studer b-67 help

[stugazz]

hello all.. i need some help,on one of my studer b-67 the take-up reel spins constantly, i have changed the power transistors (MJ411) i changed the caps on the spool motor boards, i changed the tape transport with my other working unit,
and still the take-up reel spins constantly So i know it's not the tape transport board or the power transistors or the boards on the spool motors. What else can it possibly be? thank you... any help would be greatly appresciated

[cavemaen]

Look at:

http://www.datasheetcatalog.org/datashe ... /MJ411.pdf

Best Regards,

Rudy

[stugazz]

thank you Rudy, i installed 2 brand new MJ411 power transistors, i also installed good working and tested spool motor boards on both sides, and also installed a good working and tested tape transport board from my other unit. and still the take-up reel keeps spinning? i know all these are good because when i install them back in my other unit it works fine the units are both b-67 MK1 only the one i am having problems with is a mono unit and my other one is a stereo unit i don't think this should make a difference because all the part numbers are the same

[cavemaen]

Now, the Problem is the Resistor / Condenser after the MJ411.

He makes Power without stop.

Rudy

[stugazz]

Thank you Rudy

I have 2 b-67 mk1 units, one is a stereo unit "this unit works perfect"
my second unit is a b-67 mk1 mono unit "this one both reels spin as soon as i power up"

now i took all the parts form my good unit they are identical " spool motor boards/power transistors MJ411/ and the tape transport board. and installed them on the mono unit and still the reels both spin as soon as i power up

[cavemaen]

You have found the Failure?

Bevore a lot of Years, I have on my old B67 this Failure; it was a Kondenser of the little Circuit and the Reelmotor was running without stop.

Best Regards from the Middle of Germany,

Rudy