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NEC DX3000 VCR - slow rewind problem
I need help to solve a slow rewind problem in an NEC DX3000 VCR. I've
changed the caps on the capstan motor PCB, and I've replaced the belts and tyres. I can't feel any excessive drag in the mechanism, only the light application of brake pads to maintain a minimal tape tension. The motor voltage is 7.4V which is correct according to the service manual. Fast forward is OK, but should probably be a little faster. The idler tyre has plenty of grip - I can feel the resistance of the servo in play and cue/review modes. It seems that the motor's torque is too low at the applied voltage. In fact I can easily stall the motor with light finger pressure. The drive voltage remains at 7.2 - 7.4V when I do this. I can work around the problem by adding a 3K3 resistor in parallel with R618. This results in a drive voltage of around 8.0V. If anyone knows of any other common faults with this machine, I'd like to give it a full service. TIA. - Franc Zabkar -- Please remove one 'i' from my address when replying by email. |
NEC DX3000 VCR - slow rewind problem
Sounds like the motor is bad. I have had some good luck spraying a small
amount of cleaner/degreaser into some electric motors. Used to "restore" spindle motors on early Pioneer CD players that would be slow and never come up to speed. Good luck. Scott ******** "Franc Zabkar" wrote in message ... I need help to solve a slow rewind problem in an NEC DX3000 VCR. I've changed the caps on the capstan motor PCB, and I've replaced the belts and tyres. I can't feel any excessive drag in the mechanism, only the light application of brake pads to maintain a minimal tape tension. The motor voltage is 7.4V which is correct according to the service manual. Fast forward is OK, but should probably be a little faster. The idler tyre has plenty of grip - I can feel the resistance of the servo in play and cue/review modes. It seems that the motor's torque is too low at the applied voltage. In fact I can easily stall the motor with light finger pressure. The drive voltage remains at 7.2 - 7.4V when I do this. I can work around the problem by adding a 3K3 resistor in parallel with R618. This results in a drive voltage of around 8.0V. If anyone knows of any other common faults with this machine, I'd like to give it a full service. TIA. - Franc Zabkar -- Please remove one 'i' from my address when replying by email. |
NEC DX3000 VCR - slow rewind problem
On Mon, 20 Mar 2006 15:37:57 -0800, "Scott Lane"
put finger to keyboard and composed: Sounds like the motor is bad. I have had some good luck spraying a small amount of cleaner/degreaser into some electric motors. Used to "restore" spindle motors on early Pioneer CD players that would be slow and never come up to speed. Good luck. Scott ******** The FF/REW idler is driven by the capstan via a belt. The capstan motor is the PCB type. None of the stator windings appear open. FWIW, the motor control IC is a TA7262P: http://www.datasheetarchive.com/data...rticle=3216007 The motor is in the style of the one at the top left of this page: http://www.wagner.net.au/Catalogue/04_14.pdf "Franc Zabkar" wrote in message .. . I need help to solve a slow rewind problem in an NEC DX3000 VCR. I've changed the caps on the capstan motor PCB, and I've replaced the belts and tyres. I can't feel any excessive drag in the mechanism, only the light application of brake pads to maintain a minimal tape tension. The motor voltage is 7.4V which is correct according to the service manual. Fast forward is OK, but should probably be a little faster. The idler tyre has plenty of grip - I can feel the resistance of the servo in play and cue/review modes. It seems that the motor's torque is too low at the applied voltage. In fact I can easily stall the motor with light finger pressure. The drive voltage remains at 7.2 - 7.4V when I do this. I can work around the problem by adding a 3K3 resistor in parallel with R618. This results in a drive voltage of around 8.0V. If anyone knows of any other common faults with this machine, I'd like to give it a full service. TIA. - Franc Zabkar -- Please remove one 'i' from my address when replying by email. - Franc Zabkar -- Please remove one 'i' from my address when replying by email. |
NEC DX3000 VCR - slow rewind problem
