Re: 8566B Attenuator Service
Hmmm, fussy things them electrons!
You are right, that's weird!
Desperate ideas to follow:
Have you got/tried Deoxit gold contact cleaner or something like it?
A very mild abrasive is a tiny strip of copier paper soaked in
contact cleaner and carefully drawn through the closed contacts
(downwards in this case)
Are the two leaves of the contact parallel to each other or has one
twisted slightly?
Has a tiny flake of the insulation on the actuator pin somehow
rubbed off and got stuck to the contact face?
.... I'll keep thinking...
On 15/09/2024 17:49, Jinxie via
groups.io wrote:
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Adrian,
Yes, light pressure and they do make short-circuit contact.
However, the next actuation and it's gone again. Yet there is
sufficient springiness there to provide physical
contact - just not electrical!
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Re: 8566B Attenuator Service
Adrian,
Yes, light pressure and they do make short-circuit contact. However, the next actuation and it's gone again. Yet there is sufficient springiness there to provide physical contact - just not electrical!
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Re: 8566B Attenuator Service
Thank you, Greg. I would follow your suggestion, but I'm not about to give up all hope at the prospect of fixing a pair of leaf springs!!
I've cleaned those springs with three different solvents but they still won't make electrical contact. There is plenty of 'spring' in them to make a good contact with each other, but it's just not happening. I've never had this before. Ever. Ideally I'd like to remove this pair and examine them under the stereoscope, but that's not possible. The only other thing I can try (and I'm fast running out of ideas) is abrasive paper. I have the full range of grades here from coarse to ultra-fine. Does anyone know what these springs are made from? I don't wish to rub through some delicate plating and make the situation even worse!
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Re: 8566B Attenuator Service
Where are you measuring from/to?
It looks like the solder tags sticking downwards, where the wires
are soldered on also terminate the solenoid winding wires - which is
logical - is it possible that the soldered joint has failed in some
weird way there? Can you probe (very carefully!) across the contacts
at the point they bend horizontally and disappear into the black
plastic supports??
On 15/09/2024 16:25, Jinxie via
groups.io wrote:
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Update: I've just also tried isopropyl alcohol. No
difference. Then I tried Servisol switch cleaning lubricant.
Still not making contact! It's as if there's an insulating layer
between those leaves. This is just weird.
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Re: 8566B Attenuator Service
When I started see anomalous operation of the attenuator in my HP spectrum analyzer I removed it and took off the cover to peek inside. I quickly realized that the sensitivity to any neophyte attempts to repair it would probably end in disaster. So I sent it out to Test Equipment Plus in Mississippi. It was returned repaired back to HP factory specs with a complete set of network analyzer test result documents.
Yes, it was expensive but I feel that it averted a possible disaster.
Greg
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Re: 8566B Attenuator Service
OH! I remember now after seeing a picture. The insulator on the pin is in fact what OPENS the switch. When the pins moves away. the two spring fingers make contact and THAT is what closes the switch.
Mystery solved.
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It's been years but I seem to recall some insulating material on those ... somewhere for some reason!
Update: I've just also tried isopropyl alcohol. No difference. Then I tried Servisol switch cleaning lubricant. Still not making contact! It's as if there's an insulating layer between those leaves. This is just
weird.
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Re: Agilent E4406 fails to turn on
Had a problem...+15V standby DC-DC converet. Small verticaly moumter piggy board on main PSU. Replace all (2or3) electrolitic condesators.
Milan
On Sun, 15 Sep 2024, 17:09 hardyhansendk via , <hardyhansen= [email protected]> wrote: Hi
I have experienced the same no turn on,it began to take a while before start up-later it would not at start at all.Replaced the input caps-and it worksl.
David..we have also have the schematics for RF board and Synthesizer and maybe Tim would be interested in VSA software 89601A??
Regards
Hardy? ?
-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af David C. Partridge
Sendt: 15. september 2024 16:11
Til: [email protected]
Emne: Re: [HP-Agilent-Keysight-equipment] Agilent E4406 fails to turn on
If you want a schematic of the fan board send an email offline.
-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Tim Tuck
Sent: 15 September 2024 13:07
To: [email protected]
Subject: [HP-Agilent-Keysight-equipment] Agilent E4406 fails to turn on
Hi all,
My E4406 won't turn on so I've pulled it out the PSU, and apart from some suspicious RIFA caps it appears OK.
I've also gone over the Fan control board on the suggestion that some 10k or 100k resistors might be open circuit but a simple in circuit test shows them to be OK.
While this might be not sufficient to reveal an open circuit device since the surrounding circuit might provide the return path for a resistance measurement of near value, if someone knows which resistors I should de-solder to check, please tell :)
Any other pointers to common faults to look for or a path to take would be great.
thanks
Tim
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Re: 8566B Attenuator Service
It's been years but I seem to recall some insulating material on those ... somewhere for some reason!
toggle quoted message
Show quoted text
Update: I've just also tried isopropyl alcohol. No difference. Then I tried Servisol switch cleaning lubricant. Still not making contact! It's as if there's an insulating layer between those leaves. This is just
weird.
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Re: 8566B Attenuator Service
This really makes no sense. Let's say it gets the signal to turn 'out' (up). Then the switch to turn 'in' (down) should make contact and the out/up switch should be open. SO at this point, neither coil should be ON and you should be able to move the solenoid
by hand. (those magnets are strong so it takes some effort) If the OUT/UP signal is stuck on, the solenoid would move right back into position.
You might just have to carefully test it with a bench power supply per previous discussions.
I have attached the datasheet just in case you need it.
