. Better to clean every bit of old grease with pure degreaser. ?
Next step, buy those new caps and try them :D
?
Regards
Ruben
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Re: HP microfiche collection / scanning
On Tue, Sep 13, 2022, 04:53 Peter Brown < peter@...> wrote: Most of the fiches in the collection are dated 1969 through 1979 and appear to cover the entire range of equipment that HP were selling / servicing at that time.?
It's not test gear, but I'd be very interested to know whether there are any service manuals or related documents regarding calculators, with two-digit part numbers prefixed with "000", e.g. 00067-900nn, or 9100 and 9800 series (possibly with or without a leading zero).
If you have relevant fiche, I'd be delighted to pay for it to be scanned.
Best regards, Eric
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Re: 8660C restoration attempt
Hi Ruben !
Should you need some replacement parts, I have a complete HP-8660C parted for sale.
I am in Portugal.
Regards?
Antonio/CT1TE
A 2022-09-14 22:36, RubenRubio escreveu:
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Hi there again!
Today a new problem child arrives at home, ‘79 8660C sig gen with 86634A phase modulator, 11661B freq xtender and 86603A RF section. Not a big fan of this HP era, but a few bucks for 33 kg of seventies stuff… nobody becomes bitter by a candy.?
Here you have my first impressions:
Cosmetic issues, some rust in the aluminium frame, dust inside, two keys broken (the stud still in, so easy repairable), attenuator knob in RF section needs glue too, so, not a big deal on that side.
When I opened the pannels, saw a fantastic Rifa capacitor exploded, inmediately extirpate. Then I’ve started the unit using variac, it slowly turns on without smoke or explosions. Keys, switches, RPG, anunciators, led display and meters roughly working at first sight in both mainframe and plugins. Let’s try to see something at scope. Power seems ok, a bit over the numbers I read on meter, but not bad.?Frequency is 5.6 MHz over the selection on the display?and keep this behavior. You can see this in my SA screen. Obv it doubles the error at 2 GHz as you can see in my counter. Also the spectra is wobblin’ a lot with 100 kHz of RBW, with less resolution the skirt isn’t a skirt, only high noise. Terrible.
Obviously have a loop problem. But first things first. Power supply rails are quite spot on in dc measurement,?but ripple is terrible.?Figures are three and four times?over the specs. Also I’ve cheked unregulated rails for ripple and two of them have 250 and 300 mV over the specs. In the scope (AC coupled) the waveforms look weird, like a ramp or triangle. I think some caps are dry and maybe some diodes are blown in bridges. Besides this, I saw some corrosion and blackened area in the A20 board, near C4 and C5 capacitors. Tomorrow I’ll take appart the caps and boards to evaluate them.
During measurements I noticed that the corner of the instrument that holds the power supply guts are quite hot. Actually the whole machine was, but power related parts the most. Main transformer itself reaches 50?C (122?F) and the rectifier bridges almost 55?C (131?F). I think that isn’t normal. I’ll try an experiment: leave the unit cool down and connect it again but without turn the main switch on, thus if a capacitor is drawing current, I’ll be noticed with some temperature increment. Anyway, I’ll disassemble all parts to check them properly.
Some work to be done. Again, opened ears to every chap that wants to contribute with an experience or tip. I’ll be posting updates of my adventure. Mainframe op & service manual was easy to find, but nothing about the other three parts.
Regards,
Ruben
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Re: VNA Calibration - Port Impedance - a late life ponder
What VNA are using ? Are the 2 units in measurement mode ? do you know the status of each port?.... If in measurement mode the unit measuring the port of the other VNA receive the signal from the other unit and this can generate problems ,if not measuring do you know the status of the measured port is it in RX or TX ? Ciao Gianni ? Da: [email protected] [mailto:HP-Agilent-Keysight-equipment@groups.io] Per conto di dan.meeks222@...
Inviato: mercoledì 14 settembre 2022 20:24
A: [email protected]
Oggetto: [HP-Agilent-Keysight-equipment] VNA Calibration - Port Impedance - a late life ponder ? Hello Group -
My whole life I have been calibrating VNAs and then verifying the cal by connecting Through, and looking for very good RL and IL across the band.
I'll set up my confusion / question this way: let's say I have two VNAs that are perfectly calibrated. Now I take port 1 of VNA A and connect it to port 1 of VNA B.
What I am doing is measuring VNA B's actual impedance on port 1. Which is not going to be perfect - or necessarily close to it.
The "true" impedance of any VNA port is not as good as you measure after a cal with a through.
Why is that?
After a perfect cal, with a perfect through, S11 and S22 should be showing the actual "true" impedance of the other port (port 1 is looking at Port 2, and vice-versa.
Can someone tell me what is wrong with my thinking on this? I must be wrong... but I don't know why.
Thanks in advance -
Dan
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Patricio A. Greco
Harold Foster
Kurt Poulsen
RubenRubio
