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C128 Power supply troubleshooting

I had some more time Saturday to test some of my Commodore equipment. Both of my flat C128s are in working condition, but one of my power supplies is non-functional. I used my multimeter to check voltages at the square connector, but it's not outputting anything except 11 VAC on Pin 5. Does anyone have a link to any troubleshooting guides and/or detailed schematics for these? If I know which components were most likely to be the clulprits and what the voltages are supposed to be at various points inside the unit I might be able to do some futher troubleshooting. Here are photos of the non-working unit:

Bottom Case (P/N, S/N, etc.)Top view

Bottom View

I pulled out the fuses and visually inspected them. They both looked fine, but to take this any further I will need some more information so I can test it properly. I also found this YouTube video from 2014, and was curious about the status of this project:

Jim Brain: New Commodore Power Supply

Edited by: Dragget on 2016-02-08 22:42
Re: C128 Power supply troubleshooting

Dragget wrote:

> Does anyone have a link to any troubleshooting guides and/or detailed schematics for these?

I see you have the lower-powered version of the C128 factory power supply; most C128 p.s.'s I've seen are the 4.3 amp@5 volt version. However, Ray Carlsen's pictures and text may help you out. See

http://personalpages.tds.net/~rcarlsen/cbm/c128/PS%20REPAIR/

If you still have questions, send an e-mail to Ray at rcarlsen(at)tds.net

> I also found this YouTube video from 2014, and was curious about the status of this project:

I didn't know there was a YouTube video about it. As for the status, that is unknown. However, Ray sells his own, new C128 power supplies. See

http://personalpages.tds.net/~rcarlsen/custom%20ps.html

Truly,
Robert Bernardo
Fresno Commodore User Group
http://www.dickestel.com/fcug.htm

I just found three different
Further testing
Re: Further testing

Dragget wrote:

> ...I guess I will have to email Ray Carlsen and see if he can give me any pointers.

Actually, Ray appreciates phone calls more than e-mails. If you wish his phone number, I can give it to you in private.

Truly,
Robert Bernardo
Fresno Commodore User Group
http://www.dickestel.com/fcug.htm

I have one listed on ebay
Thanks for the heads up. I
Glad you found one of the 4
Re: Glad you found one of the 4

motrucker wrote:

> Maybe I have just been lucky, but with all of the 128 PSUs I have had, I only had one that needed work.

Back in the day, I bought two CBM C128 4.3 amp power supplies from the Grapevine Group. Both didn't power up or failed soon after I received them.

Back from the Dave Needle memorial,
Robert Bernardo
Fresno Commodore User Group
http://www.dickestel.com/fcug.htm

The Grapevine Group was down
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