07-08-2024, 08:56 AM
Probably a miss-connection of a replacement capacitor to either the ground or chassis. Possibly C-14 or C19.
This radio/phono uses both a B- and a chassis "ground", Any measurements taken for radio phono operation are to B- (rake symbol) not chassis.
Note this radio/phono uses a voltage doubler power supply. The two caps C15, 14 should have a low ESR rating. If not they will be subject to heating and under loud music passages, the B+ will fall off, bass will be flat. The schematic shows thse caps with a "cup" like symbol. Long ago that symbol meant wet electrolytic literally a borax solution electrolyte. That, type of capacitor had a low ESR and was capable of passing a much greater amount of current than the "dry" types. The wet (liquid) is long gone replaced by improved plate/paste electrolytes but with design cost differences the low ESR type is not as common and costs more (processing). The application (in the radio/phono) has not changed. Low ESR is still required. BTW this type of cap is also used in certain radios where there is a slow warmup and the power supply comes up before the plate loads, voltage soars, the wet electrolytic can take that surge.
This radio/phono uses both a B- and a chassis "ground", Any measurements taken for radio phono operation are to B- (rake symbol) not chassis.
Note this radio/phono uses a voltage doubler power supply. The two caps C15, 14 should have a low ESR rating. If not they will be subject to heating and under loud music passages, the B+ will fall off, bass will be flat. The schematic shows thse caps with a "cup" like symbol. Long ago that symbol meant wet electrolytic literally a borax solution electrolyte. That, type of capacitor had a low ESR and was capable of passing a much greater amount of current than the "dry" types. The wet (liquid) is long gone replaced by improved plate/paste electrolytes but with design cost differences the low ESR type is not as common and costs more (processing). The application (in the radio/phono) has not changed. Low ESR is still required. BTW this type of cap is also used in certain radios where there is a slow warmup and the power supply comes up before the plate loads, voltage soars, the wet electrolytic can take that surge.
Pliny the younger
“nihil novum nihil varium nihil quod non semel spectasse sufficiat”