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dufflespank
New member
Hello,
I finally got around to taking my 688 apart to see whats going on under the hood. When I got this thing off ebay, it arrived tp me in pretty much non-working order, and the seller refunded me and let me keep it. So now I'm motivated to fix this thing and have a 688 for free.
My housemate has one of these so I can verify what his does and what mine does not do.
Biggest problems:
1) When you turn it on, there is a loud hum/buzz...I'm almost certain this is the motor in the tape deck as the pitch of the hum increases if you turn up the motor speed.
2) I can't get any tracks to come through the monitor. I've plugged in various instruments to the inputs and followed the procedure to assign a track, but nothing comes through. One thing I see on mine that I didn't see on my housemates was that when I assign a track, one of the led's on the volume meter for that channel turns on orange for a second and then turns off. The only time I heard anything come through the monitor was when we put a tape in and pressed play... even then, only the left channel came through the monitor.
I've opened it up and
1) The fuses on the power supply board are still good.
2) The pcb's don't seem to have any cracks.
3) There appears to be some brownish or reddish stuff on some sections of the pcb... like a thin film which could be the rosin or flux from soldering, but it appears even on the tops of the pcbs where there are no solder joints. I'm wondering if this thing has ever been spilled on.
Any clues as to what could be going on? I'd really appreciate a service manual PDF, as I would like to check the voltages at certain points in order to convince myself that the power supply is working properly. Is it possible that the noisy motor could be drawing a lot of current or something and screwing up the power for the rest of the machine? Doubtful, I know, but I'm not sure where to start.
THANKS
I finally got around to taking my 688 apart to see whats going on under the hood. When I got this thing off ebay, it arrived tp me in pretty much non-working order, and the seller refunded me and let me keep it. So now I'm motivated to fix this thing and have a 688 for free.
My housemate has one of these so I can verify what his does and what mine does not do.
Biggest problems:
1) When you turn it on, there is a loud hum/buzz...I'm almost certain this is the motor in the tape deck as the pitch of the hum increases if you turn up the motor speed.
2) I can't get any tracks to come through the monitor. I've plugged in various instruments to the inputs and followed the procedure to assign a track, but nothing comes through. One thing I see on mine that I didn't see on my housemates was that when I assign a track, one of the led's on the volume meter for that channel turns on orange for a second and then turns off. The only time I heard anything come through the monitor was when we put a tape in and pressed play... even then, only the left channel came through the monitor.
I've opened it up and
1) The fuses on the power supply board are still good.
2) The pcb's don't seem to have any cracks.
3) There appears to be some brownish or reddish stuff on some sections of the pcb... like a thin film which could be the rosin or flux from soldering, but it appears even on the tops of the pcbs where there are no solder joints. I'm wondering if this thing has ever been spilled on.
Any clues as to what could be going on? I'd really appreciate a service manual PDF, as I would like to check the voltages at certain points in order to convince myself that the power supply is working properly. Is it possible that the noisy motor could be drawing a lot of current or something and screwing up the power for the rest of the machine? Doubtful, I know, but I'm not sure where to start.
THANKS