| Attachment | Size |
|---|---|
 AC Power filter board | 649.6 KB |
| Low-voltage RGB leaky C410 | 659.91 KB |
| B+ Filter Leaking C512 | 626.06 KB |
| Monitor Case A2M4043 | 481.04 KB |
| Main board | 695.3 KB |
(crossposted on vcfed.org forums)
Hey all,
I've decided, for good or ill, to recap a newly acquired A2m4043 color monitor IIc. It is exhibiting a narrow raster image and, upon teardown and inspection, has at least a few leaky caps in the B+ filter area (among other areas). No rifa caps to be found. I've attached a few pics of the board for posterity. My plan is to replace the big leaky caps in the LIVE / B+ filter area plus whatever else I think I can handle. Mostly posting this here as a way to report progress and ask for advice. I haven't found much info on these monitors (schematics etc) yet... Here's what I do know:
Some specs:Model: A2M4043 Apple ColorMonitor IIcChassis: TWE-3003-705-910Tube Builder: ToshibaIC101: TA7644BPConfirmed leaking caps:C506, C512, C140, C410, C136
What you're calling "leaking" may not be what you think it is. In assmblies like these, the heavier components (large capacitors, inductors, and transformers) have glue applied to prevent vibrations.
Usually, the suspect caps for leaking are the small electrolytics like C220.
That's very interesing - I did not know this. Not surprisingly then, I don't know how to differentiate glue from electrolytic goo.
Can you see the attached photo referencing C512? Does that offer any clues?
The glue is rubbery and is not affected by water, where leaked electrolyte is soluble in water, alcohol, or acetone and feels "tacky".
Amine additives in the electrolyte typically have an odor described as "fishy".
Glue sometimes can cause problems, especially if it turns a brown color. That signals a chemical decomposition that turns the glue conductive and corrosive, in which case it is best to remove it. If I recall correctly, it does help to use acetone, although it is more to help soften it rather than truly dissolve that stuff.
The "C512" picture may show both a glue dot and leaked electrolyte. The leaking appears to have spread out as far as R215 in one direction, and as far as J206 in another. It should wash off in warm water, but you're right to plan on replacing C512 first if that was the leak's source.