wisdom about barber poling?

[kozz]

I gambled on this Sony 6-head vcr for cheap to replace an old JVC that had succumbed to static. It records badly but that's not the trouble since I don't record quality stuff to VHS anymore. However half - not all - of everything recorded by the JVC, when played back on the Sony has this barberpole effect:

-- perfectly horizontal lines, absolutely stationary
-- spaced about 12-13 mm apart
-- visible only over colors with high cyan or magenta value
-- turn cyan to magenta and vice versa

depending on what is in the picture the effect is a gridiron of magenta lines, of cyan lines, or a mixture...

all the barberpoled tapes are recorded in EP. No commercial SP tape has done this so far... on some tapes some recordings have this effect while others don't, on the same tape.

The model is Sony SLV-N500. I imagine the cause of this is buried deep in the circuitry somewhere, but I'm puzzled why it doesn't affect everything it plays.
oh and also a good place for shematics>

[vtech]

The effect that you are describing is not that uncommon when switching from brand to brand. ..Several possibilities that could cause this. It is possible that the recordings made on the older JVC were infact contaminated with the "barberpole" effect & might NOT have been visible while playing back on the same JVC. (ie;drying electrolytics in power supply translated into variety of video symptoms in VHS---JVC was known also). Unless the new Sony has the same problem with it's own recordings, you can pretty much forget about finding a problem.

Also it may be that due to differences in video processing circuitry, it is more visible. In general, newer VCR's tend to have somewhat a sharper & more detailed video levels which tends to amplify any irregularities a LOT more than before.

Having been in the business, I've come across this issue many times.

[Guest]

yeah, I figured someone here would have seen it though I couldn't find any documentation about it. The Sony plays its own recordings just fine, they're of lousy quality though. I should have got one from an era where recording quality was more important in the market I guess.

The JVC was beautiful before it started deteriorating, I didn't see this effect even when its playback got bad. But it does vary in intensity, it might have been there just too faint to notice.

I said it's only there on about half the JVC recordings, but I suppose it could just be unnoticeable on the other half.

I suppose I'll have to either replace all the recordings, or try to find another brand which doesn't barber-pole them. Since the Sony is mediocre at recording, that means getting another one.