C64 Power Supply Replacement Options

Since I support the CBM crowd, I've had more than a few people send me comments over the past few years, asking when I might consider offering a replacement power supply for the home computing machines (VIC-20, 64, 128, +4) Initially, I resisted for liability reasons and certification costs. But, I decided earlier this year to put off those questions for a bit and just see what might be technically and economically possible. I've chased a few ultimately fruitless options, and I thought I'd see if some fellow soul on this list might have some ideas. Obviously, the first thought was a complete custom supply. My interest was never in power design, so I am ill-equipped (and uncertain of my abilities) to design such an item myself. Thus, I started looking for a manufacturer that could design one. Absolute requirements: 5VDC at 4.3A. 9VAC at 9VA unregulated To this I added my requirements: The 5VDC be a switching PSU output ISO C13 input power jack (so I can support many areas without building custom power cords 115/230 switchable design (or two very similar designs that can handle the 2 voltages) My cost under USD$30.00 per unit. Enclosed finished case, or be able to fit in a commonly available case design. Someone put me in touch with Stontronics overseas, which worked on an initial quote. But, I think the C13 and 115/230 requirements scared them off. I solicited information from Bear Power Supplies in the US, but they did not seem too keen on continuing the discussion, so I have nothing from them. I've also tried overseas suppliers, but I have not yielded fruit yet. I've asked all the PSU suppliers on globalsources.com and alibaba.com I have struggled to find a custom PSU manufacturer that can handle a suitable design. Being frustrated with the direct approach, I thought I'd try a different path, and find a 9VAC or 5VDC single output power supply. I found a single output large amperage 5VDC supply, but then I got stumped on finding a way to synthesize a 9VAC isolated output from the 5VDC. A simplistic approach would involve creating a harsh +-9V square wave, but it needs to be at least .5A (to run the cassette deck on the 64/128), and I worry that the noise on a square wave @ 1A would wreck the audio and video noise level in the machine, which is not the best to start with. Even ignoring that, I need to double or quadruple the voltage to get the 18V rail to rail voltages I need. On the 9VAC front, I had little luck finding a suitable 9VAC supply that is 45VA or 63VA to support a 5VDC at 5A draw while leaving enough for the 5A 5VDC output. As well, I am not sure I am equipped to design a switching 5V PSU from a 9VAC source. With the old power bricks getting more brittle and prone to failure each day, I feel some sense of urgency to find some solution for folks. For liability reasons and because 5VDC is the more important voltage in the units, I myself lean towards a small box that turns 5VDC into 5VDC and 9VAC, but designing a voltage doubler/sine wave generator/isolation transformer solution is far beyond my comfort zone. If this is not a complicated task, I am wondering if someone on-list is up for a small freelancing effort to design such a unit. It needs to contend with the issues outlined in this PDF (http://www.ide64.org/power_des.pdf) in that the noted design won't work as is since I think people need to be free to use the power switch on their machine. There might not be a reasonable solution, but I thought I'd share in case I am missing an option. Jim -- Jim Brain brain at jbrain.com www.jbrain.com