Hi,
I purchased this casette deck used on ebay, but in excellent condition. It has this problem.
Cassettes play and record satisfactorily. However I have this annoying problem.
Usually in the middle of play, the take up spindle stops rotating in the middle of the play and then
deck stops playing. I turn off the deck, or even fast fwd or rewind the cassette. Then when pressing play, the playing starts, then shortly after that, the take up spindle stops rotating and the play stops. I don't have a service manual of it, but I have good understanding and technical skills. I am an engineer.
It appears it has 3 motors and 2 belts. I havent opened the case yet. Could this be a worn belt problem, which may be easy to replace,
or more of a logic control issue? Has anyone experienced such thing?
Thank you in advance for any help.
Dinu
I purchased this casette deck used on ebay, but in excellent condition. It has this problem.
Cassettes play and record satisfactorily. However I have this annoying problem.
Usually in the middle of play, the take up spindle stops rotating in the middle of the play and then
deck stops playing. I turn off the deck, or even fast fwd or rewind the cassette. Then when pressing play, the playing starts, then shortly after that, the take up spindle stops rotating and the play stops. I don't have a service manual of it, but I have good understanding and technical skills. I am an engineer.
It appears it has 3 motors and 2 belts. I havent opened the case yet. Could this be a worn belt problem, which may be easy to replace,
or more of a logic control issue? Has anyone experienced such thing?
Thank you in advance for any help.
Dinu
Some further clues here on this thread:
https://www.diyaudio.com/community/threads/how-many-cassette-deck-users-here.388312/latest
Like Rayma says, do the mechanical stuff first, before going deeper.
Teac decks were well made, but an old set is an old set.
And you may not know how carefully it was used.
Take care, read up before going deeper than a mechanical service.
Get the schematic as well if needed.
Of course, you will need meters, and other tools, I have no idea of what you have as tools, or what kind of engineer you are...
https://www.diyaudio.com/community/threads/how-many-cassette-deck-users-here.388312/latest
Like Rayma says, do the mechanical stuff first, before going deeper.
Teac decks were well made, but an old set is an old set.
And you may not know how carefully it was used.
Take care, read up before going deeper than a mechanical service.
Get the schematic as well if needed.
Of course, you will need meters, and other tools, I have no idea of what you have as tools, or what kind of engineer you are...
OK fellows. I think I have everything needed to diagnoze this, including the service manual. The machine appears in excellent shape, and it was apparently used carefully.
It is the 3rd time I opened the cover of this machine, But this time I remove the whole head assy to examine it's operation out of the machine, that means all connections were kept but I was able to measure and see how it works and what may be wrong. This is what I found: Head Assy looks visually in perfect shape. No heads wear or damaged wires. The two belts look in good shape. But when the take up reel stops working, the motor driving it does not receive power from the control unit. It drives the fwd reel during play, and also fast forwind. I thing it does also rewind. During normal play the voltage is approx 3.5 V, and during fast forwind the voltage is 4.9-5 V.
When the take up reel stop rotating, the meter measures 0 V. So the power is cut from the control board. Therefore is not a faulty motor as other suggested, but a control issue which needs to be further diagnozed. In order to detect or identify bad soldering points, I need to remove the control PCB because the solder point are underneath. This was beyond the today's task. I still think it's more a problem with an electrical component on the control PCB, maybe an electrolytic capacitor, than a bad soldering point. The electrolytic capacitors look in good shape. There are more than one microprocessor chip on the control board. If a microprocessor is causing it, then this this is not good. Again the problem happens randomly. And this machine has a very sensitive tape drive mechanism. Once the take up reeel stops rotating, and tape gets out of it's straight path at the fwd pinch roller, the machine cuts the play very quickly. So it's a control problem and not a worn out or faulty electrical motor. This would be quite hard to diagnoze. I need to look into the schematic and see where that motor is getting it's power from. It's a DC motor and it has 2 wires. This is all that I found.
It is the 3rd time I opened the cover of this machine, But this time I remove the whole head assy to examine it's operation out of the machine, that means all connections were kept but I was able to measure and see how it works and what may be wrong. This is what I found: Head Assy looks visually in perfect shape. No heads wear or damaged wires. The two belts look in good shape. But when the take up reel stops working, the motor driving it does not receive power from the control unit. It drives the fwd reel during play, and also fast forwind. I thing it does also rewind. During normal play the voltage is approx 3.5 V, and during fast forwind the voltage is 4.9-5 V.
