Thought I would create a thread to document and share restoration of my
Power Designs TP325!
I picked up this "for parts" unit to tweak a TP340A I have...but it's in better shape than I expected soooo... time for
PETA!
Exterior:I will polish the meter windows with plastic polish for hobby cars. I cleaned some sticker/marker residue from the faceplate with IPA...but it left the aluminium a bit cloudy in areas, and I'm still able to see some discoloration from where stickers have been. How to clean the aluminium faceplate properly?
Only 3 physical issues:
1. Missing voltage control knobs.
REPLACEMENT: I got
a few of these. They could be a little taller, but they will do.
2. Broken locking toggle switch for Source A / Source B tracking mode ON/OFF.
REPLACEMENT: bitseeker indicated possible replacement is Gemini/Alco DPDT Locking Toggle Switch (125V, 5A), part #A201KZQ. This part a little hard to find in single quantity, but I found comparable item that should work:
NKK Switches M2022LL1W01 from Mouser.
3. Split red banana jack.
REPLACEMENT: Sourced identically looking red/black pair from eBay.
Photos:Pictures of top and side PCB are attached. No obvious failed parts. Looks like the calibration has not been touched since manufacture.
Operationally:I have found a
problem with Source A: The corresponding pot does not control the voltage output. Instead, when the unit is turned on the voltage slowly increases starting from zero. After a few minutes it has gone from 0V to 21V...it would probably go higher but I turned the unit off.
I have not checked ripple on the outputs yet. Will follow-up with more details in the next post.
I got the service manual from
KO4BB's archive.
Does anyone happen to have higher resolution images of the schematics? Will be great to have for reference and then start the diagnosis ![Smiley :)](https://www.eevblog.com/forum/Smileys/default/xsmiley.gif.pagespeed.ic.R8GFI-pF6f.png)
Edit: Schematics from service manual is sufficient when printed in "poster" format and align the pages.