Today I bought an iMac G3 for $50 (a sixth of the cost it usually is in Perth, Australia). Of course, for that price, it's broken and so I'm trying to troubleshoot it. It won't chime or boot at all. I think it's a Summer 2000 iMac DV, based on the specs, and the latest copyright date on the bottom. It's indigo and slot-loading. It's making what I believe is an arcing sound and from my testing I think it's down to the down converter (DC) board connected to the logic board, as the arc noise doesn't happen when I remove the DC and Logic boards from the Mac (and it sounds like it's closer to the DC board than the Logic board.)
I followed the Apple guide and have tested the following:
How should I continue testing this Mac? While it appears to be a problem with the DC board, I haven't yet fully ruled out the analogue and/or power supply boards causing a problem with the DC board which in turn causes it to not run? (Also, has that +36V likely shot my logic board?)
I'd like to be able to test the voltages coming straight out of the power supply somehow, is there a guide to this?
I followed the Apple guide and have tested the following:
- Fuse on analog board is good (Multimeter usually reads 0L, when touching fuse resistance is 0.0 ohms)
- Trickle Voltage on J9, Pin 1: Should be +5V, I get 0V
- DCO Voltage on C10: Should be in a range of -1.2 to +1V, -1.2 ideal, I get -0.77V
- DC Board Voltage on J7: Pin 2 should be +12V, Pin 4 should be +5V, Pin 14 should be +3.3V, I get +36V, +0.45V, +0.45V respectively.
How should I continue testing this Mac? While it appears to be a problem with the DC board, I haven't yet fully ruled out the analogue and/or power supply boards causing a problem with the DC board which in turn causes it to not run? (Also, has that +36V likely shot my logic board?)
I'd like to be able to test the voltages coming straight out of the power supply somehow, is there a guide to this?
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