Power Designs TW5005T

[terabyte]

So in looking for a good yet inexpensive bench power supply I found this thread;
https://www.eevblog.com/forum/product-reviews-photos-and-discussion/looking-for-goodinexpensive-bench-power-supply/

  And I scored this for $77 shipped;

http://www.ebay.com/itm/200731066755?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

I tested the voltage and amperage on both sides and it was pretty stable.  The analog panel meter is a little bit off.





You can see a bunch of pictures here;
http://www.flickr.com/photos/thespeedphreak/sets/72157629697665418/

All in all I'm quite pleased.

[saturation]

NICE!  You can go wrong with a PD of this vintage.  I think this is the same model than Jim Williams has in his desk.  See lower left of photo.  Had I known of this sooner, I would have gotten PD instead of any Chinese supply of similar capacity, it also has programmable outputs at the back, IIRC.  More later on the PD thread.  I managed to track some of the manufacturers of the analog dials, they were GE, made in USA.

Worry not about the analog meters being off, if you are willing break the cal stickers and very likely a screw adjust for the meters is behind it.

[ampdoctor]

I think me and Jim have the same bench.  I thought mine was a complete mess but WOW! I guess his mind was always busy with other things.

[terabyte]

So i have been using this a lot more lately and the pots are horrific.  Any suggestions on what I should try?
I was thinking of replacing them with new 10 turn pots.

[robrenz]

If you are considering replacement why not try disassembling the pots for a real cleaning and lube. You have nothing to loose. Yeah.. I know all pots were not designed to be taken apart but that doesn't mean you can't do it.

[terabyte]

If you are considering replacement why not try disassembling the pots for a real cleaning and lube. You have nothing to loose. Yeah.. I know all pots were not designed to be taken apart but that doesn't mean you can't do it.

Well I took your advise and tool the old pot apart. It was beyond help...

[terabyte]

So I did some testing with stuff I had lying around



new vs. old 



so the new 10 turn pot is only a 5k which is actually perfect.  the psu now only goes to 26volts but it suits me better as I never really use anything over 20volts.  now I get more resolution out of that pot.  Im going to order another one and do the other side.  Now i just need something to cover the middle of the knob.





this is the pot i used; http://www.digikey.com/product-search/en?x=-930&y=-71&lang=en&site=us&KeyWords=gu5021s26

[terabyte]

sorry just one more thing...

with the pot all the way to the left I get -.12 volts.  the old pot did like -.3.  Its not a big deal but is this something easy to calibrate?

[rdl]

Now i just need something to cover the middle of the knob.

If it was me, I think I'd try to just glue the two parts of the knob together so that it would look the same as it always did.