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-   -   Grundig TK140 (https://www.vintage-radio.net/forum/showthread.php?t=198002)

computerice 2nd Feb 2023 7:36 pm

Grundig TK140
 
Hi

I have a Grundig TK 140 and I managed to replace the belts in the system and it plays, rewinds, records ok. The only issue I have left is the motor is constantly running and you can hear it.

The second issue is the fast forward is not working I suspect it from the motor constantly running and is affecting this.

Anyone know what the issue could be and how to resolve it Thanks in advance.

frsimen 2nd Feb 2023 8:19 pm

Re: Grundig TK140
 
Welcome to the forum.

The motor on the TK140 is intended to run all the time, so that isn't a fault

For fast forward, there is an idler wheel which should transfer the drive from the motor to the take up spool carrier. Make sure that the idler is free to move and that it making contact with the rubber drive collar on the motor and the take up spool carrier when fast forward is selected. A common problem on the TK140 is the rubber drive collar slipping on the motor shaft, although that is more often seen at the towards the end of winding or rewinding.


The belts can all be changed from underneath the chassis. If you weren't aware of that and undid the four "whatever you do, don't touch these!" screws on the top plate you haven't quite got the take up spool assembly back in place correctly.

If you haven't already got it, the service data for the TK140 is available from the link at the top of this page. That will show the mechanical arrangement better than I can explain it.

Paula

DMcMahon 2nd Feb 2023 9:08 pm

Re: Grundig TK140
 
Note that the TK 140 service data available from the "Downloads available" link above, consists of 2 separate PDF files both identified as TK 120, the "rtvs" file mainly only covers the electrical aspects, the "manufacturers" file covers both electrical and mechanical.

David

computerice 3rd Feb 2023 12:48 am

Re: Grundig TK140
 
Hi thanks for your reply.
The whole thing was taken apart when the belts were changed. it took two of us to get it back in the right slots.

Without the lid on even with the dial on the stop position the large wheel at the front is still going around and is still spinning. Driving the belt. I don’t know if is supposed to do that but it is very noisy. i don’t remember it doing that before we took it apart. Then again all of the belts had broken down.

just looking to get it right so i can put it online and recover my money i spent on belts Etc.
Thanks
Andy

Analogue man 3rd Feb 2023 9:02 am

Re: Grundig TK140
 
The large wheel is the flywheel and it will rotate all the time that the motor is running and that is whenever the machine is switched on.

DMcMahon 3rd Feb 2023 10:04 am

Re: Grundig TK140
 
Quote:

Originally Posted by computerice (Post 1533593)

Without the lid on even with the dial on the stop position the large wheel at the front is still going around and is still spinning. Driving the belt. I don’t know if is supposed to do that but it is very noisy. i don’t remember it doing that before we took it apart. Then again all of the belts had broken down.

As explained twice above the motor will always spin when the unit is powered up, it is designed that way.

The spinning motor with broken belts will be somewhat quieter than when spinning with intact belts but it should not be overly noisy in normal operation.

David

Welsh Anorak 3rd Feb 2023 10:08 am

Re: Grundig TK140
 
Unfortunately you've learned the hard way not to remove those red painted screws on the top deck! In case anyone else needs to change the main belt, you remove the LOWER bearing plate below the flywheel and stuff the new belt up and around. Sounds tricky and counter-intuitive - and it is - but that's how Grundig tell you to do it!

Anyway, determine whether it's the flywheel or the motor that's noisy by removing the belt from the motor pulley. If it's the motor, oiling the bearings should cure it.
If it's the flywheel, double check all the moving parts have gone back correctly, then take off the lower bearing and grease it.

These machines run very quiet so hopefully you'll manage to get it sorted.

DMcMahon 3rd Feb 2023 11:33 am

Re: Grundig TK140
 
Even though the motor mechanically can be very quiet, this series of machines sometimes can suffer with hum from the combined motor/mains transformer.

David

Tractorfan 3rd Feb 2023 2:12 pm

Re: Grundig TK140
 
Hi,
On the two Grundigs I have (a TK120 & TK149) the motor is also the mains transformer supplying heater & HT from separate windings. This is the reason it runs continuously.
Hope this helps.
Cheers! Pete.

DMcMahon 3rd Feb 2023 6:23 pm

Re: Grundig TK140
 
That is true but also many machines with separate mains transformer and capstan motor, the motor is powered up all the time the unit is switched on.

David

Analogue man 3rd Feb 2023 6:28 pm

Re: Grundig TK140
 
I believe the reason the motor runs continuously is because on start up it takes a second or so to reach full speed and if the machine was put into record with the motor starting up it would take perhaps 2 seconds for the tape to reach full speed causing any sound that is recorded to change pitch on playback from high to normal.

frsimen 3rd Feb 2023 6:35 pm

Re: Grundig TK140
 
Hello Andy,

It is possible to put a TK140 mechanism back together again having undone the locked screws, but it's not very easy. It's probably best that I don't say how I know that....!

If the alignment of the parts isn't quite right, the flywheel can scrape on the chassis and make a horrible noise. If you removed the top bearing assembly from the top plate when you dismantled it, you will need to readjust it to sort out the flywheel issue. If you didn't, the problem could be in the bottom bearing instead but that is easy to sort out.

The two spool carriers should both be in contact with the brake pads when stop is selected. In pause, the take up carrier should move away from the brake pads and the take up side spool carrier should turn. The supply carrier will move away from the brake pad when play is selected. In rewind, the supply spool carrier should move to the right to make contact with the rubber part on the motor shaft.

Fast forward should cause the take up spool to move to the left, pressing the idler onto rubber part on the motor shaft and the supply spool to move away from the brake pad. It sounds like that isn't happening, so check that the take up assembly hasn't jammed in some way and is free to be moved by the control.

You will find that there are some videos on YouTube which show TK120/TK140s with the cover removed and how the various pieces move. Compare them with yours and it may be a little clearer as to what is wrong.

Paula

DMcMahon 3rd Feb 2023 9:13 pm

Re: Grundig TK140
 
5 Attachment(s)
Photos of my TK 146 showing Rewind, Stop, Pause, Play and Fast Forward.

As Paula explains above for Fast Forward the Take Up spool should move to the left pushing the rubber idler onto the motor shaft rubber part.

David


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