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I got two of these, one is a TD-7 and one is a TD-8. They seem to respond to
input but do not make sound. The little "trigger" light lights up.

I also have one of another brand that only puts out sound through the
headphone jack.

I am comoing up with a blank finding prints fro these. Anyone know any
common failure oes or whatever, or worked on a bunch of them ? Need a couple
of tips.





First job is to make sure there is +/- 15v on the output op-amps, but you
knew that already.

Each output has a mute (2SC) transistor that shorts the output to ground. I
have found these faulty in the past, possibly damaged by connecting to a
phantom powered input channel.
You can snip through the collectors if there is room, to disable them for a
quick check, or just take them out.

Also have a look at the main and headphone volume pots to see if there is a
signal coming in and out. Most likely the problem is between here and the
outside world, including the final stage op-amps, again possibly damaged by
phantom power. They will have full DC output if toasted.
It is rare to find any problems in the digital/DAC stages.

I suspect what happens in the Phantom Power case, is that the user tries one
output to find it doesn't work, then goes round all the others trying them,
and breaking them too.



Cheers,


Gareth.