Re: Transwarp GS freezes

[Michael J. Mahon <mjmahon@aol.com>]

STYNX <stynx@gmx.de> wrote:
> What i did since the last Post:
> I resoldered the CPU-Socket, but after checking every pin, one was broken
> or lose, because the connection was cut as soon as i pressed on the
> Socket. I replaced the socket, but still i couldn't boot.
> I checked the board for other connection-problems and encountered crashes
> or garbage on the screen if the board was bent slightly. I resoldred all ICs on the Board.
> The TWGS would boot now! It ran nicely with 12,5 mhz for a whole day...
> Then i tested other oscillators ... an we are back at the beginning.
> The TWGS will crash at random times or not boot at all. Even switching
> back to 12,5mhz will result in the same problems. BUT sometime it will
> run hours without problems (at 12,5mhz).

If there was one pin that opened when you distorted the board, it would
have been a good idea to find (tricky if a buried trace) where that pin
connected, then solder a short-as-possible wire in parallel with the
intermittent trace. 

I can't stress too much that you should resist the urge to "shotgun" things
by, for example, replacing all the x or resoldering all the y. There is
almost certainly exactly one intermittent discontinuity, and once you find
it, you can fix it once and for all. 

It is the nature of mechanical intermittents that any change (temperature
cycling) in their vicinity can slightly alter the stress required to
manifest the intermittent. 

Check that pin again, and see if flexing the board (gently ;-) will cause
it to open. If so, find the closest point on the board that it normally
connects to that opens under stress.  Then solder a short, small, insulated
wire (#28 or finer) between those points and retest. 

-michael - NadaNet 3.1 and AppleCrate II: http://home.comcast.net/~mjmahon