[vcf-midatlantic] C64 Power Supply Repair/Replacement

Chris Fala chrisjpf33 at gmail.com
Sun Feb 24 13:40:17 EST 2019

Some people found a way to make it fit.


This guy also makes the “Nubrick” which Jeff B. and I have.

On Feb 23, 2019, at 10:09 PM, Jonathan Gevaryahu via vcf-midatlantic <vcf-midatlantic at lists.vcfed.org> wrote:

I have two original C64 PSUs; I saw a few people made replacements for the PSU, but at least the open design one is too large to fit inside a c64 psu 'brick' AFAIK.
See https://greisisworkbench.blogspot.com/2017/03/hi-here-is-my-design-for-c64-and-1541.html for the open design, and https://fr.retrogamesupply.com/blogs/news/update-on-the-c64-power-supply?page=2 for the 'closed, commercial' design.

The original PSU is a simple linear design plus a 3052P, a resistor, and two capacitors for the 5v section, see the schematic at https://semi-nerdly.ca/2018/06/24/building-my-replacement-commodore-64-power-supply/
The issue is commodore usually(?) filled the c64 and c128 'bricks' with epoxy or something similar, and this prevents replacing the capacitors when they inevitably go bad, or when the voltage regulator or diodes die/short and start dumping rectified 9VAC directly into the 5VDC input of the c64.

There's no crowbar circuit or fuses on the 5VDC output, and just a 3A fuse on one pin of the 9VAC output.

> On 2/23/2019 5:51 PM, Thomas Fuchs via vcf-midatlantic wrote:
> Whatever you do, don’t use original power supplies with the C64. They decay over time and will fry the mainboard (there’s no overvoltage protection). Get a modern replacement!
> —Thomas F.
>> On Feb 23, 2019, at 4:01 PM, CT via vcf-midatlantic <vcf-midatlantic at lists.vcfed.org> wrote:
>> I was lucky enough to come across an Apple IIe and C64 at the Techno Swap
>> Fest in Maryland today.
>> I was on the fence but the Apple IIe was in very good condition with some
>> additional boards (80 char, memory, CP/M) and the color monitor and duo
>> disk drive with a bunch of accessories and software.
>> The C64 comes with a power supply, joystick, some cables and software.
>> Paid $125 for everything so it seemed fair compared to eBay / CL prices I
>> could find.
>> Also they threw in an ImageWriter II if anyone is interested in it please
>> let me know.
>> I'll bring these both up to the next repair workshop I can attend for some
>> guidance on them. Likely in April.
>> Thanks and looking forward to collaborating with everyone soon.

Jonathan Gevaryahu
jgevaryahu at gmail.com
jgevaryahu at hotmail.com

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