02-01-2015, 03:14 PM
Man, I really should start studying service info before jumping into a project. I just discovered, much to my dismay, that Philco specifies 1 watt resistors throughout this set, rather than the usual 1/2 watt resistors.
Which means, of course, that I do not have roughly half of the resistors I will need.
I am going to have to replace at least two other tube sockets besides the one that is mounted upside down. One is cracked nearly in half, and another doesn't look so good. In addition, someone removed all of the tube shield bases somewhere down the line. It's a good thing I have some spare junk. I'll be using 1937 tube shield bases to replace the missing bases, so I can use any type of tube I want to and not be limited to "G" types.
And it just gets better...
A quick check with the ohmmeter section of my DMM reveals that half of the primary of the audio output transformer is bad. Well, I still have a push-pull output made for 6F6 tubes...which is what this set uses...so I'm covered there.
On the positive side, it does not appear that this one will be as difficult to rewire as was the 42-788. I hope that turns out to be true.
And the 400 ohm Candohm resistor, part (81), tests good. Why Philco put a 400 ohm resistor in series with the speaker field instead of using a speaker with a 1400 ohm field, I don't know. Oh yes, I think I do. Philco probably had speakers on hand with 1000 ohm field coils, and it was cheaper to just use them and add series resistance to make the circuit work.
Which means, of course, that I do not have roughly half of the resistors I will need.
I am going to have to replace at least two other tube sockets besides the one that is mounted upside down. One is cracked nearly in half, and another doesn't look so good. In addition, someone removed all of the tube shield bases somewhere down the line. It's a good thing I have some spare junk. I'll be using 1937 tube shield bases to replace the missing bases, so I can use any type of tube I want to and not be limited to "G" types.
And it just gets better...
A quick check with the ohmmeter section of my DMM reveals that half of the primary of the audio output transformer is bad. Well, I still have a push-pull output made for 6F6 tubes...which is what this set uses...so I'm covered there.
On the positive side, it does not appear that this one will be as difficult to rewire as was the 42-788. I hope that turns out to be true.
And the 400 ohm Candohm resistor, part (81), tests good. Why Philco put a 400 ohm resistor in series with the speaker field instead of using a speaker with a 1400 ohm field, I don't know. Oh yes, I think I do. Philco probably had speakers on hand with 1000 ohm field coils, and it was cheaper to just use them and add series resistance to make the circuit work.
--
Ron Ramirez
Ferdinand IN
