strattsp Posted October 9, 2007 Share Posted October 9, 2007 (edited) So I turned on my colecovision, and after about 5 minutes, the screen started up with a light flicker. It progressed until it was mostly static with a few seconds of video game in between. I'm almost positive it has something to do with the output, as the game screen kept going while the display died. If I let it cool off, I get a regular screen again, but not for long. Anyone know how to fix this? -Steve Edited October 9, 2007 by strattsp Quote Link to comment Share on other sites More sharing options...
Cassidy Nolen Posted October 10, 2007 Share Posted October 10, 2007 I'd install a new power switch...the originals are notoriously bad. Worth the time to do...I have resurrected a few with just that swap. Resistance=Heat= more resistance, etc as it gets hot. Better when it cools off... If you are handy with a soldering iron this is not a bad job. C Quote Link to comment Share on other sites More sharing options...
strattsp Posted October 10, 2007 Author Share Posted October 10, 2007 Power switch has been disassembled and cleaned, loaded with grease. The problem is almost certainly one of the chips or components. I would love to get a hold of a CV service tech's manual. I saw one on ebay not too long ago, but it went out of my price range. Quote Link to comment Share on other sites More sharing options...
Murph74 Posted October 11, 2007 Share Posted October 11, 2007 Power switch has been disassembled and cleaned, loaded with grease. The problem is almost certainly one of the chips or components. I would love to get a hold of a CV service tech's manual. I saw one on ebay not too long ago, but it went out of my price range. There's quite a bit of info if ya google it... also Bill Brasky just sold a tech manual here fro $30 like 2 weeks ago-- may wanna ask him if he has any input, or even if he could contact the buyer for ya. Second thing (after power switch) I'd check is the power supply itself. The components aren't perfect, but they tend to be pretty rugged from my experience. Another potentially cheap fix if the PS checks out (Use a known good working one if you can), may be to try a composite mod and bypass part of the RF unit. Cold solder joints are a known pain in the ass. Murph Quote Link to comment Share on other sites More sharing options...
strattsp Posted October 11, 2007 Author Share Posted October 11, 2007 Power supply is checked and fine. Composite mod has been done and I am getting the same results Quote Link to comment Share on other sites More sharing options...
Murph74 Posted October 12, 2007 Share Posted October 12, 2007 Power supply is checked and fine. Composite mod has been done and I am getting the same results How'd ya check it? Quote Link to comment Share on other sites More sharing options...
strattsp Posted October 12, 2007 Author Share Posted October 12, 2007 I checked voltage and current with a multimeter Quote Link to comment Share on other sites More sharing options...
Murph74 Posted October 12, 2007 Share Posted October 12, 2007 I checked voltage and current with a multimeter I'd recommend testing it on another CV system if you can. If you got 'proper' voltage out of the PS, then you're a rarity. I've tested over 30 Coleco PS's and have yet to get a 'correct' voltage. And besides, using a meter doesn't tell you much about the problem anyway-- as your symptoms state, your system works fine for about 5 minutes, meaning you PS works fine for about 5 minutes. It may work fine still after that, or it may be the source of your problem. Bottom line, to prove it good, you have to test it under load, and the easiest way to do that is to hook it up to another Colecovision and see if it does the same thing. Quote Link to comment Share on other sites More sharing options...
+5-11under Posted October 12, 2007 Share Posted October 12, 2007 Maybe the graphics chip is getting too hot. I've had one that messed up sprites after it warmed up. Try some gentle freeze spray on it occasionally, to see if the display stays on longer. If you're lucky, you'll just need a bigger heatsink. Thanks, 5-11under Quote Link to comment Share on other sites More sharing options...
strattsp Posted October 12, 2007 Author Share Posted October 12, 2007 (edited) I checked voltage and current with a multimeter I'd recommend testing it on another CV system if you can. If you got 'proper' voltage out of the PS, then you're a rarity. I've tested over 30 Coleco PS's and have yet to get a 'correct' voltage. And besides, using a meter doesn't tell you much about the problem anyway-- as your symptoms state, your system works fine for about 5 minutes, meaning you PS works fine for about 5 minutes. It may work fine still after that, or it may be the source of your problem. Bottom line, to prove it good, you have to test it under load, and the easiest way to do that is to hook it up to another Colecovision and see if it does the same thing. It worked well for 5 minutes the first time. Every time since it works for about 30 seconds. I fear soon it will not work at all. I'm 99% sure it is not the power supply, the power supply does work with other units. Edited October 12, 2007 by strattsp Quote Link to comment Share on other sites More sharing options...
strattsp Posted October 12, 2007 Author Share Posted October 12, 2007 Maybe the graphics chip is getting too hot. I've had one that messed up sprites after it warmed up. Try some gentle freeze spray on it occasionally, to see if the display stays on longer. If you're lucky, you'll just need a bigger heatsink. Thanks, 5-11under Which one is the graphics chip? It's not the Bios, right? I'm not sure which chip to target. I did let it run for a little while to see if any chips were getting hot, but none stood out as obvious problems. Quote Link to comment Share on other sites More sharing options...
Bill Brasky Posted October 12, 2007 Share Posted October 12, 2007 The graphics chip should already have a heat sink glued to it. I think it may be the only chip in there with a heat sink. Quote Link to comment Share on other sites More sharing options...
Murph74 Posted October 13, 2007 Share Posted October 13, 2007 The graphics chip should already have a heat sink glued to it. I think it may be the only chip in there with a heat sink. Yep Bill, you're correct on that. It's at U9 on the board identifiers. Quote Link to comment Share on other sites More sharing options...
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