JeffC's latest activity
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JeffC replied to the thread Classic II (early 4-ROM) black screen - RESET held low, no 15.7 MHz clock from EAGLE.I did quite a bit more testing this afternoon, the machine behaves identically with the replacement IIsi EGRET, so I think I can safely... -
JeffC replied to the thread Classic II (early 4-ROM) black screen - RESET held low, no 15.7 MHz clock from EAGLE.Thanks for the suggestion, I had forgotten the EGRET is shared by other machines. I swapped the EGRET from a known-good IIsi a few...
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JeffC posted the thread Classic II (early 4-ROM) black screen - RESET held low, no 15.7 MHz clock from EAGLE in Compact Macs.I am trying to troubleshoot a Classic II early four-ROM logic board. I picked the machine up 5 years ago, at that time it would only...
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JeffC replied to the thread Rominator II + accelerator ?.I had to scroll back and count the days since you said, and I quote, "I already hit my budget for now just getting this machine and...
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JeffC replied to the thread Iris Indigo - 12V rail problems.You could run it without the video board and see if it still freezes, that would narrow it down to the CPU board or video board. I built...
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JeffC replied to the thread Iris Indigo - 12V rail problems.Yeah the PSUs in these machines are complex. My other SGI is an Indigo2 Impact, and their PSUs are known to be quite problematic. The I2...
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JeffC replied to the thread Iris Indigo - 12V rail problems.I think this is solved. I ran two test leads out of the PSU, one connected to the 12V rail, and one to GND, so I could measure actual...
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JeffC replied to the thread Iris Indigo - 12V rail problems.I have tried with two known-good PSUs, and the symptoms are the same with either. Both PSUs also output 12V fine when bench-tested...