Very nice video repaired a VCR today got a video about it i posted today wanted to learn more about the drum on VCRs i was alway interested in how servos work. Thanks for the great demo and great work.
This video is really helpful, I have an akai vcr with a drum problem it wont even fire, I've checked all the voltages to the ribbon cable to the drum and there all correct, the drum servo must have a problem
Im working on a Toshiba VCR/DVD recorder combo. The power supply was dead (diode), replaced it and it turned on. Initially the drum wouldnt start at all. I turned it slightly with my finger a couple revolutions and tried it again and it fired up and played and entire movie. When I tested it the next morning it did the same thing. I don't know where to start. Ive fixed a ton of these and sold them but this one has me puzzled. Hoping you can point me in the right direction!
Great video.i currently have a similar problem with a vcr i was given.it was originally a mode switch problem which i fixed and it was working fine.now all of a sudden it will load and play a tape for a few seconds then stop playing because the drum is spinning way too slow.now i have a service manual for it so I'm going to see if i can find the fault.
Hi! I have an UVW 1800.. I bought a Convergence AFM216 Audio Enhancer which came with 2 connected cards and a few loose cables which i suppose they were connected to another card, but they were cutted off it. Sorry, for bothering you, but I'd like to know how to connect those loose cables, do you know how to do it? do you have a manual or schematics for it? a picture of the connections? whatever.. please if you could give me any idea on how to solve this problem i'd apreciate it so much. Thanks!
They are not usually marked on the board. Usually there is a header (connector) with test pins and nothing plugged into it. On some units they are marked SWP for Switchpoint and RF for the head amplofier RF test poing but more often than not they are not labeled. A service manual / schematic will label them. From my experience I know where most are located, and if in doubt, you can find them easily with the scope. I spent 20 years as a diagnostic engineer working on consumer electronics, so I know what to look for, and know what the waveforms look like just based on experience,
Any chance you can do a video on a VCR that has a playback that's too fast? When a tape plays it's almost like it's in FF. I've cleaned the mode switch, heads, tried multiple different tapes and even swapped out the servo and capstan (it's all one assembly) and still have the same issue. It's on Magnavox ZV427MG9 (VCR/DVD Recorder combo).
I made an error on my Sony 670 dat. I changed the reel motor with a new one. However during the removal of the large white flex cable that connects the mechanism with the main board I did not remove the power connector as stated in the manual and now the drum does not spin.
I got a Sony SLV-T2000 with doesn't power on at all, nothing. Powersupply is fine, I get the correct DC voltages. However the VCR powers on when I disconnect the 5 pin (MTR GND, D FG, D PG, D VS, MTA 12V) cable to the drum motor. Do you have any idea what I could try to fix this? The pins are not shorted. There is an IC on the board of the drum motor where the 5 pin cable connects. I would really appreciate it, if you could give me a hint. Caps on the circuit are ok i think. It's kinda weird that to VCR won't power on at all and the drum motor doesn't speed up at all when it's connected. Might this symptom be a shutdown mechanism from Sony?
Do you have any idea on fixing a U-Matic deck where the capstan motor will not turn? I measured the voltage going to the capstan motor and it's only getting 2 volts, and the machine is going into shutdown. I have the schematic. For some reason I get the 450Hz FG signals though I can see them on my scope.
@@12voltvids Okay so it is turning because the FG signals are present. The servo circuit uses PWM and I can see it on my scope. Is that why I'm seeing only 2 volts? I'm trying to find the problem. Symptom is that it won't thread a tape and after 5 seconds the tape slack LED lights up. The drum motor is turning and I guess the capstan as well, but the reel and loading motors don't turn. I looked into the service manual and it mentioned that if the "capstan reverse status" continues for 5 seconds it detects tape slack and will shut off via a signal that goes high. So I was thinking there was a capstan servo fault. I know all of the motors are okay (loading, drum, capstan, reel) Also this is a portable deck that used the small size cassette.
@@KylesDigitalLab If the take up reel is not turning or turning fast enough the tape will go slack and trigger an emergency stop so as not to eat the tape. Check your idler tires for slippage.
