Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!uwvax!umn-d-ub!umn-cs!berlin!grg
From: grg@berlin.acss.umn.edu (George Gonzalez)
Newsgroups: comp.sys.mac
Subject: Re: Dead Mac Plus Screen
Summary: It may not be the flyback...
Message-ID: <578@berlin.acss.umn.edu>
Date: 19 Aug 89 19:39:08 GMT
References: <89228.113355GAB100@PSUVM> <16@fleet.UUCP>
Organization: U of M MicroGroup, Minneapolis
Lines: 18


If you have the dreaded "vertical line" symptom, its probably just a bad
solder connection on the analog board.  The most common troble spots are
in the high-current circuit to the horizontal yoke. Often the crummy nylon
plug and socket will overheat and melt the solder that connects it to the
pc board.  If you look closely at the connector pin, you'll see a round
blob of solder, often forming a hemispherical shell *over* the connector pin,
but no longer in contact with it.  A touch with a soldering iron will
temporarily fix the problem.  A longer lasting fix is to replace the
overstressed connector with something more robust.  A good choice would
be a "trailer light connector" from a auto-parts store.


Other parts in this high current loop can fail too.  The capacitor leading
to the yoke can overheat and fail, as can the solder joints to it. These
are easily repaired if you know what to look for.

As always, don't try this if you don't know what you're doing.