Grundig TK 14 Check Out - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

DMcMahon · 22nd Apr 2021, 10:59 pm

After re-assembling the right hand side keys assembly have still got the same issue (out of the machine) where the FFD key is difficult to latch, it initially latches for a fraction of a second then unlatches. Looks like the spring tension on the FFD key is overcoming the spring tension on the latching plate, by moving the FFD key spring to a different location where it is not so stretched/strong, it is now latching better.

This may not be an issue when back in the machine as there are other springs external to the keys assembly that might help.

However there is a secondary issue where the FFD key gets jammed somehow and cannot be pressed down, can not see what is causing this.

Will fit the keys assembly back in the machine to see what then happens.

David

DMcMahon · 23rd Apr 2021, 9:23 am

Took apart again the keys assembly to see if by rebuilding it would fix the jamming issue.

No adjustment anywhere, but the right hand side end plate that is secured by 2 screws, one end of the shafts for the latching plate and the black rubber bushes & one end of pivoting lug for the Play/FFD actuating levers fit into this end plate. I was able to twist the end plate a fraction and this touch wood seems to have resulted in the mechanism no longer jamming up when FFD is pressed.

David

DMcMahon · 24th Apr 2021, 10:50 am

Refitted the re-assembled keys assembly into the unit but still struggling to get FFD latching working consistently despite trying all sorts of ideas. Basically it appears to latch but almost immediately unlatches, with everything assembled impossible to see the FFD key latching.

During refitting, compared various bits to my TK 23 & spotted a couple of small differences so located my other TK 14 for comparison. As I previously thought this other TK 14 does have a latching Pause mechanism. It has the same light blue colour scheme with the red dots on 2 of the keys, its serial number is 89199 so a lot later than the other TK 14.

Interestingly this other TK 14 has 2 additional changeover switches mounted in bottom left & right front corners which are actuated by levers mounted off the RWD & FFD keys, (as shown in first 2 photos) must try and work out later what these extra switches do.

To see the FFD latching I removed the Start and Stop keys on both TK 14's, can see no real difference. The bad TK 14 latch plate may be slightly weaker in terms of spring tension.

The metal underside of the Stop key basically sits on top of/makes contact with the latching plate and when the FFD key is pressed down, a slight movement of the Stop key may be having a hair trigger effect so trips the latch as soon as it is made. If nothing else found may try filing down the underside of the Stop key so that it does not make contact with the latch plate (Until the Stop key is pressed down of course).

Will also try swapping a few piece parts like the Stop key and various springs between the 2 units to see if fault can be swapped over. Tempted to swap over the complete key assemblies to prove that the issue is specific to the key assembly but not keen to do this as a lot of work to get assembly out in the other TK 14. Photos 3 and 4 show the FFD key latching comparison between the 2 machines.

David

8 Tracker · 24th Apr 2021, 2:45 pm

The extra 2 sets of contacts operated by FF and REW are to change the motor tappings for more torque. I have never seen a machine with them fitted in the flesh. They are shown in my July '61 copy of the TK14 service manual, but not in my October '63 TK18 or July '62 TK23 manuals. Don't know if those models were ever fitted with them.

Do you know what type of motor is fitted to your TK14 with the extra contacts?

Mark.

DMcMahon · 24th Apr 2021, 4:38 pm

Thank you Mark, I was not aware of this on this TK series but have seen similar on other R2Rs. Can now see the switches on one of my TK 14 schematics, this schematic also shows the alternative motor configuration wiring (without the switches).

The motors are different, a 7882-082 on the TK 14 without the switches and a 7882-103 on the TK 14 with switches. Cannot identify the motor make (s) but one TK 14 parts list I have indicates Papst or Bluehler, although with different listed part numbers to the numbers above.