I have a beautiful Panasonic PV 1000 from 1978. The drum spins continuously when the power is turned on. Could it be the speed servo and can it be fixed? Great videos by the way!!
He he. Neither have I. I had a bunch of my own machines that were in need of service. It started out with the 3/4" unit that is featured on the opening clip, and just progressed from there. It is more of a teaching tool for others. I am not in the repair business anymore, but still will look at stuff for people that ask. It is more of a hobby, like golf now. Something to pass the time when the weather isn't good enough for my real hobby, photography, and film making.
Some of the stuff I have done on video, and some time lapse films are on my channel. A fiew pieces of work are up on flickr, but most sits on a hard drive.
John Scarce 1500 for pal countries and 1800 for ntsc countries. 25 frames x 60 second and 30 frames x 60 seconds. Each rotation of the drum records 2 fields, 1 full frame. Now when digital came out things got faster. Digital 8 spins the drum at 4500 rpm and dv goes at the insane speed of 9000 rpm.
Thanks for the fast reply wow. i got 1 motor from those, but i have no idea if the vcr was digital or ntsc (im in europe so its ntsc). is there any way to guess what rpm was the motor designed just by looking at the motor(coils and magnet), the pcb, the drum or the rotational transformer coils?
most of them are 3 phase perm magnet(such as mine). the problem is i blew the controller by applying voltage at the wrong pins of the power cable connector. even if it wasnt blown it wouldn't be able to know what voltage to drive it at to see its full potential
12voltvids .Hello there. I have sony sl800me betamax. The image plays in black and white. Heads cleaned. the tape is clean. Black and white image on all tapes. I tried it on different tv, the links are correct i am novice. I wonder where is the problem.
The chroma information is stripped from the video during recording and converted down to 688khz on beta (629 for vhs) on playback this converted color needs to be converted back to the proper frequency and mixed back in to the video. Obviously a problem in this circuit. Could be a capacitor, ic, crystal ect.
This is very informative Dave, thank you for this. I have a question, maybe you can point me in the right direction. I have a JVC HR-S4600U VCR with a head that doesn't spin. Servo is on top like this unit. I checked the voltages on the flat cable and I'm not getting a run voltage (13V or whatever) but I do get 5V on the enable pin when a tape is inserted. Same thing at the mainboard connector so it's not a bad flat cable or head drum. Any idea where I can start looking to see why run voltage isn't being supplied? I can't seem to find a service manual for this model either. Thanks for your help man.
I did a little more tracing off the mainboard drum connector and traced pin 1 back to the PSU side and found an ICP-N15 that was open. Didn't even notice it was there the first time because I thought it was a transistor. On the supply side of it was was about 12V. I am ordering replacements ICPs from China (bleh...). Will post back here for anyone else with this issue.
Follow up on my HR-S4600U if anybody needs to know in the future. I received the ICP-N15 in the mail and replaced the bad on the VCR mainboard. Reassembled the unit and the head started spinning again. Works and plays tapes well now.
Thank you very much for your videos! I admire how "easily" you troubleshoot these machines and how quickly you get to the cause of the issue -- obviously you may have a long experience. Unfortunately, I have no experience and although your videos helped me to understand a few things, I was wondering if you or any other visitor could help me with this: th-cam.com/video/6AxS-QDrBec/w-d-xo.html I suppose that the picture and audio distortion I am getting may be due to a problem of the servo/tracking PCB, however I would like to be sure before ordering a replacement for it: Thank you very much in advance!
Very nice video repaired a VCR today got a video about it i posted today wanted to learn more about the drum on VCRs i was alway interested in how servos work. Thanks for the great demo and great work.
I love that 90's music Intro. Makes me smile and experience a deep sense of Nostalgia...! Your video made me smile...
90's misc is not as old as the 60's or the 1920's.It's more recent in compariosn.
This video is really helpful, I have an akai vcr with a drum problem it wont even fire, I've checked all the voltages to the ribbon cable to the drum and there all correct, the drum servo must have a problem
Very very nise good working from bhalodia Dipak thanks
good troubleshooting video, thanks...
