Symptoms of faulty TL783?

[BluegrassDan]

My phantom psu is spewing around 70 vdc. Changing resistors to the TL783 adjust does nothing. Could this be the symptom of a faulty TL783?

Thanks,
Dan

 

[radardoug]

Yes

 

[PRR]

Put a 10K resistor across it and try again.

Some regulators have a minimum load. This has fooled me before.

 

[radardoug]

Across it or from regulated output to ground?

 

[Audio1Man]

This is what PRR is saying, only 3 times lower. The TL783 needs a min of 15ma load to keep it regulated. 48v @ 15ma needs min of 3k20 total load. This is the load when no phantom mic is connected. This is what PRR is saying.
Duke

 

[BluegrassDan]

It has a load, and it's not my first time building this exact circuit. Like an idiot, I accidentally wired the in and out backwards while soldering from beneath. I suspect it's toast.

 

[BluegrassDan]

Replaced the TL783. All is well!