PDP 11/34 rebuild

From: Greg Elkin <ClassicComputers_at_bouncy-castle.demon.co.uk>
Date: Sun May 25 11:33:00 2003

The 11/34a I collected recently (BA11-L chasis, H777 PSU) and had
difficulty getting to power up is in better shape now that it's had a
good clean ; backplane inspected and all the dust & debris removed
from its slots (via "fart in a can", ie compressed air :), the cards
have had their edge connectors cleaned (india rubber) to be nice and

Switching to DC ON, the fans whirr happily and the front panel now
has "DC ON" and "RUN" LEDs on, with 000000 on the 7seg LEDs.

If I try to halt (keypad CNTRL + HLT/SS), the RUN LED stays on and
BUS ERR LED also comes on.

I can enter an address via LAD, and DISADD shows it again, so the
keyboard seems functional, but I can't change any memory with DEP or
EXAM as the thing is "RUN"ning...

No $ display on the console terminal yet either.

Do I need to have the RX02 and RL01 drives connected & powered up for
the CPU box to do anything? I shall try to get some grant cards to
replace the RL11, RX211 and whatever the (non DEC) DR11 card is and
see if I can at least get the console emulator to pop up on the

Off to read the 11/34 Users Manual next (many thanks to Al Kossow for
his site hosting this and so many other usefull docs)


Card configuration is :
1 AF M8266 KD11EA-control
2 AF M8265 KD11EA data path
3 AF M7840 KE11-B blackened/hot bits of PCB round resistor DIPs?
4 AB M9132 (soldered wires to FPanel)
  CF M7859 KY11-LB J1 to (FPanel)
5 AF M7891 128K*18 MOS mem
6 AF "Dr11 PHI733-1" card, unknown
7 AF M7762 RL11 controller
8 CF M7856 SLU/RTC option
9 AB M9032 terminator
  CF M8256 RX211 interface
Received on Sun May 25 2003 - 11:33:00 BST

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