_shameless_ Posted July 2, 2017 Share Posted July 2, 2017 found a hell of a deal that i couldn't pass up! came with 2 mice, tons of games, a bunch of blank floppy disks, a magnavox crt monitor, and a 1541 disk drive with a some manuals as well. all for 125$!!. I already purchased an sd adapter and next pay check i plan on getting the 64nic+ and jiffydos. Everything seems to work great save for the disk drive which just spins and the red led stays on. led to believe its one of the chips onboard(from what i gather the culprit seems to be UB4, the 6522 chip, or the 6502 chip.). Not sure if i'm going to try fixing it or not, as for UB4 it seems i will need to burn a chip or find a donor both of which aren't going to be very cheap and a donor 1541 s a bit of a risk. the 6522 and 6502 i wouldn't mind replacing just to see if that''s the issue since they are pretty cheap. I'm pretty new to the C64 scene, so what else are some of the "must have" accessories for it, or some fun things i can do with one? If i can get my disk drive working i wouldn't mind using that and keep the sd2iec as a backup till the drive craps out for good. Really my only plans right now are to browse some old BBS boards once i get a 64nic+, so i'm open to hearing any other suggestions! Also, i have a sega genesis mouse, can that be used with the C64 as well? the two mice that came with it are in pretty rough shape, and cannot verify they even work at the moment. Quote Link to comment Share on other sites More sharing options...
+cvga Posted July 2, 2017 Share Posted July 2, 2017 Congrats! I still have a ton of fun with my C-64. Some games I'd recommend playing include Jumpman, Oil's Well, practically any Infocom game, Lode Runner, and Beamrider. Quote Link to comment Share on other sites More sharing options...
shoestring Posted July 2, 2017 Share Posted July 2, 2017 2364 / 2564 EPROMs are a little pricey due to their scarcity but you can sometimes find them cheap on eBay. You can opt for a standard 2764 8kx8 eprom but will need to buy or build a 2364 to 2764 adapter. http://blog.worldofjani.com/?p=757 I had to do something similar for the character rom. http://www.jammarcade.net/commodore-64-breadbin-repair-log-7-bad-characters-part-2/ Quote Link to comment Share on other sites More sharing options...
carlsson Posted July 2, 2017 Share Posted July 2, 2017 At least on the 1541-II, if the drive keeps spinning it can also be 5V missing. The drive mechanism gets its 12V so it spins up, but the logic board never boots so it never tells the drive to stop spinning. Quote Link to comment Share on other sites More sharing options...
_shameless_ Posted July 3, 2017 Author Share Posted July 3, 2017 (edited) 2364 / 2564 EPROMs are a little pricey due to their scarcity but you can sometimes find them cheap on eBay. You can opt for a standard 2764 8kx8 eprom but will need to buy or build a 2364 to 2764 adapter. http://blog.worldofjani.com/?p=757 I had to do something similar for the character rom. http://www.jammarcade.net/commodore-64-breadbin-repair-log-7-bad-characters-part-2/ is there a way to test to see which chip may have failed? could i just replace the 2364 with a jiffydos chip if that is the issue? And also if it does end up being the 6502 or 6522, what are mt replacement options? would this work? http://www.ebay.com/itm/Conexant-Rockwell-R65C02P3-CPU-Processor-3Mhz-65C02-6502-series-/220858166872?hash=item336c2c2e58:m:m42n2HLWo5a3syzblx-oTqA or this for the 6522? http://www.ebay.com/itm/1pcs-R6522AP-R6522P-Rockwell-DIP40-CPU-ICs-/172651073688?hash=item2832ce5098:g:weEAAOSww5NZBGxw Edited July 3, 2017 by _shameless_ Quote Link to comment Share on other sites More sharing options...
shoestring Posted July 3, 2017 Share Posted July 3, 2017 (edited) You need an EPROM programmer to check the mask rom and read it in as a 2364. Most affordable programmers won't read those. My TopMax reads them though but it don't come cheap. You should also check the SRAM in the 1541. It will be a generic 6116 sram. They often go bad. I test these out of circuit using my TopMax. Piggy backing a known good 6116 can help identify a bad SRAM but not in all cases, especially if the chip is shorted internally. Yes the parts are fine. The 65c02 is the CMOS version and should be pin compatible with the standard NMOS 6502. The other chips are a little more difficult to test. But substituting the VIA and 6502 in another known working 1541 is a good way to troubleshoot those chips. A logic probe is also handy for identifying stuck and floating outputs on any of the above chips. Edited July 3, 2017 by shoestring Quote Link to comment Share on other sites More sharing options...
_shameless_ Posted July 4, 2017 Author Share Posted July 4, 2017 ok cool, i found a cheaper one, http://www.ebay.com/itm/1pcs-R6502AP-R6502-Rockwell-CPU-6502-IC-CHIP-DIP-40-/170828631732?epid=1056284449&hash=item27c62e0eb4:g:KOUAAOxyzfNRtoK4 should a r6502ap be pin compatible as well? Quote Link to comment Share on other sites More sharing options...
shoestring Posted July 4, 2017 Share Posted July 4, 2017 Yes. That's perfect, those were used a lot in arcade games. The 1541 used 4 x 2114 static ram (UA/UB 2 and 3 ). The 1541-II used a single 6116/2128. You definitely want to check those if the light is flashing continuously. Also replace the 74LS14 ( UA1 ). You can find these at any electronics store. There are actually 2 x 6552s, why don't you swap them around and see if the symptoms/behavior change ? Quote Link to comment Share on other sites More sharing options...
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