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.