Atari C-380 help needed

[AtariLeaf]

After my XEGS repair success I decided to tackle a C-380 that I bought a couple of years back, knowing it wasn't working right (got it cheap) and was hoping it was something easy. I tried reseating the main chip and resolding a couple of wonky looking solder points but no change. You can see from the pics what I get when powering on. I tried to get several close up shots of the board and it looks like several caps could be replaced but I don't know which may be the likely culprit and where to start. Any advice is appreciated.

[AtariLeaf]

If you look at the last pic you can see the voltage regulator just below the big open circle. Hard to tell from the pic but the solder points look almost burnt and with power on the unit, I get absolutely no reading so I'm thinking the regulator is dead. However I am getting some kind of picture so I'm not entirely sure. Will a 2600 voltage regulator work on one of these pong units? I have a spare I can try.

 

EDIT - I touched up the solder points and the resister gives me about 11.5 in and 6.4 out. Also is there a service manual for these? I can't find one online

 

ANOTHER EDIT - ended up replacing the voltage regulator and i'm getting a good 5V out. Also desoldered and cleaned the power switch. Still no change. In the off chance anyone is watching or has any idea please let me know. I'm assuming if it's the main IC I'm probably screwed as it would mean cannibalizing another C380 which I can't do. I have a good working Sears version but I don't want to mess with a working unit.

[AtariLeaf]

Still no go. Tried desoldering, cleaning the pins, and reinstalling the custom C011512-05 with a socket. I get different but similar graphic glitches so that was a no go. I believe there is one ram chip, the grey one, that maybe I can find a replacement for. If it's one of the custom IC's then I'm out of luck and will need a new machine and if I get a new machine then why bother with this one. I do have the sears version of this but wanted to fix it. Oh well, it's been nice talking to myself

[chas10e]

I wonder if reflowing all the solder joints under the IC chip would help.

 

my eyesight is bad and I usually don't see a cracked solder joint. is that a big capacitor to the left of the IC? is that joint ok ?

 

seems odd you get a good picture but the whole game doesn't appear

[AtariLeaf]

I wonder if reflowing all the solder joints under the IC chip would help.

 

my eyesight is bad and I usually don't see a cracked solder joint. is that a big capacitor to the left of the IC? is that joint ok ?

 

seems odd you get a good picture but the whole game doesn't appear

 

I did reflow that yep, no difference unfortunately. What you say is true, it's odd I get a picture but not the whole game. I wonder if it is that one grey chip, which I think is a ram chip, is bad. From my limited knowledge a bad ram chip might exhibit this behavior. Without board schematics it's hard to figure out what does what though. There's little technical information on these machines.

 

What I did find from Old-Computers.com. The bolded part is what leaves me to believe that the graphics issue may be this chip.

 

 

These systems were designed around a more advanced chip than the PONG-in-a-chip devices, possibly a microcontroller (believed, since the system also contains a small RAM chip which role is unknown, but believed to be for the display and/or score storage). The microcontroller is referred as C011500-1, although the system uses another Atari chip referenced C011512-05.

 

It seems to be a 16 pin ram chip. I wonder if by chance a ram chip from another machine like an 800xl might work? EDIT - Nope

[thevnaguy]

If the oscillator (the silver can device next to the main chip) is not working, it can cause the screen to freeze up and have graphical glitches as well.

[AtariLeaf]

Thanks for checking in, I'll see if I can source one of these and try replacing it. Thanks Willie