Mark
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For some reason, the lower contact pair of Y leaves will *not* make contact. They
appear to be making contact visually, but it's open circuit every time. I've tried shaving down a toothpick and cleaning the inside contact areas with ethanol but it's made NO difference at all. If I jiggle them, I can get them to make electrical contact,
but then it's lost again a moment later. Never experienced this before! Could this explain why this attenuator is permanently stuck 'on' once actuated?
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Re: 8566B Attenuator Service
Update: I've just also tried isopropyl alcohol. No difference. Then I tried Servisol switch cleaning lubricant. Still not making contact! It's as if there's an insulating layer between those leaves. This is just weird.
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Hi,
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I'm trying to troubleshoot power output problems with an 83590A oscillator plugin.
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I thought the best way to approach it was to go through the adjustment process from the start. According to the service manual this requires an HP 8755C swept amplitude analyser - which I don't have. Is it possible to use an 8756A SNA instead?
?
thanks
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Tony
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Re: N9010A 32-bit XSA Software for Windows 7
Thanks for this Stan,
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I checked and this is a 64-bit executable so I think you're right about them just going to x64 when they moved up to Windows 7 - Which would explain why they never mention the x86/x64 difference in any of the release notes for the XSA app.
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Thanks again for taking the time to grab this for me to look at. Appreciate it.
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Thanks,
TonyG
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Re: Agilent E4406 fails to turn on
Hi I have experienced the same no turn on,it began to take a while before start up-later it would not at start at all.Replaced the input caps-and it worksl. David..we have also have the schematics for RF board and Synthesizer and maybe Tim would be interested in VSA software 89601A?? Regards Hardy -----Oprindelig meddelelse----- Fra: [email protected] < [email protected]> P? vegne af David C. Partridge Sendt: 15. september 2024 16:11 Til: [email protected]Emne: Re: [HP-Agilent-Keysight-equipment] Agilent E4406 fails to turn on If you want a schematic of the fan board send an email offline.
-----Original Message----- From: [email protected] < [email protected]> On Behalf Of Tim Tuck Sent: 15 September 2024 13:07 To: [email protected]Subject: [HP-Agilent-Keysight-equipment] Agilent E4406 fails to turn on Hi all, My E4406 won't turn on so I've pulled it out the PSU, and apart from some suspicious RIFA caps it appears OK. I've also gone over the Fan control board on the suggestion that some 10k or 100k resistors might be open circuit but a simple in circuit test shows them to be OK. While this might be not sufficient to reveal an open circuit device since the surrounding circuit might provide the return path for a resistance measurement of near value, if someone knows which resistors I should de-solder to check, please tell :) Any other pointers to common faults to look for or a path to take would be great. thanks Tim
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Re: 8566B Attenuator Service
For some reason, the lower contact pair of Y leaves will *not* make contact. They appear to be making contact visually, but it's open circuit every time. I've tried shaving down a toothpick and cleaning the inside contact areas with ethanol but it's made NO difference at all. If I jiggle them, I can get them to make electrical contact, but then it's lost again a moment later. Never experienced this before! Could this explain why this attenuator is permanently stuck 'on' once actuated?
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Re: HP attenuator O-rings
I have been lurking on this topic as it is of interest. The question to ask is: If I fit "O"-rings of a particular material that will not last 30-40 years, do I really care? As long as they work for a reasonable time? The odds are the CRT will go or the mixer will get popped, or some un-obtanium part will fail before the new fitted O-rings go bad. (Unless they are totally unsuitable!).
Just my 2 cents. Maybe not worth doing too much searching for the "perfect" replacement, when "good enough" will do. Sir Robert Watson-Watts rule of the third best in application.
Regards, J. Kruth
In a message dated 9/15/2024 10:34:35 AM Eastern Standard Time, alan.bain@... writes:
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Yes - I can find Nitrile (NBR) ones from my local watch material house as crown gaskets in packs of 10 at a sensible price, but given how the ones fitted have degraded (some aren't even there any more) it seemed that FKM/Viton might be better but maybe this is wishful thinking!
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Alan
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Re: 8566B Attenuator Service
In that case, I would check how things look with power removed. Move the solenoids in/out. How does it look?
If something looks goofy, it might be the o-rings.
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Re: 8566B Attenuator Service
I agree - don't think that's your problem. I have repaired a LOT of these and have never seen those "switches" fail.
Again, I'd check the driver.
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Well, I did wonder about those sleeves. It looks? like if they wear away then rather than breaking contact they would maintain it. Not sure if that could account for the problem I'm having with that one 20dB attenuator permanently stuck on.
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Re: HP attenuator O-rings
Yes - I can find Nitrile (NBR) ones from my local watch material house as crown gaskets in packs of 10 at a sensible price, but given how the ones fitted have degraded (some aren't even there any more) it seemed that FKM/Viton might be better but maybe this is wishful thinking!
?
Alan
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Re: 8566B Attenuator Service
Many thanks for those pin-outs, Mark.
So far as these 'switches' are concerned, there's an issue I've just found with the 20dB attenuator which is sticking 'on' all the time. Those 'Y' shaped leaves aren't making contact. With all the plungers down (on), there's a short - as expected - between the leaf-pairs of all the lower Ys - except that 20dB one. How curious. There's very little that could go wrong with something that simple, but something has!
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Re: 8566B Attenuator Service
Well, I did wonder about those sleeves. It looks? like if they wear away then rather than breaking contact they would maintain it. Not sure if that could account for the problem I'm having with that one 20dB attenuator permanently stuck on.
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Jinxie