11/34 sanity check

Josh Dersch derschjo at gmail.com
Sun Apr 26 00:09:45 CDT 2015

On 4/25/15 7:34 PM, Josh Dersch wrote:
> On 4/25/15 9:34 AM, js at cimmeri.com wrote:
>> On 4/24/2015 11:32 PM, Josh Dersch wrote:
>>> While I was waiting for the Ridge's disk to dump over a 9600bps 
>>> serial port, I finally got a chance to work on my 11/34.  Picked it 
>>> up last summer and it was in good shape but the power supply was 
>>> completely dead.  I've rebuilt the supply and last night I worked 
>>> out the last few kinks.
>>> So at this point all voltages are spot-on, the AC LO and DC LO 
>>> signals are high (these are active low, right?) but I can't get the 
>>> machine to respond at all -- the "DC ON" and "RUN" lights are lit up 
>>> brightly, and the "SR DISP," "BUS ERR," and "MAINT" lights are 
>>> glowing dimly.  The status register display is dark. The system does 
>>> not respond to any keypresses on the panel.
>>> I'm getting better with UNIBUS stuff but I wanted to run this past 
>>> you guys before I whip out the debugging tools and start tracing 
>>> things.  I've taken it down to a pretty minimal configuration, sans 
>>> any memory or other stuff.  Here's what I have in the main backplane 
>>> (all others are disconnected for the time being) from right to left:
>>> Slot 1: M7266 (CPU)
>>> Slot 2: M7265 (CPU)
>>> Slot 3: (AB) M9301 (bootstrap terminator) / (CDEF) M7859 (front 
>>> panel board)
>>> Slot 4: empty
>>> Slot 5: empty
>>> Slot 6: empty
>>> Slot 7: empty
>>> Slot 8: empty
>>> Slot 9: (AB) M9302 (terminator)
>>> The "empty" slots have Grant Continuity boards installed and the NPG 
>>> jumpers on CB1-CB2 are all present on the backplane. I've confirmed 
>>> that all the right voltages are making it to the backplane (and I've 
>>> cleaned up those damned Molex connectors as well, just to be sure). 
>>> Is there anything I'm missing?  Anything I should try?  Does this 
>>> failure mode sound familiar at all?
>>> Thanks as always,
>>> Josh
>> J, try this first:
>> - test your M7859 KY11-LB console and a ram board in maint mode 
>> direct access.  See the manual for the KY11 for how to do this. Use 
>> maint mode #5 to check your MS11 at select locations, per installed 
>> boards eg. M7847 16K RAM, M9301+M9302, M7959 console. Keep the CPU 
>> out of it for now.
> Thanks, I'll give that a shot later tonight.

Update:  In addition to not responding to normal keypresses, the front 
panel also doesn't respond to maintenance-mode keypresses (CTRL-1, 
etc.).  So the problem I'm currently seeing seems to be related to the 
KY11 and thus commences my debugging session :).  I think I may dump the 
PROMs first to see if they still hold valid code...

- Josh

>> - J.

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