Alignment of the “grid” or preselector circuits was completed. Yaesu’s procedure calls for alignment starting in receive mode, then doing it a second time in transmitter alignment before doing neutralization last.
Following Yaesu’s procedure showed no instability in receive mode, but when adjusting L9, 14 in transmit mode on 15M, instability occurred. The instability went away if neutralization is done on 15M before adjusting L9, 14. I found the procedure shown in the table below worked better. The plate current was kept under about 100 mA during the tune up.
The purpose of the L2 9 MHz trap is fairly obvious since the instructions call for supplying a 9 MHz signal at the input, then tuning for a null on the S meter. There is no explanation for how to adjust the L1 trap in the manual which is at the input to a cathode follower which drives the receiver mixer. I left the signal generator at 9 MHz at the input and adjusted both L1 and L2 for a null in the S meter reading as both L1 and L2 are identified as 9 MHz traps in the material list.
The manual calls for the adjustment of a trap coil L22 but L22 does not appear either in the schematic or material list.
