Grundig TK141 advice

[Station X]

Thread reopened.

[DMcMahon]

Originally Posted by DMcMahon

I have been meaning to make 2 for ages, one for a TK 141 and the other for a TK 146, had been thinking of using some wooden doweling of suitable diameter (have the original pins), rawlplugs sound good as well.

David

I did make one for my TK 146 from circular wooden doweling which is working fine.

David

[unitelex]

I Have resumed the repair of this machine on behalf of the OP.

Comments and recommendations from the earlier part of this thread have been useful.

The machine arrived with multiple problems, firstly I removed a lot of tin/zinc whiskers from the chassis steel work with a small brush and portable vacuum cleaner...

1. Mode switch cam roller
The original clear rubber roller for the cam tends to perish, there were remnants of the rubber roller still in place so I was able to measure its diameter to be approx 10mm. The central hardened pin was still present thankfully. This measures 4mm diameter. I have some nickel plated brass spacers with 4mm bore and 8mm OD of exactly the correct 8mm length. I stretched some silicone tubing over this and it makes a perfect roller - pic attached. I have some more of these spacers and the silicon tube if anyone needs to make one send me a PM.
Note: Contrary to a certain on-line video, it is not necessary to remove the sprung plate to fit the roller, you simply pull it back against the spring and place the roller in from the inside.

2. Misplaced spool brake lever, misplaced head plate advance lever
As pointed out earlier in the thread, the RH spool brake lever (pad end) was incorrectly trapped under the RH spool. This was corrected. Also in the Play position the head pressure plate and pinch roller was not being brought forward. This was due to a similar problem, the engagement lever was on the wrong side of the driven lever. Easily corrected.
The LH spool was staying in the left position when not in rewind mode and I could not rotate the mode control further counter clockwise than the Stop position; rewind could not be engaged. There was some issue with the cam operation on the rewind push plate however after some axial pushing on the white cam from the underside it seemed to click into place and has been working since. Can't really see what was wrong, due to lack of access but it seems OK now.

3. FF idler - perished tyre
The rubber tyre is U section tyre was perished, some remnants remained so it could be measured. I had a pulley which accepted an O ring from a kit of O rings I have which produced a 43mm diameter roller with good rubber surface. The first O ring from the kit had some flash rubber on the edge which caused a noise during FF, so I replaced it with a better one from the kit which solved that issue. The pulley needed its centre drilling out to 4mm. At first it was a little undersize but with extra time on the drill press it opened up just enough. The plastic is probably not a durable as the original part but I have had it running for several hours and there is no sign of slackening of the bearing. This is used only for FF so I think it will be fine. I have retained the original wheel in case I find a suitable tyre

4. Motor mounting bushes
There is one on the underside and one on the top side of the motor. Both seem to have shrunk somewhat. The lower one is in better condition than the upper. They are still providing a soft mount however it is a little looser than I would like. I have made a cardboard shim for the lower rubber which has compensated for the shrinkage at least from the vertical perspective.

5. Motor pinion rubber wheel
The motor provides drive to the capstan via a brass pully however the spools are driven via the motor pinion rubber roller for FF and FR. It was very noisy in FR, less so in FF. The noise being relatively high frequency indicating motor pinion issue.
I found a flat spot on the motor pinion rubber. I was able to improve it by re-facing the roller while the motor was clamped and running it in conjunction with a sanding barrel on the Dremel at an angle. The flat spot is now gone and in FR it is much quieter but still a little noisy. The motor is vibrating slightly in its loose rubber mount...

6. On-OFF switch seized
Seizure of the On-Off switch (extender shaft) is apparently common on these machines. This may be jammed due to corrosion on some machines (steel shaft in Mazac barrel) but in this case it was simply dried up grease. It was freed by slight heating of the barrel using a hot air gun. It did not take much heat at all to free it. After cooling it got slightly sticky again but with the addition of some light machine oil and moly grease it is now completely free and acting smoothly. I did not feel it necessary to disassemble the switch as was shown in an on-line video. I added some heat shrink sleeve to the switch body to guard against accidental electric shock when working on the machine. Similarly I added a cover to the exposed mains fuse on the back panel.

