youngm@ihuxv.UUCP (Mark T. Young) (12/06/83)
Just when things were going so well with my C64... Garbage appeared on my monitor screen, munching its contents, and when I disgustedly turned the machine off and on to clear it, well it didn't come back on. The power light stayed off. So I opened up my C64 users guide, which told me that I had a bad fuse, and that I should take the machine to an authorized dealer... I decided that, since the warranty had expired, why pay them to do what even I could do--replace a two-bit fuse. I opened up my machine, and, after carefully unplugging the power light and keyboard connectors, removed the top half of the case. I found the fuse right away; there is only one in plain sight on the PC board. The next day I took the little critter to Radio Shack, where I learned that the fuse might be either a regular one, or a slo-blow one. Just to be safe, I bought the regular flavor. The next evening I installed a new fuse, closed up the case, and powered my machine up. I was very disappointed when my screen stayed blank, until I noticed that I hadn't connected it to my 64! Once connected to the monitor, all worked perfectly. The next day I was typing in a program, when garage appeared on the screen, and when I toggled the on/off switch... The bottom line is that my new regular fuses fry in anywhere from one second to one day, and I suspect that I really want a slo-blow fuse. As you may have guessed, I'm no hardware guru. I would appreciate any help on this problem. Should I use a slo-blow fuse, or is there something else wrong with my 64, which causes it to burn regular fuses? Note: In my Programmer's Reference Guide is a schematic, which says "1A" next to the fuse. The original fuse said "1 1/2" on it, and had a zig-zagged filament (not spiraled like the slo-blows at Radio Shack). Thanks in advance, Mark T. Young ihuxv!youngm
dollas@uiuccsb.UUCP (12/14/83)
#R:ihuxv:-59700:uiuccsb:16800003:000:1572
uiuccsb!dollas Dec 13 18:02:00 1983
Though your problem boils down to the fuse, it might be a different one.
If you drive too many peripherals using your Commodore power supply, if you
have a bad chip (the latter may be undetected unless you do something the
actual chip is needed for !!!), or, finally, if you have power surges (the
power company may be in fault for a few, but usually this is not the
problem), you end up blowing the fuse. My opinion (which might not be of
use since I don't know your exact problem) is:
(1) Check the number of peripherals that you drive. If you have (or you
can borrow) an ammeter find the current they draw. The maximum current ratings
are specified in your reference manual. Also,
(2) Remove the keyboard, and with a new fuse turn on the Commodore (be sure
that before you turn it on, the keyboard is connected). Leave it like that for
a few minutes, and then "feel" the different chips. Excessive heat (I have
burned my fingers many a time on similar occasions) is a good indication that
the chip is drawing too much current. Make sure that you touch only the top
of the chip and not the contacts.
Both of the above are non-hardware approaches to the subject. If you
have a chronic problem, probably it would be a good idea to service it in
an authorized shop.
Good Luck!!!!!
Apostolos Dollas
Dept. of Computer Science
University of Illinois
(..!pur-ee!uiucdcs!uiuccsb!dollas)