Nice repair i am impressed
Im working on a Toshiba VCR/DVD recorder combo. The power supply was dead (diode), replaced it and it turned on. Initially the drum wouldnt start at all. I turned it slightly with my finger a couple revolutions and tried it again and it fired up and played and entire movie. When I tested it the next morning it did the same thing. I don't know where to start. Ive fixed a ton of these and sold them but this one has me puzzled. Hoping you can point me in the right direction!
Great video.i currently have a similar problem with a vcr i was given.it was originally a mode switch problem which i fixed and it was working fine.now all of a sudden it will load and play a tape for a few seconds then stop playing because the drum is spinning way too slow.now i have a service manual for it so I'm going to see if i can find the fault.
Hi! I have an UVW 1800.. I bought a Convergence AFM216 Audio Enhancer which came with 2 connected cards and a few loose cables which i suppose they were connected to another card, but they were cutted off it. Sorry, for bothering you, but I'd like to know how to connect those loose cables, do you know how to do it? do you have a manual or schematics for it? a picture of the connections? whatever.. please if you could give me any idea on how to solve this problem i'd apreciate it so much. Thanks!
nice work again :)
Great video.How do you know where the testpoints are.Is it because of your experience or is it written on the board.
They are not usually marked on the board. Usually there is a header (connector) with test pins and nothing plugged into it. On some units they are marked SWP for Switchpoint and RF for the head amplofier RF test poing but more often than not they are not labeled. A service manual / schematic will label them.
From my experience I know where most are located, and if in doubt, you can find them easily with the scope.
I spent 20 years as a diagnostic engineer working on consumer electronics, so I know what to look for, and know what the waveforms look like just based on experience,
Any chance you can do a video on a VCR that has a playback that's too fast? When a tape plays it's almost like it's in FF. I've cleaned the mode switch, heads, tried multiple different tapes and even swapped out the servo and capstan (it's all one assembly) and still have the same issue. It's on Magnavox ZV427MG9 (VCR/DVD Recorder combo).
I made an error on my Sony 670 dat. I changed the reel motor with a new one. However during the removal of the large white flex cable that connects the mechanism with the main board I did not remove the power connector as stated in the manual and now the drum does not spin.
did you replace the servo circuit board or the tiny compactor?
Do we need to give V ctl for drum motor spinning. Also voltage for FG.
I got a Sony SLV-T2000 with doesn't power on at all, nothing. Powersupply is fine, I get the correct DC voltages. However the VCR powers on when I disconnect the 5 pin (MTR GND, D FG, D PG, D VS, MTA 12V) cable to the drum motor. Do you have any idea what I could try to fix this? The pins are not shorted. There is an IC on the board of the drum motor where the 5 pin cable connects. I would really appreciate it, if you could give me a hint. Caps on the circuit are ok i think. It's kinda weird that to VCR won't power on at all and the drum motor doesn't speed up at all when it's connected. Might this symptom be a shutdown mechanism from Sony?
Do you have any idea on fixing a U-Matic deck where the capstan motor will not turn? I measured the voltage going to the capstan motor and it's only getting 2 volts, and the machine is going into shutdown. I have the schematic. For some reason I get the 450Hz FG signals though I can see them on my scope.
FG is generated by the motor spinning. FG=frequency generator. If the motor isn't turning you won't have FG
@@12voltvids Okay so it is turning because the FG signals are present. The servo circuit uses PWM and I can see it on my scope. Is that why I'm seeing only 2 volts? I'm trying to find the problem. Symptom is that it won't thread a tape and after 5 seconds the tape slack LED lights up. The drum motor is turning and I guess the capstan as well, but the reel and loading motors don't turn.
I looked into the service manual and it mentioned that if the "capstan reverse status" continues for 5 seconds it detects tape slack and will shut off via a signal that goes high. So I was thinking there was a capstan servo fault.
I know all of the motors are okay (loading, drum, capstan, reel)
Also this is a portable deck that used the small size cassette.
@@KylesDigitalLab If the take up reel is not turning or turning fast enough the tape will go slack and trigger an emergency stop so as not to eat the tape. Check your idler tires for slippage.
