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Horizontal lines in crt display, mac 512k—recap?
Posted by: mloret on 2022-02-19 19:29:46
Just picked up a great deal on a Mac 512k. Fired it up and it works! However there are very faint horizontal lines that show up in the crt display. Will recapping the analog board take care of this? Other idea?
Posted by: Byrd on 2022-02-19 20:28:33
It's most likely the contrast pot up too high, crack open the 512K and you'll see CRT contrast adjustments to dial down a tad.
Posted by: mloret on 2022-02-20 05:21:52
Okay! What's the best way to do this safely? I saw a guy on youtube who did it with a chopstick that he carved...?
Posted by: LaPorta on 2022-02-20 05:26:39
You can do that, or if you foresee doing this on a few of these, there are good plastic sets on Amazon for cheap.
Posted by: mloret on 2022-02-20 05:28:15
Would this work?
https://www.amazon.com/Jonard-TK-AT...M4B&amp&psc=1&amp&refRID=5XN5RE29ACJW57JSTM4B
Posted by: dochilli on 2022-02-21 03:58:28
I use this one:
www.thingiverse.com

Adjustment Tips for Electronics Toolkits by jessenator

These are adjustment tips for the common, 4mm hexagonal bit electronics toolkit handles at the following sizes"flat blade 1.0 x 3.0 mmflat blade 1.5 x 3.0 mmhex 2.5 mmhex 3.0 mmhex 3.5 mmhex 4.0 mmCreated specifically for CRT adjustment trim pots on the compact Macintosh analog boards: e.g...
www.thingiverse.com www.thingiverse.com
Can be printed with a 3D-printer.
Posted by: mloret on 2022-02-21 05:08:54
Sadly I don't access to 3d printer.
Posted by: Byrd on 2022-02-21 16:42:14
Seriously, a stick from the back yard will do fine. Just something non conductive that fits in and turns the dial will do.
Posted by: mloret on 2022-02-21 17:10:44
Think it'll break?
Posted by: Johnnya101 on 2022-02-21 17:15:19
The board potentiometer won't, as it's made to be turned. The stick shouldn't break either. It's super easy to adjust those analog board pots. I think I have used a wooden skewer once. I bought a set of cheap plastic ones off eBay after that though.

Just take your time in general with these things...
Posted by: LaPorta on 2022-02-21 18:32:52
It shouldn't break, but if you do meet resistance, try wiggling it back and forth...30+ years of dust and such can freeze them, and you don't want to break it.
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