mac_enthusiast
Member
Hi everyone,
I was recently lucky enough to acquire an SE/30 with a Micron video card and grayscale CRT yoke board that the seller explained had been working but which had become intermittent and then ceased to function, preventing the machine from booting when it's inserted. I'd greatly appreciate people's experience on diagnosing and fixing these cards.
Here's what I have tried so far:
- I've replaced the grayscale board and wiring harness with a stock board and harness. The Mac boots happily, even with other PDS cards installed.
- When just the Micron card is installed (no Micron CRT yoke board or harness), I get the boot chime then the chimes of death and a blank, grey screen. I don't think I need the Micron grayscale harness connected to allow the system to boot? I assume it would just think it was going to be used with an external display instead.
- The most obvious potential problem is a darkened chip on the board, a resistor network, which definitely doesn't look right (photo below). It's dark, I think, because of grease from the CRT anode cap, which it had been touching when the board was inserted as it was sitting on top of a DiiMO accelerator board. I've tested the resistor network though and all the resistances seem within tolerance. Could the chip still be faulty somehow? Could there have been any HV arcing?
- There are a few traces on the back of the board where the solder mask has been scraped away from insertion/removal but there is still continuity.
So, my question is: what should I try next? What typically fails with these cards? Should I look for any chips that are getting unusually hot, which some other people seem to have reported on these cards?
I've attached some photos in case they're useful. Many thanks in advance for any help!
John
I was recently lucky enough to acquire an SE/30 with a Micron video card and grayscale CRT yoke board that the seller explained had been working but which had become intermittent and then ceased to function, preventing the machine from booting when it's inserted. I'd greatly appreciate people's experience on diagnosing and fixing these cards.
Here's what I have tried so far:
- I've replaced the grayscale board and wiring harness with a stock board and harness. The Mac boots happily, even with other PDS cards installed.
- When just the Micron card is installed (no Micron CRT yoke board or harness), I get the boot chime then the chimes of death and a blank, grey screen. I don't think I need the Micron grayscale harness connected to allow the system to boot? I assume it would just think it was going to be used with an external display instead.
- The most obvious potential problem is a darkened chip on the board, a resistor network, which definitely doesn't look right (photo below). It's dark, I think, because of grease from the CRT anode cap, which it had been touching when the board was inserted as it was sitting on top of a DiiMO accelerator board. I've tested the resistor network though and all the resistances seem within tolerance. Could the chip still be faulty somehow? Could there have been any HV arcing?
- There are a few traces on the back of the board where the solder mask has been scraped away from insertion/removal but there is still continuity.
So, my question is: what should I try next? What typically fails with these cards? Should I look for any chips that are getting unusually hot, which some other people seem to have reported on these cards?
I've attached some photos in case they're useful. Many thanks in advance for any help!
John