samgraysound
Well-known member
Hi,
I'm troubleshooting a Fostex 250 casette recorder. It will not record on to Track 1. All the other tracks work fine, and it doesn't matter what channel is routed to track 1.
I've been trying to trace the signal through the signal path and compare to working channel. I believe the signal is lost in the record/playback amplifier (attached schematic).
I don't really understand the Dolby circuit, but theoretically it should be turned off by S101. So it shouldn't matter?
The signal is not reaching the input of U103. I see it on one side of Q111 but not the other. Q111 and D108 are passing a diode test in circuit. Voltages are same on Q111 across all the channels.
I could use some help.
Sam
I
I'm troubleshooting a Fostex 250 casette recorder. It will not record on to Track 1. All the other tracks work fine, and it doesn't matter what channel is routed to track 1.
I've been trying to trace the signal through the signal path and compare to working channel. I believe the signal is lost in the record/playback amplifier (attached schematic).
I don't really understand the Dolby circuit, but theoretically it should be turned off by S101. So it shouldn't matter?
The signal is not reaching the input of U103. I see it on one side of Q111 but not the other. Q111 and D108 are passing a diode test in circuit. Voltages are same on Q111 across all the channels.
I could use some help.
Sam
I
