Re: Transwarp GS freezes

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

STYNX <stynx@gmx.de> wrote:
> Hi, about a Month ago i got a defective Transwarp GS. There had been
> modifications on the cache-board, but one of the SRAMs had the wrong
> size. After replacing the SRAMs, the CPU and the oscillator the card
> would run nicely at 9mhz. I the replaced the GALs against faster ones,
> again the card would work nicely, but now at up to 12.5mhz. I realized,
> that the SRAMs were the limiting factor. I replaced them with faster
> ones. At that Time the Transwarp would sporadically freeze and show
> either error 301 or 302. But neither replacing them with the original
> ones nor the GALs, CPU etc. Im totally stuck right now. I think the
> Cacheboardmay have died at one time or another. The crashes happen after
> about 20sec.-5min. No matter what oscillator i tried (tested 24mhz,
> 25mhz, 28mhz, 36mhz,48mhz,54mhz,64mhz and 66.6mhz). Only thing that could
> be left is the cachboard, one of the SMD-ICs on the Transwarp or the
> CPU-cable. I hate myself right now, because the card worked until i
> couldn't get enough speed. Luckily i only payed less than $20 for the
> card together with a ZIP GSX (defective too). But counting the hours of
> work i put into the cards I could have as well payed $300 for a working one ;-)

I hear you. ;-(

I think it's time to check the board and all its solder joints very
carefully. Were all the chips you replaced socketed?  If so, good, but
check them carefully. If not, and chips were unsoldered, then you may have
inadvertently caused some damage to board traces or vias. This is
especially true if it is a multilayer board. 

Of course, there is also the possibility of ESD damage to chips, so that
you don't actually have a set of good chips. This is one cause of not being
able to revert to an earlier working configuration.

I'm afraid that some more hours of diagnostic work will be needed to get it
working. 

It would be interesting to know what fraction of IIgs accelerator cards
have been made inoperative by efforts to make them faster. ;-(

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