Large noisy bar from VCR bottom Of LED TV?

[Chris_N]

I occasionally use my old Panasonic VCR to play old tapes. With my old 4:3 CRT TV the little noisy bar at the bottom was quite minimal. However, when playing on my 16:9 led TV it seems massive and covers about 10% of the picture.

I have adjusted the tracking to get the best picture but the noisy bar is still there. Interestingly, during fast forward play the bar moves out of the picture, but returns at normal play speed. I have cleaned the video head and tape path. Is this normal, or does my VCR need adjusting?

Your advice would be appreciated

Kind regards
Chris

[hodgey]

What VCR model is it? Does it move when adjusting tracking? If it does it's probably tape path alignment being off.

I have a panasonic VCR (NV-FJ621) with a similar looking issue, which was caused by the alignment between head drum sensors being out of position in relation to the brass nut thing locking the drum in place (idk how that could happen). If the bar doesn't move at all with tracking adjustment it could be a similar issue rather than a normal alignment problem.

TVs will mask the image borders to some degree, especially CRT ones, this is known as overscan. LCD ones one can often be set to display the full image and may or may not be set that way by default, so it may have been there just not as visible.

[latreche34]

If it does it on all tapes it's definitely an alignment issue, It is not recommended to use the VCR as is until repaired, chances are it's curling up or folding the edge of the tape without noticing it. Since fields are scanned top to bottom I would assume the exit guide is miss aligned. Have it repaired or just get another VCR.

Also that's the wrong aspect ratio for viewing VHS tapes on a wide screen, you should have 4:3 image with black bars on the sides. Filling the screen can make you happy but objects will be stretched horizontally, totally wrong.

[Chris_N]

Thank you all for your replies. The VRC is a "Panasonic Super Drive Cvc Super SQPB VCR VHS Video" It has been well used. The very large noisy band appears on all tapes, including professionally produced tapes recorded with standard play. (My own tapes are usually Extended play) The band was visible even on my old CRT 4:3 although it appeared much smaller. I will do some more tests and output a test tape to a DVD to see how visible the band is. I will also compare another VCR.

If it is an alignment issue, I am confident I can do this myself. Please can someone give me some instructions.

-- merged --

Update. I tried various other cassettes and they all have the same problem. Cleaning the 4 heads on the drum with VCR cleaner spray doesn't help. Adjusting the tracking using the remote control will not get rid of the bar. Also I tried adjusting the top and lower guides and the noisy bar is still there. It appears the actual tape is aligned properly so I reset the two tape guides to their original position. The cable from the head seems to be connecting to the board properly.

I tried another VCR and it gives a perfect picture without the bar using the same tapes. I suspect the problem is something inside the head is not right or something is not making a good connection. Yes I could send it to Panasonic for repair (if it can be repaired) But first I would like to have a go myself.

Any suggestions would be appreciated.

Kind regards
Chris

[hodgey]

Quote:

Originally Posted by Chris_N

"Panasonic Super Drive Cvc Super SQPB VCR VHS Video"

Do you know the model number? It's usually on the front somewhere.

It might be the same issue that I had then if tracking adjustment has no effect, one way to test is to loosen the screws on the drum motor pcb on top of the drum motor and see if turning it has an effect. If it does something that may work is to remove the motor pcb and the magnetic metal thing on top of the drum so you can loosen and turn the brass nut/ring thing. You need an allen key or hex screwdriver of the right size to loosen it. In my case I had to turn it a bit anti-clockwise to get it to the right spot. Then after moving it re-tighten so it doesn't move and screw the magnet thing and motor pcb back on. It can be a bit fiddly to get it to the right spot, as you don't really know if you are close until putting it back together and testing.

You can fine-adjust the head switch point afterwards through the service functions on the vcr, described in the service manuals, but it only works if it's like a few lines off.

[Chris_N]

Thanks for your reply. On the back it says Panasonic model No. NV-HV60EC-S. don't have a service manual. I have removed the motor coil board off on top of the head. Then there are another 2 screws to lift off the motor magnet. Then I can see a brass ring. But I have no idea how to remove that. Have you any idea how the video head comes off? I would like to remove the head to check for any signs of damage and to check the connections underneath are clean.


