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DEC M8399 Remote Boot Omnibus dual-wide option

ftcnet

ftcnet

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May 4, 2019
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Location
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M8399-Remote-Boot.png

Here's a rare one. It's the M8399 Remote Boot option. Side 1 has "PLUG INTO ROWS C AND D ONLY ON PDP/8A OR 8E" etched on it.

It's the only dual-wide Omnbus option that I'm aware of. What type of configuration needed/used this option? What did the cable connect to? Is the DEC4011 IC some sort of diode array?
 
That looks like a remote "SW" to me. I see VCC and GND and just one other connection, to DV2 (SW).

So I think it triggers the boot, but doesn't actually contain the bootstrap. Presumably the ribbon cable connection went to a remotely actuated switch of some sort. The BERG connector seems to have several grounds and a single input line.

A Google for DEC 4011 seems to suggest a quad transistor array.

Vince
 
HERE you find an information to DEC4011 that seems to be a quad transistor array according to the pointed shematic. (EK-8A002-MM-002_PDP-8A_Miniprocessor_Users_Manual_Dec76.pdf page 597)
 
I attempted to trace the logic, but I'm stumped about what connects to E1 pin 9, where the trace that leads from R2 under E1 goes, and also the trace from R3 to somewhere on J1.

So far, the transistor at E1 pins 8, 9, and 10 has input and output (through R2) that don't seem to go anywhere. The transistor at E1 pins 5, 6, sand 7 seems to pull SW to GND if biased by J1 pin 12.

Vince
 
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