The front panel needed extensive repair work: most OL-2 bulbs (blue base) had been replaced by the previous user using OL-1 (black base) bulbs, various other types of bulbs as well as several LEDs (each with an additionnal resistance and sectionning the lead of one of the resistances on the panel board).

About forty spare OL-2 (blue base) bulbs were pulled out from the front panel of a PDP-11. Contrarily to the PDP-8, the bulbs are not soldered on the PDP-11 front panel board. Instead, they are plugged in tiny tubes which are soldered on the board. These tubes were removed along with the bulbs from the PDP-11 front panel and soldered onto the PDP-8/L front panel board (the holes on the PDP-8/L panel board had to be enlarged somewhat using a drill to hold the tubes).

Here is the panel with almost all remaining black base bulbs already replaced.

We used two 2N3009B transistors (equivalent to the original DEC2 transistors) to replace two "exotic" transistors which had been put by the previous user for repairing the panel.

The logic tested OK and no TTL had to be replaced.