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IIgs Bad onboard ram

IIgs Ram

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#1 Aaron707

Aaron707
  • 6502

Posted 21 January 2017 - 11:54 PM

Greetings,

My brother picked up an Apple IIgs for me from the thrift store yesterday. I am getting an error: system bad: 02010400 when I run the self test by holding command+option during boot.

From what I can determine, this is a ram error. I removed the add-in ram card for now and re-ran the test with the same result. Does this error show ram chip bank 01 is bad?

If so, would this be the chip "UM1" on the mainboard? And last, are these the correct replacement chips: http://www.jameco.co...DRAM_41574.html

Thanks!



#2 Aaron707

Aaron707
  • 6502

Posted 29 January 2017 - 07:37 PM

Update:

 I ordered the DRAM chips in my previous post. It turns out UM1 was NOT bad. After replacing all four "standard" ram chips on the IIgs mainboard the error still appeared and programs still would not boot without crashing. As I learned recently: those four chips are BANK 0. BANK 1 is the "Fast Ram" (UH13,UH14,UH15,UH16). After replacing the four chips in BANK 1 the system passed all tests and is working correctly now. I hope someone finds this information useful. Another Apple II saved from the landfill!



#3 ScutBoy

ScutBoy
  • 6502
  • LocationNorthfield, MN

Posted 30 January 2017 - 01:42 PM

Nice work! Gotta save as many as we can :)



#4 NJRoadfan

NJRoadfan
  • 68000

Posted 31 January 2017 - 01:12 AM

The "standard" chips, which run at 1Mhz, are banks E0 and E1. The fast RAM is back 00 and 01.







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