Re: Vet for a PET

From: Larry Anderson (
Date: 2002-09-01 17:58:01

William Levak wrote:
> The fact that you can get a ready prompt when you type X means that you
> come up in the ML monitor.  There only a couple ways to do that.
>     1) a jumper on the DIAG line on the user port.
>     2) A defective chip or short on the DIAG line.
>     3) execution of the BREAK instruction, $00.

If the monitor's status registers are there, it would tell where the
program counter was at (where the instruction is that 'broke' you into
the monitor or called the monitor).  From there you may be able to tell
if it was suppoed to be a ROM routine, etc.  If there isn't status
registers when it starts up, R should give them to you.

>     4) Defective ROM, address line, or data line that causes instructions
>        to be garbled.
>     5) special ROM that comes up in ML monitor.
> If you have another machine, you can check the ROM's against the funet
> images.
> You should also check the ROM part numbers against the information on
> funet to be sure they are in the right sockets.
> Checking address and data lines gets messy.
> Bill
>        Message was sent through the cbm-hackers mailing list

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