Commodore 64 Repair - UK Vintage Radio Repair and Restoration Discussion Forum

plumbweiss · 8th Jun 2007, 5:31 pm

I'd like to get my duff C64 going again but know next to nothing about early computer architecture. I'm getting the blue welcome screen, Ready and flashing cursor, but that's all that happens. It wont react at all beyond that. Any ideas anyone..??

jim_beacon · 8th Jun 2007, 9:14 pm

sounds like the PIA that scans the keyboard. Check the connections to the keyboard are secure first.

Jim.

Sideband · 8th Jun 2007, 10:12 pm

I havn't got my old C64 now or the service manual. However I do remember having a similar problem and I ended up swapping the keyboard from another machine (a VIC 20 I think).

Rich.

Riccardo · 24th Jul 2007, 11:44 am

Quote:

Originally Posted by plumbweiss

I'd like to get my duff C64 going again but know next to nothing about early computer architecture. I'm getting the blue welcome screen, Ready and flashing cursor, but that's all that happens. It wont react at all beyond that. Any ideas anyone..??

I will give a look at my repair books and give you further assistance, anyway there's one thing you can do straight away that will give us a peak on the situation: switching the CIA chips.

The CIA chips are marked 6526 ( more rarely 8521 ), MOS or CSG, and you find them one next the other in the up-left corner of the early motherboards. On the newer boards ( revision E ) you find them split one on the left, the other on the right.

The keyboard is controlled by such chip, so if you switch them and the keyboard magically works again, you have a faulty 6526 chip - and we can work on the problem from there to bring your C64 back to life.

Riccardo

plumbweiss · 25th Jul 2007, 5:32 pm

Ok thanks, will give it a try when I've got a mo.

8th Jun 2007, 5:31 pm	#1
plumbweiss Retired Dormant Member Join Date: Nov 2006 Location: Manchester, UK. Posts: 157	Commodore 64 Repair I'd like to get my duff C64 going again but know next to nothing about early computer architecture. I'm getting the blue welcome screen, Ready and flashing cursor, but that's all that happens. It wont react at all beyond that. Any ideas anyone..??

8th Jun 2007, 9:14 pm	#2
jim_beacon Retired Dormant Member Join Date: Mar 2003 Location: Bishop's Waltham, Hants, UK. Posts: 939	Re: Commodore 64 Repair sounds like the PIA that scans the keyboard. Check the connections to the keyboard are secure first. Jim.

8th Jun 2007, 10:12 pm	#3
Sideband Dekatron Join Date: Oct 2003 Location: Croydon, Surrey, UK. Posts: 7,577	Re: Commodore 64 Repair I havn't got my old C64 now or the service manual. However I do remember having a similar problem and I ended up swapping the keyboard from another machine (a VIC 20 I think). Rich. __________________ There are lots of brilliant keyboard players and then there is Rick Wakeman.....

25th Jul 2007, 5:32 pm	#5
plumbweiss Retired Dormant Member Join Date: Nov 2006 Location: Manchester, UK. Posts: 157	Re: Commodore 64 Repair Ok thanks, will give it a try when I've got a mo.