David.Johnson@f171.n221.z1.FIDONET.ORG (David Johnson) (06/23/89)
> I have a similar problem with my computer, only one difference > is that > when it has been on for half an hour or so, it tends to > freeze up. The > characters on the screen start randomly changing colours. > Only a few at > first, but eventually all the characters on the screen > turn different this is an indication of an impending power supply death. This death could take out ram and rom in your computer. Get a New Power Supply ASAP. Later on if when you turn on the computer and the drive lights come on (normal reset sequence) and stay on and your screen stays black. You have just lost 1 or more ram chips ( lost 2 ram chips and blew up a fastload this way. It is not a vic or 6526 chip problem but the computer cannot complete its initial power on ram check so it just crashes. -- David Johnson - via FidoNet node 1:221/162 UUCP: ...!watmath!isishq!171!David.Johnson Internet: David.Johnson@f171.n221.z1.FIDONET.ORG
jgreco@csd4.milw.wisc.edu (Joe Greco) (06/25/89)
In comp.sys.cbm article <2573.24A307D6@isishq.FIDONET.ORG>, David.Johnson@f171.n221.z1.FIDONET.ORG (David Johnson) wrote: ]this is an indication of an impending power supply death. This death ]could take out ram and rom in your computer. Get a New Power Supply ]ASAP. ...or overheating chips... or ... or ... ]Later on if when you turn on the computer and the drive lights come ]on (normal reset sequence) and stay on and your screen stays black. ] You have just lost 1 or more ram chips ( lost 2 ram chips and blew ]up a fastload this way. Power supply failure doesn't guarantee that you will lose "1 or more ram chips" - trust me, I've been through quite a few 64's and even more bricks. Central site has a monster power supply, but remote sites here still use bricks.... The best hope is to find EARLY model VIC/C64 power supplies in the vented open air case. Later model VIC's and early 64's had these, they usually don't fail. When one of mine died, we fixed it easily. But the point is, a power supply can fail in a nondestructive manner, causing the computer to exhibit the symptoms you mention. THIS DOESN'T MEAN HE'S NECESSARILY LOST CHIPS! There is no need to spread such propaganda and scare people. ]It is not a vic or 6526 chip problem but the computer cannot complete ]its initial power on ram check so it just crashes. There are other things that can cause it too.... CIA (6526) chip crashes resulting in certain things not being set up, etc. Perhaps my favorite was a soldered-in SID chip that was affecting the data bus. Overheated ROM chips sometimes will return garbage (although I can't think of any reason for this behavior, I have *seen* it!)... The point: (flame on) DON'T PLAY SERVICE TECH FROM YOUR OBVIOUSLY LIMITED EXPERIENCES - Even experienced techs often don't correctly diagnose a problem right the first time. (flame off) -- jgreco@csd4.milw.wisc.edu Joe Greco at FidoNet 1:154/200 USnail: 9905 W Montana Ave PunterNet Node 30 or 31 West Allis, WI 53227-3329 "These aren't anybody's opinions." Voice: 414/321-6184 Data: 414/321-9287 (Happy Hacker's BBS)