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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Dragster on December 24, 2008, 08:47:16 PM

Title: C64 memory ICs
Post by: Dragster on December 24, 2008, 08:47:16 PM

Hi #?,

sorry for posting this here, it's not really amiga related but C= related, so, admins. if you feel this is off topic, please move the thread to the right forum.

Well, to the point. I bought a C64 a few days ago and it has a problem with memory, when started up, it shows:

"OUT OF MEMORY" error... and some garbage on the screen. I googled for this and found that the most likely reason for this to happen is some bad memory ICs. I opened the machine and found these ICs labeled as: 4264-15. I wanna buy them online, maybe a set of 4 or 5... but I can't find a place in the U.S. to buy from.

Any suggestions?

Thanks,

Dragster

Title: Re: C64 memory ICs
Post by: Zac67 on December 24, 2008, 09:09:39 PM

Can hardly believe it, but I got none left - even dug out an old 286 board...

There's plenty on ebay, prices are a bit like a rip off but you'll probably be able to fetch a set for $10 or below. Just look out for 4164, 4264, 5164, any 64k DRAM.

While you're at it - check voltage out of the PSU: if 5V is below ~4.8V you'll get RAM problems, too. In that case you need to cut it open and replace the (poorly cooled) 7805. There's another 7805 on the board, but I've never had that one die.

Title: Re: C64 memory ICs
Post by: Dragster on December 24, 2008, 10:14:26 PM

@Zac67

Hi, thanks for your reply.

Quote

Can hardly believe it, but I got none left - even dug out an old 286 board...

I have bad luck I guess! :-(

Quote

There's plenty on ebay, prices are a bit like a rip off but you'll probably be able to fetch a set for $10 or below. Just look out for 4164, 4264, 5164, any 64k DRAM.

Thanks for the info. I checked and found some labeled as "RAM MB8264-20 FUJITSU 16-Pin CERDIP 4264-3 4264D". I'm not so sure of those would do though.

Quote

While you're at it - check voltage out of the PSU: if 5V is below ~4.8V you'll get RAM problems, too. In that case you need to cut it open and replace the (poorly cooled) 7805. There's another 7805 on the board, but I've never had that one die.

Thanks for the suggestion, but I already checked the PSU on another machine and it works, I also connected another machine's PSU on this one , same behavior, so I'm pretty sure it's the memory IC(s).

Cheers!

D.

Title: Re: C64 memory ICs
Post by: amiga92570 on December 25, 2008, 12:47:00 AM

I have plenty if you care to Pmail me.

Title: Re: C64 memory ICs
Post by: Dragster on December 25, 2008, 06:10:31 AM

@Amiga92570

Thanks! PM Sent!

Cheers

Title: Re: C64 memory ICs
Post by: motrucker on December 25, 2008, 02:14:12 PM

Or - I can send you motherboard with good RAM chips REAL cheap. Just no SID chip (otherwise a good, working board)