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A-3440 4-track R2R Issues

Navcom

Navcom

New Member
I have a recently acquired Teac A-3440 that worked great during testing before purchase but after I got it to our studio, it’s slowly losing power. When I run the unit in play, it will turn and slowly start to stop until the shut-off arm swings down and the unit stops. Happens every time…runs for about 5 seconds and then dies. FF and RW work fine. It’s strung correctly. I am no expert at R2R machines but I’m not afraid to get my hands dirty with a project and have experience fixing mechanical things all my life, including audio/music gear.

It appears to be a power issue but I’m not sure where to start. The capstan is turning and I’ve replaced the capstan tire. It has new belts all around. Ive attempted to adjust the back tension and take-up torque…it has no effect. As a matter of fact, just applying a tension gage will just stop the wheel. The reels will slowly die even when just running wheel to wheel without running through the heads and manually holding up the stop arm. I can put light pressure on either wheel and it will just stop and not restart unless I hit stop and play again.. I’ve replaced the large start capacitor with new…no difference. Could this be the transformer? Power pcb? Any ideas? Appreciate any help as I’m at a loss!
 
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Navcom said:
I have a recently acquired Teac A-3440 that worked great during testing before purchase but after I got it to our studio, it’s slowly losing power. When I run the unit in play, it will turn and slowly start to stop until the shut-off arm swings down and the unit stops. Happens every time…runs for about 5 seconds and then dies. FF and RW work fine. It’s strung correctly. I am no expert at R2R machines but I’m not afraid to get my hands dirty with a project and have experience fixing mechanical things all my life, including audio/music gear.

It appears to be a power issue but I’m not sure where to start. The capstan is turning and I’ve replaced the capstan tire. It has new belts all around. Ive attempted to adjust the back tension and take-up torque…it has no effect. As a matter of fact, just applying a tension gage will just stop the wheel. The reels will slowly die even when just running wheel to wheel without running through the heads and manually holding up the stop arm. I can put light pressure on either wheel and it will just stop and not restart unless I hit stop and play again.. I’ve replaced the large start capacitor with new…no difference. Could this be the transformer? Power pcb? Any ideas? Appreciate any help as I’m at a loss!
Click to expand...

What tape are you running on it? Sounds like it could be a sticky shed issue. Tape with binder problems exhibit the symptom you described.
 
I've run three different reels on it...an older roll and two brand new rolls that I just purchased from ATR. Even without any tape installed, I just need to touch one of the reels and it will stop. It will start but then just die after a few seconds just like with the tape on it. FF and RWD work just fine as far as I can tell. They don't stop. Not sure if they are powerful as they could be or not.
 
Could be simple as it needing some lubrication. There is well know issue with the 2300, 3330, 4300, 6300 and their xx40 cousins with the pinch rollers not snapping firmly and quickly into place, also be sure to lube the motors and do a quick search on proper lubricants for that series of reel players. There are tons of videos on youtube with folks fixing the capstan pivot shaft issue. I will include a link to a video showing how a properly cleaned and lubed pivot point should snap the pinch roller into place if yours is sluggish look at some more videos on how to solve.

 
Since FF and rewind work ok, that means the reel motors and supply are ok. It is probably dirty contacts on a relay that routes the reel motor voltage through the torque adjusting resistors when it's in play. Look at the relays and see which ones engage when you push play. Then remove the relays by desoldering them, remove the cover and clean them with a piece of paper wetted with Deoxit D5. Draw it through the contacts while holding them closed. Connect your meter to the relay pins, hold it closed and measure the resistance. Keep cleaning until it's 0 Ohms.
 
Could be bad motor run capacitors on the reel motors. These are common failure points an these decks. They can be replaced with ceiling fan motor run capacitors. Don't use one that is not designed for continuous motor duty.

The capstan motor is DC, so much more complicated to troubleshoot, but the fact that the tape slackens allowing the shut-off switch to trip points to the take-up reel motor. . .

