7 Aug
2012
7 Aug
'12
11:34 p.m.
First we must decide if we have a switching or linear PSU.
Big, old and heavy with large capacitors and transformers usually idicates
linear.
If it's linear change all electrolytic capacitors, including the smaller
ones on control boards. Check rectifiers for forward and reverse resistance
whilst isolated.
Look for components that appear to have got hot or are burned and replace.
Look for dry joints on circuit boards and where flying leads are connected
to tags.
Get a Variac and turn up the volts whilst checking for overheating.
If you get that far you might want to put some load on and see how the out
put looks.
Switching PSU's - find a friend who fixes TV's
?
Rod Smallwood
?
?
-----Original Message-----
From: cctech-bounces at classiccmp.org [mailto:cctech-bounces at classiccmp.org]
On Behalf Of Alex Melt
Sent: 07 August 2012 17:26
To: General Discussion: On-Topic and Off-Topic Posts
Cc: General Discussion: On-Topic Posts Only
Subject: Re: Looking for a vintage S100 power supply
Hi all,
Related, is there a generally recommended guide for bringing up old PSUs?
Cheers
Alex
On 7 Aug 2012, at 16:55, "Rod Smallwood" <rodsmallwood at btconnect.com>
wrote:
Beware of old electrolytic capacitors.
As a minimum measure the ESR and reform then.
If possible replace them.
This also goes for the oil/paper/foil type.
I had the mains filter caps in my 8/e (1972 vintage) go.
They were in sealed cans and I managed to sweat the solder out, open them
up
and replace internally with modern mains filter rated
capacitors and
re-solder the cans.
Rod Smallwood
-----Original Message-----
From: cctech-bounces at classiccmp.org [mailto:cctech-bounces at classiccmp.org]
On Behalf Of Nick Allen
Sent: 07 August 2012 15:46
To: cctech at classiccmp.org
Subject: Looking for a vintage S100 power supply
Hey everyone, I am looking for a original S100 power supply
(transformer, diode and caps) unregulated and 8v/18v/-18v. Looking for
something fairly compact (like the one in an Altair 8800). If you have
one assembled, or ever piece parts, I would be interested in purchasing
it or trading for it.