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Atari 400 Not turning on

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#1 Redemption OFFLINE  


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Posted Wed Feb 6, 2019 4:08 PM

I am a bit new to Atari's. I grew up in the NES age so thats where my experience is. I recently purchased an Atari 400 second hand with a couple of games and a couple of joysticks. No psu.


Anyway the PSU showed up today and the Atari 400 does not seem to be powering up. PSU is brand new Atari brand C017945. I cant seem to find my multi meter but I threw a test light on the PSU and it is turning on my test light.


at the console I did lightly sand the secondary connector because it was so grimey that it looked black, now it sort of has a semi copper hue to it thats hard to catch on a camera......still need to sand a little more?


I am getting no light no sound. This is with it not hooked to anything and no cart in the slot. Any suggestions on what I need to do to solve this?


#2 Redemption OFFLINE  


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Posted Wed Feb 6, 2019 5:39 PM

I did a General break down of the unit, just to see what Im dealing with here. (first time wading through the guts of an Atari) The Ram boards all look like their seated properly.... The unit was real dirty when I got it and a first heavy cleaning of the case still didnt get enough of the grime off. Really truly any help would be appreciated.



#3 Stephen Moss OFFLINE  

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Posted Thu Feb 7, 2019 2:37 AM

I do not know much about the Atari 400 other than generally what it is but if it is not turning on the power board would be the first place to look, you can find the schematic here (power supply on page 8 ). 

First I would check the continuity (power disconnected) of the power switch, from the image it looks like a single pole double throw (SPDT) so the middle pin should read 0 ohms to one of the outside pins on the on position and the other pin in the off position.

Do the same with the interlock switch if it is one you can manually operate, I am not sure what the purpose of the interlock switch is but it may be a safety feature to prevent operation when the case is opened (case depresses it) in which case you would need to bypass it or tape it down temporarily for the power supply to function with the case off.


Then then using the centre pin of the 7805 (A202) as your ground (0V) point for the Com lead of a multi-meter measure the voltages shown on respective pins of connector J201 so that you can establish if all your supply voltages are present and correct.


I would not sand your power connector, the tin plating is there to stop the copper tarnishing/getting verdigris, cleaning it with a degreaser that evaporates like isopropanol would have been better.   

#4 Redemption OFFLINE  


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Posted Thu Feb 7, 2019 1:52 PM

I've got it turning on now. Turned out to be a problem with the interlocking switch

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