Kind regards
Chris

[lordsmurf]

Quote:

Originally Posted by Chris_N

Cleaning the 4 heads on the drum with VCR cleaner spray

I'm cringing here.

What is that?
Nothing should ever be sprayed on the head. Nothing should ever be sprayed, period.

Quote:

Originally Posted by Chris_N

I occasionally use my old Panasonic VCR to play old tapes. With my old 4:3 CRT TV the little noisy bar at the bottom was quite minimal. However, when playing on my 16:9 led TV it seems massive and covers about 10% of the picture.

This looks like an excessive overscan, specifically head-switching noise.

[Chris_N]

Thanks for the advice Lordsmurf. I also tested the VCR on a CRT and the noisy bar is massive there as well covering 10% of the picture. It doesn't go away after adjusting the tape guides. It could be overscan, or maybe some other problem with the Video head as suggested by hodgey. The question is how can I fix it?

Kind regards
Chris

[hodgey]

Quote:

Originally Posted by Chris_N

Thanks for your reply. On the back it says Panasonic model No. NV-HV60EC-S. don't have a service manual. I have removed the motor coil board off on top of the head. Then there are another 2 screws to lift off the motor magnet. Then I can see a brass ring. But I have no idea how to remove that. Have you any idea how the video head comes off? I would like to remove the head to check for any signs of damage and to check the connections underneath are clean.

Ok, this has the late panasonic mechanism (R4), so I don't know for sure, but on all other mechs with the drum motor on top there is a hex key slot on the side of the brass thing. On the slightly older panasonic I have it was a weird size though, so I had to use a screw bit to loosen it as none of my allen key thingys fit which was a bit tricky. Be aware there will be a carbon brush spring somewhere, likely either in a slot in the brass thing, or between the upper and lower drum which you have to be careful not to lose, on the slightly older panasonics it's between the drum parts, but idk for sure with this one as the manuals don't show.

Service manual
Service manual for mechanism (probably more useful)

[Chris_N]

Thank you very much hodgey. I will tackle it tomorrow and see how things go.

Kind regards
Chris

[latreche34]

If no one is being in the VCR before I don't see how the head switch alignment will go off, That Allen screw is usually tight and sealed. While I'm confident that's not how head switch miss alignment looks like, just try removing the two screws on the motor control PCB and while the tape is playing try to slightly and slowly twist it sideways, if it doesn't make any improvement just put the screws back. And tackle the P guides adjustment.

The P guides are normally adjusted using an oscilloscope while looking for an evenly thick band of frequency, Using tape can be difficult but it can be done, You should turn the guide's head very slowly and make stops and observe the picture, adjust each guide so that you get a thinner noise bar don't expect one guide to clear all the noise, then move to the other guide.

But there are other possibilities that can make this happen:
- Tape not sitting flash on the mechanism bed due to faulty loading carriage
- P guides are not fully engaged and locked in their position
- Tape tension problem
....etc, Put it this way, there is a reason why there are technicians for each technology if anyone knows how to fix his car it won't be any shops out there. DIY has its limitations and catastrophies.

[Chris_N]

Thank you all for your help. I previously adjusted the guides and the noisy bar would not budge, so I set them back to their original position. The cassette appeared to be sitting properly and the tape was running through smoothly and quietly without catching on anything. The tape tension seemed fine.

Following the advice I have received, I took off the motor coil board and the magnet and tried to loosen the worm screw holding the brass bush. I didn't have the correct tool, but found a star shaped screw bit in my collection that worked perfectly. I loosened the worm screw so that the brass bush was just loose enough to be moved under pressure. I put everything back and played a tape. I slowly moved the motor coil board about 1/8 turn anticlockwise until the noisy bar disappeared down off the screen. Then I took the bits off again so I could fully tighten the worm screw. Voilà, everything works fine now.

I have no idea why it was so out of sync. This is an old machine that has been well used, so maybe the electronics or alignment somehow drifted off course.

Thank you all for your invaluable help! I really appreciate it.

Kind regards
Chris