Results 1 to 20 of 20

Thread: LG Video tape player problem.

  1. #1
    Banned BlackDuck's Avatar
    Join Date
    Feb 2008
    Location
    Where I live
    Posts
    1,719
    Thanks
    504
    Thanked 367 Times in 237 Posts
    Rep Power
    0
    Reputation
    1146

    Default LG Video tape player problem.

    I have an LG V8824W video tape recorder that when a tape is put in and played the audio is soft and it makes a popping/clicking noise for about 5 seconds until the message, Playing. Auto tracking. disappears.

    Then frequently the picture gets white lines and the Auto tracking message reappears and the picture stabilises for a while.

    Is there some adjustment I can make to eliminate this problem?.

    Thanks,
    Duck.



Look Here ->
  • #2
    Member
    Join Date
    Jan 2008
    Posts
    272
    Thanks
    539
    Thanked 60 Times in 43 Posts
    Rep Power
    223
    Reputation
    827

    Default

    I've had to replace the pinch roller on a couple of these.
    open it up and with the tape running check to see if the tape is creeping up or down on the capstan spindle, and also check the back tension brake assembly



    Dash.

  • #3
    Banned BlackDuck's Avatar
    Join Date
    Feb 2008
    Location
    Where I live
    Posts
    1,719
    Thanks
    504
    Thanked 367 Times in 237 Posts
    Rep Power
    0
    Reputation
    1146

    Default

    Quote Originally Posted by dashinson View Post
    I've had to replace the pinch roller on a couple of these.
    open it up and with the tape running check to see if the tape is creeping up or down on the capstan spindle, and also check the back tension brake assembly



    Dash.
    Thanks for the response Dash,

    The pinch roller, capstan and the tensioner are all OK, It seems to be something to do with Auto tracking.

    When you look down onto the drive system there is a vertical post that looks like a tape head reader, it's at the right of the drum, this has 3 adjusting screws for alignment and if i move it by hand it causes the problem and the M/C has to track again to stabilise the picture.

    Duck.

  • #4
    Senior Member
    Bibliophile's Avatar
    Join Date
    May 2009
    Location
    Sydney
    Age
    75
    Posts
    1,204
    Thanks
    674
    Thanked 1,166 Times in 389 Posts
    Rep Power
    572
    Reputation
    17596

    Default

    I agree with dashinson. Sometimes you can get away with just cleaning it. Have a look and if it's shiny, almost glass like, try giving it a good clean with acetone. If it wont all come off, try rubbing it with a Scotchbrite scourer and then clean it again. Be sure to rotate it while you are doing both operations (with the power off of course) so the whole surface is treated.

  • #5
    Senior Member
    Bibliophile's Avatar
    Join Date
    May 2009
    Location
    Sydney
    Age
    75
    Posts
    1,204
    Thanks
    674
    Thanked 1,166 Times in 389 Posts
    Rep Power
    572
    Reputation
    17596

    Default

    Sorry, last post was a bit late.
    I would not adjust the audio/control head unless you have a very good reason as it will affect audio playback quality, control track recovery, tracking and interchangeability with other machines. You really need an alignment tape to do it properly. If, as you say, it comes good after a bit, something is causing the tape to move up or down as it moves across the A/C head and the most likely cause is the pinch roller or back tension band.

  • #6
    Banned BlackDuck's Avatar
    Join Date
    Feb 2008
    Location
    Where I live
    Posts
    1,719
    Thanks
    504
    Thanked 367 Times in 237 Posts
    Rep Power
    0
    Reputation
    1146

    Default

    Hells bells Booklover,
    When I first read this post I thought it sounded painful and somewhat obscene, then I realised that you were refering to the capstan.
    Quote Originally Posted by Bibliophile View Post
    I agree with dashinson. Sometimes you can get away with just cleaning it. Have a look and if it's shiny, almost glass like, try giving it a good clean with acetone. If it wont all come off, try rubbing it with a Scotchbrite scourer and then clean it again. Be sure to rotate it while you are doing both operations (with the power off of course) so the whole surface is treated.
    Quote Originally Posted by bibliophile
    Sorry, last post was a bit late.
    I would not adjust the audio/control head unless you have a very good reason as it will affect audio playback quality, control track recovery and tracking. You really need an alignment tape to do it properly.
    I think you're on the money here bibliophile, I suspect that this is where the problem is, control track recovery and tracking. as the tape is not missaligning on the head as it runs.

    The picture stabilises for about 10 seconds and then gets white lines again and the audio gets softer, then it autotracks again, just keeps repeating this cycle. so from what you've said I need to get hold of an alignment tape.

