wildrecords
New member
Hi all, first post after years of lurking.
I recently pulled a Teac Tascam 80-8 out of the corner where its been for 14 years. When I originally bought it all those years ago it worked fine except that channels 1&8 would not pass signal. I took it to a local tech who after a month tried his best and told me that the heads were finished and the machine wasn’t worth fixing. Younger me believed what the man said and took it home. I recorded with channels 2-7 for a little while before moving on to other machines and eventually forgetting about it until now!
First thing I checked was Channel 1.
I wanted to see if the heads were really as destroyed as I thought... Still didn’t work.
I cleaned the heads and tape guides and got a good look at them. Not the greatest looking but actually not as band as I remembered. I threaded the tape and realized that whoever last adjusted the tape guides did and awful job. So awful that the tape was missing Channel 1 on both head stacks entirely. I realigned the tape guides and tested channel 1. IT WORKS.
Checked channel 8.
No signal still.
Looked at the amplifier cards. Channel 8 had one blown resistor (R75).
I Swapped channel 7’s card into channel 8’s slot.
Test record/playback. Channel 8 PASSES SIGNAL.
Now that I know the heads aren’t destroyed, I decide this machine is worth working on.
One problem that seems to have developed since the last time I recorded with the 80-8 is that the capstan solenoid (actually part of the pinch roller) will not engage and lock. While testing channels 1&8, I had to manually “help” the solenoid into its full locked position, once it locked, the machine ran fairly smoothly.
I decided to test the voltage at the capstan solenoid in play mode to see how much voltage it was receiving.
It peaked at about 6v and dropped to a constant 3v when play engaged. It seems low to me but I don’t know what its supposed to be. (Anybody know?) I should note that it took me a while to realize that the solenoid was releasing from locked to free when I hit stop. That tells me the release function was at least getting enough voltage to operate. I also realized another issue.
Earlier when I said the machine ran “fairly smoothly” I meant that it was just about up to speed but on occasion I would hear it lag and slow down. This was solved when I manually “helped” the brake solenoids for both reel motors.
For a little while I had the machine running smoothly channels 1-8 for the first time!
Then something bad happened.
While I was probing and checking diodes on the power supply, something burned for about a second because I accidentally completed a circuit (naughty naughty me). I think it came from either C1 or C12 on the power supply. Since the mystery part burned, the poor 80-8 has even less voltage going to all three solenoids. None of them will lock into place even with help. (Bummer)
I discharged the capacitors from C1 and C12 and removed them. I checked them out of circuit (like a good boy) with the help of a slow multimeter.
C1 is a 25v 4700uF three pin capacitor.
My multimeter read 4395 uF.
C12 is a 50v 2200 uF three pin capacitor
My multimeter read 1697 uF.
I read on another post entitled “80-8 Total Solenoid Failure” and it led me to test the diodes leading to these capacitors. OP’s problem ended up being IC2.
I have a gut feeling that the problem lies with one of these capacitors and when it burned, the solenoid problem became worse.
Am I on the right track?
Anybody got any ideas?
Should I just replace the C1 and C12?
Do you think I should replace the IC?
What should I do?
Thanks in advance.
tldr: all three solenoids don’t engage in play mode and it seems to be a power issue. what should i do?
I recently pulled a Teac Tascam 80-8 out of the corner where its been for 14 years. When I originally bought it all those years ago it worked fine except that channels 1&8 would not pass signal. I took it to a local tech who after a month tried his best and told me that the heads were finished and the machine wasn’t worth fixing. Younger me believed what the man said and took it home. I recorded with channels 2-7 for a little while before moving on to other machines and eventually forgetting about it until now!
First thing I checked was Channel 1.
I wanted to see if the heads were really as destroyed as I thought... Still didn’t work.
I cleaned the heads and tape guides and got a good look at them. Not the greatest looking but actually not as band as I remembered. I threaded the tape and realized that whoever last adjusted the tape guides did and awful job. So awful that the tape was missing Channel 1 on both head stacks entirely. I realigned the tape guides and tested channel 1. IT WORKS.
Checked channel 8.
No signal still.
Looked at the amplifier cards. Channel 8 had one blown resistor (R75).
I Swapped channel 7’s card into channel 8’s slot.
Test record/playback. Channel 8 PASSES SIGNAL.
Now that I know the heads aren’t destroyed, I decide this machine is worth working on.
One problem that seems to have developed since the last time I recorded with the 80-8 is that the capstan solenoid (actually part of the pinch roller) will not engage and lock. While testing channels 1&8, I had to manually “help” the solenoid into its full locked position, once it locked, the machine ran fairly smoothly.
I decided to test the voltage at the capstan solenoid in play mode to see how much voltage it was receiving.
It peaked at about 6v and dropped to a constant 3v when play engaged. It seems low to me but I don’t know what its supposed to be. (Anybody know?) I should note that it took me a while to realize that the solenoid was releasing from locked to free when I hit stop. That tells me the release function was at least getting enough voltage to operate. I also realized another issue.
Earlier when I said the machine ran “fairly smoothly” I meant that it was just about up to speed but on occasion I would hear it lag and slow down. This was solved when I manually “helped” the brake solenoids for both reel motors.
For a little while I had the machine running smoothly channels 1-8 for the first time!
Then something bad happened.
While I was probing and checking diodes on the power supply, something burned for about a second because I accidentally completed a circuit (naughty naughty me). I think it came from either C1 or C12 on the power supply. Since the mystery part burned, the poor 80-8 has even less voltage going to all three solenoids. None of them will lock into place even with help. (Bummer)
I discharged the capacitors from C1 and C12 and removed them. I checked them out of circuit (like a good boy) with the help of a slow multimeter.
C1 is a 25v 4700uF three pin capacitor.
My multimeter read 4395 uF.
C12 is a 50v 2200 uF three pin capacitor
My multimeter read 1697 uF.
I read on another post entitled “80-8 Total Solenoid Failure” and it led me to test the diodes leading to these capacitors. OP’s problem ended up being IC2.
I have a gut feeling that the problem lies with one of these capacitors and when it burned, the solenoid problem became worse.
Am I on the right track?
Anybody got any ideas?
Should I just replace the C1 and C12?
Do you think I should replace the IC?
What should I do?
Thanks in advance.
tldr: all three solenoids don’t engage in play mode and it seems to be a power issue. what should i do?
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