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From: hedges@calma.UUCP (Tom Hedges)
Newsgroups: net.micro.mac
Subject: Re: Mac Video Hardware Problem...Help Please!
Message-ID: <133@calma.UUCP>
Date: Tue, 21-Jan-86 12:51:46 EST
Article-I.D.: calma.133
Posted: Tue Jan 21 12:51:46 1986
Date-Received: Thu, 23-Jan-86 20:59:14 EST
References: <338@infsc3.hatpoly.UUCP> <591@eagle.ukc.UUCP>
Reply-To: hedges@calma.UUCP (Tom Hedges)
Organization: GE/Calma Co., R&D Systems Engineering, Milpitas, CA
Lines: 18
Keywords: Video Board Failure

>My Mac video just failed.  Basically the screen is almost blank, except
>for a faint vertical line in the center of the screen (at highest setting).
>It seems to work otherwise (ie boots, and pulling up desk accessarys 
>makes the disk whir).
>
>Could anyone give me any information at all as to what part in driver
>is likely to have failed. (ie has it happened to you).
>

    I experienced a similar failure, it was a cold solder joint on the
connector to the CRT yoke (a 4 pin Molex connector near the top of the
video/power suplly board). You have to remove the paper backing to get at
the traces on the board to resolder it. It is a good idea to check the
whole board for bad solder joints as many weird failures are due to this.
If the horizontal circuit had failed completely there would be no high
voltage to CRT and thus a completely blank screen.

       Tom Hedges