07-08-2009, 12:06 AM
After some investigation I found out the the original 25 cycle phono motor, it's mounting plate, and idler wheel was manufactured by the Alliance Tool and Motor Company. After looking at the 60 cycle replacement motor I found out that it was also made by the Alliance Tool and Motor company, so in other words it's an O.E.M replacement motor, a lucky break there. I will need to study the electrical/mechanical aspect of this mechanism, the operation of the mercury switch to be specific, something doesn't look right about part of it.
I conducted a little research on the circuit used in the radio itself, the model number is a 706-A, on the paper tube diagram inside it says model 706 but it has a factory correction for the rectifier tube from a 50Y6 to a 50X6, which is what the chassis has. There seems to be several different versions of the 1201 series, the 46-1201 code 122 uses a 50Y6 and a 50A5 with the 50Y6 wired as a half wave rectifier, the 48-1201 on N.A uses a 50X6 and a 50A5 with mini IF cans, my 706-A uses a 50X6 and a 50L6, both my set and the 48-1201 have the 50X6 rigged up as a voltage doubler. So in other words the audio output stage will be capable of a little more kick with 180+ volts on the plate and 125 volts on the screen grid, in effect it's a transformerless power supply circuit and not an AC/DC one.
I will tell you this much, as much as I admire much of Philco's engineering I don't like certain aspects of this unit, in fact some are stupid, aside from the Philcote faux finish on the cabinet. While they cleverly designed this unit so that the top flips open to access the tubes and the phonograph, in order to remover the chassis from the cabinet you have to unsolder the phono input lead, the two power wires going to the phono chassis, a ground wire tying the two chassis together, and the two leads of the loop antenna. Would it honestly have hurt them to use sockets, plugs, or even spade connectors to connect the two chassis together? I know that Philco hated all things RCA but a RCA jack and socket would have been the smart way to connect the phono input, and an electrical plug and outlet to connect the phono motor. The chief engineer must have been a European or a Limey, it is so unlike Philco to do something like that.
Best Regards
Arran
I conducted a little research on the circuit used in the radio itself, the model number is a 706-A, on the paper tube diagram inside it says model 706 but it has a factory correction for the rectifier tube from a 50Y6 to a 50X6, which is what the chassis has. There seems to be several different versions of the 1201 series, the 46-1201 code 122 uses a 50Y6 and a 50A5 with the 50Y6 wired as a half wave rectifier, the 48-1201 on N.A uses a 50X6 and a 50A5 with mini IF cans, my 706-A uses a 50X6 and a 50L6, both my set and the 48-1201 have the 50X6 rigged up as a voltage doubler. So in other words the audio output stage will be capable of a little more kick with 180+ volts on the plate and 125 volts on the screen grid, in effect it's a transformerless power supply circuit and not an AC/DC one.
I will tell you this much, as much as I admire much of Philco's engineering I don't like certain aspects of this unit, in fact some are stupid, aside from the Philcote faux finish on the cabinet. While they cleverly designed this unit so that the top flips open to access the tubes and the phonograph, in order to remover the chassis from the cabinet you have to unsolder the phono input lead, the two power wires going to the phono chassis, a ground wire tying the two chassis together, and the two leads of the loop antenna. Would it honestly have hurt them to use sockets, plugs, or even spade connectors to connect the two chassis together? I know that Philco hated all things RCA but a RCA jack and socket would have been the smart way to connect the phono input, and an electrical plug and outlet to connect the phono motor. The chief engineer must have been a European or a Limey, it is so unlike Philco to do something like that.
Best Regards
Arran
