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Atari Super Pong (C-140) Problem


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#1 moonchilddave OFFLINE  

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Posted Tue Apr 23, 2019 9:22 AM

Just recently picked up this classic.  Also bought an Atari Pong Battery Eliminator.  Everything seems to be working fine - display, paddles, sound... but when playing it, when one player scores, the score display remains 0-0.    Any idea what could be wrong?  I'm thinking perhaps a bad "Start Game" switch?

 

Also, I noticed that the sound is only through the supplied speaker - not via the TV (which just puts out white noise / static).  Anyone aware of someone who modded one of these to send the sound out over the RF cord?

I plan on opening it up and doing a little cleaning (Deoxit on the paddles), look for broken/cold solder joints, and I'll probably put a brand new quality video cord on it while I'm in there.


Edited by moonchilddave, Tue Apr 23, 2019 9:40 AM.


#2 TheProgrammerIncarnate OFFLINE  

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Posted Thu Apr 25, 2019 2:42 PM

It could be, as you said, something involving the start game switch. If it's not that, then its probably an internal problem with the game chip, which can only be replaced, not repaired. Does the gameplay look completely normal except for the lack of an increasing score, also have you ever ran it with batteries instead of the AC supply?

 

Regarding audio, I could probably help you figure out how to output the sound over a RCA cable given pictures of the circuit board, although putting it into the modulator is a little more difficult.



#3 moonchilddave OFFLINE  

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Posted Sun Apr 28, 2019 3:48 AM

Ok, I just saw what a working unit looks like... mine when powered up, immediately starts playing... there is no screen with all the squares moving. So I disconnected the button (2 blue wires) and powered it up, no change in behavior. All 4 game modes work and behave as expected - just no score is kept. I’m hoping it’s not the main chip - unless there is a source for them. Have not tried batteries in it yet - but don’t see how that could be an issue.

#4 moonchilddave OFFLINE  

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Posted Sun Apr 28, 2019 11:08 AM

One other question... there are 3 2-pin test points on the board (one by the RF cable, one by the speaker, and one on the side opposite the RF cable) - any idea of what these test points are for?

I measured them with my DVM and got:

Speaker - 5.33 VDC
RF Cable - 3.44 VDC
Opposite RF - 0 VDC

#5 TheProgrammerIncarnate OFFLINE  

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Posted Sun Apr 28, 2019 11:56 AM

I have no idea what the test points are for, you'd have to see where the traces go.

 

I did a little searching for your no-start + no-score issue, the person in this thread fixed his system by replacing the capacitor and pullup resistor in the "start game" switch circuit. Its much more likely to be the capacitor than the resistor, so just follow the non-ground side of the switch to locate it for replacement.



#6 moonchilddave OFFLINE  

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Posted Sun Apr 28, 2019 1:48 PM

I have no idea what the test points are for, you'd have to see where the traces go.

 

I did a little searching for your no-start + no-score issue, the person in this thread fixed his system by replacing the capacitor and pullup resistor in the "start game" switch circuit. Its much more likely to be the capacitor than the resistor, so just follow the non-ground side of the switch to locate it for replacement.

Thanks!  It looks like the test points on either side go to the LPAD & RPAD inputs on the game IC.  The unused test point in the middle is your +5V supply.  Looking at the schematic, I don't see a pullup resistor in the start game circuit.  One thing I did notice is that I have a jumper in place of diode CR4 (and it was evident that the board had work done on it at some point - as the shield over the traces side of the board was only tacked down in 2 of the 4 corners).  And the post that you linked to - goes to this thread... LOL!

Schematic

My Board


Edited by moonchilddave, Sun Apr 28, 2019 1:59 PM.


#7 TheProgrammerIncarnate OFFLINE  

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Posted Sun Apr 28, 2019 4:33 PM

Oops, this should be the correct thread



#8 TheProgrammerIncarnate OFFLINE  

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Posted Sun Apr 28, 2019 4:44 PM

 

Looking at the schematic, I don't see a pullup resistor in the start game circuit.

It might be an internal one if that's the case

 

 

One thing I did notice is that I have a jumper in place of diode CR4

Hmm, I wonder why that was there in the first place. Its DC so it doesn't seem necessary

 

 

Anyway, according to the schematic, capacitor C14 is your most likely culprit. Do you have a soldering kit available?



#9 moonchilddave OFFLINE  

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Posted Tue Apr 30, 2019 11:52 AM

Got the cap in and replaced C12.  It's fully functional once again, thank you!!!  Now I just need to replace that one electrolytic cap, clean the pots and switches with some Deoxit, and button it all back up!

 

I still am rather curious about having a jumper in CR4 rather than a zener diode.  There apparently IS some AC in the circuit according to the images posted here (granted, those images are for Pong).  Everything seems to be working just fine, but I wonder (given the schematic I have shows it) if others have the diode or a jumper.

IMG-3820.jpg


Edited by moonchilddave, Tue Apr 30, 2019 11:53 AM.


#10 TheProgrammerIncarnate OFFLINE  

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Posted Tue Apr 30, 2019 2:16 PM

Glad I could help. I'm getting one of Atari's pong systems sometime soon to melt in acid (for emulation.) Before that I'll try to figure out how to composite mod it and send the audio to the TV.

#11 moonchilddave OFFLINE  

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Posted Tue Apr 30, 2019 5:14 PM

I noticed the game chip puts out composite & audio... couldnt be as simple as picking off the signal and running it to a jack, could it? I may give that a try and see if it works. I imagine it may need some kind of amplification. Although, it was that simple for the Odyssey 2. Ive got some TRRS jacks and cables that terminate in RCA plugs.

Edited by moonchilddave, Tue Apr 30, 2019 5:19 PM.





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