12-11-2014, 04:03 PM
Revisiting this topic to add a little new info.
Today I decided to pull the chassis again and remove that 375 pF cap (27). As it turns out, it wasn't buried too badly and I was able to remove the original with little difficulty. It appears that 375 pF is no longer a standard value, so I paralleled a 270 pF and a 100 pF to get 370 pF, and installed that in place of the original.
Result: Band 4, "31-25 M" is now working, but refuses to align properly - the oscillator trimmer for this band will only allow me to raise the 12 mc test frequency as high as 10.6 on the dial before tightening completely. As you folks may recall, I have a Canadian 51A which is very similar to this 42-730EZ, and which has the same problem.
Any suggestions? Should I try changing that homemade 370 pF cap with a 350 pF (250 pF and 100 pF in parallel)? We can't go too low, else the frequency will be way off in the opposite direction. Band 5 has an 80 pF cap in series with the oscillator coil instead of a 375 pF cap; and both bands use the same coil.
Today I decided to pull the chassis again and remove that 375 pF cap (27). As it turns out, it wasn't buried too badly and I was able to remove the original with little difficulty. It appears that 375 pF is no longer a standard value, so I paralleled a 270 pF and a 100 pF to get 370 pF, and installed that in place of the original.
Result: Band 4, "31-25 M" is now working, but refuses to align properly - the oscillator trimmer for this band will only allow me to raise the 12 mc test frequency as high as 10.6 on the dial before tightening completely. As you folks may recall, I have a Canadian 51A which is very similar to this 42-730EZ, and which has the same problem.
Any suggestions? Should I try changing that homemade 370 pF cap with a 350 pF (250 pF and 100 pF in parallel)? We can't go too low, else the frequency will be way off in the opposite direction. Band 5 has an 80 pF cap in series with the oscillator coil instead of a 375 pF cap; and both bands use the same coil.
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Ron Ramirez
Ferdinand IN