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C64 haul

I recently got 2 basically spotless C64's in their boxes to add to my collection. Inside they are clean as new and neither of them look as they were used much. The issue I have is both of them exhibit a black screen upon boot up. I have read that the most likely cause is a dead PLA chip seeing as they are getting power and the internal fuse checks out. I have read that since I do not have a dead test cart that if I were to plug in specific titles of cart games they might work as the games don't require some of the PLA functions to operate. Has anyone heard of this and if so it is a reliable test? Starting with the easiest forms of diagnosis would be the best method in my opinion and if I can avoid it I would rather avoid buying a dead test cart for the time being. Otherwise I will just set these aside and mess with them later after I have purchased the correct diagnostic tools.

Re: C64 haul

Jeff Stringham wrote:

> ...both of them exhibit a black screen upon boot up. I have read that the most likely cause is a dead PLA chip...

Yes, that would be the first thing I'd think about.

> ...I have read that since I do not have a dead test cart that if I were to plug in specific titles of cart games they might work as the games don't require some of the PLA
> functions to operate. Has anyone heard of this and if so it is a reliable test?

No, I've never heard of using a game cartridge to test out the PLA. I wouldn't consider this a reliable test.

Truly,
Robert Bernardo
Fresno Commodore User Group
http://www.dickestel.com/fcug.htm

PLA

Thank you for the help! Now the second question is where to source a PLA. I know oldsoftware.com has them for about $20 each and I have bought from them before. Does that price seem fair? I am not sure what the value of these chips are currently. Any ideas of a good source or places to avoid would be of gret help to me.
Thanks again!

Re: PLA

Jeff Stringham wrote:

> I know oldsoftware.com has them for about $20 each and I have bought from them before. Does that price seem fair?

Like many of the products that are sold by that store, the price seems a bit high.

> Any ideas of a good source...

Well, one source is to pull the PLA out of another C64. Then there are the EPROM replacements -- the one from Ray Carlsen (but Ray wants the whole computer sent to him so that he can "tune" the EPROM to the particular C64), the one from Eslapion in Montreal, Canada, and the SuperPLA EPROM from Individual Computers and its distributors.

Truly,
Robert Bernardo
Fresno Commodore User Group
http://www.dickestel.com/fcug.htm

Re: PLA

I almost forgot about http://www.arcadecomponents.com They have chip pulls and NOS chips. Specifically, the PLA is at

http://www.arcadecomponents.com/catalog/item/3054735/8335676.htm

Truly,
Robert Bernardo
Fresno Commodore User Group
http://www.dickestel.com/fcug.htm

PLA

Thanks again for all the help! I ordered 1 PLA from the link you gave me, $14.99 for NOS seems fair enough to me. After looking again at old software they do seem to have pretty high prices. $300 + for a 64! If the prices they have were actually a good market value then I would have enough to pay rent for a good couple years haha. I guess we can dream but thats about all. If it works out well then I will have to order one for my other dead machine. Part of the fun is the hunt of finding the machines and the repair is the rest of the adventure. It is a fun experience taking something that does not work and then being able to make it work like new. I always say I could be spending my money on much worse things, this is not a bad vice to have :)

Re: PLA

:) Heh, you are a much braver man than I. If I need repairs on my Commodores, I let Ray Carlsen do them. If I need repairs on my Amigas, I let the tech at The Other Group of Amigoids do them.

Truly,
Robert Bernardo
Fresno Commodore User Group
http://www.dickestel.com/fcug.htm

Hi Robert, they aren't that
Re: Hi Robert, they aren't that

Well, replacing C64 chips isn't hard part (unless they are soldered in). It's the diagnosis that is more difficult. That is why I leave the more esoteric stuff to Ray Carlsen. :)

FCUG celebrating 33 years,
Robert Bernardo
Fresno Commodore User Group
http://www.dickestel.com/fcug.htm

Hi,
To me, $20 sounds fair

To me, $20 sounds like a fair price for part that has been out of production for decades! Granted there were millions of C64's sold that somebody can do chip pulls from, but I imagine most of them get trashed (or scavenged for parts) if they are not in use. (But $300 for a C64 is just silly.) More amazing is you found somebody selling NOS parts... I mean it seems hard to believe there would be any left by now...

Anyway, I agree $14 for NOS parts is a good deal.... thanks for the link!

Say, I was thinking... maybe those NOS parts were generic PLAs that were programmed for C64 compatibility? Anybody know? I mean it does sound more reasonable than a stock of genuine Commodore parts that were never used! (Of course it doesn't matter if it is 'genuine' Commodore for most people... it just needs to work!)


I'm kupo for Kupo nuts!

PLA
Hi everyone,
C64 Custom PLAs

Thanks Raymond for supporting the Commodore community!!!!  So it seems my theory was correct (wow!).  Of course feedback from the customer is the ultimate proof... he speak highly of you, so I've book-marked you (pending his confirmation).


I'm kupo for Kupo nuts!

Re: Hi everyone,

channelmaniac wrote:

> Name here is Raymond and I run Arcadecomponents.com

I like going to your site to see what you have in the way of Commodore and Amiga chips.

> The PLA chips are new old stock 82S100 or PLS100 PLA chips programmed with code that came directly from an 82S100 PLA from a Commodore 64 that I dumped.

Oh, that is interesting. We still have a FCUG member who bought 50 supposed SID chips from China, and still after many months, he hasn't tested any of them! Ray Carlsen even offered to test them for him, but he didn't take up Ray's offer.

Truly,
Robert Bernardo
Fresno Commodore User Group
http://www.dickestel.com/fcug.htm

Custom PLA
Re: Custom PLA

Hurrah!

Truly,
Robert Bernardo
Fresno Commodore User Group
http://www.dickestel.com/fcug.htm

Great news! :)
Re: Great news! :)

channelmaniac wrote:

> All computers were dead and came from a defunct repair center in Texas so no live C64s were harmed. :)

Oh, what was the name of the repair center? I may have heard of it.

Truly,
Robert Bernardo
Fresno Commodore User Group
http://www.dickestel.com/fcug.htm

Never asked. When it was in
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