Telefunken M15 1/4 inch 2 track -potential problems with spool motor or capstain

[skaren]

Hi,

I have a telefunken m15 that has recently stopped working. It happened when an unfortunately sticky tape was used. It got stuck around the spool motor (?) and after having to cut loose the tape playback ceased working. Fast forward and rewind still works well.

http://www.youtube.com/watch?v=z9W1vBf4Jdo

I filmed this video to show what I'm on about.

Does anyone have an idea from a quick glance at this what could be the problem? Obviously it would be hard to tell without actually seeing the machine in person but anyways.

Big thanks!
Martin

 

[pvision]

Impossible to tell from the super-dark video. Is the capstan rotating? Is the pinch-roller touching the capstan when it's in play?

If the capstan isn't rotating find out why. If it is, and it continues to rotate when in play, the tape should be dragged through by the pinch roller. If the pinch roller isn't pulling in properly you won't get any drive

Normally you use a Tentelometer to measure tape tension and a spring balance to measure pinch roller pressure. You could do the latter with a simple spring balance weighing device with a hook on the end

Fuses?

Nick Froome

 

[RuudNL]

I get the impression that the capstan motor was blocked at a certain moment.
(Maybe tape sticking to the capstan, happened to me once also...)
This could have blown a fuse. I would check this first!
If this is not the problem, I would check the capstan motor electronics.

 

[skaren]

Thanks for your replies.

I should have a look at the fuses. I'll post my findings.

The capstain doesnt rotate. The pinch roller touches the capstan when in play mode.

many thanks!

 

[skaren]

Hi again,

I found that 2 of the fuses had shattered so I replaced those (top left and bottom right fuse in the pic). Unfortunately the capstan still doesn't move at all.

Is it perhaps likely that it is a problem with the capstan motor electronics then.

Thanks again

 

[skaren]

And the pic


BTW, Does anyone have a spare Capstan motor to sell in case it ends up being burnt out? Or somewhere to direct me? I have found Hilpert Audio so far. Anyone had any experience with them?

Cheers
Martin

 

[pvision]

If the motor has burnt out I think you'd have nasty burning smells.  I'd pull out the power supply and have a look at it. Check what voltages it is producing - if any - and then put a meter across the motor connections with it unplugged to get a reading off it. If it's open circuit you may have a motor problem

It's a DC motor with a quartz reference signal
http://www.hilpert-audio.de/audio/dokumente/ProspektM15A_E.pdf

It might be a blown power supply but it could as easily be something really simple. It might be missing the signal that tells the capstan motor to run. There will be a simple microswitch (or a complex optical device - you know the Germans!) to tell the machine tape is loaded.

Some machines use a tension detector - usually a swinging arm - to tell that tape is loaded and some use an optical switch where the presence of tape breaks a beam. If the machine stopped when in wind or play because the tape jammed it may have bent a switch or arm and this is stopping it working properly

On some machines the capstan runs all the time. Is this the case with the M15 or should it start the capstan motor when tape is loaded?

Nick Froome

 

[skaren]

Thanks for your post

I dont think the capstan started when tape was loaded when it was still working.

I'll look into your suggestions. I have also been adviced to check a resistor with solder fuse function near the left wind motor.

Is there anyone in London with a M15 who wouldnt mind lending their BC-TR11 card so I could rule that out?

Thanks again you who have lent your time offering advice!

 

[skaren]

I managed to fix the machine with help from Kai Hilpert who suggested that it might be the transistor with solder fuse function next to the left wind motor. Also thanks Guy_4 who helped me locate the transistor (since i in my limited knowledge I couldnt find myself).
Re-soldered the connection and the capstan starting spinning again.

Thanks all you guys

 

[zoky]

Hi All, Skaren,

Might be the same problem here - M15A just stopped playing in the middle of a 18cm reel.
Except that, all fine - winding, brakes, buttons lights, sound in Edit mode (manually);
Just capstan can't come to run.
So, maybe help us to locate that transistor with solder fuse function next to the left wind motor, mentioned in the post?

Attached here is a view, may someone tell us where's the beast?

Thanks in advance for your help;
With kind regards,
Ed

 

[marcvie]

Ive also been adviced to check a resistor with solder fuse function near the left wind motor.

THANKS! this saved my machine, i checked all cards and all fuses were good, I almost gave up.

The solder joint on the resistor/fuse broke off, the fuse wasn't blown.
I don't know why it came loose because my machine doesn't move, I guess its age related.
Anyway that advise solved my capstan motor not spinning, after a 3 month long search.

 

[ursonate]

THANKS! this saved my machine, i checked all cards and all fuses were good, I almost gave up.

The solder joint on the resistor/fuse broke off, the fuse wasn't blown.
I don't know why it came loose because my machine doesn't move, I guess its age related.
Anyway that advise solved my capstan motor not spinning, after a 3 month long search.

The fuse resistor is located on the rear underside of the appliance next to the left-hand winding motor. It is accessible from below. The contacts can be soldered provisionally, but the resistor should be replaced because the contacts are connected with a solder that has a defined melting point.

Hi All, Skaren,

Might be the same problem here - M15A just stopped playing in the middle of a 18cm reel.
Except that, all fine - winding, brakes, buttons lights, sound in Edit mode (manually);
Just capstan can't come to run.
So, maybe help us to locate that transistor with solder fuse function next to the left wind motor, mentioned in the post?

Attached here is a view, may someone tell us where's the beast?

Thanks in advance for your help;
With kind regards,
Ed

The fuse resistor is located on the rear underside of the appliance next to the left-hand winding motor. It is accessible from below. The contacts can be soldered provisionally, but the resistor should be replaced because the contacts are connected with a solder that has a defined melting point.