Replacement parts (Chips) can I still get them?
Dana
chip.
Can someone help me???
Thanks,
Malcom J. Sperry
answer as well/mac
Dana (dth...@unix.newnorth.net) wrote:
: I am looking for a supplier of IC Chips for my C64, particularly the 8701 video
Phil Hoff
>
> I am looking for a supplier of IC Chips for my C64, particularly the 8701 video
> chip.
>
the 8701 is not one of them. But here is an intriguing thing. The
Commodore Diagnostician chart lists the 8701 as U31. Then checking
the C64 schematic, they list U31 as being a 74LS629. This is NOT a
video chip. It is a dual voltage-controlled oscillator. Jameco DOES
have this chip on sale for $1.25. Is your 8701 chip a 16 pin unit?
If so, this may be the right chip.
The other intriguing thing is that at the bottom of the chart
it says "Do not use 8701 IC.", so the 74LS629 may be the proper
replacement.
Phil Hoff
Lois Finello
advise You * C.O.D * from this company)
Kasara 1-800- 248-2983 (more expensive)
These are just in case you're not lucky enough to find what you want in a
thrift shop :)
Good Luck,
+- Lois -+
afn1...@freenet.ufl.edu
Raymond Carlsen
interchangeable. Notice that the parts count is lower in the C-64s
with the 8701 (later versions of the 64).
Ray Carlsen Univ. of Washington, Seattle
*** Chance favors the prepared mind. ***
Raymond Carlsen
> the 8701 video chip.
Dana,
The only source I have for the 8701 is Unicorn Electronics @
1-800-824-3432. The 8701 is not a video chip, but a clock-oscillator
used in some of the later C-64s (note the lower parts count) and in
the C-128. Earlier 64s used the TTL logic chip #74LS629N as U31
oscillator. They are both 16 pin DIPs, but I don't think they are
interchangeable.
I have to ask: what makes you think that chip is bad? If the
oscillator is running, but off frequency, try first the capacitor
C85, which is a 0.47uF. I've repaired two C-64s in which that
intermittant cap caused the color on the monitor screen to drift...
first to a "barber pole" rainbow of colors, then no color, then the
horizontal hold was lost (diagonal bars on the screen). A hint as to
what was happening was that music playing during those symptoms would
change speed (faster or slower... can't remember). I knew the
oscillator was changing! Cooling the chips in that area would restore
normal operation for awhile, but it was the cap that was failing!!!
In both cases, it was a cheapie polystyrene unit. The newer mylar or
ceramic units are more reliable. Sorry if this is off the mark. It's
just that the first one caused me two days of grief.
Bottom line... If you can't get the 8701 anywhere, let me know. I
think I still have a few in stock. I don't usually sell parts, just
service, but...
Other Commodore chips are available through Jameco Electronics @
1-800-831-4242. They do have a minimum order of $25 or you must pay an
additional $5, plus shipping of course.
Ray Carlsen
Carlsen Electronics