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Brand New Commodore 64 Power Supply- the "Nu-Brick 64"

K

KevinO

Experienced Member
Joined
Apr 13, 2012
Messages
380
Location
Des Moines, IA USA
Introducing Nu-Brick 64! For those familiar with my Re-Brick C64 Power Supplies, these use the same internal design, but with all new parts. They're in a nice little metal case that nearly matches the C64 Breadbin. Of course, they work with 64C as well!

Nu-Brick_Front.jpgNu-Brick_Rear.jpgNu-Brick_zBottom.jpg

I'm not new to this. I've been doing the refurbished C64 power supply I call the Re-Brick for over 3 years now. Check out my Youtube videos on how those are done. Here's a link to part 1 here: https://www.youtube.com/watch?v=Fej_3XbufRA&t=3s
I had no intention of ever becoming a Youtuber (and I'm still not), but people kept asking "How do you get the epoxy out?" and that started something. You can follow the links to the other two videos showing the complete assembly.

I've been selling Re-Bricks in small quantities at VCF Midwest for 3 years, and more recently on the Commodore 64/128 page on Facebook (can we say Facebook on this forum?) and they've met with positive reviews. But the Re-Brick requires old power supplies to refurbish, and I was forever running out of cases. So I finally started building some from scratch. I had a conversation a year or two ago with Ray Carlsen and asked him if he minded, and naturally he didn't (If you know Ray, he's the nicest guy around doing Commodore repairs and building custom power supplies), so I started doing a few of my own.

So here they are!

Specifications:
120v US Model.
5vdc @ 3A, 9vac @ 1A.
Overvoltage and Short-Circuit Protection on 5v Switcher
Unit is fully grounded, external fuse on AC side,
Internal fuse on 9vac output

Price is $60 US plus shipping via PayPal. I have 3 available right now. Send me a PM here or an email at kevin.removeifyourenotaspammer@puppybreath.org.
 
Yes, it's a repost. My original post was so full of mistakes and typos that I embarrassed myself. What kind of Commodore nerd spells Commodore wrong? So I've had a bit more sleep and I'm posting it again.
 
Interesting PSU. The one I got on eBay worked until I accidentally blew the 2A 250V fuse... Note to self: be more careful. Would it hurt to use a 10A fuse rated at 250V, or is that a bad idea?
 
retro-pc_user said:
Interesting PSU. The one I got on eBay worked until I accidentally blew the 2A 250V fuse... Note to self: be more careful. Would it hurt to use a 10A fuse rated at 250V, or is that a bad idea?
Click to expand...
Bad idea. The idea of a fuse is to prevent excess current that could cause damage. So a device with a 2A fuse will deliver up to 2A, but any more than that and the fuse will blow. This is by design -- a designer added this fuse to the circuit, and chose that specific value of 2A for a reason. Presumably the reason being that more than 2 amps is likely to damage the system or cause a fire.

If the system could handle 10 amps of current safely, it would have come with a 10A fuse to begin with.
 
I already replied in the other thread, but I'll say it again...never use a larger fuse than the one that came in the device. I can't vouch for the eBay one, but I will say that on mine, the 9VAC transformer is rated at 1A. But it WILL produce a lot more current if it is shorted, and possibly overheat and start a fire. So the 2A fuse (which I also use) gives a little buffer in case of a very brief short or surge, but will blow if it's anything longer.

When I was selling my original C64 "Re-Brick" (which is a rebuilt C64 Power Supply in the original case), I included a "care and feeding" document that explained what was what and how it worked. Your question makes me realize I still need to include that on the Nu-Brick. I have the fuse ratings on the bottom sticker, but I need to go a step further. Those of us who are electronics enthusiasts have all seen a piece of equipment where they used a piece of tinfoil instead of a fuse! Horrifying. To think that one of MY power supplies could be involved in burning someone's house down, even if it wasn't my fault....yikes!
 
I pulled the 2A 250V 1/4" fuse from the other breadbin that needs repairs, popped it into the PSU, plugged in the newly acquired C64 with the RF cable, turned it on, and it fired up. Didn't realize the internal fuse for the C64 was actually 2A.

Thanks for the suggestions and the help.
 
Nu-Brick Update:

Since The 8-Bit Guy showed one of my Nu-Brick 64 power supplies on one of his latest videos, I've been swamped with requests for them. I'm building them in batches of 10, and sadly, I can only manage about one batch a month with work and family obligations. So for all those who have come here looking for power supplies, please be patient. Another batch is coming soon...maybe 2nd week in May. I will post when they are available. Thanks for your support!

20180417_204540.jpg
 
I saw that video and didnt know it was yours! Congrats on getting your product out there and all the orders! Thats great.
 
glitch said:
Nice looking power supply! Can't go wrong with a Mean-Well switcher :)
Click to expand...

Actually, it turns out you can! And I'm just making conversation here....I designed a separate 128 PS using a more heavy-duty Mean Well PS-25-5. It was rated for 80mv ripple. With a pure resistive load, it put out about 40mv p-p ripple...well within spec. But plugged into the 128 it went nuts and we had noise bouncing all over the place in the 250mv p-p range! Some kind of resonant effect, not sure what happened. But the noise was visible on the screen, and those units went back. I use the EPS-15-5 in the Nu-Brick 64, and it works just fine on the 128 with an adapter, so for my custom 128 model, I'm going to try the EPS-25-5.

Oh, and thanks for your kind comments guys. I've sold 40 Nu-Brick 64s so far, and about 50 of the Re-Bricks before that, so we've got a pretty large number of them out there working with no problems.
 
Huh, that's weird! I wonder if it was possibly cable impedance or something. Can't say I've ever had a reaction like that from a Mean-Well module, but I'm almost always installing them *in* the enclosure that uses the supply.
 
glitch said:
Huh, that's weird! I wonder if it was possibly cable impedance or something. Can't say I've ever had a reaction like that from a Mean-Well module, but I'm almost always installing them *in* the enclosure that uses the supply.
Click to expand...

YES! You just reminded me...the other problem I was getting was huge unexplained voltage drops. Using the same 18AWG cable I use on my 64 PS, I was dropping from 5.0v at the PS to 4.79 at the power connector on the 128. During my testing, I switched to a 14AWG cable just for giggles, and the voltage came up to 4.9V. So yes, cable impedance might just be involved. There's no way there should be a problem with 18AWG cable at the 2.3A that a stock 128 draws.

FOR FOLKS INTERESTED IN THE NU-BRICK: don't worry, this discussion is about my unreleased 128 prototype, which WON'T be released until I'm satisfied with the performance.
 
Huh, yeah, I wonder if you ended up with some sub-spec cable? A voltage drop of 0.21V at 2.3A would equal out to around 0.092R for the cable...which at 18 AWG, assuming stranded copper, would be around 15 feet of cable, according to the cable resistance slide rule. Half it if the ground/return was also 18 AWG, so your cable should've been around 7.5 feet for that much drop.

Thanks for discussing these issues, by the way -- it's interesting to see the design process that others go through :)
 
No, the cable is good. I've been using the same cable on everything. It's definitely an interaction of some sort. Something about the switching frequency, I'd guess. I had a conversation with Mean Well tech support about it, and while they couldn't give me an exact answer, they recommended I return the PS-25-5 and exchange it for EPS-25-5, which is what I did. I have the new units, but it's going to be a few weeks before I get them properly tested.
 
Hi Everyone...the next batch of Nu-Brick 64's is done. I've got 10 completed, one sold for sure, and I expect 2-3 more today will go to my FB contacts who were waiting on them. Price is $60 plus shipping, which is $13.65 in the continental US. Send me a PM if you want one!
 
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