PHILCO
A547B.
.
This very attractive A.C mains valve radio was made in 1947, and employs
long, medium, and two short wave bands. The cabinet is brown moulded resin.
It
is a common fault in these sets to have problems with the smoothing and reservoir
electrolytic block ( 30 + 30 uF@ 350 volts working). The option is to have
the original block reformed, or to fit a replacement block. I chose the latter
(to save time), and fitted an L.C.R replacement 50 + 50 uF @ 450 volts. This
brought some life back in to the receiver. It is wise to also check the value
of the resistor that feeds the anode of the 6Q7 valve (220k ohms), as they
always seem to drift off their tolerence value. I also replaced leaky coupling
capacitors in the audio circuits.
I
am quite pleased with the quality of the sound output on this set. The next
stage is to do some repairs on the inside of the cabinet, as previous repairers
have damaged the upper r.h (looking from rear of the set) chassis fixing hole
(self-tapping). I will fill the existing damaged hole with epoxy resin, and
then will try and re-bore the hole with the self-tapping screw (covered with
grease), whilst the glue is in the "plastic" stage of setting.
I
also will try and replace the 50k treble control (c/w single pole mains switch),
with one of a similar value, but having a double pole mains switch. This will
make it safer in operation, as at present, only the neutral line of the mains
is switched. I have such a control, albeit with a slightly shorter shaft.
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