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!
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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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Re: 8566B Attenuator Service
The switches are mechanical. There are two protruding pins and each has 2 fingers on each side. (one for each solenoid) These make sure that when the solenoid is in eith position, it cannot be energized again. Only the opposite position coil can be energized. This might help:
It sounds to me like you have a shorted driver. (I have seen this before) This is often one of these driver chips but for this unit I am unsure. (I have no schematic, etc)
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?
Can you reach this with a scope? Check inputs vs outputs if you can.
?
Mark
?
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Re: Agilent E4406 fails to turn on
If you want a schematic of the fan board send an email offline.
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-----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
Hi Jinxie,
Well perhaps some decades ago - it turns out that 76 year old eyes
are not as good as the younger version!
Yes, those gold plated sort of hairpin shaped contacts are what I'm
talking about, you can see in the picture you just sent that they
are operated by pins attached to solenoid armature.
The one on the left is in the 'de-selected' position and the upper
contact is free to close while the bottom one looks held open.
The one on the right is 'selected' so the upper contact is held open
and the bottom one free to close.
Again, from an (ageing) memory they were actuated metal pins with an
insulating sleeve pushed over them - the latter is important!
I suggest a quick continuity test with a DVM to confirm all is well?
Just FYI, I had one of these attenuators where when I opened it I
found two heads from the nylon screws holding the switch assemblies
on (the ones through the solder tags) rattling? loose in the body.
The others fell off as soon as I touched them, from memory they were
M2 x about 5 or 6 mm cheese heads, easy to replace, but why they
failed I have no idea - over torqued in production, nylon rot, who
knows?
Adrian
On 15/09/2024 14:20, Jinxie via
groups.io wrote:
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I'm unclear as to what to look for to be honest. I've taken
another picture and fortunately you have eyesight normally only
available to birds of prey. See if you can see those switches?
Attachments:
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Re: N9010A 32-bit XSA Software for Windows 7
Hi Tony,
?
Give this link a try. It's the earliest version that I have of XSA written for Win7.
?
https://www.dropbox.com/scl/fi/984nnldawqkmgshnx2qn1/XSA_Installer_A.13.07_Win7.exe?rlkey=lm0ogrpqi895nsawixbwzwxrx&st=b6jne6z7&dl=0
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Please let me know how/if it works!
?
Stan
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Re: Agilent E4406 fails to turn on
In my case it was one of the two 150k 1206 packaged SMD resistors that had gone open circuit. This caused the E4406A to fail to start up. I had to remove the 150k resistors to measure them out of circuit. I replaced both of them even though one of them was still OK.
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A couple of the 1206 packaged 100k resistors had failed in the past. this caused an issue with the fan control. It caused the fan to stay at full speed. Very noisy!
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Re: N9010A 32-bit XSA Software for Windows 7
Hi Tony,
?
I realize that my earlier reply was worded ambiguously. I didn't mean to imply that the CPU in the N9010A couldn't run? the 32-bit version of Win7. I meant that likely the Win7 versions of the XSA software are compatible only with 64-bit Win7, but I will also admit I've never tried to install XSA on a 32-bit Win7 machine.
?
During HPAK's CPU upgrade promotion, I do remember that they bragged that the new CPU card would provide significantly increased computing horsepower because of its 64-bit architecture.
?
All that being said, I'll find the oldest version of Win7 compatible XSA software that I have and try to upload it to Dropbox for you. I'll keep you posted!
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Stan
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Re: 8566B Attenuator Service
I'm unclear as to what to look for to be honest. I've taken another picture and fortunately you have eyesight normally only available to birds of prey. See if you can see those switches?
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Re: 8566B Attenuator Service
That looks like the 8566 assigned part number, it may or may not be
a 33320 series attenuator but does the assembly have the internal
switches on the side of the coils?
On 15/09/2024 13:50, Jinxie via
groups.io wrote:
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Adrian, there are no markings on this attenuator body which
indicate that it's a 33320 series one. It says on the front
label "85660-60121 ATTENUATOR / 70dB" so I'm
not sure how much - if any - similarity there is between them
and whether we can rely on that manual excerpt?
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Re: 8566B Attenuator Service
Adrian, there are no markings on this attenuator body which indicate that it's a 33320 series one. It says on the front label "85660-60121 ATTENUATOR / 70dB" so I'm not sure how much - if any - similarity there is between them and whether we can rely on that manual excerpt?
