hi, I have a problem with a Teac V5010 cassette deck I am trying to repair. I have changed the broken belts and everything seems to work ok, but the rewind function starts ok and continues for a few seconds and then stops.
The deck has full logic control, all buttons are moving electronically. There is also a slight problem with the tape speed but I will have to worry about it after I fix the rewind.
The rewind fault is present either I have a cassette in or not. The digital tape counter seems to work ok. The rewind function has a gear which clutches in one tape reel when in forward and in the other when in rewind. The mechanism seems to me that works ok. The rewind works for 2-3 seconds after all and there are lots of revolutions in the gear anyway within these three seconds, so I do not think or see any broken gear. I noticed that in the beginning of the tape, the time that takes for the rewind to stop is more than the time it takes in the end of the tape. I do not know if it tells anything to you. I cannot see a mechanical problem, at least not obvious, everything seems to move right.
Maybe a logic or sensor problem?
The manuals for the thing are here.
http://qrp.gr/hfe_teac_v-5010_7010_service.pdf
http://qrp.gr/hfe_teac_v-5010_7010_en.pdf
Any help will be appreciated to set this beast alive again.
The deck has full logic control, all buttons are moving electronically. There is also a slight problem with the tape speed but I will have to worry about it after I fix the rewind.
The rewind fault is present either I have a cassette in or not. The digital tape counter seems to work ok. The rewind function has a gear which clutches in one tape reel when in forward and in the other when in rewind. The mechanism seems to me that works ok. The rewind works for 2-3 seconds after all and there are lots of revolutions in the gear anyway within these three seconds, so I do not think or see any broken gear. I noticed that in the beginning of the tape, the time that takes for the rewind to stop is more than the time it takes in the end of the tape. I do not know if it tells anything to you. I cannot see a mechanical problem, at least not obvious, everything seems to move right.
Maybe a logic or sensor problem?
The manuals for the thing are here.
http://qrp.gr/hfe_teac_v-5010_7010_service.pdf
http://qrp.gr/hfe_teac_v-5010_7010_en.pdf
Any help will be appreciated to set this beast alive again.
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My suspicion is that the motor current sensing is detecting the current rising to indicate motor stall, and this is falsely triggering in rewind, either because of:
1) too much mechanical friction
2) the detection circuitry has become more sensitive for some reason.
Alternatively there is spindle rotation sensor that's failed.
1) too much mechanical friction
2) the detection circuitry has become more sensitive for some reason.
Alternatively there is spindle rotation sensor that's failed.
There is no way to detect the motor current. The capstan motor is directly connected to 12v from the PSU and there is no current sensing circuit if you see the service manual.
If the spindle rotation sensor has become bad would it rotate for 2-3 seconds or not at all?
All right, I will focus on this.
Do you think this could happen only in the reverse direction and not in the forward? (i.e different sensors for the reverse and the forward). Because the forward direction does work.
I am trying to locate any spindle rotation sensors from the schematic, but this has become quite difficult. Could you help me spot them? Is this "Reel pulse" seen on page 35 on area B of the control board schematic?
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Right, the only sensors I can find in the schematic are the ones marked as L and R on page 35 of the service manual. Can you spot any other that I am missing?
On the deck, I can see one opto-sensor behind each reel. I notice that one of the opto-sensors was very close to a small belt that I had to replace. This belt had been deteriorated so badly, that it had become sticky and contaminated with black sticky belt material everything it touched. Maybe on replacing I accidentally touched part of this belt on the sensor and made it light-proof, so that the logic thinks that it is always closed.
How does this sound to you?
I will try to clean this and see what will happen.
On the deck, I can see one opto-sensor behind each reel. I notice that one of the opto-sensors was very close to a small belt that I had to replace. This belt had been deteriorated so badly, that it had become sticky and contaminated with black sticky belt material everything it touched. Maybe on replacing I accidentally touched part of this belt on the sensor and made it light-proof, so that the logic thinks that it is always closed.
How does this sound to you?
I will try to clean this and see what will happen.
Oops! Until now I've always thought that this goo was an issue in Philips gear only.
Best regards!
No, I have seen it in this Teac as well as in Sherwood decks that I have only come accross. I think it is the belt material that matters (and all of them are made of rubber) in conjunction with the humidity and temperature conditions throughout the years. I wonder why they didn't use silicone belts back then.
Anyway
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