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Old 27th Feb 2020, 11:19 am   #5
Leon Crampin
Join Date: Nov 2005
Location: Surrey, UK.
Posts: 1,453
Default Re: Grundig Concert Boy 1100 (again)

The output stages run at full voltage from the power supply when the set is run on the mains. This will give an incorrect setting of the quiescent current. A decent set of batteries is usually very close to 9V, although I usually use a lab supply when setting up the output stage.

Last time I did this job, I made a mental note to solder two pieces of wire to the measuring point bridged by a solder link. By bringing these above the of board, the quiescent current can be checked without extracting the board.

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