price@uclapp.physics.ucla.edu (John Price) (03/07/91)
Hi all:
First, I'd like to thank Orin Packer and Dave Platt for their
advice on where to go for a flyback transformer. They both suggested Soft
Solutions [(503)461-1136] as a source. They are located in Oregon. They
are mentioned in Larry Pina's book (_Macintosh_Repair_&_Upgrade_Secrets_).
Apparently, they have several other Mac parts besides flyback transformers.
That having been said, I would also like to say that I ended up not
needing to get a new flyback. Instead, simply resoldering the pins on J1
and J4 did the trick. Before, I had been seeing some screen jitter and an
occaisional screen blackout. The conventional wisdom as put forth in
Pina's book is that jitter is due to a faulty flyback transformer, while
screen blackouts are due to (among other things) bad solder joints on pins
1 and 3 of J4. I decided to fix the blackout first, since I could do that
without buying any new parts (possibly). It seems to have fixed the jitter
as well (I'm using the Mac to write this - no problems).
There are two things I would like to say about Pina's book - one is
positive, one negative. First, the positive: it's *really* a great book.
I consider myself competant with a soldering iron and other electronics
tools, but I am by no means an electronics whiz - for instance, I *still*
(after using them for three years) haven't figured out how op amps work...
This book, however, makes it unnecessary to know anything about
electronics. Look up the symptom, and it tells you what the problem is,
and how to fix it. Simple as that. Also, he goes into some detail on the
theory of what it is you're fixing, so you feel that you've learned
something when you're done.
Now, the bad part about the book - the pictures. Sorry if you're
reading this, Larry, but they're *really* bad. For instance, there is a
picture on page 85 (figure 5-3) of a "cracked" solder joint. I still
haven't found it. They all look the same to me - fuzzy. I sincerely hope
that the quality of the pictures improves in the next printing of this
otherwise excellent book.
Also, if anyone can tell me *which* solder joint is cracked in this
picture, I'd appreciate it.
Anyway, I now have a happy Mac, thanks in large part to those of
you who responded to my pleas the last few weeks. Thanks a lot, everyone!
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John Price | Internet: price@uclapp.physics.ucla.edu
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Where there is no solution, there is no problem.