  • #7
    Senior Member
    Bibliophile's Avatar
    Join Date
    May 2009
    Location
    Sydney
    Age
    75
    Posts
    1,204
    Thanks
    674
    Thanked 1,166 Times in 389 Posts
    Rep Power
    572
    Reputation
    17596

    Default

    Try running your fingernail up and down the A/C head from top to bottom. If you can feel a "step" then you've got a worn head which could be causing control track problems.
    Just to explain the symptoms, the lines in the picture and the pop sounds in the audio are the result of low RF signal from the video heads, possibly caused by a tracking error. The audio becoming softer is probably caused by the machine losing the HiFi signal and reverting to the linear audio track.Your rocking of the A/C head is actually shifting the control track phase.
    The auto tracking works by phase shifting the control track pulse while looking at the peak value of the recovered RF signal from the video heads.
    If it can't find a peak or it's too low, it just keeps on trying.
    This could be caused by dirty or worn video heads.

  • The Following User Says Thank You to Bibliophile For This Useful Post:

    BlackDuck (15-06-09)

  • #8
    Banned BlackDuck's Avatar
    Join Date
    Feb 2008
    Location
    Where I live
    Posts
    1,719
    Thanks
    504
    Thanked 367 Times in 237 Posts
    Rep Power
    0
    Reputation
    1146

    Default

    Checked the head as you suggested and couldn't find any ridge or step, seems quite smooth.

  • #9
    Senior Member
    Bibliophile's Avatar
    Join Date
    May 2009
    Location
    Sydney
    Age
    75
    Posts
    1,204
    Thanks
    674
    Thanked 1,166 Times in 389 Posts
    Rep Power
    572
    Reputation
    17596

    Default

    Quote Originally Posted by BlackDuck View Post
    Checked the head as you suggested and couldn't find any ridge or step, seems quite smooth.
    I have edited my previous post with more information while you were posting yours.

  • #10
    Member
    Join Date
    Jan 2008
    Posts
    272
    Thanks
    539
    Thanked 60 Times in 43 Posts
    Rep Power
    223
    Reputation
    827

    Default

    On the pinch roller assemblies I have replaced its been the bearing inside the pinch roller that has failed!

    Dash.

  • #11
    Senior Member
    Bibliophile's Avatar
    Join Date
    May 2009
    Location
    Sydney
    Age
    75
    Posts
    1,204
    Thanks
    674
    Thanked 1,166 Times in 389 Posts
    Rep Power
    572
    Reputation
    17596

    Default

    That's a good point dash.
    Worn bearings would cause a cyclic speed variation that could give similar problems.
    Was there any 'wow' evident in the audio?
    But, of course, if it didn't drop out of HiFi there wouldn't be.

  • #12
    Banned BlackDuck's Avatar
    Join Date
    Feb 2008
    Location
    Where I live
    Posts
    1,719
    Thanks
    504
    Thanked 367 Times in 237 Posts
    Rep Power
    0
    Reputation
    1146

    Default

    Quote Originally Posted by Bibliophile View Post
    Try running your fingernail up and down the A/C head from top to bottom. If you can feel a "step" then you've got a worn head which could be causing control track problems.
    Just to explain the symptoms, the lines in the picture and the pop sounds in the audio are the result of low RF signal from the video heads, possibly caused by a tracking error. The audio becoming softer is probably caused by the machine losing the HiFi signal and reverting to the linear audio track.Your rocking of the A/C head is actually shifting the control track phase.
    The auto tracking works by phase shifting the control track pulse while looking at the peak value of the recovered RF signal from the video heads.
    If it can't find a peak or it's too low, it just keeps on trying.
    This could be caused by dirty or worn video heads.
    I've cleaned the heads several times to no avail.
    As I said earlier, I think you're on the money with the A/C head and Phase shifting as I've had a feeling that the M/C electronics are trying to correct some error in signal alignment/reading/tracking or similar.

    The heads look good but this means nothing.

    The person who gave me the machine said that it's only a few years old and had little use, It just didn't work any more.

    When I took the cover off I found that the power board had been broken by someone pressing down on it, this was easy to fix by soldering a bridge across the broken tracks.

    As the machine owes me nothing it will be no real loss if I can't get it working, but it would have been handy in the guest room as there is no satellite connection there.

    again Bibliophile and dashinson,
    thanks for the help and ideas,
    Duck.

  • #13
    Registered User mate's Avatar
    Join Date
    Jun 2008
    Posts
    1,615
    Thanks
    88
    Thanked 162 Times in 118 Posts
    Rep Power
    0
    Reputation
    -233

    Default

    hey blackduck, a non technical aspect. is it more than one tape that gets the effect?
    iam a bogan

  • #14
    Premium Member
    mandc's Avatar
    Join Date
    Jan 2008
    Location
    Gold Coast
    Age
    70
    Posts
    3,747
    Thanks
    1,994
    Thanked 2,560 Times in 1,311 Posts
    Rep Power
    907
    Reputation
    29275

    Default

    Quote Originally Posted by mate View Post
    hey blackduck, a non technical aspect. is it more than one tape that gets the effect?
    Thinking the same thing. The ferric oxide coating comes detached from the backing as the tape ages (or is cheap crap) so the heads only last a short time before the muffled audio kicks in.
    Used to happen all the time on my old cassette deck with old dodgy tapes. From memory the audio head is a separate part from the helical scan head unless its Hifi...not sure about this though.
    Last edited by mandc; 28-06-09 at 08:58 AM.

