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Author Topic: Otari MX5050BII2 Problem  (Read 6594 times)

Offline Arnold_Layne

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Otari MX5050BII2 Problem
« on: March 30, 2008, 05:08:11 PM »
I'm having problems getting rid of wow and flutter on this deck. I've narrowed it down to tape slippage at the capstan/pinch roller. If I play a tape, I can affect the tape speed by grabbing the supply reel. The capstan continues to spin but the tape stops. I have inspected the pinch roller, and it's not sticky. It still bounces back into shape if you put pressure on it. It does have very small cracks I can see if I look closely but it does not feel dry rotted. The capstan is very smooth where the tape passes and I fear this may be the cause of the problem. Is there a way to refinish a capstan to give it more "grab"?

Steve


Offline ironbut

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Re: Otari MX5050BII2 Problem
« Reply #1 on: March 30, 2008, 08:27:53 PM »
If the rubber is cracked at all, it probably means that it also isn't very compliant. It probably feels pretty hard. The cracking is also an indication that the rubber has dried with some shrinkage. Either way, your probably not getting proper force against the tape/capstan. First off, I'd try and remedy this with some rubber restoring chemicals. Sometimes, they can do wonders. I use a couple of different chemicals but the link below sells a rubber restore kit. I'd give that a try and if that doesn't work (that's the easy fix) you'll probably want to either replace the rollers or have them re-rubberized (I can't believe that word didn't get a reaction from my spell checker!). There's a few choices here, but I'd go with Terry's Rubber (the link for this in in the sticky at the top of the general forum).
If your rollers seem to have a little 'give' to them still, the pinch roller tension probably needs to be adjusted. If you have a service manual, it'll be cover in there. It's one of the basic adjustments that would be checked in regular servicing. If you replace or resurface the rollers, this needs to be done since the diameter of the rollers will be different. The procedure will probably require some sort of tension gage but your manual will cover that. Don't be shocked by the amount of force that the pinch rollers apply. It's usually a lot.
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Offline Arnold_Layne

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Re: Otari MX5050BII2 Problem
« Reply #2 on: March 31, 2008, 05:23:26 PM »
Thanks ironbutt. I will give the rubber restorer a try first.

Steve

Offline ironbut

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Re: Otari MX5050BII2 Problem
« Reply #3 on: March 31, 2008, 09:04:55 PM »
Hey Steve, I just read a thread on the Tape Trail and it may be that you have the same problem, just not as severe. It was solved by lubricating a pivot. You might try this first and if that isn't it, from the number of responses on that thread, it's probably a good idea to do anyway.
http://www.audioasylum.com/forums/tape/messages/1/11593.html
steve koto
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Offline docb

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Re: Otari MX5050BII2 Problem
« Reply #4 on: April 01, 2008, 09:31:09 AM »
If I may make a couple of suggestions - I would be inclined to clean and lube every point that seems logical to lube if one pivot turns out to be sticky. Adding more lube without cleaning the surfaces first is kind of like wiping your 4x4 with a damp washcloth after getting back from a day in the mud. It just spreads the old gunk out over the surface. For metal to metal surfaces I like naptha as a cleaner and an automotive assembly lube with molybdenum. You don't need much, just a thin film. Also, you might try Formula 409 and a terry cloth towel for scrubbing the surface of the pinch wheel. If you can get the surface to go from slightly glazed to a matte finish it will probably pull tape pretty well.
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