Re: I bought a working HP3400A, however it doesn't.
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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Re: HP-8753E Power Cycles at Start Up
Several possibilities I have run into in HP gear. If the power transformer goes through a molex connector to the mother board the contacts on the MB may have heated and poor connections. I have seen this a number of times and am sure thats?why the unit was dumped and now lives happily on my bench. If a switching supply there are small start up caps that if the switcher does not come up in a short period restarts the power control circuit. Lastly a bad memory?chip causing a restart IRQ can give this appearance. Those have been my experiences?good luck. Paul WB8TSL
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Re: HP-8753E Power Cycles at Start Up
Hi Peter:
I will start on this today, and post my results. As I stated elsewhere, to my surprise the service manual is pretty decent in regards to Power Supply diagnosis. I did look there first, because I did a repair about a year ago on the CPU board and recalled distinctly there was virtually no useful information in the service manual other than ¡°replace board X¡¯.
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On Aug 27, 2022, at 7:48 AM, peter bunge <bunge.pjp@...> wrote:
? 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
Hi Burt:
Luckily I have a replacement of both, but will start with the pre regulator (I think that is they call it). I was looking through the Service Manual last night. This part of the 8753E has a decent amount of information. I remember when I was troubleshooting a CPU Problem there was almost nothing of use to guide you. Of course no schematics so I may open the pre regulator (PSU) and see if it¡¯s obvious.
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On Aug 27, 2022, at 1:34 AM, Burt K6OQK <biwa@...> wrote:
?Hi Rich,
Considering that the power supply is a switcher, I suspect that some of the capacitors have gotten low enough in value that they don't allow the power supply to start.? Capacitors don't always fail in a destructive manner.
There are two supplies in the power supply "case."? A primary supply and a secondary supply.? The primary supply,? among other things, will generate a pulse, commonly referred To as a ticking.? This pulse charges a capacitor in the secondary supply.? once that capacitor is charged up enough to run the secondary supply the secondary supply will turn on.? I suspect that capacitor has lost the ability to charge up enough to allow the secondary supply to start.? At this point I'd recommend either shotgunning the power supply or replacing it.
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Re: HP-8753E Power Cycles at Start Up
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
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
Hi Rich,
Considering that the power supply is a switcher, I suspect that some of the capacitors have gotten low enough in value that they don't allow the power supply to start.? Capacitors don't always fail in a destructive manner.
There are two supplies in the power supply "case."? A primary supply and a secondary supply.? The primary supply,? among other things, will generate a pulse, commonly referred To as a ticking.? This pulse charges a capacitor in the secondary supply.? once that capacitor is charged up enough to run the secondary supply the secondary supply will turn on.? I suspect that capacitor has lost the ability to charge up enough to allow the secondary supply to start.? At this point I'd recommend either shotgunning the power supply or replacing it.
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Re: Hp 8590a spectrum analyzer
On Friday, August 26, 2022 at 03:33:56 PM PDT, Richard Cook <richardcook331@...> wrote:
I have acquired a? hp 8590a . I'm new to this equipment and the confidence says fail fail,,,fail. It says RE-BW shape fail. I'm not new to electronics , mostly hame radio repair but this is my first spectrum analyzer.? Can anyone tell me the area this failed comes from.?
Thanks?
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Re: Hp 8590a spectrum analyzer
Thank you John. I just got the manual, I got that fail taken care of . The only rail I have now is noise . Could this be bad caps in the power supply. ? The 4 green leds are lit steady. I haven't seen a schematic of the power supply anywhere. Thanks
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I've made a number of boards that are about 4 inches long, that
have LEDS in parallel (I wanted 5.0 volt operation).? The size is
roughly the width of a CCFL tube.? You'd want to use 0805 or 1206
LEDS, more likely 0805.? Those could be put in series depending on
your supply voltage.? Alternatively, there are companies that make
replacements (already built) of CCFL tubes.? You might search such
things.? Naturally, you'd need to remove the inverter and run it
from the appropriate supply voltage.? It goes with reference to
the CCFL tube number or perhaps the instrument.? Since I make my
own, I know little else about what's commercially available.
Harvey
On 8/26/2022 7:18 PM, Yves Tardif
wrote:
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Hi Dan,
?
Yes, I saw and checked
this small fuse, but the cause was that the backlight tube
is damaged.
So, I replaced
temporarily with LEDs that I had here from a defective LED
bulb.
It works very well but
it is not very aesthetic (inside the instrument, held in
place with kapton tape).
If I decide to stay with
LEDs, I will replace with smaller LEDs to have about the
same diameter as the defective tube.
?
Yves QC, Canada
?
?
?
?
Yves:
When you get to the backlight driver PCB, look for a little
surface mount fuse. They tend to go open on these type
boards....
