Date   : Sun, 25 Apr 2010 09:49:55 +0100
From   : mike@... (Mike Tomlinson)
Subject: Model B Sync issue / Master 128 PSU issue

In article <h2z2e00544e1004241024l92c485c0o6ad31f7ca457bbcf@...
om>, adam colley <hideki.adam@...> writes
>
>Also, I have a Master 128 with dead PSU, I've replaced the 220uF
>capacitor but no joy, loaded or unloaded it gives 0.2v on 5v and 0.7v
>on 12v, there is no audible whining...

Check the startup resistors - they're two high-ish value 1W or 2W
resistors in series, 180k ohm or similar IIRC. One is at the edge of the
board and I think the other is at right angles to it.  

Their purpose is to provide a small voltage to get the PSU started, and
they can go open.  BE WARN?D! - if one of these resistors is open, the
mains smoothing capacitor will charge up and have nowhere to discharge
to, and retains its charge for an astonishingly long time (I've seen
several days).  A belt off that does hurt.

-- 
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