A portion of my collection- Many pictures

[GearTechWolf]

Very nice "disassembling". I would suggest using the transformer with new electronics. Please take a look at Kojro's video (and the following ones 9.1, 9.2) relating to the same power source.

Oh hey, thanks! I'd looked for something like that but hadn't found those videos*, I'll take a look!
*(mostly because I'd been searching for forum-threads rather than considering videos)
My power-brick is/was the black one with only a half-inch wide strip of fins on the outside, but the inside and the upside-down potting method looks nearly identical! (well, aside from also having a different color of the potting material)

 

[Jaginus]

Oh hey, thanks! I'd looked for something like that but hadn't found those videos*, I'll take a look!
*(mostly because I'd been searching for forum-threads rather than considering videos)
My power-brick is/was the black one with only a half-inch wide strip of fins on the outside, but the inside and the upside-down potting method looks nearly identical! (well, aside from also having a different color of the potting material)

I guess the most "expensive" part is the transformer. With around 5 bucks in passives, I suppose you could rebuild it and have an "own made" and much more trustful power supply. If you do it, please consider posting some pictures. I would love to see it up and running.

 

[GearTechWolf]

I'll be doing that, since I almost certainly have all the parts on hand! Plenty of old ATX supplies I've salvaged for parts and lots of parts gathered from other junk through the years. Just need to scare up a perfboard to put them on.
I'm thinking I may attempt to resurrect the original circuit as well, with the old board and the intact components plus a few replacements.
Just to see how the (mostly) original circuit performs in comparison. (with a saver-circuit between it and any computer I connect it to, of course)

 

[GearTechWolf]

Welp, time for more pics! Someday I'd like to etch/have made a replica board to match the original boards in these supplies, maybe do a small run of them and see if anyone wants to buy them for ultra-correct restorations.
Anyhow, here is the glued-together board, both with the original components in their places and without.


I got the broken track soldered back together and cleaned off the flux for the last couple pics.
The super-glue cooked off a bit when soldering and made my eyes burn, nasty stuff!

 

[Jaginus]

A replica board is the best solution! Guess you're having a lot of fun reviving it

 

[GearTechWolf]

I am! Next hurdle is that the 9-volt winding on the transformer is putting out 10.4 volts, possibly due to it being wound for 117 volts and modern supply is 120 volts. Might not be able to use the original transformer for the new build because of this, not certain how high is too high yet.
That would be a pain as I'd have to hunt up a different transformer that had multiple output windings with the right voltages and sufficient wattage.
Not even sure where my spare transformers are located, aside from the pile of board-mounting ones salvaged from various power-supplies and the power-supply sections of old TVs or other appliances. Could be a useful one there, though I've no idea how I'd tell wattage capabilities.
Shoestring budget requires inventive solutions! Good brain exercise.
Say, is there a good place to look up specifications on old salvaged transformers? Most have identification numbers on them.
Got a little absent-minded earlier and hooked up a little circuit with a bridge-rectifier and a lm3805 for testing.
Only problem was, I'd just been testing the transformer from the C64 supply and I hooked up the little rectifier circuit directly to the mains!
*FZZARK* The voltage-regulator vented its innards as plasma and soot. The rectifier diodes of the full-wave bridge rectifier are probably still fine, they're quite large, but the little voltage regulator stood no chance against 120VDC!
So that was my *oops* for this week.

 

[Jaginus]

I am! Next hurdle is that the 9-volt winding on the transformer is putting out 10.4 volts, possibly due to it being wound for 117 volts and modern supply is 120 volts. Might not be able to use the original transformer for the new build because of this, not certain how high is too high yet.
That would be a pain as I'd have to hunt up a different transformer that had multiple output windings with the right voltages and sufficient wattage.
Not even sure where my spare transformers are located, aside from the pile of board-mounting ones salvaged from various power-supplies and the power-supply sections of old TVs or other appliances. Could be a useful one there, though I've no idea how I'd tell wattage capabilities.
Shoestring budget requires inventive solutions! Good brain exercise.
Say, is there a good place to look up specifications on old salvaged transformers? Most have identification numbers on them.
Got a little absent-minded earlier and hooked up a little circuit with a bridge-rectifier and a lm3805 for testing.
Only problem was, I'd just been testing the transformer from the C64 supply and I hooked up the little rectifier circuit directly to the mains!
*FZZARK* The voltage-regulator vented its innards as plasma and soot. The rectifier diodes of the full-wave bridge rectifier are probably still fine, they're quite large, but the little voltage regulator stood no chance against 120VDC!
So that was my *oops* for this week.

