PDP-11/34 DD11-PK CPU backplane

Parent Category: How-to's Category: DEC hardware errors, and how to repair them Written by Administrator

Error: Pins were found with bad solder.


  1. GRANT chain was open, despite proper Jumpering.
  2. Use Ohm-meter and a magnifying glass and lot of light to detect this.
  3. Error behavior of the same machine may change, if a card is exchanged, or just plugged in and out.

Explanation: Some pins are not soldered in properly, and loose contact to the printed circuit board over time. This is an manufacturing failure.



Repair: No repair possible. Replace backplane.

Contact: Jörg Hoppe