Synertek’s SYM-1 microcomputer, programmable from the hex keypad, with 6-digit LED readout.

The SYM-1 appears to be dead. It does not give its customary “beep” when powered up, the display remains blank, and there is no response to any key presses. Further, some of the chips appear to have rotted. I have removed it from Microtron in preparation for the robot’s long-awaited system upgrade. Also gone are the original A/D converter circuitry, the bumper-hit detection circuitry (both circa 1982), and a slew of old wires.

My current thought regarding most of the legacy circuitry is to keep boards if they work; remove or replace them only when needed.

Microtron knows which direction it is turning because of a potentiometer that reports the current position of the turning wheel back to the central processor. The original potentiometer that was installed in 1981 had apparently disintegrated at some point while the robot was in storage.

As one of the steps needed to get Microtron working again, I replaced the pot’ and pressure-mounted dowel today.

Pictured above on the right is what is left of the old potentiometer, and on the left is the new replacement pot’ and dowel.

Directionless —^

Installed!