Hi,
Do not worry about those 10.4 volts, as they are AC and there is no load whatsoever when you measured it. They will be rectified correctly as you're in tolerance for the AC-DC rectifier and the diode bridge will support it. It always varies and will be rectified by the 7405 and 7412 inside your C64. Scared that all those old bricks could damage mi C64(s), I built my "cheapo" (as you can see, inside a Tupperware) power source for my C64s. Included are some pictures where you could see that the AC power source delivers precisely 10.4v without any load. My C64s work seamlessly with it and it is correctly rectified within specs for the 74xx

 

[GearTechWolf]

Oh, well that's very reassuring to know, thank you!
Now I just have to find an equivalent to the original voltage regulator, as all the other parts seem to be intact according to my limited tests.
Seems like a good use of Tupperware to me! I used an old pill-bottle to house an audio-jack and cord when I made a quick-and-dirty 6.35mm (1/4 inch) female to 3.5mm (1/8 inch) male adapter to test an old airplane headset I picked up from the thrift-store. It worked! (headset did too)

 

[Jaginus]

Oh, well that's very reassuring to know, thank you!
Now I just have to find an equivalent to the original voltage regulator, as all the other parts seem to be intact according to my limited tests.
Seems like a good use of Tupperware to me! I used an old pill-bottle to house an audio-jack and cord when I made a quick-and-dirty 6.35mm (1/4 inch) female to 3.5mm (1/8 inch) male adapter to test an old airplane headset I picked up from the thrift-store. It worked! (headset did too)
View attachment 1244990

So good you found my pictures useful. Just go ahead and test-test-test before powering your computer. Tupperware is top-notch technology and as you could see, openings have been made with cutting-edge laser technology
You should test it before with a dummy load. Please take a look at this video (this guy is amazing, BTW):

Amazing use of the pill-bottle. People just throw them away and they are indestructible and could be used for many different things....

 

[GearTechWolf]

Oh definitely! Got plenty of spare parts to build a dummy-load with.
Could do automotive bulbs and/or large ceramic resistors with a fan blowing over them. (the fan being additional load)
Thanks for the link! He does fun impressions. XD

 

[Jaginus]

BTW, reading back two messages, I misspelt 7405 and 7412 <--- WRONG !!!. They are 7805 and 7812. from the 78xx rectifiers series. Sorry

 

[GearTechWolf]

No worries, I figured it was just a typo, but thanks for clarifying!

 

[GearTechWolf]

More pictures! First off, the fully-cleaned and repaired transformer, with the two broken posts glued back on and jumper-wire soldered to the thermal(?) fuse, plus one section of enameled wire reattached after it broke off where it got nicked during depotting.
Also seen is where the potting epoxy stuck to the edges of the laminations.

Then, the case of my black brick, which seems to be the less-common version, P/N 251053-02.

Finally, the cleaned, repaired (with super-glue and baking-soda), and sanded circuit-board.

Think I may clear-coat it to give it a more uniform look.

 

[GearTechWolf]

Oh, almost forgot, the fins on the sides are short and don't go from top-to-bottom like the other black brick with the molded Commodore symbol on top.

 

[Jaginus]

Hey GearTechWolf, Amazing job !!!. Obvious suggestion, but check continuity as these boards are -by now- not 100% reliable. I can wait for more pictures...

I've been searching for links that could help, in two different projects. Perhaps they could bring you some ideas:

Source 1:

cps5.pdf

drive.google.com

Source 2:

Google Drive: Sign-in

Finally, I was able to find the link to something I remembered yesterday night that I've crossed over before: a protection circuit for your C64 brick (goes between the brick and the C64) in the case the power source delivers more voltage. I came to this when I was thinking to rebuild a C64 power brick, but I just came up with the idea of using new materials and keeping the brick for aesthetics and display. You could even include it as a part of the source or use the ideas for other computers/power sources. Very interesting circuit:

Overvoltage protector

Comodore 64 overvoltage protector - Hacks - Mcbx

Build a Commodore 64 overvoltage protector

oldcomputer.info

Have fun, mate !!!!

 

[GearTechWolf]

Thanks for the links!
I was planning on building a protector but hadn't found a full schematic yet, so this is very timely!
The repaired PCB tests properly on all tracks, including the ones where I repaired breaks with bridging solder-blobs.
Found a case for the vintage Power General +5 (and +12, unused) switching supply, and a toroidal transformer that puts out 10VAC on both of the secondary windings, so I may make another power-supply from that.

 

[Jaginus]

Thanks for the links!
I was planning on building a protector but hadn't found a full schematic yet, so this is very timely!
The repaired PCB tests properly on all tracks, including the ones where I repaired breaks with bridging solder-blobs.
Found a case for the vintage Power General +5 (and +12, unused) switching supply, and a toroidal transformer that puts out 10VAC on both of the secondary windings, so I may make another power-supply from that.

Glad to help. Please post some pictures when you have it up and running. You're mastering power supplies manufacturing and there's also joy beyond the computer itself. Very glad to be useful and can't wait for the pictures

 

[GearTechWolf]

Small update-
Got the original PS board reassembled with new 7805 regulator/heat-sink and otherwise original components.
And of course, pictures-

The dented, sleeveless capacitor, the chipped tantalum along with its intact mate, the two resistors, and the pair of diodes.
All original parts extracted from the brick! Hopefully they play nice with the 'new' (dated '88) 7805 regulator.
While I currently lack a meter capable of testing the 4700uF 16V electrolytic, both tantalums are unshorted and read very close to their stated values, as do both resistors, while the diodes are unshorted and read nearly the same values on my meter.
So! Rig up the lot of it with a line-cord, the original transformer, and at least 8 gator-clip leads, to get this-

Then we brace ourselves and gingerly place the plug in the wall-socket to receive...

