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  #1  
Old 02-06-2018, 12:47 PM
CPQ5360 CPQ5360 is offline
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Casio VF-3000 (similar to Hitachi/RCA VHS camcorder) tape path issue

Hi all - I recently procured a circa 1988 Casio VF-3000, a very rare portable TV/VCR based on a Hitachi/RCA VHS camcorder mechanism.

The mechanism has a minor issue - while playing a tape, slack forms on one side of the tape at the pinch roller, which eventually folds over and makes a long diagonal crease in the tape. It only happens sometimes, but when it does, it does it repeatedly, every few seconds.

The pinch roller is a little on the smooth/hard side, but not bad. I cleaned it with alcohol and roughened it up a little with an emery board, but that hasn't helped.

I have a video of it here:

https://www.youtube.com/watch?v=L4LZXsoJgg8

Any ideas? It almost seems like a guide is misaligned, making the tape move slightly diagonally, but I really don't know. Any help is appreciated.
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Old 02-06-2018, 05:16 PM
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A bad pinch roller can cause the tape to walk up or down the capstan. Also look at the take up reel tension and back tension. I've seen VCRs where the felt fell off the tension band. If it's otherwise playing ok, I wouldn't mess with the alignment unless it looks like someone has already been in there.
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Old 02-06-2018, 05:58 PM
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Alcohol is only mildly effective at fixing dry/hard/slick rubber. A product called 'goof off' will do a decent job of dissolving the hard outer layer (it also attacks plastic so pull the pinch roller out). Automotive belt dressing is a good follow up to the goof off...It will add new stickiness to the rubber. I've used that combo on everything from 40's phono idlers to broadcast Umatic decks with good results (even on some really lousy rubber).
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Old 02-06-2018, 08:49 PM
CPQ5360 CPQ5360 is offline
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Quote:
look at the take up reel tension and back tension
Tension on both sides feels good (easy to trick it into playing without a tape inserted). Felt on both sides is present and engage when they should.

Quote:
A product called 'goof off' will do a decent job of dissolving the hard outer layer
Would Goo Gone be a suitable equivalent? I do have that on hand.
When you say to pull the roller out, so you mean remove it from the machine, or actually pull the rubber part off of the plastic part it sits around?
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Old 02-06-2018, 11:21 PM
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Pretty cool machine, I've never seen one.

Can you remote the pinch roller and scruff it up with some sandpaper?
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Old 02-07-2018, 09:11 AM
djfivos djfivos is offline
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Use rubber renue on the pinch roller.
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Old 02-07-2018, 08:15 PM
CPQ5360 CPQ5360 is offline
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So I did some research, and was confident that I could try Goo Gone on the pinch roller, so I did so. It seemed to improve the roller a little - it's a bit softer and more grippy now. However, it hasn't improved the issue much, if at all.

I've noticed that the tape it does it to most is a pre-recorded T-50 tape. When I try it with a T-120, it does it extremely infrequently, if at all, in a couple of hours of playing. So I'm back to wondering if it is a tension issue, since the T-50 would of course have less rolling resistance than a T-120. I'll find a couple more tapes and see how they work.
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Old 02-08-2018, 10:44 PM
CPQ5360 CPQ5360 is offline
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Some more things I can report after digging into the VCR more:

The idler is a gear, not a tire, so issues there.

There are two belts aside from the loading belt, and both are in impeccable shape - I almost wonder if they're replacements.

Something interesting I've found is that if I put a little extra pressure on the spring-loaded tension arm on the supply side, the problem seems to resolve (there is no tension arm on the take-up side). In addition, I can confirm that the problem is definitely worse on shorter tapes. These two things make me wonder if it actually could be a tension issue - shorter tapes would present less resistance from the take-up reel, after all. Maybe something needs to be done to increase the spring tension on that tension arm? Or to increase the strength of the felt brake on the supply reel?
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Old 02-09-2018, 09:22 PM
CPQ5360 CPQ5360 is offline
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Found some more things of note - first off, I discovered that the supply-side tension arm can have its spring set to five different positions, presumably to adjust the tension. I tried all five, and it didn't really change anything.

Second, I found that if I put a layer of masking tape over the pinch roller and play a tape, the problem is completely solved. With the introduction of a ton of W&F, of course.

Finally, I dug out my 1994 RCA VHS camcorder to compare the feel of the pinch roller, and it turns out that the pinch roller in this unit is in worse shape than I thought. So it looks like I'll be trying Rubber Renue, and if that fails, replacing the pinch roller.

Problem is, I have no idea how to remove the roller in this thing. There's a screw inside the core, which can be seen in the video linked in my original post, but it just turns forever when I try to unscrew it, so beats me.
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Old 02-11-2018, 09:42 AM
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I would like to see a photo of the camcorder itself as well as the tape transport area. Maybe that will refresh my memory and I can offer up something.
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Old 02-11-2018, 02:41 PM
CPQ5360 CPQ5360 is offline
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Here's an album of images. Not actually a camcorder, but it uses a standard Hitachi camcorder mechanism. Specific camcorders that I believe have the same mechanism are the Hitachi VM-3100A and the RCA CPR-250.

https://imgur.com/a/ZcX3P

I'm gaining confidence that it's down to a hard pinch roller, so I've ordered a bottle of Rubber Renue, and will be giving it a try once it arrives.
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Old 02-11-2018, 03:41 PM
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Very cool! Thanks for those photos! I've never seen one of those before! I would agree- like a RCA CPR250. Worked on dozens of those camcorders, and their ilk.

Yes, I believe the pinch roller is truly the problem provided you've ruled out the other suggestions mentioned here. I was replacing pinch rollers in that mechanism in the 90's (seemed like well earlier than should have been) and so I'm sure yours would be shot by now, as well.

I wonder if any one could recover it? I get laminator rollers recovered all the time by http://www.rotadyne.com/rubber-manufacturing/basic-polymer-types/ but would have no idea what they could offer you.

Good luck with it!
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