Grundig TK 14 L working but buzzing - UK Vintage Radio Repair and Restoration Discussion Forum

gavriloP · 5th May 2006, 7:56 pm

Greetings from Finland,

I bought an used Grundig TK 14 L open reel tape recorder and it is working but there is little problem with this buzzing hum that gets very irritating especially with louder volume. If i stop machine that buzz is still there. If I then touch speaker switch that is located in the back with inputs and outputs it goes away. Nevertheless when I start playback again that buzz comes back. Also when I record stuff with GDM311 microphone (haven't tried nothing else yet) it is there too.

I opened the machine because there were something rattling inside and I found out that two of the bolts from one big transformer had dropped and last two were very loose too. I tightened them and other screws too and buzz got much quieter (it seemed there were less harmonics). Anyway, the noise is still there.

the inner circuits and components "seem ok" but are they most likely culprits to this symptom? Only thing that looks suspicious is some strange "Grundig Oscillator cell" component that seems little bit gunky with messy brown bottom. I am novice with these machines but it would be nice to get this thing working better.

And btw I don't have manual or schematics so I also wonder about those DIN connections, there is three of them one with microphone symbol(3-pin), other with something that looks like a speaker(3-pin) and third one with two waves on top of each other(5-pin). I would like to make adapters so I could use this beast with my more modern mics, preamps and DAW.

-Mikko

gavriloP · 5th May 2006, 8:02 pm

Oh, and I forgot that I changed the mains voltage to 240V (it is 230V here in Finland) from 220V. When it was on 220 that buzz was louder. I did this before I found out that loose transformer.

-Mikko

DOFFERY · 6th May 2006, 4:36 pm

Just a brief message , the 3 pin mike input , connect to pin1 & 2(common earth)
wavy lines is for output, from pins 3 & again 2 (earth)
"top hat" you call speaker is for radio/diode input again pin1 & 2

gavriloP · 7th May 2006, 8:42 pm

Thank you very much! Now I can continue checking.

-Mikko

5th May 2006, 7:56 pm	#1
gavriloP Retired Dormant Member Join Date: May 2006 Location: Turku Posts: 3	Grundig TK 14 L working but buzzing Greetings from Finland, I bought an used Grundig TK 14 L open reel tape recorder and it is working but there is little problem with this buzzing hum that gets very irritating especially with louder volume. If i stop machine that buzz is still there. If I then touch speaker switch that is located in the back with inputs and outputs it goes away. Nevertheless when I start playback again that buzz comes back. Also when I record stuff with GDM311 microphone (haven't tried nothing else yet) it is there too. I opened the machine because there were something rattling inside and I found out that two of the bolts from one big transformer had dropped and last two were very loose too. I tightened them and other screws too and buzz got much quieter (it seemed there were less harmonics). Anyway, the noise is still there. the inner circuits and components "seem ok" but are they most likely culprits to this symptom? Only thing that looks suspicious is some strange "Grundig Oscillator cell" component that seems little bit gunky with messy brown bottom. I am novice with these machines but it would be nice to get this thing working better. And btw I don't have manual or schematics so I also wonder about those DIN connections, there is three of them one with microphone symbol(3-pin), other with something that looks like a speaker(3-pin) and third one with two waves on top of each other(5-pin). I would like to make adapters so I could use this beast with my more modern mics, preamps and DAW. -Mikko

5th May 2006, 8:02 pm	#2
gavriloP Retired Dormant Member Join Date: May 2006 Location: Turku Posts: 3	Re: Grundig TK 14 L working but buzzing Oh, and I forgot that I changed the mains voltage to 240V (it is 230V here in Finland) from 220V. When it was on 220 that buzz was louder. I did this before I found out that loose transformer. -Mikko

6th May 2006, 4:36 pm	#3
DOFFERY Retired Dormant Member Join Date: Aug 2004 Location: Blackpool, Lancashire, UK. Posts: 1,488	Re: Grundig TK 14 L working but buzzing Just a brief message , the 3 pin mike input , connect to pin1 & 2(common earth) wavy lines is for output, from pins 3 & again 2 (earth) "top hat" you call speaker is for radio/diode input again pin1 & 2

7th May 2006, 8:42 pm	#4
gavriloP Retired Dormant Member Join Date: May 2006 Location: Turku Posts: 3	Re: Grundig TK 14 L working but buzzing Thank you very much! Now I can continue checking. -Mikko