When the take up reel stop rotating, the meter measures 0 V. So the power is cut from the control board. Therefore is not a faulty motor as other suggested, but a control issue which needs to be further diagnozed. In order to detect or identify bad soldering points, I need to remove the control PCB because the solder point are underneath. This was beyond the today's task. I still think it's more a problem with an electrical component on the control PCB, maybe an electrolytic capacitor, than a bad soldering point. The electrolytic capacitors look in good shape. There are more than one microprocessor chip on the control board. If a microprocessor is causing it, then this this is not good. Again the problem happens randomly. And this machine has a very sensitive tape drive mechanism. Once the take up reeel stops rotating, and tape gets out of it's straight path at the fwd pinch roller, the machine cuts the play very quickly. So it's a control problem and not a worn out or faulty electrical motor. This would be quite hard to diagnoze. I need to look into the schematic and see where that motor is getting it's power from. It's a DC motor and it has 2 wires. This is all that I found.
Its not mechanical. it's electrical. See my last post. When this happens the electric motor driving the fwd reel does not get power from the control PCB.
I have the whole service manual, including all schematics. And yes, this deck is built like a tank. 🙂 Thank you, Naresh.
All is clean and the belts are in good shape. The problem is electrical. not mechanical.
Electric power will come from the board with two wires, more than that could be sensing only...
See the other thread, relays and capacitors need checking.
You can remove the motor, connect to external 5 V, and leave it on for 5 minutes, see if anything odd happens.
Go there after ruling out bad contacts in wires and relays, and changing all the electrolytics. Could be stupid fault like dry joint...enjoy.
See the other thread, relays and capacitors need checking.
You can remove the motor, connect to external 5 V, and leave it on for 5 minutes, see if anything odd happens.
Go there after ruling out bad contacts in wires and relays, and changing all the electrolytics. Could be stupid fault like dry joint...enjoy.
Spray the relays as well, if you can, but a relay giving up as if coil over heated is not trustworthy, better to replace it.
Whilst this does appear to be an electrical problem if either of the two belts or the take up spool clutch is slipping the spool sensor will cut power to the motor. Silly question have you tried a different cassette? Sometimes the spool inside a cassette will catch as it turns and fool the sensor into stopping the tape. High end machines can be sensitive to different tapes.
Movement of the cassette tape during play is monitored by an opto electrical system.
The underside of the take up and supply reel has a reflective/non reflective pattern.
(alternative black and silver blocks).
Under the reel tables is a LED/photo transistor assembly, that generates the pulses if the reels are turning.
Failure of these pulses puts the deck in stop mode.
Carefully remove the reel tables and clean the underside and the photo assemblies.
Make sure not to lose any small part!
The underside of the take up and supply reel has a reflective/non reflective pattern.
(alternative black and silver blocks).
Under the reel tables is a LED/photo transistor assembly, that generates the pulses if the reels are turning.
Failure of these pulses puts the deck in stop mode.
Carefully remove the reel tables and clean the underside and the photo assemblies.
Make sure not to lose any small part!
So, I sent this tape deck for repair to George Meyer AV, an excellent electronics shop in Los Angeles CA.
They fixed it and very quickly. The issue was the take up spindle motor. They replaced the motor and installed
original belts. They said the wrong belts were installed in a previous repair. It's alright now but the repair cost like $500. This was the price I paid on ebay for this machine. Well, this is life. Thank you all for your replies.
They fixed it and very quickly. The issue was the take up spindle motor. They replaced the motor and installed
original belts. They said the wrong belts were installed in a previous repair. It's alright now but the repair cost like $500. This was the price I paid on ebay for this machine. Well, this is life. Thank you all for your replies.
Yes. But it was not a cassette's fault. I tried everything I was able to. I'm using high quality cassettes. I am not an electronics repair technician. But I am handy at repairs, an aerospace engineer myself. To me it appeared like a control issue. The take up motor would lose power when the mechanism shut down. I measured the voltage with a multi meter. It went to zero, when this occured. This is a very sturdy machine and quite heavy, very well built. I sent it for repair to an excellent repair shop in LA. The motor was the faulty part, and some belts. It works fine now. Thank you.
