TRS-80-Model 1 Monitor
Posted: Sat Jun 30, 2012 10:28 pmNot too much time to spend on restoration projects due to CHESS musical rehearsals but I did briefly look at that $3 Model 1 monitor I got off Trade Me the other day.
It cleaned up quite well. Not what I'd call museum quality but acceptable enough. Opened it up and found one of the plastic screw holders had broken off, which is why the screen was a little loose. However, there was enough of the holder left to re-insert the screw (it and the bracket were sitting loose at the bottom of the chassis) and secure the screen in that corner though.
A switch on shows nothing. No raster and no glow in the tube neck. Seems to be some power getting through though as the board gets warm. I suspect something wrong in the Power horizontal circuits, maybe a power transistor. I haven't checked any voltages yet. I've got a copy of Sams Facts for the Model 1 which has schematics, voltages and a trouble shooting guide (at least for a 110V version). After CHESS (or if I get a clear day before hand) I'll see if I can diagnose what's wrong.
It cleaned up quite well. Not what I'd call museum quality but acceptable enough. Opened it up and found one of the plastic screw holders had broken off, which is why the screen was a little loose. However, there was enough of the holder left to re-insert the screw (it and the bracket were sitting loose at the bottom of the chassis) and secure the screen in that corner though.
A switch on shows nothing. No raster and no glow in the tube neck. Seems to be some power getting through though as the board gets warm. I suspect something wrong in the Power horizontal circuits, maybe a power transistor. I haven't checked any voltages yet. I've got a copy of Sams Facts for the Model 1 which has schematics, voltages and a trouble shooting guide (at least for a 110V version). After CHESS (or if I get a clear day before hand) I'll see if I can diagnose what's wrong.