B3R0V0N
11-30-2009, 11:24 AM
Hello, I have a problem with my Odyssey 2. I am getting sound and a black screen but no graphics. When I press enter the game starts and the sound is working fine but no graphics. Thought it might have been a RF modulator issue but i was able to get changes in the video by inputting the audio into the video of the RF modulator. I all so checked pin number 6 and 28 for the 5v dc and it was there on IC 612130-1 other wise known as IC 5. Anyone got a clue as to what should be my next move on this. Thanks, in advance.
channelmaniac
12-01-2009, 05:11 PM
If you have a logic probe or oscilloscope, check for signals on pins 18-20, 4, 5, 7, 8, and 10 on IC5 (612130-1). IC5 is the sound/graphics chip.
Next check the color encoder chip (IC1) on pins 7-13 for signals, 1 for +5v, and check/adjust R4 (Video Level Adjust).
IC3 and IC4 could affect it too. They connecrt the video, vertical blank, and horizontal blanking signals between the CPU, IC5, and IC1.
THose are the most obvious things to check. It could be a problem in one of the discrete components (transistors, diodes, resistors, etc...) as well, but those are more difficult to check.
I have parts for the O2 listed on my website: http://www.arcadecomponents.com and have a spare parts unit in storage.
Google o2-svc.pdf to get the service manual.
B3R0V0N
12-02-2009, 04:36 PM
It was IC1 the color encoder chip. Thanks, again for your help.
channelmaniac
12-03-2009, 12:18 AM
You're welcome. I have the chip on my site if you need one.