Reforming PAS quad caps

Hey,

I have another PAS2 just sitting around collecting dust. I would like to keep it stock as possible, so I'm wondering what is the procedure to reform the caps, especially the quad cap.

Any help would be greatly appreciated.

Mike

Eskimo wrote:Hey,

I have another PAS2 just sitting around collecting dust. I would like to keep it stock as possible, so I'm wondering what is the procedure to reform the caps, especially the quad cap.

Any help would be greatly appreciated.

Mike

Just add B+ BUT limit current and take your time. PAS has no fuse so you might
destroy the transformer if you just plug it in.
Install a 10k resistor in series with the 12x4, before the first cap. Turn on and
measure voltage buildup. if it get warm stop and retry next day.

But, reforming is not the only problem, it might also loose capacitance.

You also have 2 large caps in the filament circuit and a se rectifier. They might also age without
graze.
Replacing all of the above with :
http://www.tubular-well.se/index.php/webshop/reservdelar/tubes4pro-psu-detail
or simular board will fix all the above concerns.

replace the quad cap and the filament caps with this board, top of page
http://www.tubenirvana.net/pas3-power-supplies.html

T4H,

That may be an option, but I wanted to keep this set of Dynas as stock as possible.
You know, the nostalgia thing.

Mike

at a bare minimum, replace the 50 year old quad cap with this . . .
http://www.dynakitparts.com/dynakit-products/capacitors/MULTI-SEC-ELECTROLYTIC-CAPAC
and replace the selenium rectifier with a 1N4004 or better, along with a pair of new electrolytics 2200 or 3300uF rated 35vdc

Eskimo,
Envision that quad-cap as your avatar. It ages over time and even a blow-torch or a shot of dry ice won't straighten it back up.

So what's the advantage of using an expensive quad can cap over 4 cheaper electrolytics (other than the obvious ease of mounting/installation)?

Not much dave except the mounting.

Here is an alternative to the expensive can cap:

http://www.dynakitparts.com/dynakit-products/capacitors/MULTI-SECTION-ELECT-CAPACI

Or you could buy tube nirvana's power supply #8 and eliminate a lot of junk.