[time-nuts] HP-5372A and HP-5372A operation with no CRT display.

[Lester Veenstra]

Magnus:
   The suspects were not hard to locate, leaking black goo.  I did measure the actual values of most of the larger electrolytics on the A17, for future reference.  On two boards, C414, 3300 mfd 35 vdc had to be replaced with new 3300 mfd 50 vdc units.  One board had a good C414 with only in place a 4.7 mfd component. Replaced this also with 3300 mfd 50 vdc.

One board also needed C406, 450 mfd 50V replaced.

Now all three boards,on bench, with just 12Vdv applied produce a nice raster , intensity controllable with variable 0-5 vdc on video input.

Waiting on some female pins to arrive to make up a jumper cable from the mother board to an external A17/CRT for final test before reassembling the system.

Certainly not as exciting as bring Cesium Beam standards back to life, but I do like to keep the old boat anchors glowing, even if they only have a single vacuum tube. HI .
 
Lester B Veenstra  K1YCM  MØYCM  W8YCM   6Y6Y
lester at veenstras.com


-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces at lists.febo.com] On Behalf Of Magnus Danielson
Sent: Sunday, July 05, 2020 3:33 PM
To: time-nuts at lists.febo.com
Subject: Re: [time-nuts] HP-5372A and HP-5372A operation with no CRT display.

Hi Lester,

Good to hear your progress.

So, I gather that you managed to successfully repair it, and it was a
capacitor issue that I also had experienced.

Which caps did fail for you? I think I recall a 50 uF bipolar cap.

Cheers,
Magnus