[comp.sys.cbm] HELP! C64 video dead

jeff@eng.umd.edu (Jeffrey Frey) (01/05/91)

Our C64, hooked up to a color TV through the built-in video modulator,
has stopped sending letters to the screen.  On power-up there's video
(a uniformly blue TV screen, no snow or other noise) but none of the
power-on messages, like "READY".

Probably the dreaaded static electricity which tends to destroy our C64
every year at this time (the kids WON'T learn to touch the grounding wire)
has murdered another chip.  Anyone have an idea on which one it might be,
or what alternative explanation there might mbe?

Jeff

treesh@bach.helios.nd.edu (01/05/91)

Since your getting a nice blue color on your screen, but no power on
message, I would start with swapping out the BASIC and then KERNAL rom
chips.  If that wont do it, try PLA and 6510 next.
 
ctfm

llaria@cup.portal.com (Tracy M Wirs) (01/05/91)

that happened to me once....... and it turned out that the chip for the space
bar had fried.  The best thing to do is to get that machine to a repair shop.

another possibility: your power source has gone kaput.  try another power 
source (preferably a new one) and rule out this possibility before anything 
else.......

llaria@cup.portal.com  <internet>
sun!cup.portal.com!llaria  <uucp>

Patrick_Andreas_Maher@cup.portal.com (01/08/91)

Your problem is the 6526 chip most likely.  The chip controls
all the outputs.  The chip it located on the far left side. You
can pick up your C64 and look where the modem goes and see the two
chips.  When you touch the joystick ports and get a little shock the
first place it goes is to those chips.  The one on the far left is 
the first one to go out.  I have had this happen to my C64 and to my 
C128.  When it happened on my C64 I got alot of weird characters on
my screen when I powered up and some of the keyboard did not work.  On
my C128 the joystick port 2 did not work correctly.  So, most of the
time it will be this chip.  The chip runs around 12.95 plus shiping
from a lot of dealers.  You can check out most of the Commodore magazines
like RUN or whatever and look in the back of the magazines for there