A lit bulb and a stable 5 volts! How about that.
Now, I need to buy more solder because I used the last I had on-hand to reassemble that.
After all, I have a saver-circuit and an improved-version power-supply to build!
Reforming the original black plastic casing of the brick (it's a bit warped/ballooned from the chemicals the epoxy out-gassed) and gluing its ends back on will be a whole 'nother adventure.
But I've got JBweld Plastic Bonder, CA-glue with baking-soda, and a heat-gun, so it's mostly a matter of making wooden forms from lumber scraps to help massage it back into proper square shape, or close enough.
Plus I've got a couple threads about salvaging DIN plugs and alternate uses for dead IDE/floppy cables to write up/take pictures for.
Always lots to do when one has many hobbies. And this is only one aspect of my life amongst many. Such is life.
Have fun out there on your own projects and stay safe!
To be continued when I have time.

 

[Jaginus]

Small update-
Got the original PS board reassembled with new 7805 regulator/heat-sink and otherwise original components.
And of course, pictures-
View attachment 1245264View attachment 1245265
The dented, sleeveless capacitor, the chipped tantalum along with its intact mate, the two resistors, and the pair of diodes.
All original parts extracted from the brick! Hopefully they play nice with the 'new' (dated '88) 7805 regulator.
While I currently lack a meter capable of testing the 4700uF 16V electrolytic, both tantalums are unshorted and read very close to their stated values, as do both resistors, while the diodes are unshorted and read nearly the same values on my meter.
So! Rig up the lot of it with a line-cord, the original transformer, and at least 8 gator-clip leads, to get this-
View attachment 1245266
Then we brace ourselves and gingerly place the plug in the wall-socket to receive...
View attachment 1245267
A lit bulb and a stable 5 volts! How about that.
Now, I need to buy more solder because I used the last I had on-hand to reassemble that.
After all, I have a saver-circuit and an improved-version power-supply to build!
Reforming the original black plastic casing of the brick (it's a bit warped/ballooned from the chemicals the epoxy out-gassed) and gluing its ends back on will be a whole 'nother adventure.
But I've got JBweld Plastic Bonder, CA-glue with baking-soda, and a heat-gun, so it's mostly a matter of making wooden forms from lumber scraps to help massage it back into proper square shape, or close enough.
Plus I've got a couple threads about salvaging DIN plugs and alternate uses for dead IDE/floppy cables to write up/take pictures for.
Always lots to do when one has many hobbies. And this is only one aspect of my life amongst many. Such is life.
Have fun out there on your own projects and stay safe!
To be continued when I have time.

Hello there,
I love the way you started your post, with a "small update"
Fantastic job you are doing here, trying to keep everything "on age" and rebuilding everything. About the case repair, please include some pics when you finish it. Would really like to know the way to restore DIN plugs, as those "from the factory" are so difficult to open without damage. I still have to recover a couple of them for my Amigas, as I have to sort it out with a computer power source. Keep up the good work !!!

 

[richarjo]

No picture for this at the moment as it's stored away near the ceiling in the corner of the dining room, but I pulled it out enough to check the label.
I have the monitor/power-supply, the main system unit, and the keyboard of a Sinclair PC500SD.
Searches years ago lead me to believe it was a clone of an Amstrad computer (of what model, I don't recall) but now I'm not so sure.
The main unit and keyboard are fine (aside from having to hack-together a new cord for the keyboard) but the monitor, which doubles as the power-supply is in very poor shape after it was smashed/stripped for recyclable parts by an employee of the PC-repair shop it was dropped off at.
Functionality of the main unit is unknown since I lack a power-supply and a compatible screen.
(something to do with horizontal and vertical sync being combined on the same signal/pin)
The monitor/power-supply is missing a CRT (smashed/necked, but I still have the yoke, I think) and its primary circuit-board is missing chunks after the largest heat-sinks were crudely ripped off, taking components and hunks of PCB with them.
Other than that and the gaping holes in the badly-yellowed case, it's in fine shape!
I have schematics for the Amstrad unit it was supposedly cloned from (...somewhere, on another computer) but was stymied back then by the difficulty of locating the old/rare/obsolete multi-function voltage-regulator (finding only 1 source) and not being able to spare the coin to get it.
Any/all data anybody can point me towards would be great.

Don't know much about psu's other than having replaced the schottky resistor on an Amiga A500 unit and recapped an Atari STE psu but with the video output to a monitor, a cheap cga to vga chinese board clone of the GBS 8200 uses composite sync so it might do the trick for VGA out.

Arcade Game RGB/CGA/EGA/YUV to VGA HD Video Adapter Converter Board Game GBS8200 | eBay

YUV Component signal auto scan (480i, 576i, 720i, 1080i, 480p, 576p, 720p, 1080p). 1 RCA to VGA Converter Board. Supports VGA Output (640x480, 800x600, 1024x768, 1360x768). Supports all types of VGA monitors (CRT, LCD, PDP, Projector, etc).

www.ebay.com.au