PDP customer on Cleveland, OH needs urgent help

[Unibus]

> From: Jay West <jwest at huey.classiccmp.org>
> Just got a call from a PDP-11/05 customer in Cleveland OH. They are in a
> crisis situation due to a dead 11/05. They suspect memory problems but
> there may be power supply issues as well.
> 
> If there is anyone local to them with 11/05 parts and or expertise, can
> you please call me right away?
> 
> Best number to reach me right now is 314-494-7338
> 
> This company is willing to pay for help as the 11/05 being down takes
> their milling machine down.

Probably too far away, but some thoughts.
Be careful what cards you pull out as the power supply has a crowbar 
arrangement that trips if you have too light a load (DC supply line voltage 
rises above trip point). Case of refer to the manual and check the supply 
voltages. Relatively easy on the 11/05 if you have the maintenance manual.

The processor & power supply can be checked by storing and executing 
instructions from the general registers. If you can't store/read from front 
panel you probably have a power supply problem or problems with that logic. 
If the problem is down to the processor boards you really need a hex width 
extension card and the maintenance cards to single step the processor.

Core memory can be tested and then track down problems with a CRO if you 
can't board swap your way out of trouble. If caught with dead 
core and you have the 10-1/2" high processor unit can install later generation
MUD then install a MOS memory board. Just have to move the power 
cabling.