Dan in Chandler, AZ
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Re: "ADDITIONAL STANDARDS ARE NEEDED" when using E-Cal
I am going to beg to differ. I use Ecal(s) on my 8510 with an 85097 (+small PC) and get excellent results. I have compared results to both the Ecal confidence standards and my fixed standards - good agreement and where they differ, I think I'd go with the Ecal.
I have not used the 85060, but suspect the PC based software is derived from the 85060 application. Does anybody know what the CPU in the 85060 is?
Cheers!
Bruce
Quoting "Dr. David Kirkby, Kirkby Microwave Ltd" <drkirkby@...>:
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On Fri, 26 Aug 2022 at 15:44, dan.meeks222@... <dan.meeks222@...>
wrote:
I love the idea of ECal but I am close to giving up and cutting my losses.
Sell the working 85060 + 85062-60002 (1-26.5G) and hopefully have enough $$
to buy a standard cal kit.
Thanks
Dan
I would not trust an old Ecal myself. There's a comment on one of the
Keysight forums from one of the Keysight employees (I think Joel Dunsmore),
that the newer models of Ecals are much more stable than the old ones. I
have had Ecals, but now only use a mechanical cal kit. I trust that more,
and I can get it calibrated. To quote from
*"Characteristics of the Ecal module impedance standards change due to
aging, drift, and other factors. To meet the Ecal performance
specification, it¡¯s critical to periodically update the S-parameter data of
the impedance standards stored in the Ecal internal memory." *
Dave
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HP-8753E Power Cycles at Start Up
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
|
On Fri, 26 Aug 2022, Yves Tardif wrote: Here is a replacement CCFL tube: Hi Dan,
Yes, I saw and checked this small fuse, but the cause was that the backlight
tube is damaged.
So, I replaced temporarily with LEDs that I had here from a defective LED
bulb.
It works very well but it is not very aesthetic (inside the instrument, held
in place with kapton tape).
If I decide to stay with LEDs, I will replace with smaller LEDs to have
about the same diameter as the defective tube.
Yves QC, Canada
De : [email protected]
<[email protected]> De la part de Daniel Nelson via
groups.io
Envoy¨¦ : 26 ao?t 2022 18:26
? : [email protected]
Objet : Re: [HP-Agilent-Keysight-equipment] 4395A clip manual
Yves:
When you get to the backlight driver PCB, look for a little surface mount
fuse. They tend to go open on these type boards....
Dan in Chandler, AZ
--- * * KSI@home KOI8 Net < > The impossible we do immediately. * * Las Vegas NV, USA < > Miracles require 24-hour notice. * *
|
Hi Dan, ? Yes, I saw and checked this small fuse, but the cause was that the backlight tube is damaged. So, I replaced temporarily with LEDs that I had here from a defective LED bulb. It works very well but it is not very aesthetic (inside the instrument, held in place with kapton tape). If I decide to stay with LEDs, I will replace with smaller LEDs to have about the same diameter as the defective tube. ? Yves QC, Canada ? 
? 
? ? Yves:
When you get to the backlight driver PCB, look for a little surface mount fuse. They tend to go open on these type boards....
Dan in Chandler, AZ
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Option 1D5 is the option with an oven for reference, but option 1D6 is the TIME GATED SPECTRUM ANALYSIS option, and there is room for a BNC connector on the rear panel when this option is installed as you mention.
Thank you for the information regarding the YIG and relays, I will check this out in detail.
