An Attempt at a New Power Solution for the Coleco

[nathaniel.lockha]

I came into a couple CVs lately that were lacking controllers and power supplies. Luckily, I had the PSU and controllers already so I could test them, but it annoyed me that I didn't have PSUs to go with them. The current solutions are a bit expensive for my liking, plus I wanted to have something that could run off a normal 'ol 12v supply with a 2.1mm x 5.5mm barrel plug. 

So here it is: a ColecoVision power supply that runs from a single 12v 3a power supply. The 12v is regulated down to 5v with a 7805, and the -5v is achieved with a charge pump inverter. The charge pump is only capable of supplying 100ma of current, but for the VRAM, it's plenty.

I gave it some preliminary testing; leaving it on for a few hours and playing some games of Donkey Kong. Would love to know if it plays nice with some of the other expansions, especially the Roller Controller, given that it uses the power port. 

Anyway, here's the github. Would love to have some thoughts/comments/suggestions on this thing.

[allansim]

I like that it takes a standard supply and can be mounted in the CV.  Great work!

[+-^CrossBow^-]

Wonder if using a dc-dc switcher converter in place of the linear regulator would allow for a smaller amperage 12v source to be used? If this is designed to be installed internally, where is the recommended location? Or is all of that in the github and I just need to go poking around in there a bit LOL.

 

[Captain Cozmos]

If the power supply is changed then have a fork connected to the original plug to supply the Roller Controller with power.
Then remind whomever inherits the thing to never use an original Colecovision power supply.
I will never understand the design choices Coleco Engineers made considering the Atari 2600 out several years earlier had no issues with expansion devices like a track ball.

[Captain Cozmos]

2 minutes ago, -^CrossBow^- said:

Wonder if using a dc-dc switcher converter in place of the linear regulator would allow for a smaller amperage 12v source to be used? If this is designed to be installed internally, where is the recommended location? Or is all of that in the github and I just need to go poking around in there a bit LOL.

 

Personally I would hook up a Chevy V8 with a Holly double pump. But that's me.

[nathaniel.lockha]

20 minutes ago, Captain Cozmos said:

Personally I would hook up a Chevy V8 with a Holly double pump. But that's me.

Ah yes, the oft overlooked Coleco expansion module, the Engine Block

[nathaniel.lockha]

25 minutes ago, -^CrossBow^- said:

Wonder if using a dc-dc switcher converter in place of the linear regulator would allow for a smaller amperage 12v source to be used? If this is designed to be installed internally, where is the recommended location? Or is all of that in the github and I just need to go poking around in there a bit LOL.

 

It's in the github 😊 I've got a pic in there where it's mounted. I designed it though so you could go either way; installing it internally or leaving it on the outside and grafting an original power cable (or newly made one) onto it. I just wanted folks to have the option, and also to keep the cost down.

 

The use of linear regulators is also down to cost - of course, you can use newer, more efficient DC-DC converters (in fact, I did for my first successful build), but it didn't take away from the current needs of the CV.

[cscotty]

Resurrecting this post as I am in need of a new PSU and I'm currently looking to build my own.  Any updates on the schematics or use of other circuit parts to improve the efficiency?  Also, its been almost 2 years.  Would you still recommend this build?

 

Thanks for the good work on this!

[NIAD]

https://lundyelectronics.com/product/colecovision-power-supply-adapter/
 

[MMarcoux66]

Lundy's stuff is amazing but curious if this still is a viable solution for those on a budget. I was thinking of having some boards made and trying it to see what my testing shows. Was thinking about designing an external 3D printed piece that plugs into the back and incorporates this board. Would probably cost <$30 including the adapter if my estimates are good.

Edited September 22 by MMarcoux66

[N0mi]

10 hours ago, MMarcoux66 said:

Was thinking about designing an external 3D printed piece that plugs into the back and incorporates this board. Would probably cost <$30 including the adapter if my estimates are good.

Sounds good! 

In the meantime, wouldn't the ColUSB be an option?

I know it's not available at the moment but can be pre-ordered.

