A2000 halts on boot with Buddha Plus One installed

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Don't Panic. Please wash hands.

    Hi,


    I recently bought a Buddha Plus One and put it in my newly fixed A2000. Right now the computer won't boot when I have the card inserted. The halt signal is stuck in high. With the 2.0 Kickstart I see some activity on the data bus for about 0.5 seconds before the halt signal is set. With Diagrom, halt is set right away. I have one other Zorro card, a Ariadne v1.2, that I have tested in in the computer and that works fine so the Zorro bus can't be totally broken. I have fixed some vias and traces on the motherboard to get the A2000 working. A previous owner have failed with at CPU socket replacement and damaged some pads and vias. So I have removed the socket and fixed the vias and traces but opted to have the CPU on an adapter board in the CPU slot instead of trying to reinstall the socket. Other that that the board and PSU are recapped and the smallish battery damage is fixed. My question is what should I investigate next? I have an oscilloscope if that helps.


    Thanks!

    /Tore

    Quote from _tlt

    The halt signal is stuck in high.

    First of all, the Buddha doesn't even work with the Halt signal, so looking at this is not looking at the Buddha at all. Second, the

    Halt signal is active-low, so you are looking at a CPU that is happily running.


    Quote from _tlt

    My question is what should I investigate next?

    Check all vias and traces around the CPU socket, the 86-pin CPU slot and the six 20-pin bus drivers. The battery damage can be anywhere. It doesn't spread in a perfect circle around the leaking battery.


    Jens

    Quote from Jens

    First of all, the Buddha doesn't even work with the Halt signal, so looking at this is not looking at the Buddha at all. Second, the

    Halt signal is active-low, so you are looking at a CPU that is happily running.

    Sorry, I mistyped. I mean stuck low. Yes, I noticed that the halt pad was not hocked up to anything on the Buddha. I was just trying to describe the symptom of the system.

    Quote from Jens

    Check all vias and traces around the CPU socket, the 86-pin CPU slot and the six 20-pin bus drivers. The battery damage can be anywhere. It doesn't spread in a perfect circle around the leaking battery.

    I have checked everything as far as I know but I will check once more. Maybe I missed something. It's a rev 4.1 board it the gives any clues.


    Thanks

    Tore

    I have done a lot more continuity testing and scoped all signals on the Zorro bus. Everything seems to be there. I think the data bus looks strange on the scope and when a compared to a A500 that looked much cleaner. So my next action is to modify the resistor network and replace the 74LS245s. Any suggestions would be appreciated.

    I really haven't repaired any battery damage of an A2000 yet. I do own one that needs such a repair, and I have designed a board that is meant to be soldered under the main board, containing all the original traces, but I never got around to installing that and make a decision about turning this into a product.


    Jens