On Sat, 03 Mar 2012 08:45:51 +1100, Franc Zabkar
wrote:

On Fri, 2 Mar 2012 15:30:36 -0500, "John Smith"
put finger to keyboard and composed:

Socket pin V, Chip pin V.

1 -16.5, -1.04
2 0.01, -1.98
3 0.01, -0.66
4 0, 0
5 -2.39 -2.39
6 76.6 -2.38
7 0, -1.29
8 0.3 0.122
9 0.3 0.3

Something tells me that this can't be a TA7317P despite its markings.

It sure looks that way. That said, I can't see any economic incentive
to counterfeit a part that I can buy for AU$2.75 in single quantities.

Maybe you should bite the bullet and buy it as a spare part from
Panasonic or Yamaha?

BTW, the more I examine the circuit, the more errors and anomalies I
find. For example, AFAICS there is a 50V capacitor (C409) in the 40V
phantom power supply that would be operating at 49V. I have a feeling
that the correct HV supplies should be +/-55V, not 75V.

It begins to sound like somebody "hot rodded" the amplifier. And did a
shoddy job of it.

There is also a PNP transistor (Q405) in the -15V supply that is drawn
as an NPN, and a 2SD transistor (Q401) in the 40V supply is listed as
a 2SC in the parts list.

My overall impression is that it's a shoddy product.

- Franc Zabkar