Popping Noise - Loewe Opta Rheinperle 3715W -

Hi

I've this annoying issue on this model.

It's a popping noise, always present, even a ZERO volume, in TA input selected.

Already changed all Electrolythic Capacitors, DiodeRectifier, stage coupling capacitors.

Also tried a new transformer.

Checked all anodes lines on EL84 EABC80 and still can't find the source of this random popping noise.

Can anybody help?

Kindest

Riccardo

EM: Moved -> Model-related posts must always started from the model page

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Is the noise ONLY there in TA position, not at AM or FM? Is it somehow influenced by the bass or treble controls or if the output stage is loaded with a resistor of a few ohms in parallel to the loudspeaker?

From the schematic, i see that the anode supply for the IF and RF valves is disconnected by the switch f8-f9 in TA position, it could be interesting to know if the popping ceases if this switch is shorted.

Another possibility is problems with any components in the AF feedback network (all components from R37 at the feedback winding of the output transformer to R27 at the cold end of the volume control), try replacing any paper capacitors still left there and check all resistors, in particular carbon composition resistors if there are any such ones in this radio. From the pictures at the model page it looks like most resistors are of the more reliable carbon film type, but its not unusual to find one or another carbon composition resistor even in sets that are mostly equipped with carbon film parts.

Also, i would check the anode resistor for EABC80 and its decoupling network (R29, R30, C67) .

To thank the Author because you find the post helpful or well done.