Apple 12" RGB Power Supply Transplant

[Scott Baret]

Last week, I got another 12" RGB from a buddy who had one in his garage. I plugged it in and it worked fine, but the CRT has these epically huge scratches all over it.

Needless to say, I don't want to use that screen with kids I work with.

I have another 12" RGB in really good cosmetic shape, but something seems to be bad on the power supply. My thought is to transplant the guts, sans CRT, from the new one into the "good" one.

Has anyone done this before and how bad is it? Also, do you think eight days is enough to discharge the CRT to the point where I can yank the anode cap with my insulated pliers, which I use to take them out in most cases? (I know eight days is plenty sufficient for Macs; in fact, I've done them within 5 minutes, but I've never worked with the power supply on this monitor before).

I'd like to go as "whole for whole" with the transplant as possible since the CRT is the only thing I want to keep in the existing enclosure. Once I get this completed, by the way, I'll have fully restored the "fixer upper" LCII I got almost a year and a half ago...

Yes, I do know about Revision A and Revision B parts on these monitors and have read the service manual. I'm hoping they're the same (I think their manufacture dates are only about a month apart). Having dealt with plenty of Mac Classics (and having written the original CRT FAQ on them), I know all too well about mismatches here...

 

[techknight]

Its really easy. 

Just make sure you leave the Yoke, and all that stuff alone. Just transfer the logic board only. The CRT/Yoke assembly is probably the same. 

If you take off or move the yoke on a color CRT, you are in for a rude awakening. The alignment process is convoluted and a nightmare. 

As far as the anode lead is concerned, Just ground a flatblade screwdriver through a 100K ohm resistor, and slip it under there. 

the CRT Neck driver board is probably siliconed in place, with a razor and a VERY CAREFUL process, you can cut it free and unplug it. Its far easier swapping the whole assembly with the CRT neck board as well, than replacing the lower board leaving the CRT board intact because that involves alot of soldering.