04-24-2024, 10:27 PM
Hello Everyone;
I finally got around to taking the chassis out of this set today, vacuumed a large accumulation of dust off of it, and from the inside of the cabinet. The good news is that the output transformer, the IF transformers, and the oscilator coil test good. Most of the resistors are good, I think maybe two had drifted somewhat, even the big wire wound dropper tested good. According to the date printed on the filter condenser can it was likely manufactured in the fall of 1956, this model certainly had a long run.
The spider is loose on the Celestion made speaker, which is apparently a common issue with the ones in these sets, so I vacuumed up the dust on both sides of the cone, and on the basket, to prepare for regluing. I will need to shim around the voice coil with plastic strips, but hopefully will not have to remove the cone to do this.
Unfortunately a good percentage of the steel brackets of the dial mechanism, and the back plate behind the plastic dial diffuser, are rusty. Ironically the chassis itself is made out of sheet aluminum, but not this backing plate which does nothing but hold the dial lamps and a plastic diffuser. Apparently Bush Radio didn't believe in plating their hardware, every other screw into the Bakelite cabinet was also rusty, so I needed to squirt each screw with WD40 to get them out. It's very odd because I have never encountered this issue with machine screws in a North American Bakelite cabinet, did the Bakelite itself cause them to corrode?
I still need to test the tubes, I only have one tube tester with a socket for testing Rimlock tubes. They were a Phillips invention, they have eight pins, with a locating stud on the side of the base, sort of a transitional glass tube type between the octal and Phillips Loctal style tubes, and the seven and nine pin tubes Phillips used up until the end of the tube era. Hopefully they test good or I will have to put this set into drydock for a while, and won't get to try out a voltage doubler scheme. The heater string adds up to 116.6 volts, plus two 3.5 volt dial lamps, with a 75 Ohm shunt resistor in parallel with them.
Regards
Arran
I finally got around to taking the chassis out of this set today, vacuumed a large accumulation of dust off of it, and from the inside of the cabinet. The good news is that the output transformer, the IF transformers, and the oscilator coil test good. Most of the resistors are good, I think maybe two had drifted somewhat, even the big wire wound dropper tested good. According to the date printed on the filter condenser can it was likely manufactured in the fall of 1956, this model certainly had a long run.
The spider is loose on the Celestion made speaker, which is apparently a common issue with the ones in these sets, so I vacuumed up the dust on both sides of the cone, and on the basket, to prepare for regluing. I will need to shim around the voice coil with plastic strips, but hopefully will not have to remove the cone to do this.
Unfortunately a good percentage of the steel brackets of the dial mechanism, and the back plate behind the plastic dial diffuser, are rusty. Ironically the chassis itself is made out of sheet aluminum, but not this backing plate which does nothing but hold the dial lamps and a plastic diffuser. Apparently Bush Radio didn't believe in plating their hardware, every other screw into the Bakelite cabinet was also rusty, so I needed to squirt each screw with WD40 to get them out. It's very odd because I have never encountered this issue with machine screws in a North American Bakelite cabinet, did the Bakelite itself cause them to corrode?
I still need to test the tubes, I only have one tube tester with a socket for testing Rimlock tubes. They were a Phillips invention, they have eight pins, with a locating stud on the side of the base, sort of a transitional glass tube type between the octal and Phillips Loctal style tubes, and the seven and nine pin tubes Phillips used up until the end of the tube era. Hopefully they test good or I will have to put this set into drydock for a while, and won't get to try out a voltage doubler scheme. The heater string adds up to 116.6 volts, plus two 3.5 volt dial lamps, with a 75 Ohm shunt resistor in parallel with them.
Regards
Arran
