02-13-2013, 07:41 PM
Hi Stephen
The theory found in the following thread on aligning a Model 60 should (hopefully) prove helpful:
http://philcoradio.com/phorum/showthread.php?tid=5788
Scroll down to post #12, by me.
Yes, a 38-116 is quite a different monster from a 60, but these points still hold true:
Do not rely on your ear. Connect an analog AC voltmeter, preferably, at the speaker to the two plate leads of the output transformer primary. Safety first! Do not do this with power on, else you will receive a nasty shock! Connect everything before applying power to the radio. You can use an analog multimeter, but not a digital one. It must be set to AC volts. If it has several volt range settings, start at a higher range and work your way down to a lower range until you get a strong reading on the meter without pegging the needle. The AC voltage you will be reading will actually be quite low compared to the high B+ potential.
Keep the signal you feed into the radio as low as possible, just enough to barely hear the "beep" of the signal generator with the volume control turned to maximum while being able to see good deflection on your meter. This is important!
The 580 kc padder is adjusted differently than most of the other trimmers. Here, we will utilize a process known as rocking. What you need to do now is, find the signal on the dial. Now, adjust the trimmer (12) either clockwise or counterclockwise very slightly. Turn the dial of the radio to find the signal again. Note in the meter whether the signal is higher or lower than before. If lower, turn trimmer (12) in the opposite direction and try again. If the signal is louder, continue turning (12) slightly and finding the signal with the tuning knob, watching the meter to see if the signal continues to increase in strength. Eventually, you will come to a point where the signal does not get stronger and in fact will start to get weaker. When this happens, adjust (12) slightly in the opposite direction from how you were turning it to find the peak again. At this point, the 580 kc signal may not appear exactly at 58 on the dial. That does not matter. What you have done is to align the set's oscillator to track properly with the set's IF chain. This step is important for best operation of your radio. After doing this, repeat the 1500 kc adjustments to get the dial spot on at 150 on the dial. As I said, 580 may not come in exactly at 58 but if the "rocking" procedure has been done correctly, the AM band will be tuned for its best performance with the set's oscillator tracking properly with the set's IF.
Is yours a Code 121, or 125?
The theory found in the following thread on aligning a Model 60 should (hopefully) prove helpful:
http://philcoradio.com/phorum/showthread.php?tid=5788
Scroll down to post #12, by me.
Yes, a 38-116 is quite a different monster from a 60, but these points still hold true:
Do not rely on your ear. Connect an analog AC voltmeter, preferably, at the speaker to the two plate leads of the output transformer primary. Safety first! Do not do this with power on, else you will receive a nasty shock! Connect everything before applying power to the radio. You can use an analog multimeter, but not a digital one. It must be set to AC volts. If it has several volt range settings, start at a higher range and work your way down to a lower range until you get a strong reading on the meter without pegging the needle. The AC voltage you will be reading will actually be quite low compared to the high B+ potential.
Keep the signal you feed into the radio as low as possible, just enough to barely hear the "beep" of the signal generator with the volume control turned to maximum while being able to see good deflection on your meter. This is important!
The 580 kc padder is adjusted differently than most of the other trimmers. Here, we will utilize a process known as rocking. What you need to do now is, find the signal on the dial. Now, adjust the trimmer (12) either clockwise or counterclockwise very slightly. Turn the dial of the radio to find the signal again. Note in the meter whether the signal is higher or lower than before. If lower, turn trimmer (12) in the opposite direction and try again. If the signal is louder, continue turning (12) slightly and finding the signal with the tuning knob, watching the meter to see if the signal continues to increase in strength. Eventually, you will come to a point where the signal does not get stronger and in fact will start to get weaker. When this happens, adjust (12) slightly in the opposite direction from how you were turning it to find the peak again. At this point, the 580 kc signal may not appear exactly at 58 on the dial. That does not matter. What you have done is to align the set's oscillator to track properly with the set's IF chain. This step is important for best operation of your radio. After doing this, repeat the 1500 kc adjustments to get the dial spot on at 150 on the dial. As I said, 580 may not come in exactly at 58 but if the "rocking" procedure has been done correctly, the AM band will be tuned for its best performance with the set's oscillator tracking properly with the set's IF.
Is yours a Code 121, or 125?
--
Ron Ramirez
Ferdinand IN
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