Onkyo TA-2070 - No left channel

priglmeier

New Member
Hey all,

I own a Onkyo TA-2070 and it does function for the most part except the left audio channel.
The meters show no output and there is no audio from the left channel out of the rear of the unit.

I downloaded the service manual and I have gone through the schematics for the left channel.
So far I have not found any bad components.

I have worked on 1980s + arcade machines for a long time and I have repaired a lot of gear, but the schematics have me a bit lost. I am wondering if there are folks who have worked on this unit or know of other places to look? Arcade schematics have test points, repair examples, etc. and this manual has nothing. Could the Head itself be bad / failed?

thanks
 
Record a 400 Hz 0dB signal on a full working deck.

Then play it on the Onkyo

Looking at the schematics, follow the signal path with a scope until you loose the signal. Use the component side for easy and quick identification, and connect you scope to resistors or ic as their pins are easier to reach that capacitors or transistors.

Then narrow you research using the solder side of the printed circuit board.

Culprits are usually capacitors or tape monitor relays.
 
That makes sense. In old arcade games, 80% of issues are old capacitors. I'll power on the HP 16500c logic analyzer and use the scope. I wish the schematic were a bit easier to read and follow... I'll let you know what I find.
 
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