Re: Grundig TK27 - Low audio output
David and Lawrence,
Big thank you for all your feedback, i have 100% proof of fixing the intermittent low play volume. final problem, maybe other fixes along the way as well, but most likely this was the real cause.
While playing, a tap on the table would drop the volume, (more tapping around the outer case, resulted in decreased and increase of the volume)
As i had a friend with me, we played it vertically, (he held the reels in) and with the PCB Dropped and the record / play switch shield off, i found putting pressure on middle contact of at1.4, the sound came back to 100%, and when let got, to rely on spring pressure the volume would drop !!!
So, some more sanding of at1.4- C102 contacts, and increasing the pressure on the middle contact its playing well, and no amount of tapping or banging can change the volume.
When i get time next will chase the record problem, as David suggests. Now that i have a readable manual and solid bias at the head and erase, finding why the audio is not modulating the bias should be an easy fix
Most simple but challenging problem i had so far..
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