Set both tone controls on the AF board to 50%. Frequency response is
essentially flat from 40-6khz and down 3db at 16 khz. If you want it flat
to 16 khz, just turn up the treble tone control a bit.
There is a problem with the alc kicking in too early on AM. To fix this,
connect a 10k resistor between pins 2 and 3 of P22/J15 on the I-F board.
This will raise the point at which the alc kicks in.