TRS-80 Model 4 help requested

From: Tony Duell <>
Date: Fri Feb 28 18:27:35 2003

> Drive speed can be roughly adjusted using the decal on

That's easily accurate enough to get the machine to boot, BTW. Just make
sure you use the right circle of marks on this decal -- there's one for
50Hz and one for 60Hz. That's the frequency of the supply to the
(fluorescent) lamp you use to observe the decal, of course.

Tweak the preset until the marks appear stationary.

> the motor and adjusting the pot on the speed board
> with a non-ferrous screwdriver (like a TV Adjustment
> tool).

It's a preset pot, and the adjusting screw is isolated from everything.
You cna use a normal screwdriver to tweak it.

Older drives have a motor speed PCB on the back of the drive chassis --
the preset is on there. Later drives have the circuitry on the main logic

Received on Fri Feb 28 2003 - 18:27:35 GMT

This archive was generated by hypermail 2.3.0 : Fri Oct 10 2014 - 23:35:57 BST