40-195 Restoration - Printable Version
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RE: 40-195 Restoration - RodB - 01-24-2022
It looks like part #12, an RF choke connected across a 10k resistor to the plate of the 1232 tube. The other end would be connected to another resistor and a 100pf cap.
RE: 40-195 Restoration - VintageRocks - 01-24-2022
Makes sense, thank you Rod.
RE: 40-195 Restoration - VintageRocks - 01-29-2022
Question, what does it mean "use loop on generator" in the instructions attached?
Also, which one of these instructions should I use for a 40-195?
Thanks in advance!
RE: 40-195 Restoration - RodB - 01-29-2022
Create a loop antenna transmitter with a coil of about 5-6 turns of wire 4-6 inches in diameter and connect the hot side of your signal generator to one end. You now have a radio transmitter that varies the radio reception signal strength by how close it is to the receiver.
The second set of instructions can be used for the 40-195 alignment (note upper right corner).
RE: 40-195 Restoration - VintageRocks - 01-29-2022
I see, thank you for the clarification Rod as this is a new procedure for me.
One question is does it also need a ground on the signal generator?
RE: 40-195 Restoration - RodB - 01-29-2022
Normally no. The loop is small enough to be a short and usually reduces the signal output. But you can always try an earth ground on the other end of the loop just to note the effect.
RE: 40-195 Restoration - VintageRocks - 01-29-2022
Rod,
Connecting the loop to the output and tuning the signal generator to the same wavelength as the radio, say 580khz, I should hear a tone from the SG on the radio?
If not, what am I doing wrong?
RE: 40-195 Restoration - RodB - 01-29-2022
Where are you in the alignment procedure? Make sure the band switch is on broadcast.
RE: 40-195 Restoration - VintageRocks - 01-31-2022
Operation 1 was successful connecting to terminal 1 on the back of the radio using a .1mfd inline and the ground to the chassis.
Operation 2 is iffy where the signal does not seem to be very strong if at all.
Operation 3 seems to work.
Now to qualify something, under Connecting Aligning Instruments, I am not removing the tubes and replacing with an aligning adapter. I am not sure what it even is.
I found this document for aligning Philco's which seemed easier to follow but still not much luck.
RE: 40-195 Restoration - VintageRocks - 01-31-2022
I should mention that I am using an Eico 330 signal generator that seems to be in working order.
RE: 40-195 Restoration - RodB - 01-31-2022
I'm not sure what the aligning adapter is but I can guess. I would say it gives you the capability to use a test meter of lower ohms-per-volt to measure the AVC voltage. Meters of the day would "load" a circuit and indicate a false reading. Using a high impedance DMM or VTVM will have very little impact on the AVC voltage providing it is connected to the high side of the volume control.
RE: 40-195 Restoration - VintageRocks - 02-02-2022
I am looking for some guidance with how to go through and validate voltages on the tube pins. I thought I saw someone post something with the tubes and pinnings but I am not positive.