Hi,
You've tried most of the standard things. Here's one more to try: As bizarre and counterintuitive it sounds, washing the logic board may fix the problem. Some have used a dishwasher, others a good soak in some soapy water, and still others an alcohol bath. The electrolytics on those compacts tend to leak badly over time, leaving a conductive residue that wreaks havoc. Just rinse and dry thoroughly before powering up.
I found in the trash a fat Mac that gives a checkerboard pattern when the power is applied. There is no startup tone audible. The pattern is about 15 squares wide and 40 squares high. Any ideas on repairing the problem (besides buying a Macintosh 128 logic board)? Here is what I have tried so far, after Googling: Pull the RAM and ROM chips and upgrade card (see below), and reseat them (in correct orientation, of course). Same checkerboard. Replace the 2 banks of 1256-15 chips with known good 1256-12 chips. Same checkerboard. Replace the 2 banks of 1256-15 chips with known good 1256-10 chips. Vertical stripes. Replace the 2 banks of 1256-15 chips with known good 164-12 chips. Blank screen. Quick power off, power on cycle. Same checkerboard, but a few pixels reversed.
-- 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:compact.macs@mail.maclaunch.com> 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/>
--------------------------------------------------------------- iPod Accessories for Less at 1-800-iPOD.COM Fast Delivery, Low Price, Good Deal www.1800ipod.com ---------------------------------------------------------------
