Super Pong C-140 No audio or video

[Leufion]

Hi all,

I have a Super Pong model C140 that I've been working on for a little while. When I first turned it on I was able to get video and audio and then it all went dark and silent. When I opened up the system I noticed how dirty and corroded it was inside so I did some thorough cleaning and replaced the C1, C17 and C30 caps. I wasn't able to get video or audio, but after tracing the voltage I noticed that CR1 and CR5 didn't seem to be working correctly so I replaced those as well.
 

Looking at the schematics from Jerzy Sobola I am able to trace voltage from having 1.12v from L1+L2 through to C24. It stops after this when the T1 transformer is supposed to send it to C27 through to the RF jack. Are there any tests I can do on the transformer to see if it's the issue or not? Any chance of bypassing it?

 

As for the audio line it's odd because the Q1 transistor connects to the speaker wire connectors, at 6.12v, but as soon as I plug the speaker wire into the connector it goes down to 0.62v. I don't know if that means the wire is bad or something is wrong with the speaker.

 

Any ideas on what to check next? 

[fluxit]

Did you see this thread?  You can check both sides of the transformer for continuity, and you could also check it with an inductance meter, but so long as it has continuity, and isn't shorted you should be fine as far as the transformer is concerned.

 

 

[Leufion]

I did see that thread thankfully - it provided good schematics and part numbers for the system. Testing continuity between both sides of the transformer it appears that all 4 pins are grounded.