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Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc.

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Old 18th Jul 2023, 7:07 pm   #21
Karl T 01
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Default Re: Grundig TK 141

Thanks again for the suggestions and the effort put in to helping me with this.
As a complete novice I'm not sure if I'm testing the right connections. Going on the little experience I have, I tested the Red and Black wires on the left hand side of the motor. I got a reading of 115 using the AC setting on the multimeter. No more info on the display so I'm presuming that's Volts. I'll try upload a photo.
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Old 18th Jul 2023, 7:22 pm   #22
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Default Re: Grundig TK 141

I made another video showing the armature rotation, it's the same as the pulley.
https://youtu.be/3p-QCCf_VJo
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Old 18th Jul 2023, 7:37 pm   #23
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Default Re: Grundig TK 141

The motor has a couple of windings in series. You're probably measuring across just one of them and that will measure 115V if you apply 230V.

The motor shaft should spin readily if you turn it by hand when the drive belt is removed. It looks like it is binding for some reason. Try tapping the shaft as I suggested earlier, and check that there is nothing obviously causing the binding. If you haven't already done so, a small drop of light oil on the top and bottom bearings may help. Don't apply lots of oil as it will just make a mess and get onto the rubber drive parts.

Paula
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Old 18th Jul 2023, 8:02 pm   #24
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Default Re: Grundig TK 141

As Paula says the mains supply is connected across 2 series connected primary windings of the mains transformer part of the motor, these on mine measure around 35 Ohms each, the red and black are across one winding so the voltage across one winding is half of the mains supply voltage.

On my TK 146 red and black measure 117V and the other primary winding blue and green also measures 117V, you will measure the full mains voltage across blue and red which should be close to 240 volts depending upon your local mains voltage.

Also as Paula says looks like you have a stiff motor, should be easy to manually rotate (ensure machine is unplugged from the mains first) the motor armature in both directions even with belt fitted to pulley.

If very stiff to rotate and Paula's suggestions do not help try loosening the 4 securing screws that secure the U shaped motor assembly clamp to see if the armature then frees up, if it does then you need to retighten the screws tapping the shaft as required to achieve a free shaft rotation.

David
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Old 18th Jul 2023, 9:45 pm   #25
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Default Re: Grundig TK 141

Just checked the voltage across the red and blue wires. Got a reading of 230-233v. I tried loosening the 4 screws and tapping the shaft. There's no issues with turning the shaft in either direction by hand.
While loosening the 4 screws I noticed that the 2 nuts on the mounting bolts for the motor are slightly loose. The motor can be rocked in and out and side to side. I ran the machine and tried moving the motor slightly, the vibration ceased when I had the motor pulled slightly outward.
I'm thinking the motor may need to be unmounted and the shaft taken out to see if something is rubbing on the inside?
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Old 18th Jul 2023, 10:49 pm   #26
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Default Re: Grundig TK 141

It turns out that the shaft was very slightly leaning forwards. I pushed it back with a screwdriver and it spun perfectly. Placed the belt back on and it's spinning better than it has done since I got it, (almost silent). Thanks so much for all your help I wouldn't have had a clue what to do otherwise.
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Old 18th Jul 2023, 10:54 pm   #27
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Default Re: Grundig TK 141

https://youtu.be/0mMY-DaltZw
The end result, many thanks to all involved.
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Old 19th Jul 2023, 12:13 am   #28
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Default Re: Grundig TK 141

Unfortunately that was a temporary fix. As soon as I put it back together it went back to the position that is causing the problem. I can't get a spanner in to tighten the two nuts on the motor mounting and I have no idea how to keep the shaft from leaning forward.
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Old 19th Jul 2023, 12:35 am   #29
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Default Re: Grundig TK 141

https://youtu.be/7Or0vnFP1Us
The state of play at the moment.
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Old 19th Jul 2023, 10:42 am   #30
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Default Re: Grundig TK 141

I took the motor out and cleaned the shaft. Put it back together and the motor pulley spins freely. Still a bit of work to do as it's now making noise. Trial and error definitely comes to mind...
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Old 19th Jul 2023, 11:34 am   #31
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Default Re: Grundig TK 141

Quote:
Originally Posted by Techman View Post
Quote:
Originally Posted by Karl T 01 View Post
All bulbs working.
The thermal clutch that Reelman mentions in post #5 may be worth considering - it's not something I'm personally familiar with on these motors.
I also am not familiar with the thermal clutch but believe have found it referenced in the TK 141 Service Sheet. First attachment references the motor pulley safety fuse at Fig 8. Second attachment shows Fig 8 section of the drawing.

