DEC PDP-11/45 backplane +5 ECO

Fritz Mueller fritzm at fritzm.org
Mon Apr 26 00:06:27 CDT 2021


Very interesting -- thanks for the info, folks!  My backplane has none of this wiring.

I'd really like to see if the traces also look the same, too, though there is no real rush.  Hopefully it will be more convenient for Josh to get some straight-on pictures, since his backplane is already pulled.

There is also this ECO:

> KB11A-B0008 CODE: DF DD: E WL: E SEP-72 [FCO]
> 
> Problem: Small peripheral controller slots in KB11-A panel, slots 26 thru 28, are not wired to accept some quad module controllers: NPG, PA, PB, LTC, ACLO, DCLO and +15V are missing. Correction: Revise wiring to include signals listed above.

...which I have previously verified is *not* implemented on my backplane.  I first noticed this because a DL11 in slots SPC slots 26-28 malfunctioned with incorrect signaling levels (because no +15V), but worked just fine if moved over to a backplane expansion.  

The fact that my backplane is not wired to support trap to 114 on parity err (machine halts instead) has been previously discussed here.  Serial number 152 on this one -- seems an early bird indeed.



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