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Replacing a C64 power supply with an ATX one

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PgrAm

Experienced Member
Joined
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276
Location
Toronto, Canada
So I bought a C64 real cheap for about $10. The problem however is that I do not have a power supply for it and I heard that the stock ones are pretty crap. I have seen people make power supplies from ATX PSUs but could not find many details on this, I could probably rig up something pretty simply but I have 2 questions.

1. Could this be dangerous to my C64
2. Can I steal the 9VAC off an old Nintendo adapter, its labeled as 9v AC at 1.3 amps but I have no idea what kind of amperage the C64 needs
 
The Original Commodore brick is rated for 9Vac @ 1A with 5Vdc @ 1.5A .So you can use the 5v from the ATX power supply and the 9VAC from the Nintendo adapter.I'm also using an AT power supply for the 5V and an old modem adapter for 9VAC.
Here is the pinout:http://www.c64-wiki.com/index.php/Power_Supply_Connector and also here: http://personalpages.tds.net/~rcarlsen/cbm/c64/C64%20PS/pstester.txt
Be careful when you'll make the connections on the DIN plug because with an error on the 5V line you'll end up with a dead c64! :(
 
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angel_grig said:
The Original Commodore brick is rated for 9Vac @ 1A with 5Vdc @ 1.5A .So you can use the 5v from the ATX power supply and the 9VAC from the Nintendo adapter.I'm also using an AT power supply for the 5V and an old modem adapter for 9VAC.
Here is the pinout:http://www.c64-wiki.com/index.php/Power_Supply_Connector and also here: http://personalpages.tds.net/~rcarlsen/cbm/c64/C64%20PS/pstester.txt
Be careful when you'll make the connections on the DIN plug because with an error on the 5V line you'll end up with a dead c64! :(
Click to expand...

Cool thanks,

I'll get right on it, do you think you could upload a picture of your setup?
 
I you want something a bit neater, and you are willing to build something, it would be simple to reduce one of the 12v outputs from your ATX supply to 9v, using 1 x 7809 voltage controller, 2 x capacitors and a small heatsink. 7809 is rated for 1 amp.

To see the simplest circuits, search Google for "7809 circuit". Less than $7 parts.

If I were doing that, I would probably mount the little circuit-board (carefully) inside the case of the ATX supply so it would be cooled by the PSU fan. Alternately, you could mount it outside the PSU on the fan grille. Or sit it on a bigger heatsink like those used inside PCs for CPUs and other hot chips. The amount of heat generated is not that great (about 3v worth), but it's generally safer to not let heat build up during prolonged use.

rick
 
That is 12V DC though. While the 9V AC might be rectified inside the computer for most purposes, some pins on the user port and I believe TOD clock relies on the AC. There has been designs to generate a square wave AC which people who know despise as troublesome as it isn't sine.

Going the other way around, you could get a beefy 2x9V AC transformer, something like 2-3A or better per winding, and use a diode bridge etc to bring 9V AC down to 5V DC at the same time you keep the other 9V AC untouched. There was a fellow on the Retro Computer Museum forum who built a such PSU for his C64 + C128. The key is to find an inexpensive 9V transformer that has enough juice. There are a few sellers on eBay if you like to build something. Of course you can get a weaker 9V AC transformer and connect in parallel with an ATX power supply using 5V DC but it might take more space and be messier.
 
I've seen the old 3rd-Paty Estes/Phoenix CPS-10, and the Microline C64 power supplies (I have one of the latter which needs minor repair), but these are rare. Good C64 OEM power supplies are getting more and more rare as they age, as we all know.

Curious - if it's so easy to build a proper C64 power supply, then why on Lemon64 and other dedicated forums are there literally dozens of threads with people looking for a good, high-amperage power supply solution? Is it because they want a more professional solution than a 9v/5v high-amp wall wart plugged into an extension cord and wired to a DIN connector?
 
Ok so I've managed to grab 5v of my PSU but my multimeter gives me 9.99 volts from the 9VAC adapter, is this ok?

All I have to do now is solder the all this to a DIN connector, where would I get that connector? it has a few more pins than a standard DIN.
 
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My current setup is this:

c64power (Large).jpg

As you can see I replaced the AT power supply with the power supply from an IDE to USB adapter like this:http://www.ebay.com/itm/USB-2-0-to-IDE-SATA-S-ATA-2-5-3-5-HD-HDD-Adapter-Cable-/180550148600?pt=LH_DefaultDomain_0&hash=item2a09a0a1f8#ht_3731wt_1170

My 9vAC adapter outputs 10.60v so you are OK with yours!
It's not very easy to find a DIN connector nowdays,at least in my neighborhood .I had to go to the center of Athens to find it because my other option was ebay.And the funny thing was the expression on the sellers' faces :Errr..you want what?DIN connector?For what reason?Anyway....
I hope in Toronto you can find an electronics shop with DIN connectors or else I can check if I have 1 or 2 left to send you.
Another solution for a power supply I found on the web is this one:http://www.ide64.org/stuff.html but I have not tested it..
 