Rich
Capture.JPGCapture1.JPG
 
Not necessarily. They are fed with a higher voltage during FF and REW so maybe that overcomes the reduced torque due to phasing issues caused by the caps. The lack of take-up during play would seem to point directly at the reel motor. Check to see if it gets very hot.
 
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Richard P said:
Could be bad motor run capacitors on the reel motors. These are common failure points an these decks. They can be replaced with ceiling fan motor run capacitors. Don't use one that is not designed for continuous motor duty.

The capstan motor is DC, so much more complicated to troubleshoot, but the fact that the tape slackens allowing the shut-off switch to trip points to the take-up reel motor. . .

Rich
View attachment 3055231View attachment 3055233
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I referred to it as the start capacitor in my OP but I believe it’s the same one. It’s the dual 7uF, 250v large can cap. I’ve replaced it with new caps and it still does it.
 
petes'picks said:
Could be simple as it needing some lubrication. There is well know issue with the 2300, 3330, 4300, 6300 and their xx40 cousins with the pinch rollers not snapping firmly and quickly into place, also be sure to lube the motors and do a quick search on proper lubricants for that series of reel players. There are tons of videos on youtube with folks fixing the capstan pivot shaft issue. I will include a link to a video showing how a properly cleaned and lubed pivot point should snap the pinch roller into place if yours is sluggish look at some more videos on how to solve.

Click to expand...

Not that it couldn’t be bit I don’t believe tha capstan is the problem. Probably should’ve posted this originally but here’s a video of what’s going on…


 
dr*audio said:
Since FF and rewind work ok, that means the reel motors and supply are ok. It is probably dirty contacts on a relay that routes the reel motor voltage through the torque adjusting resistors when it's in play. Look at the relays and see which ones engage when you push play. Then remove the relays by desoldering them, remove the cover and clean them with a piece of paper wetted with Deoxit D5. Draw it through the contacts while holding them closed. Connect your meter to the relay pins, hold it closed and measure the resistance. Keep cleaning until it's 0 Ohms.
Click to expand...
Interesting about the relay(s). I will check that!
 
All…

here’s where I’m at. I have a capacitor replacement kit and have replaced all the caps on the power supply board, the control board, and the stop sensor board. Also the start caps as noted in the OP (the huge can cap that’s 7uF x 2). Problem still exists. I think I will try cleaning relays as recommended and see if that helps. Also, here is a video of what’s going in. Should’ve posted this originally. Sorry!…
 
Navcom said:
I referred to it as the start capacitor in my OP but I believe it’s the same one. I
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Sorry, I missed that . . . .

Take-up reel tension is adjusted using the three large ceramic resistors in the top right corner looking from the back. You'll need a spring scale to measure the tension for both small and large reels. It could be that the resistor to slider connection has become corroded over time and just needs a cleaning. It could also be dirty relay contacts as mentioned above. . . . All of these would result in reduced voltage to the motor and reduced torque as you are witnessing. It's a simple circuit so it should be fairly easy to confirm where you're losing voltage:

Capture.JPG
 
Richard P said:
Sorry, I missed that . . . .

Take-up reel tension is adjusted using the three large ceramic resistors in the top right corner looking from the back. You'll need a spring scale to measure the tension for both small and large reels. It could be that the resistor to slider connection has become corroded over time and just needs a cleaning. It could also be dirty relay contacts as mentioned above. . . . All of these would result in reduced voltage to the motor and reduced torque as you are witnessing. It's a simple circuit so it should be fairly easy to confirm where you're losing voltage:

View attachment 3056963
Click to expand...

LOL. Also said in the OP that I adjusted those too.

it is a simple circuit but I’m not an experienced electrical guy. I can work but I need some direction on where to start. For Instance, I can run a multimeter but I have no idea where or what to test. But I’m willing to learn. I want to learn.
 
Normally I wouldn't try to send someone off to another forum, but it could be time to put this before the people at Tapeheads. Quite a lot of TEAC experience over there.
 
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