| I don't know for sure but... Seems I remeber hearing or reading
that it is the GLU chip that usualy causes the problem. Probably
because of the type of chip and socket (leadless chip carrier I think).
Of course there are the ROMs and a couple (only one or two) other chips
in sockets that may cause problems. The ROMs are in DIP sockets which
usualy hold chips fairly well, though I have known chips to come loose
from them.
I understand newer STs do have hold down clips on the GLU chip,
but I don't know if it's something you can add after the fact or
wether it means replacing the whole socket.
In my opinion the 1" drop test is a real poor way to fix any problem
(even though I've heard of repair shops doing this), for two reasons:
1. Even if it does fix the problem it probably doesn't totaly reseat
the chip, so similiar problems may recurr (as you noted).
2. You may DAMAGE something in your ST (drive mechanism/heads or
even ICs). It could crack etch or jar loose poor solder joints (causing
more and harder to find problems).
Hopefully someone else has a bit more information, but I thought
I'd post my $.02 worth incase they don't.
Ray
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| The custom gate arrays usually need to be clipped down. This usually
includes the MMU & GLUE chips, which are the 2 that I believe caused
the most trouble. Basically any square chip that doesn't have a
clip should. The problem was with some of the older sockets, that
allowed the chips to work their way out.
Best thing is take it to an authorized Atari service center and
have them install the clips, so you know you are getting the right
ones. I doubt they would charge much, they would probably sell
you the clips separately as well.
-Dave
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| Thanx to all for the help.
We were going to do the fix ourselves, but I think I will have a
service center do it, just to make sure (besides, there is one a
block away from my house)
regards
Bob K.
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