68kMLA Classic Interface

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Lisa 2 - Funky analog board

Posted by: CelGen on 2010-09-27 16:53:21 I bought a Lisa 2 off someone and it was supposedly "not working" ...I also need to figure out how to remove the thin layer of regular black spraypaint it's covered in... Anyways, "broken" turned out to be battery spooge and nothing on the display. The battery issue was cleaned up and the traces were patched. but the video issue remains. An image can be received from the composite out port but it's out of sync. Seeing how every monitor I have thrown at it so far has not managed to sync with it, I assume I need some really special monitor. Anyways, through trial and error I swapped parts with another Lisa until I replaced the Analog board, at which point it spring back to life. Now I am certain that the fault lies in the analog board. Where exactly I am not sure. I have been poking around with my scope and I don't think I have found anything but this boils down to me not know what I am doing. Would anyone else have an idea on what might be up?

Posted by: CelGen on 2010-10-07 20:00:44 Nothing? :-/ Surely someone has a bit more knowledge on how the analog board works.

Posted by: jsarchibald on 2010-10-07 20:14:27 I've heard that Retr0brite peels paint straight off, so I guess you could brighten your machine at the same time as removing that horrid black. What were they thinking??? Make sure you cover up the Apple logo, as it will strip the colored paint off that too. As for the board, it's too far above my skill level, but hopefully someone else can help?

Posted by: Scott Baret on 2010-10-10 16:51:18 It's been years since I've worked on a Lisa, and I don't recall much about the analog board off the top of my head, but given that this is an Apple product, it may be worthwhile to replace the capacitors. I can't guarantee this will solve anything, but it may be a start. As for the paint, I've seen worse. Those who were on the board a year ago probably remember the infamous "*Ouch* Free IIci" that I picked up from a Craigslist seller. It was covered in bright yellow paint, which the seller said would make the Mac run faster (his words). After taking a few parts from it to fix another IIci, I sold the rest of the machine to a fellow MLAer, who managed to clean it up (not sure if he replaced the missing parts). There is hope for this Lisa!

Posted by: JRL on 2010-10-10 20:25:53 ^I still have that IIci! Still works great after I replaced the missing parts. Never did have time to get all of the paint off though. Don't have any clues about the Lisa, but a good way to get off the paint is using Dot 3 (ONLY) brake fluid. It won't harm the plastic at all, and it works very well. Rubbing alcohol works too, but it can eat the plastic's texture. EDIT: LOL; this was my 1337th post! 😛

Posted by: Bunsen on 2010-10-10 22:26:20 I think it looks kind of cool ...     / runs away

Posted by: CelGen on 2010-10-10 22:50:56 My a stroke of luck, I do have a bottle of brake fluid handy that should do the trick. Should I just spread it on, wait, then rub the paint off or put it on a rag and rub away? I thought it was caps too but it just really does not feel like one. I would expect a lot worse in symptoms but who knows. I guess I can recap it and see what happens.

Posted by: Bunsen on 2010-10-11 07:38:01 Should I just spread it on, wait, then rub the paint off or put it on a rag and rub away? You will be removing all the electronics first, right?

Posted by: CelGen on 2010-10-12 08:56:50 >_> All the panles have been removed form the metal chassis so I can mess with them without worrying about what's happening to the internals.

Posted by: JRL on 2010-10-12 15:58:21 When I cleaned the paint off my IIsi, I just used Qtips dipped in the brake fluid. It takes a while, but you will probably need a little elbow grease for the hard-to-reach spots. Also, it HAS to be Dot 3 brake fluid. Anything else melts plastic instantaneously, so be careful.

Posted by: Osgeld on 2010-10-12 16:02:00 of course when you want paint to stick to plastic, it peels off in a week sux dough-nut

Posted by: CelGen on 2010-11-07 15:55:36 BuMP Got some free time to try the brake fluid and it sorta worked. Immediately it does not eat the plastic off but if I apply some on a panel and leave it for a while, the paint softens up enough that I can start to scrape it off with my fingernail. Still, I can't just wipe it off. Should I let it soak for a lot longer or should I find something a bit more abrasive to remove the softened paint?

Posted by: CelGen on 2012-11-07 18:09:33 BuMP. Wrapping up the Analog board problems. The contrast knob while still secured in place with a bit of epoxy was oxidized out so it wasn't passing any reading and thus the video signal stopped there. A bit of contact cleaner and twisting the knob a few times fixed all the video problems. :lisa2:

Posted by: insaneboy on 2012-11-08 08:33:20 soak it in the brake fluid won't hurt the plastic. I did over night soakings to get old paint off RC car bodies. probibly could do it one side a day in a pan of some sort (I used a photo developing tray my self)

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