Wednesday, January 28, 2004
Dishwasher results
A couple of weeks ago I put 18 logic boards in the dishwasher (normal wash with detergent, air dry for several days). Before washing, none of them would show a happy mac; most displayed a scrambled or checkerboard video pattern. The results were that 16 improved to show happy Mac: 2 classics with bad sound, 2 SE/30's with bad sound, 8 classic II's with bad sound, and 4 classic II's that seem to be ok! I discarded 1 classic that was still scrambled after the wash. Also, 1 SE/30 turned out to have a bad #1 SIMM socket and will probably be discarded.
My conclusion is that dishwashing is pretty effective at restoring old logic boards that fail, presumably due to leaking capacitors. But it is less effective at restoring the sound circuits that commonly fail. Replacing certain caps is a known fix for the sound problem, particularly on the SE/30. The reason for doing the wash now was to decide if I had enough working classic II Macs to make that model my donation system this spring. The answer is no, so I will be donating SE FDHD units once again.
In other updates, I found the problem with the 6100 at the school: the ethernet dongle had bent pins at the AAUI end. But I put a 500M scsi drive in there, and it seems to have failed, so next visit I will install a different drive. I updated a 6200 in my wife's classroom. Part of the AR update is QuickTime 5 or 6 (I always use 5). But it seems that Zoombinis doesn't like that version of QuickTime. So I will attempt to downgrade the 6100 to QuickTime 4 since Zoombinis is more important to her than AR.
I did go back to RD&S one more time, to help them move. They didn't get a new workshop, just a free but rather lousy storage area. Less than 100 Macs made the move to storage, and more than 100 were destroyed. I'm going to suggest some ideas to them on how they can continue to function from the storage area, but I suspect they will do nothing until they get a new workshop (if ever).
My conclusion is that dishwashing is pretty effective at restoring old logic boards that fail, presumably due to leaking capacitors. But it is less effective at restoring the sound circuits that commonly fail. Replacing certain caps is a known fix for the sound problem, particularly on the SE/30. The reason for doing the wash now was to decide if I had enough working classic II Macs to make that model my donation system this spring. The answer is no, so I will be donating SE FDHD units once again.
In other updates, I found the problem with the 6100 at the school: the ethernet dongle had bent pins at the AAUI end. But I put a 500M scsi drive in there, and it seems to have failed, so next visit I will install a different drive. I updated a 6200 in my wife's classroom. Part of the AR update is QuickTime 5 or 6 (I always use 5). But it seems that Zoombinis doesn't like that version of QuickTime. So I will attempt to downgrade the 6100 to QuickTime 4 since Zoombinis is more important to her than AR.
I did go back to RD&S one more time, to help them move. They didn't get a new workshop, just a free but rather lousy storage area. Less than 100 Macs made the move to storage, and more than 100 were destroyed. I'm going to suggest some ideas to them on how they can continue to function from the storage area, but I suspect they will do nothing until they get a new workshop (if ever).
