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Atari 2600 Jr high voltage after regulator

atari 2600 Jr

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#1 tr0x OFFLINE  

tr0x

    Combat Commando

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Posted Fri Dec 7, 2018 9:56 AM

Hi,

I recently acquired an Atari 2600 Jr (PAL), but it shows no signs of life: the led indicator remains unlit and no RF signal comes out of the console.

I opened it and found with a DMM that *after* the 7805 regulator there's the same high voltage of the external power supply, so I replaced the regulator but the voltage is still the same both at the input and output pins.

What can be wrong with it?

 

Thank you!

 

 



#2 Osgeld OFFLINE  

Osgeld

    Quadrunner

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  • Location:Nashville, TN

Posted Fri Dec 7, 2018 10:33 AM

Is it getting ac or dc input (it needs to be dc)

#3 tr0x OFFLINE  

tr0x

    Combat Commando

  • Topic Starter
  • 3 posts

Posted Fri Dec 7, 2018 10:53 AM

Is it getting ac or dc input (it needs to be dc)

DC power brick, that works with another 2600 Jr.

I also replaced all the electrolytics capacitors.



#4 Stephen Moss OFFLINE  

Stephen Moss

    Stargunner

  • 1,106 posts
  • Location:Cambridge, United Kingdom

Posted Mon Dec 10, 2018 2:25 AM

Sounds like there is no GND (0V) connection to the Regulator.

Try doing a continuity check from the power socket to the middle pin/metal tab of the regulator, if you get a reading of Zero or only a few ohms it is probably OK and the problem lies elsewhere, if you get a high or infinite resistance reading you will have to trace where the problem is. A bad solder joint on the regulators GND pad or crack between the regulator GND pad and the GND track would be the first places I would look, if it is not there then either check the continuity of the GND track from the power socket to the regulator a few inches at a time until you find the break or solder a piece of wire from the power socket to the regualtor.  



#5 tr0x OFFLINE  

tr0x

    Combat Commando

  • Topic Starter
  • 3 posts

Posted Mon Dec 10, 2018 8:48 AM

Sounds like there is no GND (0V) connection to the Regulator.

Try doing a continuity check from the power socket to the middle pin/metal tab of the regulator, if you get a reading of Zero or only a few ohms it is probably OK and the problem lies elsewhere, if you get a high or infinite resistance reading you will have to trace where the problem is. A bad solder joint on the regulators GND pad or crack between the regulator GND pad and the GND track would be the first places I would look, if it is not there then either check the continuity of the GND track from the power socket to the regulator a few inches at a time until you find the break or solder a piece of wire from the power socket to the regualtor.  

 

Atari 2600 Jr motherboard, new power connector
new power connector

I checked and found that there isn't any connection between bottom and top layers at the jack power connector, maybe the via is corroded.

So I installed a new power connector with two wires soldered both on top and bottom pads of the pcb, and it works perfectly :)

Thank you very much!
 


Edited by tr0x, Mon Dec 10, 2018 8:48 AM.






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