Because the motor is now working intermittently depending upon the motor shaft tilt position, think it is unlikely that the solder fuse has failed.

David
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File Type: pdf 1.pdf (46.0 KB, 30 views)
File Type: pdf 2.pdf (297.2 KB, 29 views)
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Old 19th Jul 2023, 12:04 pm   #32
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Default Re: Grundig TK 141

Sounds like you have done a motor strip down but here are some photos for general reference.

David
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Old 19th Jul 2023, 12:47 pm   #33
Karl T 01
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Default Re: Grundig TK 141

I did David, I thought if I cleaned up the inside of the motor and shaft it might sort out the problem, also wanted to tighten the nuts on the motor mounting, it seemed like the only option. The shaft seems to be pulling to the right. Should the pulley wheel on top spin freely or should the whole assembly turn if I turn the pulley wheel? I think I might need to find some new circlips, on mine the pulley wheel at the top turns without the rest of the assembly turning with it.
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Old 19th Jul 2023, 2:01 pm   #34
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Default Re: Grundig TK 141

With it assembled the whole assembly should turn if you turn the pulley wheel, however if you block the armature from turning, then the pulley wheel can be turned but not spin around the motor shaft.

If you remove the circlip then the pulley will spin around the motor shaft, this is because the tension is removed from the spring and this allows the pulley to easily spin around the motor shaft.

The motor pulley fuse referenced in Post 32 when solder melted will allow the pulley to turn around the motor shaft according to the description, I do not really understand this as cannot visualise the part and how it actually works.

David
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Old 19th Jul 2023, 2:06 pm   #35
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Default Re: Grundig TK 141

As referenced in the Thread link at Post 19, the lower circlip also has to be in place, otherwise the spring will not be tensioned and pulley will turn around the motor shaft.

David
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Old 19th Jul 2023, 2:15 pm   #36
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Default Re: Grundig TK 141

On one 60s Grundig I serviced, the spring loaded pulley detached itself from the motor shaft and was slipping. Check that. On a tk120 the motor bearings were so sticky it refused to start!
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Old 19th Jul 2023, 4:33 pm   #37
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Default Re: Grundig TK 141

The clutch arrangement can slip rather too readily in my experience. Make sure that you don't have any oil on the spring and the parts it makes contact with. It's not unusual for the drive to slip on towards the end of the spool of tape on rewinding or fast forward on these models, but there shouldn't be any trouble during normal play/record operation.

As others have said, both circlips need to be in place for the system to work properly.

Paula
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Old 19th Jul 2023, 4:53 pm   #38
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Default Re: Grundig TK 141

Thinking about it more, I think the referenced motor pulley safety fuse must be the silver conical shaped piece. On the wide end it has a small lip that looks to be possibly soldered. This end makes firm contact with the underside of the motor pulley by the action of the spring (which sits inside the conical piece) being compressed.

This firm contact enables the pulley to rotate when the motor rotates, if the solder melts due to overheated motor, then I guess this is enough to disable the pulley from rotating even though the spring is still compressed.

David
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Old 19th Jul 2023, 5:00 pm   #39
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Default Re: Grundig TK 141

Quote:
Originally Posted by ben View Post
On one 60s Grundig I serviced, the spring loaded pulley detached itself from the motor shaft and was slipping. Check that. On a tk120 the motor bearings were so sticky it refused to start!
The spring in the TK 141 is just a standard spring that is not attached to anything. The motor shaft spring used on some of the TK 14-23 series is a torsion spring that does attach to the motor shaft and can be a nightmare to remove/refit in my experience.

David
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Old 19th Jul 2023, 5:08 pm   #40
Karl T 01
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Default Re: Grundig TK 141

Thanks the information is very much valued. I'm fairly bamboozled by the whole drive shaft thing at the moment. I'm fairly certain it has something to do with it pulling towards the right (towards the idler), and slightly to the front. In one of the videos I posted I was able to push the shaft slightly with a screwdriver and it ran perfectly. Took the motor off, checked the shaft for damage and checked if it looked straight and it seemed fine. After reassembling it again seems to be pulling to the right. The belt doesn't seem to be overly tight. I'm thinking maybe if I can get a piece of metal in to the side of the rubber cap below the drive pulley assembly it might stop the pull to the right.
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