dcer10 Posted December 15, 2006 Report Share Posted December 15, 2006 Hi All,Ive got myself 5 dead black commodore 64 external power supplies, which all seem to be dead. They all have a similar fault in that the 5v works on most on them, but the 9v is low (around 3-4v). Does anyone know any common repair methods? Is it easy to replace the actual transformer? If so what spec would it be?Thanks!!John Quote Link to comment Share on other sites More sharing options...
Jaicen Posted December 15, 2006 Report Share Posted December 15, 2006 Unfortunately, the PSU is toast. They're potted in epoxy so it's not possible to get in and do anything to them. You'd be better off just getting a new transformer and starting from scratch. The only thing you could check is that there may be a short in the wires somewher between the brick and the plug, but it's unlikely if you have five with the same symptoms. On a related note, you say that the PSU's are the black brick type. These were left over from the ill fated 264 series (plus/4, C16, C116). Do any of them have the square type computer connector on the back?? I've got a plus/4 with no power supply, I had to make an adapter to use a round C64 connector, but if you have a square connector going spare i'd be very very interested! Quote Link to comment Share on other sites More sharing options...
dj3nk Posted December 15, 2006 Report Share Posted December 15, 2006 i've got a c16. do you need the plug from the cable or the connector in the case? i dont have the supply any more. Quote Link to comment Share on other sites More sharing options...
Jaicen Posted December 15, 2006 Report Share Posted December 15, 2006 I actually need the square cable on the end of the power supply lead, the bit that plugs into the computer. I guess you don't have what i'm looking for then?? On the other hand, I wouldn't mind acquiring a C16 for my collection if you have one going spare ;) (I'm in the UK if that helps). Quote Link to comment Share on other sites More sharing options...
dcer10 Posted December 16, 2006 Author Report Share Posted December 16, 2006 Hiya,Sorry I dont think they are the type you are looking for. The ones I have which are dead are mostly this one:http://home.iprimus.com.au/king_willy/kw64/graphics/mine/c64pow.jpgIts odd in that the 9v AC is actually 3-4v DC on the problem ones.. Thats before it even gets to the board! They can be taken apart easy so I think repairs could happen. Does anyone know the type of transformer used? I also have a couple which are for the disk drives too, the beige sealed ones. Unfortunantly none with the plugs you want, sorry!Does this help you??http://staff.washington.edu/rrcc/cbm/plus4con.txtThanks!John Quote Link to comment Share on other sites More sharing options...
dcer10 Posted December 16, 2006 Author Report Share Posted December 16, 2006 I did find a guide for the repair of the PSU...Look at:http://staff.washington.edu/rrcc/cbm/wallwart.txtIf you have the same problem. Dont know how effective it will be.Thanks,John Quote Link to comment Share on other sites More sharing options...
Jaicen Posted December 16, 2006 Report Share Posted December 16, 2006 Thanks for the link, I've already fabricated an 'adapter' to use with my old C64 PSU. I used a 6pin DIN connector and cut off two of the prongs. It works fine, but there is the possibility that I could connect it upside down if I'm not paying attention, and that would suck to say the least!! It's no big deal really, as i'm on the lookout for a C16 (or C116, I wish!), if I can find one cheap enough with a PSU, then I can use that for both. With regards to your particular problem, it points toward a short somewhere in the coils of your transformer, in which case you'd need to replace that anyway. Other than that, I can't be of much help to you i'm afraid. Quote Link to comment Share on other sites More sharing options...
dcer10 Posted December 17, 2006 Author Report Share Posted December 17, 2006 Thanks :) Do you know what the specs of the transformer are?? Quote Link to comment Share on other sites More sharing options...
Jaicen Posted December 17, 2006 Report Share Posted December 17, 2006 As far as I know, it's a simple 9VAC transformer of about 1A. The +5vDC line is fed off the secondary to a passive diode rectifier, and this is what's responsible for all the C64's with dead memory chips. As they age, the diodes start to break down, feeding more voltage into the C64. It's pretty poor considering how cheap an LM series rectifier would have been. Personally, I'd just use a standard 9VAC transformer and rectify it down to 5v. If you use a heatsink your rectifiers will be just fine. I know a lot of people complain that they get hot, but they're supposed to, that's how they work! That said, you may be able to find a transformer with twin 4.5 or 6v secondaries, in which case you could use both in series for your 9v (or 12v) supply, and one half for your 5v. This would be a more efficient design, but it's likely to be more expensive. Quote Link to comment Share on other sites More sharing options...
dcer10 Posted December 17, 2006 Author Report Share Posted December 17, 2006 Funnily enough most of the bricks that wont work with the SID synth will actually power up the C64 computer itself, but with no sound (no ive not taken the SID chip out of this commodore). Bizzare! Thanks for the info on the transformer, I will see if I can get one and put it into the brick. Quote Link to comment Share on other sites More sharing options...
