Colecovision Power Supply

trueyanksfan · Post by **trueyanksfan** » Wed Aug 13, 2008 7:16 pm

I recently picked up a Colecovision for my collection at a local garage sale. Unfortunately, I only get black screen; no sound or video. After some testing I see that my power supply is putting out the correct voltages (+5, -5, +12) UNTIL I flip the switch on at which point the +5 drops to .8 with the load.

I cracked open the power supply and was surprised by all of the components inside! Does anyone have any suggestions on how to find the faulty component?

Thanks so much,

Matt[/u]

eurddrue · Post by **eurddrue** » Wed Aug 13, 2008 8:25 pm

Well, I'm no colecovision expert, but if you could show some pictures, buy another power supply, or do something of the sort to be helpful to us? I think I worded that wrong, something to help us figure out your dilemma, would greatly be appreciated.

If it were me I would wait 24 hours and try again, maybe it has an automatic fuse shutoff so you dont fry your system like the n64. Try it on different tvs i guess, or if a friend has a colecovision, try using his/hers.

trueyanksfan · Post by **trueyanksfan** » Wed Aug 13, 2008 9:05 pm

If I were to buy another power supply, I don't think I would have a problem anymore.

Seriously, though, I have read that Colecovisions are well known to have problems with their power supplies. I was hoping someone here has had experience repairing them and could point me to a common issue (i.e. one of the power transistors, etc.) that would cause my +5v line to drop as soon as I switch on the power.

ArugulaZ · Post by **ArugulaZ** » Wed Aug 13, 2008 10:37 pm

Holy crap, you opened the power supply?! You love to live dangerously, don't you? One of the first things I learned in computer class is NOT to open monitors or power supplies, as they're both filled with electric death. And not the cool kind that clears the screen of flippers in Tempest 2000, either.

I suppose there's a way to drain the charge with a very large capacitor, but I don't remember the specific details. I just keep CRT monitors closed, because I don't want to look like Yahoo Serious for the next five weeks.

grossaffe · Post by **grossaffe** » Thu Aug 14, 2008 1:00 am

ArugulaZ wrote:Holy crap, you opened the power supply?! You love to live dangerously, don't you? One of the first things I learned in computer class is NOT to open monitors or power supplies, as they're both filled with electric death. And not the cool kind that clears the screen of flippers in Tempest 2000, either.

I suppose there's a way to drain the charge with a very large capacitor, but I don't remember the specific details. I just keep CRT monitors closed, because I don't want to look like Yahoo Serious for the next five weeks.

I accidentally touched an open power supply once. got 120V AC sent through me. That was an unwelcome surprise.

Dr. KillGood · Post by **Dr. KillGood** » Thu Aug 14, 2008 1:40 am

I opened a dead PSU 330W from a computer and messed with it but nothing happened to me?

Maybe cus it was dead. )^=

grossaffe · Post by **grossaffe** » Thu Aug 14, 2008 2:20 am

Dr. KillGood wrote:I opened a dead PSU 330W from a computer and messed with it but nothing happened to me?

Maybe cus it was dead. )^=

I think the one I touched was plugged in. My hand slipped and went into it.

Dr. KillGood · Post by **Dr. KillGood** » Thu Aug 14, 2008 4:07 am

grossaffe wrote:
Dr. KillGood wrote:I opened a dead PSU 330W from a computer and messed with it but nothing happened to me?

Maybe cus it was dead. )^=
I think the one I touched was plugged in. My hand slipped and went into it.

Well, theres your problem.

timmeh87 · Post by **timmeh87** » Thu Aug 14, 2008 8:59 am

Just use an old computer power supply to test it.

Maybe its not the power supply anyways.

trueyanksfan · Post by **trueyanksfan** » Thu Aug 14, 2008 3:38 pm

I hadn't thought of a computer power supply. I will give that a shot. Also, I appreciate everyone's concern and will be sure to leave all power supplies unplugged while working on them.

APHawkes · Post by **APHawkes** » Fri Aug 15, 2008 6:22 am

It's not just about the power supply being unplugged. Every power supply that I've seen had a capacitor or two which will hold a charge for DAYS after power is removed. If you happen to touch between the two leads you'll get a nasty shock, sometimes in the thousands of volts! Same thing with CRT televisions/monitors. That's the main concern, the charged capacitors.

Yeah, if I were you I'd just grab an old AT (that is, non-ATX) style PC power supply and rig that up a connector for testing.

Oh, and from what I've read the switches themselves on the Colecovision have issues. Maybe it's shorting out somewhat?

trueyanksfan · Post by **trueyanksfan** » Fri Aug 15, 2008 4:26 pm

Thanks APHawkes for the advice. One quick questions before I fire it up. Does the current output matter? The PC power supply will be putting out significantly more amps than the Colecovision.

Thanks for helping an electronics novice.

Dr. KillGood · Post by **Dr. KillGood** » Fri Aug 15, 2008 5:24 pm

You should unplug ANY ELECTRON DEVICE before messing around inside of it.

APHawkes · Post by **APHawkes** » Sat Aug 16, 2008 7:00 pm

Having more Amps is always ok. Just don't go over on Volts! It's just the way things work: you always want your Voltages as CLOSE as possible and Amps supplied to be at LEAST as much as the demand.

It should be fine. Just double-check all your connections before you power the thing up. And let us know what happens!

grossaffe · Post by **grossaffe** » Sat Aug 16, 2008 7:22 pm

Dr. KillGood wrote:You should unplug ANY ELECTRON DEVICE before messing around inside of it.

don't worry, I have a valid excuse; I was in a hurry