aeg: 78WK (78 WK); - 'switchable' coupling capacitor?

Gentlemen,

This posting relates to servicing problems on my Telefunken model 776WK but is cross-referenced due to VERY common circuitry. . . . I also place a similar post to the TFK 776WK model.

While reviewing the schematics for the AM2 to AL4 audio coupling capacitors on the model AEG 78WK, and very similar circuits on the Telefunken 776WK and Telefunken 876WK, I notice the switchable extra coupling capacitor installed on the AEG78 and the TFK 876WK - but not on the telefunken 776WK.

Was that perhaps an intentional circuit change, or an omission on the schematic of the 776WK.

There are also differences within the AL4 output (control grid g1 resistor ratings) on the respective models - from 100/.5M ohms to 1,000/.5M ohms

I had for a brief period of time reception of stations on the MW and KW bands although the alignment was off by approximately 60 to 70kHz. After replacing the BF2 transformer, and confirming continuity on both sides, now I am back to the "mute" radio. . .

I would be most appreciative if any member has had similar experiences and could provide some helpful hints!

NOTE:
All tubes have been replaced with new ones, EXCEPT the AB2 detector. . . .That tube has been ordered from a seller in Europe and will be installed within the next week or so.

Respectfully,
Robert
 

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