[net.micro.cbm] Problem: poor resolution

nms@hopd3.UUCP (Neil Scribner) (10/23/84)

The resolution (clarity) of characters, edges, whatever on
my 10 mo. old C64 is deteriorating.  The problem does not
become noticeable until the machine has been turned on for
at least 30 min.  The characters will alternately get
fuzzy, then clearer, and finally just stay fuzzy.
The problem seems to be getting worse with age.
I suspect that part of the TV subsystem is reacting to
the heat. ( I use a standard color TV.)
Has anyone else had this problem or know how to cure it
short of sending the machine back to the factory?

kurt@fluke.UUCP (Kurt Guntheroth) (10/24/84)

I had occaision to open my c64 up at one time and pry up the metal cover
over the video circuitry.  It turns out that this cover serves not only as a
shield for EMI but also as a heat sink for the VIC II (video controller).
There is a dab of heat sink compound on the VIC that makes thermal contact
with the metal shield.

My c64 had only a tiny dab of heat sink compound.  Since I feared it would
not make contact when I closed the case, I got a tube of the stuff and put
a generous dollop on the top of the chip.  The result was that my c64 has
noticably sharper video now, presumably due to the fact that my video
controller is running cooler.

Now, I can't recommend you dissassemble your computer just for fun, but if
you are having trouble with ugly video you might try this.
-- 
Kurt Guntheroth
John Fluke Mfg. Co., Inc.
{uw-beaver,decvax!microsof,ucbvax!lbl-csam,allegra,ssc-vax}!fluke!kurt

kev@voder.UUCP (Kevin Hoskins) (10/30/84)

> The resolution (clarity) of characters, edges, whatever on
> my 10 mo. old C64 is deteriorating.  The problem does not
> become noticeable until the machine has been turned on for
> at least 30 min.  The characters will alternately get
> fuzzy, then clearer, and finally just stay fuzzy.
> The problem seems to be getting worse with age.
> I suspect that part of the TV subsystem is reacting to
> the heat. ( I use a standard color TV.)
> Has anyone else had this problem or know how to cure it
> short of sending the machine back to the factory?


     One possible solution that I have been wittness to
is replacing the VIC-II chip with the latest revision, rev.
EIGHT (8). This latest version has by far the 
best video quality of any of the revisions I've seen.
Check with a local service rep or contact 
Commodore directly to obtain the needed device.
(Please verify that the present device is rev 7 or less.)