Spirantho
New member
Hi everybody,
Maybe somebody here can help.
My A4000 has been unreliable for some time. I assumed it was a dodgy connector or something because I found that when I pushed on the Zorro backplane or sometimes the CPU card, it'd boot normally.... but I think now that may have been coincidence.
Anyway, since then it's got worse. I now have the A4000 on my desktop with nothing attached but a Chip RAM SIMM (known good) and the 68030 CPU card.
Occasionally, it boots. Usually, it doesn't. It just gives a dark grey screen.
Looking at the address lines on the Kickstart 3.1 ROM U176, I can see that when I cold or warm boot the machine (C-A-A works fine) the ROM is accessed for about 1/2 second, then a brief 1/4 second or so of flat line, and then usually it starts oscillating the address lines on pins 2-9 (A0-A7). Pin 1 (A17) is high at 5V. I can't read the other address lines easily. /CE is ground (active), and /OE on the ROM is inactive once it has entered this cycling state, so it must be reading something else.
I have:
recapped the board (electrolytics only). Voltage is now about 4.91V.
swapped CIAs
Re-flowed Gary and Ramsey.
Resocketed the socketed DIL chip.
reflowed the ROM sockets.
Cleaned the CPU connector.
Cleaned it again, with contact cleaner.
And again.
I also have a CS-PPC which doesn't boot in the same way but I can't reach the ROMs to test them with that; the 3630 is more convenient.
I think I need an A1200 motherboard from somewhere so I can start swapping chips around, but does anyone have any advice in the meantime?
Just to re-iterate, when it boots, it tends to work perfectly.
Thanks if anyone can help!
Maybe somebody here can help.
My A4000 has been unreliable for some time. I assumed it was a dodgy connector or something because I found that when I pushed on the Zorro backplane or sometimes the CPU card, it'd boot normally.... but I think now that may have been coincidence.
Anyway, since then it's got worse. I now have the A4000 on my desktop with nothing attached but a Chip RAM SIMM (known good) and the 68030 CPU card.
Occasionally, it boots. Usually, it doesn't. It just gives a dark grey screen.
Looking at the address lines on the Kickstart 3.1 ROM U176, I can see that when I cold or warm boot the machine (C-A-A works fine) the ROM is accessed for about 1/2 second, then a brief 1/4 second or so of flat line, and then usually it starts oscillating the address lines on pins 2-9 (A0-A7). Pin 1 (A17) is high at 5V. I can't read the other address lines easily. /CE is ground (active), and /OE on the ROM is inactive once it has entered this cycling state, so it must be reading something else.
I have:
recapped the board (electrolytics only). Voltage is now about 4.91V.
swapped CIAs
Re-flowed Gary and Ramsey.
Resocketed the socketed DIL chip.
reflowed the ROM sockets.
Cleaned the CPU connector.
Cleaned it again, with contact cleaner.
And again.
I also have a CS-PPC which doesn't boot in the same way but I can't reach the ROMs to test them with that; the 3630 is more convenient.
I think I need an A1200 motherboard from somewhere so I can start swapping chips around, but does anyone have any advice in the meantime?
Just to re-iterate, when it boots, it tends to work perfectly.
Thanks if anyone can help!