Mr modnaR Posted December 17, 2006 Report Share Posted December 17, 2006 That said, you may be able to find a transformer with twin 4.5 or 6v secondaries, in which case you could use both in series for your 9v (or 12v) supply, and one half for your 5v. This would be a more efficient design, but it's likely to be more expensive.i've tried to do this design, but it won't work i'm told. you have to have three 6V secondaries and use one for the 5V supply, and the other two for the 12V.read through this embarrassing saga to find out why:http://www.midibox.org/forum/index.php?topic=7389.msg49565#msg49565 Quote Link to comment Share on other sites More sharing options...
dcer10 Posted December 17, 2006 Author Report Share Posted December 17, 2006 Ouch, that would have hurt! Thanks for the warning :)I think im in over my head so im going to hunt for a C64 PSU replacement, probably easiest. Quote Link to comment Share on other sites More sharing options...
dcer10 Posted December 19, 2006 Author Report Share Posted December 19, 2006 Some extra info about all this...I have several C64 power supplies. This one:Is working fine and is in my 4x sid, I put in a 500ma fuse but apart from that its untouched.I have several of these:which mostly seem to boot up the C64 computers, but not the SID. They usually give 9v where I expect 14, and around 3-4v where I expect 5.All of which wont power up my new (not related to the 4xsid) power board which is this:http://www.ucapps.de/mbhp/mbhp_4xsid_c64_psu_optimized.pdf (the optimised psu). Then I also have a few of these:and one of these:which is a drive psu so I guess not very handy...which usually gives 12v where I expect 14, and around 3-4v where I expect 5. This one also boots up the C64s fine but not the SIDs.Is it possible that they are all dead and wont run the SID except that top one? Doesnt seem realistic since most of them boot up the C64 psu ok. Different pinning? Different specs?? That doesnt seem possible either since my original SID used one of the black ones ok, but the black PSU blew up and took the sid with it (I used the smaller non optimised PSU board on that one:http://www.ucapps.de/mbhp/mbhp_sid_c64_psu.pdf )Ive bought 2 other black ones in my quest to fix this problem, and they seem to all measure the same output voltages as the ones that wont boot up a sid but will boot up a C64...Im confused!Can anyone shed some light on all this??Thanks,John(PS not my photos) Quote Link to comment Share on other sites More sharing options...
Jaicen Posted December 19, 2006 Report Share Posted December 19, 2006 It just occured to me, are you measuring the two voltages in DC mode?? You should have +5vDC and around 9VAC. If you try to measure the AC line with a DC DMM, you won't get a correct reading. Quote Link to comment Share on other sites More sharing options...
dcer10 Posted December 20, 2006 Author Report Share Posted December 20, 2006 On the output line of the power board Im measuring all DC, but on the actual PSU ive been looking at the 9v ac and 5vdc. Oddly where I would expect AC on some of them im reading DC but no AC! I will post the actual results from the PSU itself tonight. Quote Link to comment Share on other sites More sharing options...
Jaicen Posted December 20, 2006 Report Share Posted December 20, 2006 Well it just seems a little strange that you're getting the same readings more or less from such a large number of PSU's. I'm sure they can't all have the same fault! Did I read that you can power a C64 with them??? If so, then they're probably working ok and there's something wrong with your testing equipment/procedure. Quote Link to comment Share on other sites More sharing options...
dcer10 Posted December 21, 2006 Author Report Share Posted December 21, 2006 Your 100% correct! I was reading the voltages wrong on the plug (how retarded since Ive made 2 sids before). Also several of the PSU's were actually damaged too. Last nite I figured out my error. I was measuring the 9vac to earth insttead of to eachother so it looked like dc, and also was reading the wrong pin for the 5vdc, its on the other side of the earth pin! Now I have a heap of cleaned up working PSUs! Oddly enough still none will power up my 4x sid except the one in the photo in this thread (the beige one). The others will power a single sid version , but when plugged into the fully stuffed version it wont even power up the screen!Thanks for your help :)JohnPS after thinking some more about which ones I have had over time I do recall having a very big commodore psu (maybe twice the size of any of these ones) which may have had a square plug on the end of the cable which someone had cut and gaffer taped on there. If I come across it I will send you a photo to see if it is what you need.Also as a note, the pinning is different on the first psu shown (b&w image) in this post, and that has lead to a lot of confusion too. Quote Link to comment Share on other sites More sharing options...
Jaicen Posted December 21, 2006 Report Share Posted December 21, 2006 Hehe, there you go then! I guess it doesn't hurt to check for human error once in a while ;) I had a similar problem with my PIC burner, couldn't get it going at all for days till I realised my LED's were in backwards ::)If some of the PSU's aren't powering the 4xSID's, it's possible that they're not able to supply enough current, which is why many have failed just powering C64's. Try turning off the backlight of your LCD and see if it works then. If you do find that PSU plug, i'd be very interested in seeing it :o Quote Link to comment Share on other sites More sharing options...
dcer10 Posted December 21, 2006 Author Report Share Posted December 21, 2006 Im pretty sure that the 4xsid problem is that the psu I used for it has the different pinning. It doesnt say its a C64 PSU, but it is from commodore. It has the same output only the 5v is on the other side of the earth for some reason. Wierd! That psu wont power a single sid either as the pinning wont work. All in all my problem is solved for now, and I will certainly let you know if that plug shows up. From memory it is similar looking to the square scsi plugs on the back of older mac laptops (not identical but similar). All the best,John Quote Link to comment Share on other sites More sharing options...
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