I have a beautiful Panasonic PV 1000 from 1978. The drum spins continuously
when the power is turned on. Could it be the speed servo and can it be fixed?
Great videos by the way!!
On the old machines the drum runs constantly when the power it on.
How small a capacitor is it???
My JVC HRS-7600U drum is not spinning, what could be the problem?
Wow... servicing VCRs, I havent done that in ages....
He he. Neither have I. I had a bunch of my own machines that were in need of service. It started out with the 3/4" unit that is featured on the opening clip, and just progressed from there.
It is more of a teaching tool for others. I am not in the repair business anymore, but still will look at stuff for people that ask. It is more of a hobby, like golf now. Something to pass the time when the weather isn't good enough for my real hobby, photography, and film making.
Where can I see some of your photography Dave?
Some of the stuff I have done on video, and some time lapse films are on my channel. A fiew pieces of work are up on flickr, but most sits on a hard drive.
Are you on Facebook? maybe you could make a page/group and upload them, I'm a photographer too, I do lots of long exposure, star trail shots.
nick fatsis
no I don't use Facebook.
what rpm do theese run at?
John Scarce
1500 for pal countries and 1800 for ntsc countries. 25 frames x 60 second and 30 frames x 60 seconds. Each rotation of the drum records 2 fields, 1 full frame.
Now when digital came out things got faster. Digital 8 spins the drum at 4500 rpm and dv goes at the insane speed of 9000 rpm.
Thanks for the fast reply wow. i got 1 motor from those, but i have no idea if the vcr was digital or ntsc (im in europe so its ntsc). is there any way to guess what rpm was the motor designed just by looking at the motor(coils and magnet), the pcb, the drum or the rotational transformer coils?
John Scarce
They are 3 phase ac motor controlled by the motor drive ic. They will go whatever speed you drive them to.
most of them are 3 phase perm magnet(such as mine). the problem is i blew the controller by applying voltage at the wrong pins of the power cable connector. even if it wasnt blown it wouldn't be able to know what voltage to drive it at to see its full potential
btw im asking because im making custom drive circuitry
12voltvids .Hello there. I have sony sl800me betamax. The image plays in black and white. Heads cleaned. the tape is clean. Black and white image on all tapes. I tried it on different tv, the links are correct i am novice. I wonder where is the problem.
The chroma information is stripped from the video during recording and converted down to 688khz on beta (629 for vhs) on playback this converted color needs to be converted back to the proper frequency and mixed back in to the video. Obviously a problem in this circuit. Could be a capacitor, ic, crystal ect.
@@12voltvids Thank you 12voltvids
This is very informative Dave, thank you for this. I have a question, maybe you can point me in the right direction. I have a JVC HR-S4600U VCR with a head that doesn't spin. Servo is on top like this unit. I checked the voltages on the flat cable and I'm not getting a run voltage (13V or whatever) but I do get 5V on the enable pin when a tape is inserted. Same thing at the mainboard connector so it's not a bad flat cable or head drum. Any idea where I can start looking to see why run voltage isn't being supplied? I can't seem to find a service manual for this model either. Thanks for your help man.
I did a little more tracing off the mainboard drum connector and traced pin 1 back to the PSU side and found an ICP-N15 that was open. Didn't even notice it was there the first time because I thought it was a transistor. On the supply side of it was was about 12V. I am ordering replacements ICPs from China (bleh...). Will post back here for anyone else with this issue.
Follow up on my HR-S4600U if anybody needs to know in the future. I received the ICP-N15 in the mail and replaced the bad on the VCR mainboard. Reassembled the unit and the head started spinning again. Works and plays tapes well now.
Thank you very much for your videos! I admire how "easily" you troubleshoot these machines and how quickly you get to the cause of the issue -- obviously you may have a long experience. Unfortunately, I have no experience and although your videos helped me to understand a few things, I was wondering if you or any other visitor could help me with this: th-cam.com/video/6AxS-QDrBec/w-d-xo.html I suppose that the picture and audio distortion I am getting may be due to a problem of the servo/tracking PCB, however I would like to be sure before ordering a replacement for it: Thank you very much in advance!
Picture / sound distortion is more likely a mechanical alignment issue.