"Franc Zabkar" wrote in message ... On Mon, 20 Mar 2006 15:37:57 -0800, "Scott Lane" put finger to keyboard and composed: Sounds like the motor is bad. I have had some good luck spraying a small amount of cleaner/degreaser into some electric motors. Used to "restore" spindle motors on early Pioneer CD players that would be slow and never come up to speed. Good luck. Scott ******** The FF/REW idler is driven by the capstan via a belt. The capstan motor is the PCB type. None of the stator windings appear open. FWIW, the motor control IC is a TA7262P: http://www.datasheetarchive.com/data...rticle=3216007 The motor is in the style of the one at the top left of this page: http://www.wagner.net.au/Catalogue/04_14.pdf "Franc Zabkar" wrote in message . .. I need help to solve a slow rewind problem in an NEC DX3000 VCR. I've changed the caps on the capstan motor PCB, and I've replaced the belts and tyres. I can't feel any excessive drag in the mechanism, only the light application of brake pads to maintain a minimal tape tension. The motor voltage is 7.4V which is correct according to the service manual. Fast forward is OK, but should probably be a little faster. The idler tyre has plenty of grip - I can feel the resistance of the servo in play and cue/review modes. It seems that the motor's torque is too low at the applied voltage. In fact I can easily stall the motor with light finger pressure. The drive voltage remains at 7.2 - 7.4V when I do this. I can work around the problem by adding a 3K3 resistor in parallel with R618. This results in a drive voltage of around 8.0V. If anyone knows of any other common faults with this machine, I'd like to give it a full service. TIA. - Franc Zabkar -- Please remove one 'i' from my address when replying by email. - Franc Zabkar -- Please remove one 'i' from my address when replying by email. Bad idler, bad reel belt, and I've seen a metal pin come out of a lever underneath which enables the rewind mode. The white nylon/plastic arm develops a crack which allows the pin to fall out. Mark Z. |
NEC DX3000 VCR - slow rewind problem
On Tue, 21 Mar 2006 12:51:18 GMT, "Mark D. Zacharias"
put finger to keyboard and composed: "Franc Zabkar" wrote in message .. . On Mon, 20 Mar 2006 15:37:57 -0800, "Scott Lane" put finger to keyboard and composed: Sounds like the motor is bad. I have had some good luck spraying a small amount of cleaner/degreaser into some electric motors. Used to "restore" spindle motors on early Pioneer CD players that would be slow and never come up to speed. Good luck. Scott ******** The FF/REW idler is driven by the capstan via a belt. The capstan motor is the PCB type. None of the stator windings appear open. FWIW, the motor control IC is a TA7262P: http://www.datasheetarchive.com/data...rticle=3216007 The motor is in the style of the one at the top left of this page: http://www.wagner.net.au/Catalogue/04_14.pdf "Franc Zabkar" wrote in message ... I need help to solve a slow rewind problem in an NEC DX3000 VCR. I've changed the caps on the capstan motor PCB, and I've replaced the belts and tyres. I can't feel any excessive drag in the mechanism, only the light application of brake pads to maintain a minimal tape tension. The motor voltage is 7.4V which is correct according to the service manual. Fast forward is OK, but should probably be a little faster. The idler tyre has plenty of grip - I can feel the resistance of the servo in play and cue/review modes. It seems that the motor's torque is too low at the applied voltage. In fact I can easily stall the motor with light finger pressure. The drive voltage remains at 7.2 - 7.4V when I do this. I can work around the problem by adding a 3K3 resistor in parallel with R618. This results in a drive voltage of around 8.0V. If anyone knows of any other common faults with this machine, I'd like to give it a full service. TIA. - Franc Zabkar -- Please remove one 'i' from my address when replying by email. - Franc Zabkar -- Please remove one 'i' from my address when replying by email. Bad idler, bad reel belt, and I've seen a metal pin come out of a lever underneath which enables the rewind mode. The white nylon/plastic arm develops a crack which allows the pin to fall out. Mark Z. The belt is fine, and the top and bottom halves of the idler lock together in rewind and FF modes. There is no slippage. The only real drag appears to come from the weight of the tape. In FF/REW modes the capstan runs in open loop mode, ie the motor is supplied with a fixed voltage. The tape is fully retracted into the cassette housing and the pinch roller is disengaged. Both plastic levers and pins are intact. I've replaced a sticky brake pad on the take-up lever and the performance has improved, but it's still a little on the slow side. It looks like it might be just designed that way shrug. - Franc Zabkar -- Please remove one 'i' from my address when replying by email. |
