A VHS tape audio 'damage' question.

[Eidolon]

This is a new one on me. I'm a bit puzzled, hopefully somebody will have some idea.

I recently got my Panasonic NV-J35 repaired after it'd had been out of cmmision for a while, on account of the 1983 model TV I recently aquired.

The J35 had some problems, and came back nicely fixed. Now I seem to be having issues relating to audio.

At frist it sounds like the problem with the pinch roller, where a tape top gets creased, but upon opening the tapes and looking at the top, there's no visible physical damage, but the audio definately seems to have been affected somehow. I have watched 3 tapes already this week, and either they all have the smae problem, or the VCR is somehow negatively affecting the audio on the tapes. It comes and go's, and upon playing the tapes back, is always in the same places afterwards.

Otherwise, is there possibly some reason why the VCR cold be reading the tpaes like this, despite ther being no visible damage? All the tapes are different makes, from different sources, so all in all I'm a bit puzzled.

Any help appreciated. Thanks

[john.north]

If the sound is wooly and low output the two main causes are insufficient supply spool back tension or the audio head incorrectly aligned. The pinch roller if faulty would affect the tape and possibly mark it. If the top edge of the tape is very slack as it passes the audio head this would indicate that it is set incorrectly. there are three adjustments for correct ACE head adjustment, height, forward tilt, and vertical axis, a test tape needed for satisfactory results. Incorrect take up spool torque could possibly cause problems normally at the beginning of tapes and nearly always causes tape damage due to trying to wind the tape faster than the capstan can supply it.

[HamishBoxer]

If the ACE head adjustment is sealed then its most like correct,do not just twiddle!Put your finger on the tape after ACE head and see if there is a reasonable but not excess tension.

The tension band on LHS spool can fall apart ie the felt pad comes adrift or incorrectly adjusted.

[julie_m]

If this machine is actually affecting tapes in a way that is causing audio problems when played on other equipment (but no visible damage is evident), then that almost certainly indicates that the audio / control head requires demagnetising.

[Boom]

Are the tapes that you are playing recorded on it when it was faulty?

[Nicklyons2]

Before doing anything else obtain a known good tape and check the machines's 'interchange'. To do this: manually mis-track the video i.e. adjust the tracking control (maybe only accessible on the remote control) until the picture begins to break up. On a machine which is correctly aligned when mis-tracked the picture will be equally bad top to bottom; if the picture breaks up in thin banded segments the tape guides are out of alignment. Although these tape guides are primarily intended to guide to tape onto the video drum correctly they do have a significant effect on the tape path as a whole and on most machines their misalignment noticeably affects audio performance.

[Eidolon]

Well, I've had some developments here. Looks like it's the pinch roller according to the local repair shop, which is annoying, as it had a new one (allegedly) fitted not too long back.

There was a few symptoms in the end during playback. Bad muffled sound, tracking fuzz intermitent at the bottom, 'wobbly' audio, occasional tracking issues across the whole screen, and when I examined some of the tapes more closely, I found that a lot of them had been damaged along the bottom. It looks like the tape is slipping down while playing. It'll be back in for repair next week.

Diverging slightly, is there much chance of getting a new pinch roller for this machine? I'm tempted to stock up on them if I can find some of them anywhere. Worn pinch rollers seem to be the most common problem I ever encounter over the years.

[HamishBoxer]

A decent quality p/roller does not fail for years normally. Is this perhaps a guide alignment problem or similar?

[Michael Maurice]

Where did you get the pinch roller from?

Did you replace just the roller or the whole assy?

Was it a genuine Panasonic Part?

My experience has been that you should use only genuine service parts.