mons2b wrote:Was thinking of a switch but the spirit of Jack frowned at me. lol. Still ill consider it. Ive seen the schematic and the 9v ac seems to come straight off the transformer, some power supplies might have a cap there to smooth the ripple but its not known for causing problems being left as is. What causes the 5v dc to grow is aging of the caps inside the power supply. The problem is if you have a heavy weight power supply its most likely a solid block of epoxy so you need a ice pick or chemicals to try to dissolve it. Or you can heat it (200 degrees) and wear a gas mask. Im not keen on those plans.
Maybe I should call the box the Jackulator accessory. Ive seen the common overseas options. A good but expensive power supply and a voltage warning gadget the later is great but kind of pointless these days as I think theres few C64 PSU's still within the safe spec. With the Jackulator the PSU can do its worst upto 23v whatever comes out will be lowered to 5v so as your supply ages and gets worse it just wont matter.
nzswift wrote:I'd be keen unless it's mega$$$$
mons2b wrote:Hi NZ
Yes it could be the regulator too. Its just often said to be the caps. Bit hard to tell when they are "Frozen in carbonite" like Han Solo. Ill just take the DC output and feed it into a circuit that will drop the voltage down and regulate it. So completely external to the existing supply. You will be able to unplug and use the "Jackulator" as I am calling it with any C64 power supply. It will not increase the amps you can get out of the original power supply so hardware hackers loading down their C64 with many accessories will probably need a new power supply with a higher spec. Also 128 users it wont work for that machine as it is at the moment.
Given feedback ive spent a few hours trying to find a cheap double pole switch so you can save your C64 switch. Loads of single pole switches. Gets harder to find a cheap one when you go to double pole which is a must because of the dual voltage output! . So a switch is in. Still considering a power led but im trying to make this cheap and each little thing adds up to a higher parts total plus longer for me to assemble it.
I hope to have a rough prototype to show you guys soon. Still waiting on more parts. I cant wait to have it working as I cant currently run my own C64 breadbins that I want to diagnose IC issues. Cant do that with the high volts coming out now. Commodore specs say no more than 5.1 to 5.5v. I will set my device to aim for 4.8 to 4.9 to keep the ICs cooler. Ie the hard to replace SID!
Often it's not the regulator itself, but a 'dry joint' between the regulator's GND lead and the PCB. This is caused by expansion and contraction of the joint as the power supply heats up during use and cools down again when turned off. I think the epoxy causes the fault by preventing the regulator body from moving freely with expansion, so the leads expand through the PCB and break the solder joints.nzoomed wrote:other forums suggest its the regulator itself that gives out because the epoxy is an insulator and does not allow the regulator to cool down, in turn causing damage.
bhabbott wrote:Often it's not the regulator itself, but a 'dry joint' between the regulator's GND lead and the PCB. This is caused by expansion and contraction of the joint as the power supply heats up during use and cools down again when turned off. I think the epoxy causes the fault by preventing the regulator body from moving freely with expansion, so the leads expand through the PCB and break the solder joints.nzoomed wrote:other forums suggest its the regulator itself that gives out because the epoxy is an insulator and does not allow the regulator to cool down, in turn causing damage.
With no ground reference the regulator puts out the maximum voltage it can, typically over 7V. This was the #1 cause of fried C64s back when I was repairing them in the early 90's.
Dry joints are often intermittent. If you have a potted power C64 supply it's best not to use it at all (even it tests OK) until the joints have been examined, and preferably resoldered. The PCB is usually only covered with a thin layer of epoxy, so you may be able to see the regulator terminals just below the surface. The epoxy can be softened with heat from a soldering iron, then pried off to expose the joints. Reflow the joints with fresh solder and you will probably find the power supply works properly again.
mons2b wrote:Hi NZ Zoomed.
Ive found a nice switch that looks like it will do the job. Prob will skip the led but considering adding a fuse to protect the circuit regulator. I believe the c64 will work ok on 4.8. The reason I said that as a low point is that if your power supply is perfect then the regulator add on will possibly lower it to 4.8 as theres a unavoidable slight voltage drop. Unlikely but had to mention it. Ill try to tune them for 4.9 so unless your power supply was blessed by the Pope it will likely be putting out more than 5 volts so everyone should be ok. Everyone being 5 people. . If people like them I may make a few more. I hope people like them. Below is a pin out so anyone can check with a cheap multi-meter and see what their supply is putting out. Ive found some official commodore notes that say 5.1v is too much.. but I would say definitely put that supply away if its reading more than 5.2. Just not worth it with the age of the chips now. Apparently high 5 volt lines also kill your ram chips which are a pain to replace. Both rare and unsocketed in most cases. I made another dive in my garage and found a rare 64 power supply. No epoxy, has screws and with open vents, tested it and it was sitting on 5.16 or so. This will be my fav supply for sure. I have a few of the sealed modern bricks but they are the Han Solo editions. LOL.
7 PIN DIN ‘C’ FEMALE at the computer.
2 GND (5V negative pole)
4 nc or +5V in
5 +5V in
6 9VAC in
7 9VAC in
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