68kMLA Classic Interface

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Anyone got dumps of the IIfx GALs?
Posted by: Arisotura on 2021-10-05 09:04:06 As title says. Basically, my IIfx isn't giving any sign of life, and here's what I observed so far: UJ7, UK7, UL8 and UN9 get really hot. Not sure if that's indicative of any fault? These chips seem to be GAL16's. I'd understand why one would fail, but... all of them, at once? So I'm unsure there. I also found that the FPU select line from the OSS is low, so I figure the computer gets stuck trying to do something with the FPU. The FPU select line goes through UL6, entering at pin 19 and coming out of pin 26 to go to the actual FPU. But, that's the thing: while pin 19 was a solid low, pin 26 was at like 3.7V, which doesn't seem right. I desoldered UL6, wired it to a socket to put it in the Minipro and see what's inside. It reads (as a GAL20V8), but the contents are mostly just a repeating pattern of 0 0 1 1 0 0 1 1... So: anyone got proper dumps of these GALs I can compare to? Or alternately, some replacement chip?
Posted by: Bolle on 2021-10-05 09:09:16 I'd be surprised to see they are GALs... never seen a board with GALs in place yet. Usually they're PALs and those won't read with the GAL algorithm on your MiniPro. They also won't read with a programmer that supports PALs because they're all locked. Been there, did that, tried to read them all so far. Besides that PALs getting really hot usually is perfectly normal (like hotter than all the other chips you've got on that board)
Posted by: trag on 2021-10-05 17:26:31 Ditto what Bolle said about PALs getting hot. The first time I put my thumb on one in operation, I thought something was broken -- but it wasn't; it was just normal operation.
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