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Strange Issue: Quadra 700 won't boot with monitor attached

jmacz

Well-known member
Updating this thread.

PRAM - I think the CR2032 is fine. My guess is in the process of trying things and pulling the batteries, I'm getting into some corrupted PRAM state. Seems like changing VRAM requires a PRAM zap also. But my system is back using the CR2032 with MeowToast and it's fine.

VRAM - When the issue was happening, I tried all configurations, no additional VRAM, 1MB, and 2MB. Issue happened in all three configurations so I don't think it's any of the removable VRAM modules. And as stated earlier, I was running 640x480 at 24million colors just fine on the 13" so that can't be it.

RAM - tried all different configurations of RAM as well and that also did not help when the issue was occurring. The RAM modules in my Quadra are also new (less than a year old), and I swapped in RAM from my other Macs. Didn't help. So I'm ruling out the memory.

Monitor - None of the pins from the cable are inputs into the Mac outside of the sense pins which are fine (as reported earlier). The rest are outputs from the Mac to the monitor. So I can't see this being the issue.

Current State - system has been stable for the past few days with constant power offs, restarts, running benchmarks, diagnostics, things that put load on the disk (Zulu), pulling the power and then powering up after power drain, etc. This is with all of the RAM, VRAM in place and the CR2032 PRAM battery. And running the 16" monitor that caused the issue.

One Potential Issue - not sure how important the ADB bus is for detecting startup disks. I need to look into some docs further but given the system allows for key combinations in determining which SCSI ID to boot from, I believe there's a relation? I am not 100% sure, but I think most of my tests were done using my Kensington Turbo Mouse 3.0 as the mouse. The last few times I hit the issue described in this thread (blinking Mac disk icon and crashes), I had connected/disconnected this mouse. The mouse started getting flaky so I opened it up and I found that the ADB connection port (which has a 5 wire ribbon soldered onto the control board) was in bad shape... the ribbon should have been stiff due to the soldering joints but it was flopping around and sure enough, as I removed the control board, the solder joints on 3 of the 5 wires failed and snapped. I think they were still connected but about to fail -- not sure whether this may have played a role or not in this whole issue.
 
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