David

22nd Apr 2021, 10:59 pm	#21
DMcMahon Dekatron Join Date: Apr 2019 Location: Worthing, West Sussex, UK. Posts: 6,603	Re: Grundig TK 14 Check Out After re-assembling the right hand side keys assembly have still got the same issue (out of the machine) where the FFD key is difficult to latch, it initially latches for a fraction of a second then unlatches. Looks like the spring tension on the FFD key is overcoming the spring tension on the latching plate, by moving the FFD key spring to a different location where it is not so stretched/strong, it is now latching better. This may not be an issue when back in the machine as there are other springs external to the keys assembly that might help. However there is a secondary issue where the FFD key gets jammed somehow and cannot be pressed down, can not see what is causing this. Will fit the keys assembly back in the machine to see what then happens. David

23rd Apr 2021, 9:23 am	#22
DMcMahon Dekatron Join Date: Apr 2019 Location: Worthing, West Sussex, UK. Posts: 6,603	Re: Grundig TK 14 Check Out Took apart again the keys assembly to see if by rebuilding it would fix the jamming issue. No adjustment anywhere, but the right hand side end plate that is secured by 2 screws, one end of the shafts for the latching plate and the black rubber bushes & one end of pivoting lug for the Play/FFD actuating levers fit into this end plate. I was able to twist the end plate a fraction and this touch wood seems to have resulted in the mechanism no longer jamming up when FFD is pressed. David Attached Thumbnails

24th Apr 2021, 10:50 am	#23
DMcMahon Dekatron Join Date: Apr 2019 Location: Worthing, West Sussex, UK. Posts: 6,603	Re: Grundig TK 14 Check Out Refitted the re-assembled keys assembly into the unit but still struggling to get FFD latching working consistently despite trying all sorts of ideas. Basically it appears to latch but almost immediately unlatches, with everything assembled impossible to see the FFD key latching. During refitting, compared various bits to my TK 23 & spotted a couple of small differences so located my other TK 14 for comparison. As I previously thought this other TK 14 does have a latching Pause mechanism. It has the same light blue colour scheme with the red dots on 2 of the keys, its serial number is 89199 so a lot later than the other TK 14. Interestingly this other TK 14 has 2 additional changeover switches mounted in bottom left & right front corners which are actuated by levers mounted off the RWD & FFD keys, (as shown in first 2 photos) must try and work out later what these extra switches do. To see the FFD latching I removed the Start and Stop keys on both TK 14's, can see no real difference. The bad TK 14 latch plate may be slightly weaker in terms of spring tension. The metal underside of the Stop key basically sits on top of/makes contact with the latching plate and when the FFD key is pressed down, a slight movement of the Stop key may be having a hair trigger effect so trips the latch as soon as it is made. If nothing else found may try filing down the underside of the Stop key so that it does not make contact with the latch plate (Until the Stop key is pressed down of course). Will also try swapping a few piece parts like the Stop key and various springs between the 2 units to see if fault can be swapped over. Tempted to swap over the complete key assemblies to prove that the issue is specific to the key assembly but not keen to do this as a lot of work to get assembly out in the other TK 14. Photos 3 and 4 show the FFD key latching comparison between the 2 machines. David Attached Thumbnails Last edited by DMcMahon; 24th Apr 2021 at 10:55 am.

24th Apr 2021, 2:45 pm	#24
8 Tracker Hexode Join Date: Jul 2009 Location: Mablethorpe, Lincolnshire, UK. Posts: 286	Re: Grundig TK 14 Check Out The extra 2 sets of contacts operated by FF and REW are to change the motor tappings for more torque. I have never seen a machine with them fitted in the flesh. They are shown in my July '61 copy of the TK14 service manual, but not in my October '63 TK18 or July '62 TK23 manuals. Don't know if those models were ever fitted with them. Do you know what type of motor is fitted to your TK14 with the extra contacts? Mark. Attached Thumbnails

24th Apr 2021, 4:38 pm	#25
DMcMahon Dekatron Join Date: Apr 2019 Location: Worthing, West Sussex, UK. Posts: 6,603	Re: Grundig TK 14 Check Out Thank you Mark, I was not aware of this on this TK series but have seen similar on other R2Rs. Can now see the switches on one of my TK 14 schematics, this schematic also shows the alternative motor configuration wiring (without the switches). The motors are different, a 7882-082 on the TK 14 without the switches and a 7882-103 on the TK 14 with switches. Cannot identify the motor make (s) but one TK 14 parts list I have indicates Papst or Bluehler, although with different listed part numbers to the numbers above. David Attached Thumbnails