I just finished a 65 chassis and besides the 3 screws behind the tuning assy there is nothing else to adjust, I can pick up low end stations left and right on the high end of the dial but the low end is dead from about 1000 down, it is like the low end has been moved up. when you tune down you can hear it cut out as if the power was turned off. would anyone have any suggestions of what to look for? All coils, caps, tubes and resistors are good or have been replaced. Thanks, Todd
Typically the alignment of a TRF set with screen grid tubes is to adjust the trimmers at 1500kc. Do all of your coils have good continuity??
Terry
All coils check ok, when I said " like the power was turned off " it is actually more like you pulled the antenna off, the faint hum is still there just no static. Thanks, Todd
Are any of the plates rubbing on the tuning condenser??
Terry
No plates touching, the main problem is that the station tuned in does not match the dial. the tuning range needs to be brought down about half of the dial for example a station at 500 comes in at 1200 on the dial. Todd
Start by turning each trimmer counterclockwise about 1/4 turn, then check your dial. It should be down toward the bottom of the dial a bit. If it is, what you can do (if you don't have a sig gen) is use the lowest frequency station you can hear, and tune the dial a bit lower at a time, then adjust the trimmers back to it. Repeat as necessary, then go back to the high end and align that for 1500 or as close as possible with an available signal.
All I can get with the 3 trimmers is a louder signal and even with a generator I can not tune any signal higher than 1000 with the plates full open. Could the trimmers be bad, maybe the material between the plates deteriorated?
As you open (counterclockwise) the trimmers, you should be able to tune the main tuner down the dial to get the same station. This is because opening the trimmers reduces the capacitance in the circuit, so you need to add more with the main tuner to compensate. That your trimmers are not allowing for this is puzzling. Even more puzzling is that looking at the Rider's schematic for this chassis, it shows no trimmers at all. :-/
Does the local-distance switch (32) have any effect? Or is yours one of the early versions without a local-distance switch, with the AC switch where the local-distance switch goes in later versions of the 65?
It acts as it should on strong stations but is has no effect on tuning and as for the trimmers there are 3 behind the tuning condenser like the ant. trimmer on an aa5 but 2 of them have a lock nut as if they were not supposed to be adjusted no 4 on the schematic is the only adjustment. One thing i did notice is that the original part values did not match the schematic all resistors were 100 instead of 200 and a couple of the caps were .05 instead of .1 was there a change in production that would have made the new parts i installed as per the schematic a problem? thanks, Todd