Apple Disk II, was Re: TRS-80 Model I
pete at dunnington.plus.com
Sun Feb 4 18:48:36 CST 2007
Dave McGuire wrote:
> On Feb 4, 2007, at 4:05 PM, Tom Peters wrote:
>> Before even letting the customer leave the premises, I'd quickly take
>> out the four screws that held on the cover and show them the blackened
>> spot on the inside of the cover, then show them the 74LS125 in the
>> middle of the board, which invariably had been cracked or cratered.
I remember it well :-)
>> The documentation clearly said, connect the ribbon cable to the
>> controller with the cable exiting AWAY from the board. But there were
>> any number of folks that went the long way around, and put a great
>> deal of effort into bending the cable sharply where it exited the ID
>> connection, so that they could plug it into the controller card
Or the right way round, but one pin displaced, sometimes.
>> This usually resulted in a spectacular failure of the '125.
> Did that failure take out anything else, or did replacing only the
> 74LS125 solve the problem?
9 times out of 10, that was the only replacement required. If you were
unlucky, you might also lose the MC3470, but I only ever had to replace
about half a dozen of those.
Pete Peter Turnbull
University of York
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