HP 4195A network/spectrum analyzer repair

[fenugrec]

Hi,
(wasn't sure whether to post this in the Repair subforum or in here, since it's a test equipment repair !)

I recently acquired a defective HP 4195A network / spectrum analyzer, with a symptom which I believe is fairly common on these units : no display on power on, two LEDs "EXT REF" and "UNLOCK" on front panel that stay on.

I thought I'd try my hand at making a repair video :
https://youtu.be/0VhyDC1DTCk

didn't turn out as nice as I hoped : I thought I was filming in 720p but it was actually 720x480 !


Does anyone have a copy of the "Adjustment program" floppy disk for these units ? I'm not equipped to do a full calibration / adjustment on these but I'd be interested in checking out the software.

[gkar]

Standard problem with these units is the NiCd cell battery.
If the battery is dead, the unit will not start at all.

Replace the battery with the same type and capacity.
The battery normally lasts around 10 years, so put a sticker on the 4195A and replace it in 5 years intervals!

I'm told that the battery contains calibration data. To not lose this data, make sure to power the battery pins on the PCB externally when replacing the battery.
If the 4195A battery is dead, it doesn't matter of course.

Even if one has no intention to use a dead 4195A, remove the battery. They leak and destroys the PCB.
The instrument works without the calibration data, but starts up a bit rough in performance.

I do not have the software, but please let me know if you find it!

[TAMHAN]

Lovely video, grec.

I can recall there is a service menu, at least I used it when I was in Ljubljana to pick up mine. But the tests dont say much.

Also, be prepared to exchange a DAC in the bottom unit...