M7264 Troubleshooting

Noel Chiappa jnc at mercury.lcs.mit.edu
Wed May 22 17:04:55 CDT 2019

    > On the LSI-11/2, with the machine stopped, 'run' was off, and the
    > output on AF1/AH1 was always high (i.e. not asserted).
    > I don't have any guesses as to what the behaviour of yours is about.

Hah! Eureka! I had a brainwave, and decided to look at my machine with
the serial console board pulled out!

I then get the exact same behaviour on SRUN as you're seeing - a very brief
spike every so often (about every 25 usec, here).

So I'd be looking pretty hard at your DLV11-E; start by making sure it is
configured correctly.

Past that, you'll need prints; Manx claims there aren't any online, but there
are a set in the jumbo assemblage, ET-LSI-11 (MP00706); the DLV11-E prints are
on pp. 31-37.

All you have to do to get a nice 'scope loop is to power the machine on; the
CPU will dutifully try and read the RCSR, in a fairly tight loop.

Probably worth picking up a spare DLV11 of some type for fault localization
via board-swapping/etc; DLV11-J's can be found on eBait for not a large sum.


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