And DO NOT touch or move any of the custom tuning materials such as those white wire "pigtails" or the thin metal strips bent around resistors. Don't move anything, and don't let any bumps occur to these parts when cover is off!

These attenuators were not considered field serviceable, I assume needing HP technician test jigs to re tune if any components are replaced.

I saw some disturbing comments in some forums speculating that those white "pigtails" wire were dangling connection leads from testing at the factory that were just snipped off and left behind! Bad assessment!

Two pics, one of attenuator DC injection points in red and other vernier contacts epoxied.

You might research on the web, plenty of discussions. It is not a new concept.

Here is one for example:

Hello,
I have got an Agilent E4406A VSA that the PSU is hiccupping due to a supply rail overload.
I pulled all the daughter boards and I get down to the CPU board + the front panel and that still causes Hiccup and green LED pulsing on the front panel.
I then pulled the CPU board and the fan control board as I know the unit should power up OK without it.
The PSU comes up Ok and the front panel shows a white blank screen so looks like the CPU board is pulling it down.

I pulled the CPU and started measuring with a DMM around the yellow tant SMD caps to look for a dead short.
Most of them show around 1 kOhm and above bar some that presumably are in parallel over several locations on the board and find they measure around 200 ohms.

Anyone seen / know of any issues to do with the CPU pulling down the power supply?

A little bit of history... I got this unit recently and it would not power on. The orange LED was on but no action from the power switch. Pulling the fan control board made the unit power up Ok and work. I ended up replacing 3 x 100 k SMD resistors after doing a measure. They were open circuit. The unit then worked for a while and was happy I had fixed it until the hiccupping occurred and got to where I am now with the fault.

Any ideas welcome..

Thanks,

Simon
ZL1SWW

开云体育

Ok I had to go look at the correct unit this time ?
My 8920B options:
001, 004, 010, 013, 051 & 102

Being new to the HP line what is option 55??

Thanks Robert I just sent payment. What burner do you use I’ve been thinking of getting one but I use windows 11 and i don’t see many that will work??

Drew

I've not seen a copy of the AM test suite. If anyone has a copy I can burn it to a card.

Robert.

Thanks for the info Dave! ?We were a computer/TE service company and you wouldn’t (well maybe you would) believe) how hard it was to push proper measures. The IT guru and I were the only computers on the network, over 100 units, NOT brought down by a virus infestation, we did our own thing, kept on top of it and were safe.. the nice thing was upper management finally woke up….

good words to live by in this digital age

Steve

If you decide you need something new and fast, the best bang for your buck is probably copper mountain.? Their TR1300 2-port to 1.3 GHz runs $4K.? Lighthing fast, good interface, and great dynamic range.

Oh boy your correct I copied my 2600 info one the wrong page! Oh man I’m sitting home with a 101 fever so I blame the meds!?

those options listed are for a Motorola /GD R26XX

Regardless the latest firmware on the 8920B is 6.01

Hello Jared,

I don't know if someone has suggested this already, but did you check the 8920A CLIP??? It has some similarities to modules in the 8648. See:



Tom

Do you know what mechanism causes the contacts to be "cleaned"??? I wonder if this method would work on other types of contacts that are "fuzzy".?

Re:-

"You cannot put these on your network for security reasons as they're completely prone to viruses and other attacks."

True...?? Also, you don't know what might already have got in and has infested it's OS, just waiting for another LAN and it's residents to "have a go at".

I speak from experience re that.? In a past job, we had a demo HP VNA to evaluate.? I forget the exact model, but avery nice instrument indeed.? The salesman said that it can print measurement results to a network printer...? So we tried.? (Na?ve that we were back then...)

Within 10 minutes, other people in the office were complaining their PC's were running slow and behaving strange.

Again, I forget exactly what it was, but when investigated, that "Demo" VNA was utterly infested with all the (then) current (and plenty of old) common Windows malware, and two of them had "got out"...

(We had AV of course, but our IT people back then had failed to keep it up to date.? Manual updates, we only had dial-up internet access then.)

When we informed HP (UK sales office) they seemed unconcerned (this was a while ago.)? So, I wonder how many other potential customers got hit, or even contributed to the infestation.

"Trust No One", and NEVER connect anything you don't know the the full history of, to your LAN, unless you can sweep it first and verify it is clean.

Take care.

Dave B.
Ex Technical Manager AR UK Ltd, and before that EMV Ltd.

PS:? It's not "Just" a Windows problem either.? Some commodity Network Attached Storage devices, have intentional functionality to reach out and attempt to scan the other LAN residents by default, for whatever reason!?? Some too, have a default "phone home" facility!? (Wherever "home" might be...)

--
Sent from a MicroSoft free zone:

Thanks for the photos!

I can confirm that I do not have options 1E2 or 1E6 as the parts don't exist in my unit. They aren't options I need anyway so no problems there.

The 1EA high power option is intriguing me though. With no reference to special parts in the 'Replaceable Parts' section of the service manuals I have found online, I'm wondering how a repair technician is to ensure that the option still works if the mysterious critical part is inadvertently replaced? How to ensure the part is not replaced with a non option part if there is no differentiation in the manual?

Which has me thinking further, is it just a software option? Maybe it changes the gain settings on the amplifier or attenuator settings to allow more upper range?

I wonder if just using the adjustment software etc to tell the instrument that it has the option installed will enable it?

Worth digging deeper I think, that high power option is a useful one...



Jared.

The following files and folders have been uploaded to the Files area of the [email protected] group.

• /Bench Briefs, Product Notes, Service Notes, Journals, Tutorials and White Papers/HP Measurement and Computation News/1975_May_Jun_HP_Measurement_And_Computation_News.pdf
• /Bench Briefs, Product Notes, Service Notes, Journals, Tutorials and White Papers/HP Measurement and Computation News/1976_May_Jun_HP_Measurement_And_Computation_News.pdf
• /Bench Briefs, Product Notes, Service Notes, Journals, Tutorials and White Papers/HP Measurement and Computation News/1978_Jul_Aug_HP_Measurement_And_Computation_News.pdf
• /Bench Briefs, Product Notes, Service Notes, Journals, Tutorials and White Papers/HP Measurement and Computation News/1980_Jan_Feb_HP_Measurement_And_Computation_News.pdf

By: Wolfgang Schraml <wschraml@...>

The B/C/D units have the A10 frequency extension board which is on the far side of the card cage and encased in a cast aluminum housing (the first photo showing the barcode). I don’t think the A10 is used for the A models.

Here are some photos I took of the inside of my unit. Maybe these will help. The pulse option (1E6) is the gold block next to the reverse power protection unit. The modulation option (1E2) is a board mounted underneath the RPP/Pulse sub-chassis. I can’t find a description of where the high power option (1EA) is from the manual but I assume maybe it’s integral to the A10 board? The manual doesn’t have anything that jumps out at me about it, though I’ve only given it a cursory overview.?