Macintosh Plus Video Problem

#1 Tue, 24 Jul 2007 - 01:05

Hey there,

I recently got two Mac Pluses,

One of them has this weird issue.

There is a dashed vertical line down the center of the screen.

I will post a picture later.

Does anyone know what the problem is?

#2 Tue, 24 Jul 2007 - 01:25

Sounds like a component failure on the analog board so the horizontal sweep doesn't work. Larry Pina discusses this in The Dead Mac Scrolls. May just need resoldering of a connection, and/or replacing a capacitor or inductor. You should be able to find the actuall part references with google - I'm at work so I can't look it up in the book.

(A quick Google search finds this page: http://www.jagshouse.com/vertical.html - but I can't vouch for it without crosschecking with the Pina book)

#3 Tue, 24 Jul 2007 - 03:33

I think your right.

The lack of fan could cause the life of a Macintosh Plus to end early for some users. As the power supply would heat up, solder joints inside it would fracture causing a bright vertical power line to run down the center of the screen.

Thats what Wikipedia says. Sounds right. Except mine is dashed. But same thing really I guess.

#4 Tue, 24 Jul 2007 - 06:22

Dashed line, eh? Hmmm...how far apart are the dashes? Specifically, are they spaced apart by a greater distance than the standard raster lines?

(I posted a reply to your other post about the vertical line problem). In any case, I put together a doc that covers this and other problems (and their fixes). Our gracious host with the most has archived it somewhere on this site, but I have no idea how one accesses it. Perhaps he will be forthcoming with some instructions. Version 1 is over at Gamba's site; Version 2 has pics, and the material has been rearranged a bit for clarity.