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-----Message d'origine----- De : [email protected] < [email protected]> De la part de Sergey Kubushyn Envoy¨¦ : 26 ao?t 2022 17:11 ? : [email protected]Objet : Re: [HP-Agilent-Keysight-equipment] 4395A clip manual On Fri, 26 Aug 2022, Dr. David Kirkby, Kirkby Microwave Ltd wrote: Option 001 is a HARDWARE one requiring a board that goes into that empty slot. Cable with BNC connector is hooked to that board. It should be also enabled in the configuration to actually work. The ovenized oscillator (1D6? don't remember which one is which) is pure hardware -- the oscillator was added to a rear panel and its output BNC connector installed in a normally plugged hole. It took power from the normally unused connector on the motherboard. No other connections to the rest of the instrument, no software awareness/control. You can keep using existing reference and system would not know about that option at all. Or you can connect that oscillator output to external reference input on the rear panel and it will be using that. There is absolutely nothing special there, just a standalone ovenized oscillator conveniently installed inside the instrument. The other option for a gated measurement is just a BNC connector installed into normally plugged hole in the rear panel and connected to a normally unused connector on the motherboard. Also require enabling in software configuration. Impedance measurement (010) is purely software, just need to be enabled in the configuration. No additional software required for any options, it is all included in the main firmware just not enabled. Now for the internal tests. If your instruments passes ALL internal tests without errors that does NOT mean yet it is working at all. The main weak spot in 4395A is YIG oscillator. Most of those units sold on eBay have their YIGs dead. Keysight asks something around $10K for a replacement if they happen to have one. The original one in older units (most of what's being sold) is unobtanium so they offer to replace it with a newer one that also requires a new driver board. That carries that $10K+ price. Yjey tried to negotiate it with me dropping to something like $7K but didn't go any lower than that. SOME of those YIGs fail with their output dropped but still oscillating. Those can be fixed by adding a MicroCircuits amplifier to them (~$100). However, some of the YIGs are totally dead without ANY output. Those can't be fixed. It might be possible to fix if one has die bonding equipment and, most importantly, proper replacement FET part in die form but that is way beyond regular user capabilities. I've seen YIG repair services for Agilent 856x Spectrum Analyzers (expensive, circa $1K, but worth it) on eBay but unfortunately nobody offers such services for 4395A YIGs. If you are lucky to get a unit with working YIG oscillator I would suggest replacing ALL relays in the input module (there is 9 of them in there). I had 3 4395A instruments and all 3 had at least couple of relays faulty. They are not dead but when you try to test for response flatness you will find that it fails (or ALMOST fails) at some ranges. This is almost certainly bad relays in the input module. On Fri, 26 Aug 2022 at 20:47, Yves Tardif <yves_tardif@...> wrote:
Hi,
Option 010 is a software option only.
I think that¡¯s the impedance analyzer option.
Option 1D6, is it a software option with just a BNC connector to add
to the rear output.
Option 001, is it a software option with just a BNC connector to add
to the front output.
Before worrying about those options, it might be worth looking to see
if they are actually useful. I don¡¯t have a 4395A, but have thought of
buying one. I believe I concluded a couple of the options were pretty useless.
Yves
Dave
--
Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@...
Telephone 01621-680100./ +44 1621 680100
Registered in England & Wales, company number 08914892.
Registered office:
Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT,
United Kingdom --- * * KSI@home KOI8 Net < > The impossible we do immediately. * * Las Vegas NV, USA < > Miracles require 24-hour notice. * *
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Re: Hp 8590a spectrum analyzer
Richard,
There are adjustments for the shape of the bandwidth filters.? Search for "8590A service guide" and download it from Keysight.? (Keysight? shows up as the second? hit when I do a Google search.)? The first sheet says something like "Manual Updating Supplement", but it really contains the whole guide, less most schematics.
?
I think the adjustments are in section 2.
--John Gord
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On Fri, Aug 26, 2022 at 03:33 PM, Richard Cook wrote:
I have acquired a? hp 8590a . I'm new to this equipment and the confidence says fail fail,,,fail. It says RE-BW shape fail. I'm not new to electronics , mostly hame radio repair but this is my first spectrum analyzer.? Can anyone tell me the area this failed comes from.?
Thanks?
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On Fri, 26 Aug 2022 at 22:10, Sergey Kubushyn < ksi@...> wrote: On Fri, 26 Aug 2022, Dr. David Kirkby, Kirkby Microwave Ltd wrote:
Option 001 is a HARDWARE one requiring a board that goes into that empty
slot. Cable with BNC connector is hooked to that board. It should be also
enabled in the configuration to actually work.
I did not write that - someone else did. You are quoting, but quoting the wrong person.?
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Hp 8590a spectrum analyzer
I have acquired a? hp 8590a . I'm new to this equipment and the confidence says fail fail,,,fail. It says RE-BW shape fail. I'm not new to electronics , mostly hame radio repair but this is my first spectrum analyzer.? Can anyone tell me the area this failed comes from.?
Thanks?
|
Yves:
When you get to the backlight driver PCB, look for a little surface mount fuse. They tend to go open on these type boards....
Dan in Chandler, AZ
|
Re: "ADDITIONAL STANDARDS ARE NEEDED" when using E-Cal
I love the idea of ECal but I am close to giving up and cutting my losses. Sell the working 85060 + 85062-60002 (1-26.5G) and hopefully have enough $$ to buy a standard cal kit.
Thanks
Dan
I would not trust an old Ecal myself. There's a comment on one of the Keysight forums from one of the Keysight employees (I think Joel Dunsmore), that the newer models of Ecals are much more stable than the old ones. I have had Ecals, but now only use a mechanical cal kit. I trust that more, and I can get it calibrated. To quote from
"Characteristics of the Ecal module impedance standards change due to aging, drift, and other factors. To meet the Ecal performance specification, it¡¯s critical to periodically update the S-parameter data of the impedance standards stored in the Ecal internal memory."
Dave
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Craig Petersen
Burt K6OQK
Sergey Kubushyn
Dr. David Kirkby, Kirkby Microwave Ltd