Odyssey 2 video issue

[jtn050]

Hi,

I recently picked up an Odyssey 2. When I turned it on, I could hear the sounds it made through my tv, but the screen was completely blank. I took it apart and cleaned the motherboard, which had some corrosion, and since then the screen now shows a strange flicker of lines whenever there is sound, but if there is no sound the screen stays blank. The pattern of the lines seems to be affected by the pitch of the sounds. I can tell the game is playing in the background, because the sounds match up to what should be happening in the game. One more issue that I have found is that the included power supply seems to be outputting 13.5 volts AC instead of 11.5. Could this be the source of the issue? I'm having some difficulty finding O2 power supplies compatible with my version online. I've also cleaned out the RF modulator and reseated the CPU and Video/audio chips, but nothing changed.

I've attached a picture of one of the brief static flashes when there is sound.

[emerson]

The fact that your power supply measures a little high is not a big issue, especially if you're measuring it with an open load (without the console connected). Looking at the schematic, it appears the AC power runs directly to a full wave rectifier then to a 5V DC regulator. I'd assume your power supply is safe as is, as long as it can supply the necessary current. I use an original NES power supply with my Odyssey2. It's rated 9V AC but measures 10.65V AC open load.

 

What channel is your tv set to? I notice when I set my tv to channel 3 I get the correct sounds but the picture is garbage. Setting my tv to channel 4 fixes it.

 

Useful tech info: https://console5.com/wiki/Odyssey2

[jtn050]

I've tried the RF modulator on channel 3 and 4, but both have the same output.

[emerson]

When you reseated the chips did you clean the pins and ic sockets? Double check they are installed in the correct direction and that no pins accidentally bent underneath the chips. It's possible whatever caused the corrosion inside also damaged the capacitors, have you checked those? Try reflowing the solder joints that had corrosion on them.

 

Have you checked continuity of the wires that connect the main board to the rf modulator? Check for a signal on the video wire as well. If both of those are good, then check inductor L5 inside the rf modulator and ensure the video signal is getting to the 612178-1. If that all checks out, start looking at the video signals between the 612130-1 and 612160-1 chips. Ensure the logic gates on the video and blanking signals are good.

[jtn050]

Thanks for the help, when I get a chance I'll test those points and reflow the solder joints. The caps look good. I'll also make sure to clean the pins on the ICs because I didn't do that the first time.