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    Reforming PAS quad caps

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    tubenutr

    Posts : 62
    Join date : 2015-01-25
    Age : 59
    Location : Northern Ontario

    Reforming PAS quad caps

    Post by tubenutr on Mon Feb 29, 2016 5:26 pm

    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

    peterh

    Posts : 680
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: Reforming PAS quad caps

    Post by peterh on Mon Feb 29, 2016 5:34 pm

    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.

    tubes4hifi
    Admin

    Posts : 1292
    Join date : 2008-11-30

    Re: Reforming PAS quad caps

    Post by tubes4hifi on Tue Mar 01, 2016 9:24 pm

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

    tubenutr

    Posts : 62
    Join date : 2015-01-25
    Age : 59
    Location : Northern Ontario

    Reforming PAS capacitors

    Post by tubenutr on Fri Mar 04, 2016 9:46 pm

    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

    tubes4hifi
    Admin

    Posts : 1292
    Join date : 2008-11-30

    Re: Reforming PAS quad caps

    Post by tubes4hifi on Sat Mar 05, 2016 12:12 am

    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

    deepee99

    Posts : 1337
    Join date : 2012-05-23
    Location : Wallace, Idaho

    Re: Reforming PAS quad caps

    Post by deepee99 on Tue Mar 22, 2016 11:17 am

    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. Very Happy

    daveshel

    Posts : 148
    Join date : 2011-11-06
    Location : Tucson AZ USA

    Re: Reforming PAS quad caps

    Post by daveshel on Tue Mar 22, 2016 10:01 pm

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

    tubenutr

    Posts : 62
    Join date : 2015-01-25
    Age : 59
    Location : Northern Ontario

    Re: Reforming PAS quad caps

    Post by tubenutr on Tue Mar 22, 2016 10:27 pm

    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.

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    Re: Reforming PAS quad caps

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