Tape Project Forum
Tape Machines => Reel to Reel Tape Machines => Topic started by: King Arthur on November 21, 2012, 02:20:00 PM
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Hi There
I have recently made a purchase of an ex-radio station MX5050 BII. It's in good working order but unfortunately there is a bit of a problem with the brakes when the stop button is pushed. Basically, when the stop button is pressed when either in the play or ff/rw function the brakes lock in immediately and the reels come to an abrupt halt. When testing the stop button in ff mode it pulled on the tape and stretched it rather badly. I've just had the unit serviced and the technician seems to think there is not much that can be done... Can some one please shed some light on whether I can make it work any smoother? I'm hoping to use this deck to mix down from my 8 track and don't want to spend money on new tape if it's going to be stretched...
This is the comment on it I got from the tech:
That machine was designed so that when you hit the stop button the motor power switches off and the mechanical brakes are activated. It's a fairly basic mechanism design - on a more sophisticated unit the tape would be slowed down by applying reverse torque, then the brakes would activate just as the tape came to a standstill. The mechanical brakes have a force differential of about 3 to 1, clockwise to anticlockwise. Thus when stopping the tape the trailing brake has more braking effect than the leading brake, to avoid the tape "throwing a loop". This effect is much increased when using 7" reels - you will find it a lot smoother using 10 1/2" reels.
When you dropped the unit to me the brake differential was more like 10 to 1, because of the accumulation of friction material from the brake bands onto the brake drum, resulting in an even more fierce "stop" - so having cleaned the drums, this is about as good as it gets. My recommendation would be to either use 10 1/2" reels (always more preferable) or to hit the opposite fast wind button to slow the tape, then hit stop when the tape has pulled right up.
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5050s are generally pretty gentle tape handlers. The big "wraparound" synthetic brake pads/bands are way better than the teeny ones on a Technics deck. That said, the brake adjustment itself is surprisingly crude. Did your tech try to set the brake tension at a lighter setting? Are the brake pads themselves clean?
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What the tech told you to do is rock the reels. This is the only way to avoid runaway tape when fast winding on my Revox A77.
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I managed to figure out what the issue was. Both of the tape arms had springs/screws detached and missing from inside of the unit. I fixed them up and also changed the position of some adjustable springs on the brakes and now all is well.
Thanks for your help.
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Good evening Mr. Ahbez,
Reel happy you got the Otari running right. It is an excellent tape deck and treated right it will be with you and provide great service for a long time.
bob williams