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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Heiroglyph on August 02, 2011, 03:23:09 PM
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I've recently acquired a few good A4000 CPU cards, so here is one last try at diagnosing this one before I put it up for sale.
At one point it ran, but the combination of bad motherboards and RAM that I had caused other issues making it hard to diagnose any individual problems.
It had stopped booting at all and mechy noticed that the 33Mhz oscillator didn't look soldered well. He was right, I added a makeshift socket (couldn't find a 14 DIL locally) and it started booting again.
Now in a well tested Amiga, here are my symptoms:
With SCSI enabled, won't boot, just sits there occasionally blinking the screen as if rebooting. Only attached device is a SCSI CF adapter.
Without SCSI, if an IDE drive on the A4000 controller has an RDB, it starts booting, then gives a software failure. Not a Guru, but a dialog saying that SDH0: failed. This particular drive is SFS formatted and known to work in an 040 configuration in the same machine.
With just a floppy that includes the 060 libs, it will boot and fun from it just fine and all memory is shown. Doesn't show any problems.
If I can't sort this out, I'll sell it as is, but I'd like to get it working, it's the best card I have.
Quickpack 060 XP Rev 2
PC68060RC66C
33mhz onboard, so running at 66mhz
4x16MB RAM well tested in other cards
Wait states inserted to account for > 50ns memory and 66mhz CPU
I can supply current jumper settings and documentation if anyone thinks it will help.
It has been hacked on a few times:
I intend to order some 14 DIL sockets to replace the pinheader I used temporarily.
It had a soldered on 50pin scsi cable which I replaced with a socket when it was obvious that the old cable was bad.
It has had the 68pin scsi soldered on as well.
Neither of these two hacks appears to be a problem as far as I can tell, but when I replace the socket I may remove them too and start over.
Thanks in advance.
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Tried running the card slower?
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I did, but I don't trust this makeshift socket. I think the 33mhz worked because it had solder on the legs, making it contact better.
Once I get a real socket I'll try a 25mhz and maybe another 060 chip to be safe.
I don't see how running at 66mhz (it's rated speed) would cause this particular 100% reproducible problem though. I'd expect no boot, random errors or progressively worse errors as it heats up if it was frequency related.
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Without SCSI, if an IDE drive on the A4000 controller has an RDB, it starts booting, then gives a software failure. Not a Guru, but a dialog saying that SDH0: failed. This particular drive is SFS formatted and known to work in an 040 configuration in the same machine.
With just a floppy that includes the 060 libs, it will boot and fun from it just fine and all memory is shown. Doesn't show any problems.
Do you have the proper 060 libs installed on the hard drive?
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Do you have the proper 060 libs installed on the hard drive?
No, it's booting from a floppy that has them.
Even an unformatted but partitioned drive causes the error when booting with the floppy though.
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man your stubborn :)
First fix the hokey soldered oscillator,with socket or another xral(which i'm sending out in the morning ;))and stick the 060/50 cpu i left at your house in the board,and let see if the thing will run ;)
i suspect that the cpu has a broken mmu or fpu,or the board was never intended to run 66mhz(thats not the original cpu it came with) or the its the hokey xtal soldering.more than likely the 66mhz overclocking is screwing with the scsi chip.these are all guesses,but easy to eliminate each.
in any case you won't get anywhere until you fix it right. your care package will go out in the morning ;) oh and i had some oscillator sockets,so im sending one.
mech
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Awesome, I haven't ordered any yet. Thanks!
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man your stubborn :)
i suspect that the cpu has a broken mmu or fpu,or the board was never intended to run 66mhz(thats not the original cpu it came with) or the its the hokey xtal soldering.more than likely the 66mhz overclocking is screwing with the scsi chip.these are all guesses,but easy to eliminate each.
RAM may be unstable at 66Mhz too. Use 50Mhz. Or 56Mhz if you like, but not more.