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Late Model 60 sensitivity/bandwith when tuning
#12

Here are comprehensive alignment instructions for late model 60 sets (with four IF adjustments and wave trap):

1. Remove the grid clip from the 6A7 tube. Attach a grid clip from a junk set to the 6A7 grid cap and clip the high end of your signal generator to this grid clip. Attach the low end (grounded end) of your signal generator to the Philco 60's chassis.

2. Do not rely on your ear. Connect an analog AC voltmeter, preferably, at the speaker between the green and white leads (plate and screen grid). 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.

3. Turn the radio on, volume control all the way up, dial set at low end of AM band, tuning condenser plates fully meshed. Make sure the band switch is set to AM (counterclockwise). Adjust the signal generator to produce a 460 kc signal. Feed a modulated 460 kc signal into the 6A7 grid cap. Keep the signal as low as possible, just enough to barely hear the "beep" of the signal generator while being able to see good deflection on your meter. This is important!

4. Adjust the various screws, hex nuts, etc. as follows, using the illustrations below to guide you to the locations of the various adjustments. Use a plastic or Bakelite 1/4" hex adjusting tool designed for adjusting Philco trimmers; a metal socket wrench will throw the adjustments off to a certain degree.

5. Adjust trimmer (26A) for maximum output.

6. Adjust trimmer (26) for maximum output.

7. Adjust trimmer (18 ) for maximum output.

8. Adjust trimmer (17) for maximum output.

9. You should notice as you adjust these, that the signal will get louder. Reduce the output at the signal generator as this happens. You want to keep the input signal weak, barely audible.

10. Remove the temporary grid clip from the 6A7 grid cap and reattach the proper grid clip to the 6A7 tube. Unhook your signal generator.

11. Now, connect one lead of a 200 pF mica or ceramic condenser to the antenna clip of the set. Connect the high end of your signal generator to the other end of this condenser. Low end of the signal generator to chassis ground as before.

12. Crank up the output of the signal generator, which is still set at 460 kc. For this next adjustment, you want a loud signal.

13. Adjust the wave trap trimmer (accessible through a hole in top of the chassis) for minimum output.

14. Now set the signal generator for a 1400 kc signal and turn it down again; for the remaining adjustments, we want the weakest possible signal from the generator once again. Tune the radio to exactly 140 on the dial.

15. Adjust trimmer (6) for maximum output.

16. Adjust trimmer (5) for maximum output.

17. Tune the signal generator to produce a 600 kc signal. You may have to turn up the generator output for a louder signal here. After doing this, find the signal on the dial of the set; it will be near but probably not exactly at 600 kc.

18. Now we will adjust trimmer (12). This is adjusted differently than all of the others. 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 600 kc signal may not appear exactly at 60 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.

19. Now, you must set your signal generator back to 1400 kc and, still using the lowest possible signal so that it is barely audible yet reads well on your meter, repeat steps 14 through 16.

20. Congratulations, your 60 is now properly aligned. Icon_biggrin

[Image: http://i326.photobucket.com/albums/k420/...lign60.jpg]

--
Ron Ramirez
Ferdinand IN


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