11/34 sanity check

js at cimmeri.com js at cimmeri.com
Sat Apr 25 11:34:02 CDT 2015

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.

- J.

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