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Re: 8566B Attenuator Service
Not sure if you saw my other reply a few minutes back?? I'm assuming
this attenuator is the style that has the internal coil switch
contacts - if it's the 'select' coil that's stuck on, have you
checked that the N/C contacts have opened and the N/C contacts have
closed for the solenoid in question?
On 15/09/2024 13:33, Jinxie via
groups.io wrote:
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Yeah, I get that, Steve, but this is not the issue with
this pad's solenoid. It flicks back and forth freely when
there's no power applied. But once it's energized to 'on'
it's stuck there and can't be pried away again. That coil
is remaining energized. Once that happens, there's no
changing it. If I enter 0dB or 10dB, that 20dB one is
always in circuit.? So for example, entering 10dB will
result in me getting 30dB of attenuation and 0dB will get
me 20dB. No wonder I couldn't calibrate it!
Adrian - it's the? second one from the left in the
photo.
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Re: 8566B Attenuator Service
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On Sep 15, 2024, at 7:29?AM, Jinxie via groups.io <paul666@...> wrote:
? Yeah, I get that, Steve, but this is not the issue with this pad's solenoid. It flicks back and forth freely when there's no power applied. But once it's energized to 'on' it's stuck there and can't be pried away again. That coil is remaining energized.
Adrian - it's the? second one from the left in the photo.
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Re: 8566B Attenuator Service
Yeah, I get that, Steve, but this is not the issue with this pad's solenoid. It flicks back and forth freely when there's no power applied. But once it's energized to 'on' it's stuck there and can't be pried away again. That coil is remaining energized. Once that happens, there's no changing it. If I enter 0dB or 10dB, that 20dB one is always in circuit.? So for example, entering 10dB will result in me getting 30dB of attenuation and 0dB will get me 20dB. No wonder I couldn't calibrate it!
Adrian - it's the? second one from the left in the photo.
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Re: 8566B Attenuator Service
One of the most common causes I’ve seen of stuck attenuator sections is decomposing o-rings caused by attempts to clean the attenuator contacts with chemicals that attacked the o-rings. They become sticky like glue and will latch an attenuator section inline no matter what the solenoid does.? A broken or damaged push rod will have the same effect.?
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On Sep 15, 2024, at 3:40?AM, Jinxie via groups.io <paul666@...> wrote:
? Incidentally, if anyone can explain why partially perished o-rings which are still in-situ can cause problems to the functioning of these attenuators I'd like to be disabused of my ignorance on the matter!
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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
Hi, just realised that the attached page 5 of the 33320 service
manual will probably explain it way better than me!
On 15/09/2024 12:20, Jinxie via
groups.io wrote:
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Okay. Well I have an 'intermediate update.' Cycling through 0
to 70dB I can see all solenoids switching seemingly normally -
apart from the second from left in the photo. Commencing with
all attenuators in the 'up'/off position, It flicks 'on' okay
but then remains stuck there and won't release again. And
clearly its coil is remaining energized as it can't be manually
flicked off, either. Not sure if this could account for the
problem I've had or whether there are other things amiss (such
as the perished o-ring) also.
So, anyway, once that first 20dB attenuator is switched in,
it cannot be switched out again and there's a minimum of 20dB
attenuation permanently in-circuit. Could there be an issue with
the control logic?
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Re: 8566B Attenuator Service
Okay, are you sure the internal switching contacts are working as
intended?
It's been a few years since I was inside one but my memory is that
there are two per solenoid?
Effectively a N/C one when the solenoid is in the 'de-selected'
state and a N/O one that closes when it is selected.
They function in a break before make way where the power to the
'select' coil is routed through N/C contact and the power to the
de-select coil through the N/O contact.
So, if the actuator rod is gunked up with gooey o-ring and not?
moving freely over it's full travel I guess that might explain what
you are seeing - which coil is remaining energised?
On 15/09/2024 12:20, Jinxie via
groups.io wrote:
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Okay. Well I have an 'intermediate update.' Cycling through 0
to 70dB I can see all solenoids switching seemingly normally -
apart from the second from left in the photo. Commencing with
all attenuators in the 'up'/off position, It flicks 'on' okay
but then remains stuck there and won't release again. And
clearly its coil is remaining energized as it can't be manually
flicked off, either. Not sure if this could account for the
problem I've had or whether there are other things amiss (such
as the perished o-ring) also.
So, anyway, once that first 20dB attenuator is switched in,
it cannot be switched out again and there's a minimum of 20dB
attenuation permanently in-circuit. Could there be an issue with
the control logic?
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Jinxie
David C. Partridge
