Fostex B16 audio dead.

andre tchmil · Jun 19, 2016

I'm trying to repair a Fostex B16 machine.
All mechanical functions are working, All power regulators are working.
no audio is coming through, counter display reads EEEE.EE
any idea ?

gyraf · Jun 20, 2016

Some digital power supply line gone off?

andre tchmil · Jun 20, 2016

gyraf said:
Some digital power supply line gone off?

Without a service manual that's going to be difficult to trace I'm afraid.

RuudNL · Jun 20, 2016

I used to have the full service documentation of the B16, but I sold it together with the machine years ago...
Strange that there is interaction between the tape counter and the audio circuits.
Looks that there is an internal supply voltage missing.
Can you measure the supply voltage(s) on the audio PCB's?

andre tchmil · Jun 20, 2016

RuudNL said:
I used to have the full service documentation of the B16, but I sold it together with the machine years ago...
Strange that there is interaction between the tape counter and the audio circuits.
Looks that there is an internal supply voltage missing.
Can you measure the supply voltage(s) on the audio PCB's?

hi Ruud.
I measure +/- 9 volt on the audio pcb rails.
anything else missing ?

RuudNL · Jun 20, 2016

The good thing is that the + and the - voltages are the same.
This would suggest that these voltages are correct, however I would have expected + and - 15 V.
Can you find the voltage regulators in the power supply?
It is so long ago, that I really don't remember the supply voltages.
The only thing I know for sure is that the G16 used +15, -15 and +5V.
(I can't imagine that they drastically changed the power supply.)