Samsung TXR2765 shuts down ~7 sec after turn on

[Mark_eh7]

Secondary supplies look OK (according to PCB silk-screen; no schem):
+135, +15, +12, +7; then downstream off the 78R0x regulators, +9, +5, +5. HV comes up, too.

I get a little tune before it shuts down - announcing a protection circuit kicking in?
There's an STRX6759 with OVP, OCP, and FB pins; they measure about 0.7, 1.1, and 1.4 V respectively.
I'm not familiar with this device, but I'm guessing it's OK if it's letting the HV come up?
The diodes in the circuit check OK, and the solder joints look good (around the flyback too).

Anyone have any experience with this device or chassis?

Thanks,
Mark