GAB100@PSUVM.BITNET (George A. Brownfield) (08/16/89)
Another problem from Happy Valley - after about 1/2 hour of use, my Mac Plus
will start having video problems... the screen will just blank out. Tapping
on the side of the machine will restore it temporarily, but after a few more
minutes it will blink, but not restore.
A friend with his now-upgraded Fat Mac had a similar problem, but he just
replaced his entire vertical board. I can't afford that, and I have the
advantage of a trained electrical technician as my best friend <-= Now, what
we need to know is, what to fix?? We've checked and tightened all the grounds
on the screen and the frame -- this seems to be a known problem, does anyone
know where we should be looking before we go and replace every connector to
the video tube??
Thanks for all your help out there.... -- G
-------
George A. Brownfield GAB100 @ PSUVM
Aerospace Engineering Major
The Pennsylvania State University
BITNET: GAB100 @ PSUVM
UUCP: {akgua,allegra,cbosgd,ihnp4}!psuvax1!psuvm.bitnet!gab100
"Women, cats, and golf; man was not meant to understand these things."proctor@cme.nbs.gov (Fred Proctor) (08/17/89)
It seems that quite a few people have been having problems with their
Mac Plus screens dying on them. A very similar thing happened to several
of our Mac Pluses-- after about two years of use, the video board went
bad, and all we got was a thin vertical line. It turns out that the
problem was the flyback transformer on the vertical (analog) board.
Apple repair shops are not authorized to replace just the transformer,
so they charge you $200 for a new board instead of $20 for a transformer.
I ordered some transformers from the company below at about $20, and I
plan on replacing the next bad one myself. If you don't cover your
tracks, you'll violate the warranty, however.
MCM Electronics
858 E. Congress Park Drive
Centerville, OH 45459-4072
800-543-4330
Cat Sechrist, x268fosler@inmet (08/18/89)
My Mac Plus had the same problem. I just took the unit apart, and then resolder all the LARGE solder joints. This fix the problem on my Mac, and I have been using it for a year and a half without any problems since I did it. Carl Fosler
macak@lakesys.UUCP (James Macak) (08/18/89)
In article <1509@manta.cme.nbs.gov> proctor@cme.nbs.gov (Fred Proctor) writes: >It seems that quite a few people have been having problems with their >Mac Plus screens dying on them. A very similar thing happened to several >... >I ordered some transformers from the company below at about $20, and I >plan on replacing the next bad one myself. If you don't cover your >tracks, you'll violate the warranty, however. ^^^^^^^^^^^^^^^^^^^^ So many times we read about a concern for violating Apple's Mac warranty, yet so often that extremely meager warranty has already expired! After 90 days, there is no doggone warranty to violate, maim, destroy, nullify, vaporize or lose. The sucker has _already_ self-destructed. So don't worry about your wonderful warranty after the first 3 months.... it's already long gone! Jim (yes, I'm unhappy about the short warranty) Macak -- macak@lakesys.UUCP (James Macak) or lakesys!macak@csd1.milw.wisc.edu
mel@fleet.UUCP (mel) (08/18/89)
>Another problem from Happy Valley - after about 1/2 hour of use, my Mac Plus >will start having video problems... the screen will just blank out. Tapping >on the side of the machine will restore it temporarily, but after a few more Check for two or three "cold solder joints" on the back of the vertical circuit board on the left side of the Mac Plus (looking from the front). These joints account for about 80% of the Mac Plus failures.
grg@berlin.acss.umn.edu (George Gonzalez) (08/20/89)
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.