View Single Post
Old 16th Dec 2021, 11:02 pm   #76
DMcMahon
Dekatron
 
DMcMahon's Avatar
 
Join Date: Apr 2019
Location: Worthing, West Sussex, UK.
Posts: 4,982
Default Re: Grundig TK27 - Low audio output

Quote:
Originally Posted by Phantomrose1999 View Post

Some questions please:

1) Should the magic eye move during play ? I think It used to do that and has stopped, forgot. I do not think so.

I think contacts at 1,6 & at 2,6 are the contacts (actuated by the Record button being pressed down) post the ECC 81 outputs that switch the record signal through to the EM84 and also through to the Record heads.

2) i tried it without the metal PCB shield and only got loud buzzing, so put it back.. I have put insulation tape on parts of the shield, as the original insulator came off. could it be oscillating that is causing the low volume..

The amplifier can be sensitive and generate noise/oscillate without the metal shield fitted, particularly if the PCB is hinged down. Difficult to know for sure but I would doubt that the oscillation is the root cause of the low volume.

3) My mobile phone when transmitting is causing the buzzing i kept hearing, put it in flight mode and the intermittent buzzing has gone. Never seen this before. Have not experienced similar.


Anyway, i wont touch the record button for a week, and just see if play is
consistent as its working perfectly at the moment.

When i next get a chance, i will do it properly and connect a sig gen to the head input, and trace it through all stages with a cro..

David

Last edited by DMcMahon; 16th Dec 2021 at 11:16 pm. Reason: Update
DMcMahon is offline