NEC DX3000 VCR - slow rewind problem
"Franc Zabkar" wrote in message ... On Tue, 21 Mar 2006 12:51:18 GMT, "Mark D. Zacharias" put finger to keyboard and composed: "Franc Zabkar" wrote in message . .. On Mon, 20 Mar 2006 15:37:57 -0800, "Scott Lane" put finger to keyboard and composed: Sounds like the motor is bad. I have had some good luck spraying a small amount of cleaner/degreaser into some electric motors. Used to "restore" spindle motors on early Pioneer CD players that would be slow and never come up to speed. Good luck. Scott ******** The FF/REW idler is driven by the capstan via a belt. The capstan motor is the PCB type. None of the stator windings appear open. FWIW, the motor control IC is a TA7262P: http://www.datasheetarchive.com/data...rticle=3216007 The motor is in the style of the one at the top left of this page: http://www.wagner.net.au/Catalogue/04_14.pdf "Franc Zabkar" wrote in message m... I need help to solve a slow rewind problem in an NEC DX3000 VCR. I've changed the caps on the capstan motor PCB, and I've replaced the belts and tyres. I can't feel any excessive drag in the mechanism, only the light application of brake pads to maintain a minimal tape tension. The motor voltage is 7.4V which is correct according to the service manual. Fast forward is OK, but should probably be a little faster. The idler tyre has plenty of grip - I can feel the resistance of the servo in play and cue/review modes. It seems that the motor's torque is too low at the applied voltage. In fact I can easily stall the motor with light finger pressure. The drive voltage remains at 7.2 - 7.4V when I do this. I can work around the problem by adding a 3K3 resistor in parallel with R618. This results in a drive voltage of around 8.0V. If anyone knows of any other common faults with this machine, I'd like to give it a full service. TIA. - Franc Zabkar -- Please remove one 'i' from my address when replying by email. - Franc Zabkar -- Please remove one 'i' from my address when replying by email. Bad idler, bad reel belt, and I've seen a metal pin come out of a lever underneath which enables the rewind mode. The white nylon/plastic arm develops a crack which allows the pin to fall out. Mark Z. The belt is fine, and the top and bottom halves of the idler lock together in rewind and FF modes. There is no slippage. The only real drag appears to come from the weight of the tape. In FF/REW modes the capstan runs in open loop mode, ie the motor is supplied with a fixed voltage. The tape is fully retracted into the cassette housing and the pinch roller is disengaged. Both plastic levers and pins are intact. I've replaced a sticky brake pad on the take-up lever and the performance has improved, but it's still a little on the slow side. It looks like it might be just designed that way shrug. - Franc Zabkar -- Please remove one 'i' from my address when replying by email. Did you look at the lever underneath the unit which is part of the reel unit? It changes how the reel unit engages. Mark Z. |
NEC DX3000 VCR - slow rewind problem
Franc Zabkar wrote:
: The belt is fine, and the top and bottom halves of the idler lock : together in rewind and FF modes. There is no slippage. The only real : drag appears to come from the weight of the tape. In FF/REW modes the : capstan runs in open loop mode, ie the motor is supplied with a fixed : voltage. The tape is fully retracted into the cassette housing and the : pinch roller is disengaged. Both plastic levers and pins are intact. : I've replaced a sticky brake pad on the take-up lever and the : performance has improved, but it's still a little on the slow side. It : looks like it might be just designed that way shrug. You know you might not be that far off with that last comment. I'm not totally sure of the that model number but if this machine is from the mid/late 80's, I had a DX-5000 bought new and in all the machines I ever owned, it had the slowest rewind/fast forward. I mean I'm talking about 7-10 minutes easy to