MAINDEX-11 CZKMA Diagnostic?

Johnny Billquist bqt at
Thu Aug 20 08:59:45 CDT 2015

Don't these diagnostics only print messages out if the switch register 
is set in the "proper" way.
And as the 11/23 do not have a switch register, most diagnostics added a 
software switch register that could be accessed by hitting some key.

Have you looked in the PDP-11 Software Diagnostics Handbook?


On 2015-08-19 21:13, Ben Sinclair wrote:
> Thanks everyone! It's running right now, and seems to be passing,
> however the parity error LED on the board is lit.
> The docs mentioned that ZKMA's messages (plus the source) would lead
> me to a potential bad module, but it doesn't seem to be failing.
> VMJAB0 doesn't run at all on my system. It turns off the run light as
> soon as it starts.That's why I was wanting to try the diagnostic
> mentioned in the MSV-11 manual.
> On Wed, Aug 19, 2015 at 7:25 AM, Johnny Billquist <bqt at> wrote:
>> On 2015-08-19 04:36, Ben Sinclair wrote:
>>> I'm again trying to debug my PDP-11/23, and I believe I'm having
>>> trouble with my M8067-LB/MSV-11 memory.
>>> According to the manual, there is a diagnostic program called CZKMA
>>> (for my 18-bit system), but I can't seem to find it.
>>> I have all of the xxdp images from AK6DN, but this one doesn't appear
>>> to be on any of those. Some searching shows references to it and even
>>> a (poorly) scanned source listing, but does anyone know if I can get
>>> it on a TU58 image or another format?
>> Others have already given pointers and help. I thought I should point out
>> that when a diagnostic is called CZKMA, the actual filename in XXDP will not
>> have the leading 'C', and in addition it will have two characters appended,
>> which gives a version.
>> So, the normal way to refer to the diagnostic CZKMA as a file in XXDP would
>> be ZKMA??
>>          Johnny

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