Odyssey 2 tech help

DommieDommie
in Help Wanted!
Hey everybody,

I posted this the other day in atariage, but nobody really had any insight as to what the problem might be or how to fix it.

I have 2 O2's that both have the same exact problem - when I insert a cart and power it on I get either a solid color on the screen or a jumble of junk characters/sprites.  Sometime this wonderful phenomenon is accompanied by a loud buzzing sound from the TV speakers.  Here is a pic of the screen to get an idea of what I'm talking about:

image

I have about 30 or so O2 games, all with the same or similar results.  Now, the O2 carts are a real pain to open since the screws are hidden behind the cart label, but I do have one cart missing the label so I opened that one up to see if I could spot any corrosion on the cart pins.  They looked remarkably clean, but I tried cleaning them up some anyway - still no dice.

I also took the console apart and inspected the board and cart connector slot - everything looked good, but I did notice a few very small bits of rust colored corrosion and a small bubble where these spots occurred.  I poked at them a bit and as best I can tell it's just defects from the manufacturing process.  Anyhow, somebody a while ago suggested that the electrolytic capacitors on the board may be dried out and bad.  I finally got around to replacing the caps (at least the electrolytic ones) on the board, except for one little 1uF cap at the top of the board that I accidentally bought the wrong cap to replace it with.  And still I have the same problem.

Also, I heard of people leaving their O2 on for a while to "warm up" the system.  I tried this also - no dice.  Any thoughts as to what the problem could be?  I'm stumped.

Comments

  • RetroHackerRetroHacker
    I would be inclined to say that it has something to do with the RAM. If I remember correctly, the Odyssey2 uses internal CPU ram for most stuff, then an external RAM chip for video registers. So, if I had a guess, I'd say that there is something wrong with that external RAM. According to the schematics in the Odyssey service manual, it shows what looks like a 24 pin 256byte static RAM chip at IC9. Unfortunately, the manual does not give a proper part number, only a Magnavox stock number for this chip. I don't know what an equivilent part would be.

    Does this chip have any markings?

    -Ian
  • MachineGexMachineGex
    Are you using the same power supply on both systems? If so, try another power supply....but it really sounds like both systems are bad...... but it is so weird that the both have the same problem. Very strange....

  • DommieDommie
    Originally posted by: MachineGex

    Are you using the same power supply on both systems? If so, try another power supply....but it really sounds like both systems are bad...... but it is so weird that the both have the same problem. Very strange....



    Yeah, I only have 1 power supply - original marked Odyssey 2 power supply.  I haven't tested it because I seem to have misplace my multimeter.  image
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