AC fuse as in the mains side? My first check would be if there are no RIFA X/Y caps that have died & shorted.
Wilko
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I would check at the input of the power supply for a shorted filter cap. or a shorted rectifier diode.
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On 2025-04-02 9:01 pm, Jeff Acree via groups.io wrote: Friends,
My beloved HP8920B RF Communications Test Set started blowing the 5A AC fuse today.? It blows as soon as you push the power switch.? I am wondering if there is a common problem I could look for.? Tomorrow I may try to see if it will run on 12VDC. It has a connector and switch for DC operation.? Any advice appreciated.
Thanks!
Jeff
--
This email has been checked for viruses by AVG antivirus software.
www.avg.com
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Re: E5052A Power On Test (3.3V Bus Supply)
I was able to source some CS5208-1 from Kynix. Had good results ordering obsolete/obscure parts from them before:
?
Also finished designing some adapter boards to bring the A3 out of the chassis and allow for "hot" testing.?
They connect together using Samtec SFSD .050" wiring harnesses, which come in all sorts of lengths. Hopefully 24" of wire doesn't mess up signal integrity too much.?
?
?
?
?
I just ordered parts and boards. If its successful I'll share gerbers and BOM so others can use.?
?
In the mean time, does your firmware disassembly have any useful hints as to what that error means? Looks like its pointing out a particular .cpp file in the FW related to the A3.?
Also, if anyone has info on LEDs that would also be great. Wish I had a working unit to look at and compare which LEDs are lit/not lit. Of course service manual doesn't say anything.?
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Re: Manuals for an HP3456B DMM?
Yes. There was a time when a 3458A was on my list of expensive instruments to acquire for my lab, but I ended up with the 3456A as an interim solution and it has fulfilled my needs. I wish I could find a replacement for the small aluminum panel on the RH side on which the binding posts are mounted because mine is badly and deeply scratched, but tha's a nit.
It sounds as if i should scan my 3456A manual and upload a copy of the PDF to the HP Wiki. I an in the process of scanning a Tektronix 7934 manual (the foldouts are tedious to properly scan), so the 3456A manual scan would be queued behind that.?
Everyone should own an HP 345xA, a Fluke 27 and af least one Simpson 260, lol.
On 4/2/25 22:48, Dave Daniel via wrote:
> They made 3455s, 3456s, 3457s and 3458s. I think but am not sure that
> these were all "A" models, i.e., 3456A. My understanding is that the
> 3458A is the (or one of) gold standard(s).
? ?The 3458A is indeed the gold standard, and one of the few instruments
to be made with all three names on the front.
> I own a 3456A.
? ?They are great meters, even (especially?) by today's standards.
? ? ? ? ? ? ? -Dave
--
Dave McGuire, AK4HZ
New Kensington, PA
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Re: Manuals for an HP3456B DMM?
On 4/2/25 22:48, Dave Daniel via groups.io wrote: They made 3455s, 3456s, 3457s and 3458s. I think but am not sure that these were all "A" models, i.e., 3456A. My understanding is that the 3458A is the (or one of) gold standard(s). The 3458A is indeed the gold standard, and one of the few instruments to be made with all three names on the front. I own a 3456A. They are great meters, even (especially?) by today's standards. -Dave -- Dave McGuire, AK4HZ New Kensington, PA
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Re: Manuals for an HP3456B DMM?
They made 3455s, 3456s, 3457s and 3458s. I think but am not sure that these were all "A" models, i.e., 3456A. My understanding is that the 3458A is the (or one of) gold standard(s).
I had no idea they made a 3456B. Are you sure it isn’t a 3465B?
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Friends,
?
My beloved HP8920B RF Communications Test Set started blowing the 5A AC fuse today.? It blows as soon as you push the power switch.? I am wondering if there is a common problem I could look for.? Tomorrow I may try to see if it will run on 12VDC.? It has a connector and switch for DC operation.? Any advice appreciated.
?
Thanks!
Jeff?
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Re: Manuals for an HP3456B DMM?
I had no idea they made a 3456B. Are you sure it isn’t a 3465B?
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Manuals for an HP3456B DMM?
Does anybody know where I can find manuals for an HP3456B DMM?
The HP site has a manual for the 3456A, how different is the 3456B from the 3456A?
?
Thanks,
BobH
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Re: Success: Repair HP3455A Multimeter
Thank you for posting your story, some other 3455 owner will benefit someday.
Dave Wise
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Hi all,
I checked U16 the latch connected to the driver U5 with a scooe.?
The output pin 15 ( connected to pin 9 of U5) was not stable and so I replaced U16.
Now the 3455 is working again.
At least no FET, only U6 and U16 replaced.
Ralf
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Success: Repair HP3455A Multimeter
Hi all,
I checked U16 the latch connected to the driver U5 with a scooe.?
The output pin 15 ( connected to pin 9 of U5) was not stable and so I replaced U16.
Now the 3455 is working again.
At least no FET, only U6 and U16 replaced.
Ralf
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Re: hp-410b, early manual
Thanks Ron, that is the oldest 410B manual I've seen.? It's for early non-prefixed Serial Number?401 through 7228.
Dave Wise
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In the course of refurbishing an old -410b, I was a bit confused in that my unit does not correspond to a manual stored here in our Files section.? So, I purchased a manual online and discovered that it matches the unit that I own, so I have scanned it
and loaded into our files section today.? Cheers.
--
Ron Lawson
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In the course of refurbishing an old -410b, I was a bit confused in that my unit does not correspond to a manual stored here in our Files section.? So, I purchased a manual online and discovered that it matches the unit that I own, so I have scanned it and loaded into our files section today.? Cheers.
--
Ron Lawson
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Re: LCR Meter E4980A Power On Test Fail
Thanks Nigel, I have updated the firmware from A.04.00 to A.05.00. Unfortunately, the failure persisted. Since it was able to passed all other tests, except CPU[2]: 16 tests failed, it seems like a hardware issue on the CPU board? I will have to order some IC parts to replace on the CPU board.
?
Best regards,
KC
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RF Alignment Failure in Agilent CXA signal analyzer N9000A
I have Agilent CXA Signal Analyzer N9000A, I'm getting these errors, please help.
?
I referred manual and it suggested to check 50Mhz with -24dB, But when I check in my equipment its showing 50Mhz with -60dB. While I trace it out it was across H270(HMC270MS8G) where I was getting 50Mhz with -60dB but near FPGA it is exact 50Mhz with -24dB, so does it represent there is problem with H270 or any other if yes please help me, And any blue print of this will help a-lot.
?
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Re: Request HDD image for Agilent Infiniium DCA 86100C mainframe
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Re: HP83712B EPROM content
No, it is not the same as for the 83732A. I tried but it is not working properly.
?
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Re: HP83712B EPROM content
"tom_iphi via groups.io" <iphi@...> writes: Hi,
does anyone happen to have the data of EPROMs U7 and U24 of the HP83712B?
I seem to have lost data... ko4bb has Not sure whether that's the same.
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Hi,
?
does anyone happen to have the data of EPROMs U7 and U24 of the HP83712B?
I seem to have lost data...
?
Tom
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Re: HP 85047A test set on 8753A analyzer -- switch control board jumpers to retrofit for opt 009 (mechanical switch)
Working on a 85047A test set which needs to be retrofitted with mechanical switch 33311B,
Any suggestions at this point?
I have looked at the circuit diagram of the 85046A, and noticed a capacitor value changed between the mechanical and electronic relays. Could that be the problem?? Dave
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Kevin A.
Dave McGuire
Steve Byan
Ralf Rosche
Dr. David Kirkby, Kirkby Microwave Ltd