rewind a T-120. It didn't take long to fail completely, within the first year it couldn't rewind the tape all the way and from that point, needed the idler tire changed twice a year if not more often. At first I thought the generics from MCM were just poor, going to NEC direct was expensive (whole idler, not just the tire) and didn't help. Eventually I think I ended up using the reverse scan. I really liked that machine, was some weird non-standard vhs compared to everyone else, had some kind of real ram based digital memory with a bunch of tricks that could be utilized. Was the first vhs that could do frame by frame slow-motion without noise bars because everything was read off the ram. Some kind of built in TBC (sort of). Could freeze frame an image and toss it into a PIP mode with the tape still playing in the background. But mechanically it ranked in the bottom on my list. -bruce |
NEC DX3000 VCR - slow rewind problem
"Bruce Esquibel" wrote in message ... Franc Zabkar wrote: : The belt is fine, and the top and bottom halves of the idler lock : together in rewind and FF modes. There is no slippage. The only real : drag appears to come from the weight of the tape. In FF/REW modes the : capstan runs in open loop mode, ie the motor is supplied with a fixed : voltage. The tape is fully retracted into the cassette housing and the : pinch roller is disengaged. Both plastic levers and pins are intact. : I've replaced a sticky brake pad on the take-up lever and the : performance has improved, but it's still a little on the slow side. It : looks like it might be just designed that way shrug. You know you might not be that far off with that last comment. I'm not totally sure of the that model number but if this machine is from the mid/late 80's, I had a DX-5000 bought new and in all the machines I ever owned, it had the slowest rewind/fast forward. I mean I'm talking about 7-10 minutes easy to rewind a T-120. It didn't take long to fail completely, within the first year it couldn't rewind the tape all the way and from that point, needed the idler tire changed twice a year if not more often. At first I thought the generics from MCM were just poor, going to NEC direct was expensive (whole idler, not just the tire) and didn't help. Eventually I think I ended up using the reverse scan. I really liked that machine, was some weird non-standard vhs compared to everyone else, had some kind of real ram based digital memory with a bunch of tricks that could be utilized. Was the first vhs that could do frame by frame slow-motion without noise bars because everything was read off the ram. Some kind of built in TBC (sort of). Could freeze frame an image and toss it into a PIP mode with the tape still playing in the background. But mechanically it ranked in the bottom on my list. -bruce Ditto on the DX-5000 machine. I have one too and you might as well read a book waiting for it to rewind. The whole NEC line of that era just didn't rewind with any speed at all. The 7-10 minute waiting time seems very accurate. -- David Farber David Farber's Service Center L.A., CA |
NEC DX3000 VCR - slow rewind problem
On Wed, 22 Mar 2006 12:51:49 GMT, "Mark D. Zacharias"
put finger to keyboard and composed: "Franc Zabkar" wrote in message .. . On Tue, 21 Mar 2006 12:51:18 GMT, "Mark D. Zacharias" put finger to keyboard and composed: "Franc Zabkar" wrote in message ... On Mon, 20 Mar 2006 15:37:57 -0800, "Scott Lane" put finger to keyboard and composed: Sounds like the motor is bad. I have had some good luck spraying a small amount of cleaner/degreaser into some electric motors. Used to "restore" spindle motors on early Pioneer CD players that would be slow and never come up to speed. Good luck. Scott ******** The FF/REW idler is driven by the capstan via a belt. The capstan motor is the PCB type. None of the stator windings appear open. FWIW, the motor control IC is a TA7262P: http://www.datasheetarchive.com/data...rticle=3216007 The motor is in the style of the one at the top left of this page: http://www.wagner.net.au/Catalogue/04_14.pdf "Franc Zabkar" wrote in message om... I need help to solve a slow rewind problem in an NEC DX3000 VCR. I've changed the caps on the capstan motor PCB, and I've replaced the belts and tyres. I can't feel any excessive drag in the mechanism, only the light application of brake pads to maintain a minimal tape tension. The motor voltage is 7.4V which is correct