[vcf-midatlantic] MAC with squashed screen

Ian Primus ian.primus.ccmp at gmail.com
Thu Apr 28 08:09:22 EDT 2016

Kind of covered - in my class on CRT monitor repair, I mentioned
vertical problems like this, and in my old Mac class, I went over some
of the basics there, but, didn't specifically get to this as it
relates to Macs. It's hard to cram that much information into a one
hour class - I had to move rather quickly.

The 128 uses a pair of discrete transistors for it's vertical driver.
One of the caps in that circuit has failed/is failing. I'm guessing
it's C6. Failing that, it's either C5 or C11. While you're in there,
be sure to resolder the yoke connector, it's a very common point for
cold solder joints (will cause total loss of deflection)


On Thu, Apr 28, 2016 at 7:57 AM, william degnan via vcf-midatlantic
<vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:
> I am thinking about working to repair the display on my '84 MAC,
> occasionally the horizontal is "squashed" although for now it recovers.
> Was this covered in any VCF E classes this or last year?
> http://vintagecomputer.net/browse_thread.cfm?id=95
> I assume there are a few places on the web that describe MAC repairs like
> these, but any comments as to what to target are welcome and will save me
> some time.
> b
> --
> @ BillDeg:
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