E3 RAM chip in backwards after removing language card

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taos23's picture
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E3 RAM chip in backwards after removing language card

I made a terrible mistake on my Apple II. I removed the language card and when i put the ram chip from the card into E3 I put it in backwards. Very unfortunate as i've don't this 100 times. When i turned it on, the RAM chip got hot. It was only on for maybe 5 seconds. Now when i turn it on i get the first beep, drive spins and then an error beep with address c002 listed, or sometimes 2025. I've tried removing all the other ram chips except first row, same problem. Could all of the RAM chips be bad? Any idea what other chips could be bad? I do have chips from a different computer to try.

 

 

 

 

 

taos23's picture
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More info

It boots a diagnostics disk OK, boots almost immediately. The RAM shows OK. All other disks stop with error *C002 or *2025. Seems like it's having trouble loading beyond first track. Things i've tried:

  • Working floppy control and disk drives
  • Working power supply (eliminating low voltage)
  • ROM chips
  • Various other chips but not all of them, yet 

It's an early Apple II with the marked 16k selectors, and i don't know if those could be bad 

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The RAM chip that was

The RAM chip that was reversed will definitely be bad. You replaced that already?

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When burned (while burning)

When burned (while burning)  this poor 4116 DRAM IC could have passed 12V and/or -5V to other directly connected ICs which in turn could have burned them too...

taos23's picture
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Got it working with other RAM

Got it working with other RAM chips. The diagnostics disk said the original ones were OK but apparently they were not. I ended up using the monitor and CALL -151 .... 34:14 to identify the bad RAM. Shew

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Shit happens

I did that but with the 341-0020 ROM of the language card instead of  a 4116, RIP.

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