  • #15
    Super Moderator
    Fernbay's Avatar
    Join Date
    Jan 2008
    Location
    Newcastle
    Posts
    4,684
    Thanks
    1,515
    Thanked 3,458 Times in 1,141 Posts
    Rep Power
    670
    Reputation
    15830

    Default

    Sounds like a worn ACE head.

    If I remember correctly, they are not avalible as such. They come as an intergrated part of the main deck assy.
    Reality is an invention of my imagination.
    ಠ_ಠ

  • #16
    Banned BlackDuck's Avatar
    Join Date
    Feb 2008
    Location
    Where I live
    Posts
    1,719
    Thanks
    504
    Thanked 367 Times in 237 Posts
    Rep Power
    0
    Reputation
    1146

    Default

    Quote Originally Posted by mate
    hey blackduck, a non technical aspect. is it more than one tape that gets the effect?
    Problem occurs on all tapes, old or new, but seems worse on tapes recorded on a mono machine.
    Quote Originally Posted by Fernbay View Post
    Sounds like a worn ACE head.

    If I remember correctly, they are not avalible as such. They come as an intergrated part of the main deck assy.
    The problem is something to do with auto tracking, as the sound is low and muzzy until the Auto Tracking message appears on the screen, then the sound and picture become clear.

    As I don't know the working principle of the auto tracking system it makes it a bit of "Hit and Miss" to try to work out how to adjust it.

  • #17
    Super Moderator
    Fernbay's Avatar
    Join Date
    Jan 2008
    Location
    Newcastle
    Posts
    4,684
    Thanks
    1,515
    Thanked 3,458 Times in 1,141 Posts
    Rep Power
    670
    Reputation
    15830

    Default

    Trust me - The ACE head - (Audio / Control head) - In LG's they are built on the brink
    Reality is an invention of my imagination.
    ಠ_ಠ

  • #18
    Banned
    Join Date
    Jan 2008
    Posts
    1,101
    Thanks
    180
    Thanked 92 Times in 65 Posts
    Rep Power
    0
    Reputation
    -336

    Default

    If you are familiar with what the CTL head is, then watch the tape as it rides across it.
    The tape should not be drifting up or down , but should be following the exact same path across this head.
    Any vertical movement, even 1 millimetre could cause loss of ctl pulses.

  • #19
    Banned BlackDuck's Avatar
    Join Date
    Feb 2008
    Location
    Where I live
    Posts
    1,719
    Thanks
    504
    Thanked 367 Times in 237 Posts
    Rep Power
    0
    Reputation
    1146

    Default

    Quote Originally Posted by Fernbay View Post
    Trust me - The ACE head - (Audio / Control head) - In LG's they are built on the brink
    You're probably right Ferny, I think most of the LG stuff is on the brink when it leaves the factory.

    I might seem to be a dinosaur sticking with tapes but I have 4 DVD players and only 1 will play a DVD right through, the others play about 3/4 the way through and start to jump and lock up despite cleaning the laser lens and keeping the DVD's in pristine condition.

  • #20
    Banned BlackDuck's Avatar
    Join Date
    Feb 2008
    Location
    Where I live
    Posts
    1,719
    Thanks
    504
    Thanked 367 Times in 237 Posts
    Rep Power
    0
    Reputation
    1146

    Default

    Quote Originally Posted by moeee View Post
    If you are familiar with what the CTL head is, then watch the tape as it rides across it.
    The tape should not be drifting up or down , but should be following the exact same path across this head.
    Any vertical movement, even 1 millimetre could cause loss of ctl pulses.
    I assume that the CTL head (ACE?), is the head about 40mil after the scanning head.

    I have watched the tape transport system for any indication of missalignment or any minor deviation in the track taken by the tape, nothing seems amiss, so I'm sure that it's an electronic feedback problem.

  • Similar Threads

    1. Replies: 1
      Last Post: 14-11-08, 06:15 PM
    2. Screwy Windows Media player problem
      By cmangle in forum PC Software
      Replies: 3
      Last Post: 05-11-08, 01:10 PM
    3. Windows Media Player Problem
      By Biggun in forum PC Software
      Replies: 6
      Last Post: 05-09-08, 04:37 PM
    4. DVD Player/ Burner problem ??
      By gordon_s1942 in forum PC Hardware and Printers (including 3D Printers)
      Replies: 2
      Last Post: 25-06-08, 11:09 PM
    5. windows media player problem
      By chopp in forum PC Software
      Replies: 2
      Last Post: 08-04-08, 03:52 PM

    Bookmarks

    Posting Permissions

    • You may not post new threads
    • You may not post replies
    • You may not post attachments
    • You may not edit your posts
    •