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Colecovision won't power on - help?


5 replies to this topic

#1 reverendshoebox OFFLINE  

reverendshoebox

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Posted Sun Jan 14, 2018 4:38 PM

Hey all.

 

I have a Colecovision that won't power on.  No black screen, no BIOS screen, nada.

 

I've verified via multimeter that the power supply seems to have 12, 5, and -5 volts where it should, including where it connects to the board, but when I switch the power on, the 5 volt reading jumps down to 1.6.

 

Is this an expected drop, or an indication that I've got a bad power supply?

 

If the former, where should I look next?

 

Thanks much,

-=ShoEboX=-

 



#2 SignGuy81 OFFLINE  

SignGuy81

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Posted Sun Jan 14, 2018 4:41 PM

That isn't an expected drop and more than likely indicates a bad component pulling the power supply down.



#3 reverendshoebox OFFLINE  

reverendshoebox

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Posted Sun Jan 14, 2018 7:04 PM

Thanks for the response.  Do you mean a bad component in the power supply or in the Colecovision itself?  And if it's in the Colecovision, how do I go about diagnosing the issue further?

 

-=ShoEboX=-



#4 SignGuy81 OFFLINE  

SignGuy81

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  • Location:Bassett, VA

Posted Thu Jan 25, 2018 7:23 PM

I believe you have a shorted component inside the Colecovision itself.  Is any part inside the Colecovision feel hot?  See if any of the chips feel hot.



#5 grips03 OFFLINE  

grips03

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Posted Thu Jan 25, 2018 8:22 PM

Measure +5v to ground on top of all the ICs, ohm leads right on top of the IC legs.  Write down the resistance going as many places as the ohm meter supports.

 

Example 50.001 and 50.009 ohms. 

 

Does the hot to the touch IC also show the least amount of the resistance?

 

If yes, perhaps that is the bad IC.  Clip the ground leg of that IC, does the resistance change between ground and +5v? 

 

If resistance does not change, then resolder that ground you just cut and keep trying.



#6 reverendshoebox OFFLINE  

reverendshoebox

    Star Raider

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Posted Fri Feb 23, 2018 10:30 PM

Hey all.  I ended up trying another AC adapter and I'm up and running.  Thanks for the advice, greatly appreciate it!!






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