Recently I manage to acquire a sega rally 1 twin.
Left side is blind (no monitor),so I cannot test it,while the right side is “correctly” working…
I only have an audio issue with that…
Basically the first time I play with the cab,the left audio channel stop working after a few minutes.
If I shutdown and restart the cab,the left audio speaker come back to life…but only for a few minutes than stop again.
So I swap the audio board with the other one in the left side.
This time I cannot hear audio from the left speaker at all.
A friend of mine told me that probably could be those chips (only the one manage the left channel)on the audio board to be faulty TA8225H.
Then I bought two new chips so he’ve replaced both on the audio board (the one originally on the working right side….the one I can hear the sound on the left for a few minutes).
I reconnect this audio board but nothing…..
No sound at all from the left channel,just like when I swap the board with the left side board….
Do you know what else could that be?
A model 2 stack problems,or a cablage problem??
Please let me know if you can.
Thank you.
It could be many things.
The board you are talking about is called the Amplifier board.
Basically, you have the Sound Board, which contains the sound banks, the Pre-Amp board, which mixes the sounds to the right speakers, and then the Amp board, which connects to the preamp and speakers.
Replacing the two Toshiba MOSFET is a great start. Look for damaged component, leaking caps on the AMP in the LEFT Speaker part of the circuitry.
The other Amplifier that is not working at all might just as well be damaged, so do not base your diagnostics using it. Keep using the half working one.
One you think there are no problem on the AMP board, we can then start looking down the chain.
