Macintosh Classic II vertical collapse.

MacintoshClassic

New Tinkerer
Dec 17, 2022
6
0
1
Hey all, reaching out because I need some help/advice. I’ve been restoring a Mac Classic II but ran into an issue with the analog board caused by my own error. Story goes: replacing the bottom row of known leaky caps was successful. However still had no sound and the fan wasn’t working so I went back to replace the four caps near the HDD power plug. Arduous but the machine still powered up even without the desired results (logic board probably). But now I noticed four lines (picture 3) at the top of the screen so I decided to do adjustments with the potentiometers. This is when tragedy struck: my screwdriver slips and hits one of potentiometer legs, and now only a single horizontal line appears on screen (picture 1, turned down the brightness to prevent damage). And it got worse because the CF1 capacitor (picture 2) where I heavily struggled to attach is loose again even after redoing the solder so I can’t test properly. I plan to have the board checked by someone more experienced than me who also has tools to check voltages. I’ve seen others online say it could be the RL2 resistor, the TEA2037a chip, or something random. If anyone else has had this problem and successfully fixed it, please let me know. Thanks for reading.
 

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Paralel

Tinkerer
Dec 14, 2022
115
47
28
A single horizontal line is an indication that you have lost your vertical sweep. If I had to guess, based on what happened, your vertical size adjustment pot is probably shot, which is why it collapsed into a single line. If you replace it that should hopefully take care of it.

Also, you trimmed the pots using a conductive or a non-conductive screwdriver? You always want to use a non-conductive tool for pots adjustments. Conductive tools can mess up the adjustment (or, in your case, slip and cause a short).
 

MacintoshClassic

New Tinkerer
Dec 17, 2022
6
0
1
A single horizontal line is an indication that you have lost your vertical sweep. If I had to guess, based on what happened, your vertical size adjustment pot is probably shot, which is why it collapsed into a single line. If you replace it that should hopefully take care of it.

Also, you trimmed the pots using a conductive or a non-conductive screwdriver? You always want to use a non-conductive tool for pots adjustments. Conductive tools can mess up the adjustment (or, in your case, slip and cause a short).
Stupidly I was using a metal screwdriver, gonna order plastic tools after getting the machine assessed. I’ll be sure to check for shorts on the pots, think I was doing the one for width or something else but will check all of them.