7. 3 Drive belts
All three drive belts were missing. I bought a set online
The flywheel belt fitted nicely, as did the RH spool belt (both via the lower bearing access)
The tape counter belt supplied with the kit seems oversize. It did drive the counter but later fell of during FF. I may have got the belt order incorrect, I got a kit sold for TK46 assumed this would also fit TK141 - maybe there is a difference.. I have another belt in stock which works for the counter so no worries, but would be helpful for future reference if somebody knows if TK46 has a different sized counter belt...

8. RH spool making scratching noise
After disassembly of the RH spool I found all felt pads to be missing.

I obtained some felt pads but not sure if it needs all 9 positions populating and what is the required felt pad thickness/height?

Hopefully a forum member will be able to clarify the above.

In the meantime I have cleaned the heads and de-magnetised

BTW one of the chrome slider knobs, (volume) is missing. If anybody has one spare it would be much appreciated.

Best Regards
Chris

[unitelex]

From the picture kindly provided by David in post #30 I can see the correct population of the felt pads - 3 off - picture attached
I obtained some felt pads (for furniture) and used my die cutter to cut some 10mm diameter circular pads. The die cutter came in a set of 10 sizes - new unused but they were all quite blunt. I had to sharpen the 10mm one on my grinder. It now cuts well.
I found it best to cut this dense felt by rotating the cutter under hand pressure as the hammer action did not seem to work so well.

Also included is a picture of the mode switch roller assembly

Chris

[DMcMahon]

Yes 3 felt clutch pads, I measure them as around 9.5mm diameter and around 3.9mm thick, the idea is you are supposed to try them in the 9 holes for best clutch action which seems to me to be extremely difficult/subjective, the far outer holes evidently provide the strongest clutch.

The TK 141 and TK 146 tape counter drive belts should be identical size.

Excellent work and reporting Chris.

David

[DMcMahon]

Originally Posted by unitelex

7. 3 Drive belts
All three drive belts were missing. I bought a set online
The flywheel belt fitted nicely, as did the RH spool belt (both via the lower bearing access)
The tape counter belt supplied with the kit seems oversize. It did drive the counter but later fell of during FF. I may have got the belt order incorrect, I got a kit sold for TK46 assumed this would also fit TK141 - maybe there is a difference.. I have another belt in stock which works for the counter so no worries, but would be helpful for future reference if somebody knows if TK46 has a different sized counter belt...
Chris

Is that a typo or did you mean TK 146 ? TK 46 is a totally different type of recorder

David

[DMcMahon]

Is the copper coloured rectangular spring clutch plate also missing in the RH spool assembly, not shown in photo above ?

David

[unitelex]

Yes typo sorry I got the belts for TK146, the counter one is too loose

Copper coloured spring clutch plate? presume it is missing, have not found it

Chris

[DMcMahon]

Looks like only fitted to Supply reel table, as it is not fitted on my TK 141 Take Up.

David

[unitelex]

OK that's a relief.

Mechanically it plays smoothly, pauses, FF and Rewind OK
Also Stop !

Smooth transition between modes with no tape spill.
So assume the 3 felt pads were sufficient.

I will re-connect the speaker and test the amplifier etc

Regards
Chris

[DMcMahon]

Yes as per Post 45 three pads are correct.

David

[DMcMahon]

Originally Posted by unitelex

BTW one of the chrome slider knobs, (volume) is missing. If anybody has one spare it would be much appreciated.

I have one, PM me your address and I will post it, no charge but would be nice to get one of your cam roller parts.

David

[hergest74]

I have had the machine back thanks to a great restoration thanks to Chris, which is now working again. I need to learn a few things as I am not really used to reel to reel players but am finding it easy enough.

[DMcMahon]

Enjoy it.

David