according to the service manual. Fast forward is OK, but should probably be a little faster. The idler tyre has plenty of grip - I can feel the resistance of the servo in play and cue/review modes. It seems that the motor's torque is too low at the applied voltage. In fact I can easily stall the motor with light finger pressure. The drive voltage remains at 7.2 - 7.4V when I do this. I can work around the problem by adding a 3K3 resistor in parallel with R618. This results in a drive voltage of around 8.0V. If anyone knows of any other common faults with this machine, I'd like to give it a full service. TIA. - Franc Zabkar -- Please remove one 'i' from my address when replying by email. - Franc Zabkar -- Please remove one 'i' from my address when replying by email. Bad idler, bad reel belt, and I've seen a metal pin come out of a lever underneath which enables the rewind mode. The white nylon/plastic arm develops a crack which allows the pin to fall out. Mark Z. The belt is fine, and the top and bottom halves of the idler lock together in rewind and FF modes. There is no slippage. The only real drag appears to come from the weight of the tape. In FF/REW modes the capstan runs in open loop mode, ie the motor is supplied with a fixed voltage. The tape is fully retracted into the cassette housing and the pinch roller is disengaged. Both plastic levers and pins are intact. I've replaced a sticky brake pad on the take-up lever and the performance has improved, but it's still a little on the slow side. It looks like it might be just designed that way shrug. - Franc Zabkar Did you look at the lever underneath the unit which is part of the reel unit? It changes how the reel unit engages. Mark Z. There is one lever that engages the idler assembly. It's working fine. - Franc Zabkar -- Please remove one 'i' from my address when replying by email. |
NEC DX3000 VCR - slow rewind problem
On Wed, 22 Mar 2006 16:59:41 -0800, "David Farber"
put finger to keyboard and composed: "Bruce Esquibel" wrote in message ... Franc Zabkar wrote: : The belt is fine, and the top and bottom halves of the idler lock : together in rewind and FF modes. There is no slippage. The only real : drag appears to come from the weight of the tape. In FF/REW modes the : capstan runs in open loop mode, ie the motor is supplied with a fixed : voltage. The tape is fully retracted into the cassette housing and the : pinch roller is disengaged. Both plastic levers and pins are intact. : I've replaced a sticky brake pad on the take-up lever and the : performance has improved, but it's still a little on the slow side. It : looks like it might be just designed that way shrug. You know you might not be that far off with that last comment. I'm not totally sure of the that model number but if this machine is from the mid/late 80's, I had a DX-5000 bought new and in all the machines I ever owned, it had the slowest rewind/fast forward. I mean I'm talking about 7-10 minutes easy to rewind a T-120. It didn't take long to fail completely, within the first year it couldn't rewind the tape all the way and from that point, needed the idler tire changed twice a year if not more often. At first I thought the generics from MCM were just poor, going to NEC direct was expensive (whole idler, not just the tire) and didn't help. Eventually I think I ended up using the reverse scan. I really liked that machine, was some weird non-standard vhs compared to everyone else, had some kind of real ram based digital memory with a bunch of tricks that could be utilized. Was the first vhs that could do frame by frame slow-motion without noise bars because everything was read off the ram. Some kind of built in TBC (sort of). Could freeze frame an image and toss it into a PIP mode with the tape still playing in the background. But mechanically it ranked in the bottom on my list. -bruce Ditto on the DX-5000 machine. I have one too and you might as well read a book waiting for it to rewind. The whole NEC line of that era just didn't rewind with any speed at all. The 7-10 minute waiting time seems very accurate. The supply voltage to the capstan motor is derived from an RC PWM circuit. I managed to increase the rewind speed by reducing the value of R (R618). Changing the take-up brake pad also helped. - Franc Zabkar -- Please remove one 'i' from my address when replying by email. |
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