PDP-8/L not incrementing properly

From: vrs <vrs_at_msn.com>
Date: Sun Nov 9 23:16:06 2003

From: "O. Sharp" <ohh_at_drizzle.com>
> That said... I'd try other commands that affect the AC (TAD would be a
> good candidate) to see if they did anything out of the ordinary. Hope-
> fully they won't <g>, and that would narrow down the search. If the
> problem is confining itself to rotates, it would be worth trying each
> of the four rotates (RTL, RAL, RAR, RTR) to see if all of them are
> malfunctioning or just a subset of them. The rotate signals are all
> generated on the same card - the M617 at E31, if the 8/L and 8/I
> share the same backplane layout - so that might be a good starting-
> point to look for trouble. (Look for the page "Shift & Carry Gate
> Control" in the schematics. The rotate signals go from there to the
> "Major Register Gating" page, where they choose the rotate-data to
> be gated into the AC.

That M617 is at B09 in an 8L, according to my copy of the schematic.

    Vince
Received on Sun Nov 09 2003 - 23:16:06 GMT