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Negative. It is indeed directly due to Schottky diode degradation, as stated in the Hp Service Bulletin 4274a-12?? ,? referenced above: " Improvement for Memory Backup Battery" ... " Symptom and

You're pointing out a problem "we" all will have. The people who are experts in the equipment we *can* repair are vanishing, as is their knowledge.? I think that the answer is going to be an

Spent some time today checking through the rest of the line - basic checks on passives look ok. Transistors look ok. Noticed the driver getting hot though. Not making any progress, despite trying to

The 3570A system is spoken for.

Damn, if only we hadn't lost George Hnatiuk not long ago. :-( He could've answered that question right off the top of his head. One approach to make this determination is to put a chip clip on the

That's what happened with a Marconi signal generator I have. It was quite a high-end one for its day and still fetches quite a tidy sum on Ebay, so I really wanted to get it fully working if at all

"My last 2 used SA's puchases both had blown 10 and 20dB attenuator wafers. Never risk DC damage for a half dB. There is no repair possible, just used scrap parts. Lucky for me the mixer diodes were

tiny update to the above, replaced +100v driver and that helped immensely! +100, -100, +248 all work, adjust and appear happy! I gained .5v on my -12.6 line, but its still sitting at -3v. wrote:

This question is for a future project. The HP 3478A has an internal bus that is used to read data from an internal memory with battery backup. I'm interested in knowing when calibration data is read

What are these O rings? I have a spare attenuator if the installed one is blown. Not sure if it's compatible or not but it's an electronically-switchable type and does 10 through 70dB. Model number's

The fact that 0 and 10 dB look different from 30 dB does point to a problem with the attenuator. In addition, there could be other problems as well. I would first confirm that the rest of the signal

Getting closer, seeing some signs of life finally. Not all the way but progress is progress. I've found that CR16 and CR17 were not good, and the pass trans was also not happy anymore. I've replaced

My last 2 used SA's puchases both had blown 10 and 20dB attenuator wafers. Never risk DC damage for a half dB. There is no repair possible, just used scrap parts. Lucky for me the mixer diodes were

Likely Attenuatoar O-Rings

I got a Grizzly G8689.? It's the mini-mill version, roughly a Sieg X3.? There are better ones out there, you might try looking at LittleMachineShop.com.? I've never had a problem with them and they

When I mentioned a shear, I did not mean shears.? You can get a PC board shear from Harbor Fright that will do about 12 inch wide material for not very much.? I would not try to use metal shears (as

The Q indicates it was a custom part and data sheets are not available (unless someone leaked one). [email protected]> wrote:

I believe it's because schotty's leak more so at low currents it matters? I doubt it's a diode degrading issue. I have some hw with 45 year old schottky diodes that work just fine (mixers).

Notes & possible concern: ?Schottky Diodes in these Sram circuits. Some instruments having a Battery backed up ( non Dallas ) Sram seem to have a ?"Ram Shutdown" circuit that provides for seamless

Anyone done this with a? *suitable*? 3.6V Li+? Battery replacement, for? a BR-2/3a? 3.0V Li+ cell ? Some older instruments have an Sram ( non Dallas ) Battery such as the BR-2/3a? 3.0V Li+