8 Jan
2012
8 Jan
'12
8:41 p.m.
I have a "Thinker Toys Universal Interface Board" here, and I've been trying
to figure it out. This is an early version of the Morrow Switchboard. It has a copyright
date of 1978. The manuals available online are for the more common Morrow Switchboard, Rev
2. Comparing this board to a Switchboard reveals some subtle differences, but by and
large, the boards are the same. This older version I have has no solder mask, while the
Rev 2 has a blue solder mask. There are minor component placement differences.
The most drastic difference seems to be the comparators that read the switches at the top
of the board. As found, the board had a LOT of trace cuts and jumps, and some traces just
plain peeled off - all around those four LS266's at the upper right, directly under
the SW5 and SW6. Attempting to figure out what was done is nearly impossible. The switches
themselves are still connected to the 266's with factory traces, at least, most of
them - but the rest of the inputs were a mess of wires with bad solder joints. Of
course... it doesn't work, and the wiring of the switches doesn't even come close
to matching the schematics. Not only that, the factory traces that remain don't match
the schematics. I mean, the switches wouldn't even be in the same order. It's a
mess.
So... does anyone have the schematics for this thing?
-Ian