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PgrAm said:
...All I have to do now is solder the all this to a DIN connector, where would I get that connector? it has a few more pins than a standard DIN.
Click to expand...
They're all standard, that's what DIN means ;-)

7-pin plugs are relatively rare but you might get by cutting the eighth pin off an 8-pin (note: there are two types of 8-pin DINs).
Try A1 Electronics on North Queen St. behind Sherway Mall, or Active Surplus on Queen near Spadina. Or eBay of course.

Or just buy the whole PS from TPUG:

http://www.tpug.ca/index.php?option=com_content&view=article&id=73&Itemid=70
 
MikeS said:
They're all standard, that's what DIN means ;-)

7-pin plugs are relatively rare but you might get by cutting the eighth pin off an 8-pin (note: there are two types of 8-pin DINs).
Try A1 Electronics on North Queen St. behind Sherway Mall, or Active Surplus on Queen near Spadina. Or eBay of course.

Or just buy the whole PS from TPUG:

http://www.tpug.ca/index.php?option=com_content&view=article&id=73&Itemid=70
Click to expand...

Thanks man I'll probably try Active surplus, I know they have a bunch of DINs but I wasn't sure about 7-pin
 
The reason why Lemon64 is flooded with such threads is that very few are DIY'ers and very many are experts who shoot down every DIY solution as being unsafe in one way or another. There is a myth about a lot of witchcraft is involved when designing a long term working power supply.
 
carlsson said:
The reason why Lemon64 is flooded with such threads is that very few are DIY'ers and very many are experts who shoot down every DIY solution as being unsafe in one way or another. There is a myth about a lot of witchcraft is involved when designing a long term working power supply.
Click to expand...

Can't be any worse than the stock power supply.
 
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OK so I finished my power supply but I think there might be a problem with my c64, the power supply is delivering the right voltages but I'm getting nothing but fuzz on my TV screen its hooked up via the built in RF modulator using an rca to coax adapter, the power light on my c64 is on but there is absolutely nothing on my screen, is it possible that my 64 needs 12VAC instead of 9VAC? Its an original c64 not the c64c. If something else is wrong where should I start?
 
PgrAm said:
...where should I start?
Click to expand...
Both C64 & TV on the same channel (3 or 4)? Bad coax cable or bent pin? Dirty channel selector switch on C64?

If all else fails, come out to a TPUG meeting (next one on April 19); lots of expertise there.
 
MikeS said:
Both C64 & TV on the same channel (3 or 4)? Bad coax cable or bent pin? Dirty channel selector switch on C64?

If all else fails, come out to a TPUG meeting (next one on April 19); lots of expertise there.
Click to expand...

I found a blown fuse inside my c64 and I replaced it but I still have the same problem, I also checked the fuse again after trying to turn it on but it was fine. I tried using an external RF modulator from my VIC-20 but once again same problem, I know the coax cable works I tested it with my VIC-20 and I am absolutely sure the TV is on the same channel I tested both. The channel selector on the c64 looks clean. Does anyone know of a troubleshooting guide for c64 repair?

If I can't figure out the problem by April 19th then I'll bring it to TPUG.

EDIT: reseated all the removable chips still nothin'
 
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Sounds like it's got more problems than could be solved at a regular meeting; wonder why the fuse blew in the first place...

Maybe you can cobble together a video/sound cable and see if the sound and/or composite video work by any chance.
 
MikeS said:
Sounds like it's got more problems than could be solved at a regular meeting; wonder why the fuse blew in the first place...

Maybe you can cobble together a video/sound cable and see if the sound and/or composite video work by any chance.
Click to expand...

made a composite cable but I still get nothing but fuzz.

could my VIC-II chip be dead?

EDIT: I did some internal probing and found that my PLA chip was burning hot, could this be the problem?
 
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There was a loose connection on the 9v part of my din connector, I fixed it and now I get a black screen instead of fuzz, I can also run the tape drive now before I couldn't. there is no indication that keyboard commands are being received I am missing a serial cable so I can't check my floppy drive. I tested the RAMs for heat and they seem to be fine. also now that I got 9v my SID has warmed up and my PLA doesn't seem so hot anymore.

I don't have any cartridges so I can't test that way.

Can anybody help me diagnose?

EDIT: My 6510 is not getting the 5v it requires does that narrow it down?
 
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OK 80% sure now that the problem is my KERNAL rom, it operates maybe 3 times hotter than my other roms. Where could I acquire a new rom?
 
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