VHS Playback issue

[Toodlebug500]

Hi, I wondered if anyone could spare the time to help me with an VHS playback issue I've been having. I recently got a player that persists in displaying diagonal lines across the picture. These don't seem to be fixable through adjusting the tracking. Any idea what the problem could be?

The tapes are fine and I have no issues with them on another player I have.

I've attached an image for reference, the diagonal lines appear more defined last time I tested the player than in this imagine and there are less of the short horizontal lines that also in this photo.

Thanks,

Tom

[Horris]

Try lining the top of the cabinet with aluminium foil.

Dave

[Toodlebug500]

Hi Dave,

Thanks for the advice, I gave it a go, but didn't seem to do anything. I guess the reasoning behind the foil is to avoid electrical interference?

As you can see in the attached pictures the player in question is a LG Neetee branded player. It has a plastic top casing so I guess it could require some shielding although I think there is a metal part on at least part of the underside of the casing.

Also in the picture you probably notice a lot of other electrical devices around that would increase the likelihood of interference?

Let me know if I'm right with the interference thing, or not

There's also some images of how the picture is looking at the moment, it's a bit different than before, however this is with or without the aluminium foil covering the player.

[The Philpott]

Wear to the video head?

[Nuvistor]

Originally Posted by The Philpott

Wear to the video head?

Certainly looks like a head problem of some sort.

[Norman Raeburn]

I thought it was head wear at first glance, however the interference is a diagonal pattern which suggests to me an earthing problem with the head amp of lower cylinder assembly. Probably no help to the op if they have no technical knowledge. Norman

[winston_1]

Remove the brush on top of the video head and clean it.

[jayceebee]

There are many things that could cause this, two that spring to mind are the head discharge brush/brushes which could be dirty or ripple on the voltage supplied to head amplifier.

If it is the discharge brushes then try very lightly placing a finger on the rim edge of the spinning head drum, it will make the effect much worse. Knowing the make and model number might help.

John.

Edit. Post crossed with Norman

[Toodlebug500]

Thanks for all the advice, I appreciate it. It's true I'm no sort of expert in this area but I'll certainly investigate all advice given.

The make and model of the player is LG BN200IB.

What I find interesting is apparently the player was working fine until it was shipped to me. Since it arrived I've had this persistent playback issue.

I'm wondering if this effect could be caused by some sort of damage in transit?

Thanks again.

[dj_fivos_sak]

Looks like worn heads or bad grounding of the head drum. Did you try cleaning them?

[Maarten]

Worn heads or bad grounding won't give diagonal lines, but can give 'bullets' as seen in the first picture. On the other pictures it looks very much like interference, possibly from a nearby TV set or switch mode power supply? Mostly this will result in moving vertical lines instead of diagonal, so the frequency must be a little off. Hence more likely to be a switching power supply (maybe even in the recorder itself) than a TV set, but you never know.

Since this is not a general issue but has something to do with a particular set, it is advisable to give the exact model of the VHS recorder as well.

Anyway, I would try unplugging everything except the VCR and TV and/or physically relocating the VCR as far away from other equipment first. If that doesn't help try drum grounding, and only after that other options should be considered in my opinion.

[mark2collection]

Almost certainly a drum/amplifier grounding issue.

The brush on the drum itself, LG's of this generation tended to have the brush mounted underneath. They normally have a smidge of grease on them to stop any squealing. Remove the brush (usually a single screw) clean off the old muck, make the contact points on the drum shaft & brush, bright & shiney, then add a tiny spot of grease again, reassemble.

The head amplifier may not be grounded properly, or the main deck to the PSU. You may find a flat spring-type grounding arrangement for the deck to the PSU, it's probably tarnished by now.

As mentioned previously, could be the VCR's power supply too.

Worth a look.

Mark

[ben]

I have had this caused by:
-loose drum strap.
-Deck not fastened securely to pcb/mounts
-Bad capacitors in the power supply secondary.

[Toodlebug500]

Thanks again for all your replies, they are much appreciated.

I decided to take the top off the player to inspect the machine while it was working, much to my surprise, with the top off there were no picture issues.

Once I placed the top back on the player, the lines reappeared.

I'm happy to know that the player does essentially work now, however, I'd really like to be able to use it with the top attached...

In light of this discovery does anyone know what the problem could be?

As I mentioned before, apparently the player was working fine before shipping it to me, which makes me wonder what could have happened in transit to effect the playback while the top of the player is attached??

[dave walsh]

Not really my [magnetic] field Tom I see you have tried the suggestion by Horris/Dave in post 2? He must have had a reason for making it Did you actually manage to link the foil to the metalwork I wonder? Your player is unlikely to have had a totally smooth ride on it's journey, so anyone of the grounding issues that were mentioned previously by the real experts could have been exacerbated.

The lid removal has clearly done something to affect things but what? Is the change of stresses on the case when you do that affecting the grounding in some way I wonder. I might be inclined to try out the player in a different place to rule out local interference.

Cheers,

Dave

[Toodlebug500]

Yeah tried that one, it didn't seem to have an affect sadly.

[Grubhead]

Check where the fixing screws of the top cover fit. It might be that the screw is making contact with something it should not, or that the movement puts a strain on a solder joint, causing a problem.

[Toodlebug500]

Wow! It's working properly! I worked out where the point of contact with the lid and player that was causing the problem was. It was specifically down one side of the player.

There is metal running down the sides of the lid interior where the screw fittings attach. On one side of the player, when this part made contact bottom half of the case I would get the diagonal lines appearing on screen.

I did actually end up using aluminium foil, I taped two pieces over each of the pieces of metal surrounding the screw holes, placed it on top and problem fixed! Then I just screwed the lid back on.

Previously I had just attached the foil to the top of the interior, which was obviously not where the problem was.

Thanks so much for your help everyone, I've learnt a bit through this process!

[Toodlebug500]

Many thanks Dave, aluminium foil did fix the problem in the end! I just hadn't attached the foil to the problem area which turned out to be around screw holes on one side of the player, which had some metal surrounding them.

[dave walsh]

Actually, it looks like a "joint" first place for Horris, Grubhead and me-a "joint" contact/screening problem. Glad you managed to sort it. In my [limited] experience this sort of thing can sometimes be resolved without finding an actual answer but you have-great!

Dave W