[N0mi]

Just got word from DragonBox shop in Germany that the ColUSB will be available again this week and they just updated their website so it can be ordered now.

 

https://dragonbox.de/de/produkte-furs-colecovision/colusb-usb-netzteil-furs-colecovision.html

 

I don't know about Stone Age Gamer, but I'm guessing they might re-stock as well. 

 

[Ruggers Customs]

I'd caution against any internal/external switching power supply mods.  They can introduce a good bit of noise into the circuit, which is easily seen in RF, composite video and sometimes RGB.  The ColUSB doesn't do this in all NTSC/PAL (I know, I've personally tested them all in all three video modes) motherboard revisions and Lundy Electronics' adapter with the specified Meanwell power supply doesn't seem to either in NTSC consoles.

 

Of course, if you want to do it for your own personal console then that's totally fine but I don't think it would be ethical to sell to the public until extensive, proper testing has been done on multiple consoles.  But that's just me.

Edited September 23 by Ruggers Customs

[MMarcoux66]

13 hours ago, N0mi said:

Sounds good! 

In the meantime, wouldn't the ColUSB be an option?

I know it's not available at the moment but can be pre-ordered.

True but was looking at possible other options. The ColUSB is an awesome device, but just not readily available and this one seemed almost too good to be true from a cost standpoint. 

2 hours ago, Ruggers Customs said:

I'd caution against any internal/external switching power supply mods.  They can introduce a good bit of noise into the circuit, which is easily seen in RF, composite video and sometimes RGB.  The ColUSB doesn't do this in all NTSC/PAL (I know, I've personally tested them all in all three video modes) motherboard revisions and Lundy Electronics' adapter with the specified Meanwell power supply doesn't seem to either in NTSC consoles.

 

Of course, if you want to do it for your own personal console then that's totally fine but I don't think it would be ethical to sell to the public until extensive, proper testing has been done on multiple consoles.  But that's just me.

You are the expert on ColecoVisions! Probably very true on the noise and I've seen some on one of those other CV replacement power supplies from the guys in MN on a system I have. Had not thought of that as I was pretty early in looking at this design. 

 

Testing is obviously key, and I was curious if anyone has tested it beyond the original designer. I was looking at expanding the design to something external which could be shared for DIY people. Too much liability in selling :).

 

[Ruggers Customs]

2 hours ago, MMarcoux66 said:

True but was looking at possible other options. The ColUSB is an awesome device, but just not readily available and this one seemed almost too good to be true from a cost standpoint. 

You are the expert on ColecoVisions! Probably very true on the noise and I've seen some on one of those other CV replacement power supplies from the guys in MN on a system I have. Had not thought of that as I was pretty early in looking at this design. 

 

Testing is obviously key, and I was curious if anyone has tested it beyond the original designer. I was looking at expanding the design to something external which could be shared for DIY people. Too much liability in selling :).

 

Well, what I said wasn't meant for anyone in particular, but just a general statement.  So please don't think I was being a negative Nancy here.  I know some will argue with me on this, but Colecovisions vary from revision to revision, so new things, whether it's a video upgrade, ram upgrade or power substitute needs to be tested on multiple systems preferably with a scope in tow.  A popular engineer who makes replacement retro hardware will completely back up my statement.  Some motherboard revisions will be fine with a switch mode power supply, and some won't. 

 

John Lundy does this before any of his products are even hinted at being available because he's an engineer.  Nick Piegdon did the same with his TMS-RGB with the help of engineers and my thorough testing.  Dragonbox who makes the ColUSB is also an engineer who put his product through all the necessary testing and certifications for retail.  I however, I'm no electrical engineer or expert.  If anything, I'm just an electronics janitor at best.  While I have countless pcb designs on Eagle, they will never see the light of day until I run them by an engineer first to catch any issues I've missed or to make sure it's done properly and to make sure it's thoroughly tested.  I wouldn't even consider releasing them for free as open source for hobbyists.  I don't expect everyone to do this but that's just how I see it.