> If this has been asked before, pardon me. I have a Mac Plus with 4 MB RAM > and a performer (I think) accelerator that worked fine for many years and > all of a sudden began to reboot by itself over and over. Any ideas on how > to fix it? I have a sentimental attachment to the machine but don't want > to spend a lot.
It can occasionally be caused by the programmer's switch on the side, as noted by someone else already, but in my experience, it is more commonly caused by a poor connection. The wiring harness that feeds power to the logic board from the analog board terminates in a wide connector. Over time the connector pins stop making good contact. The cure is simply to pull the connector out, and put it back on. Doing this a couple of times usually scrapes off whatever oxide is making the thing flake out. Resolder the connections on the board, too. Bad solder joints are a fairly common problem with these old machines. Any time I open up a classic Mac, I also routinely re-solder (with fresh solder, not just reheat) the four notorious solder joints on the analog board that accept the crt yoke harness (can't miss it -- it's the only four-wire connector that goes to the thing around the neck of the crt). Reseat all ram, too, while you're at it. And if everything checks out ok, but it still reboots on its own, double-check the power supply voltage (+5 is most important). If it's significantly out of spec (say, outside of 4.75 to 5.25), tweak the voltage adjustment pot on the analog board. Be careful, because you are now working on an exposed, powered-on machine. If you adjust it from the outside (as is normal), turn counterclockwise to *increase* the voltage. Make only small adjustments at a time. If you raise the voltage too much, an internal overload protection circuit will shut it down, and you'll get stuck in the "whup-whup-whup" loop. Good luck! -- Prof. Thomas H. Lee Center for Integrated Systems, CIS-205 420 Via Palou Mall Stanford University Stanford, CA 94305-4070 http://www-smirc.stanford.edu 650-725-3709 voice, -3383 fax -- Compact Macs is sponsored by <http://lowendmac.com/>. Support Low End Mac <http://lowendmac.com/lists/support.html> Compact Macs list info: <http://lowendmac.com/lists/compact.shtml> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive:<http://www.mail-archive.com/compact.macs%40mail.maclaunch.com/> --------------------------------------------------------------- >The Think Different Store http://www.ThinkDifferentStore.com ---------------------------------------------------------------
