DEC PDP-11/45 backplane +5 ECO

[Fritz Mueller]

Hi Josh,

Among the pictures linked from your message about the H742a parts, there is one picture of you backplane.   I have been looking for some time for information about the following 11/45 ECO:

> KB11-00001 CODE: D May-72 [ECO]
> 
> Problem: Etch carrying +5V current from Mate-n-Lock pins to backpanel pins is not heavy enough to carry required current. Correction: Run 24AWG wire in parallel with etch on panels which already have Mat-n-Lock assembly installed. Increase thickness of conductor with solder bead if Mate-n-Lock assembly not installed. PDP-11/45 system serial number 101 and later.

The wiring arrangements at the top of your backplane look to be a bit different from mine, and I believe you may have this ECO implemented.  While you have your backplane out, could I ask that you take some closeups around the Mate-n-Locks along the top?  I'd be very interested to see the board traces and the details of the red bus wiring there.

Pictures of the toasted 11/45 suggest that the original machine had the older power wiring scheme (distribution panel mounted vertically on back of cabinet instead of horizontally at top of cabinet, etc.) although your KB11A serial number badge is >2000, which is curious...