FT-857 low power on 6m
I have bought 5 years ago from a local om the ‘’fabulous’’ FT857 with a malfunctions of the microphone, the fabulous quartz filter and a low power in 6m band.
The microphone and the filter was repaired in russia and the 6m malfunction was discovered after the returned back of the transceiver.
After i repaired my ICOM IC746, i tried to repair the 6m problem as i taught the LPF or the relays are the responsables.
I took some larges copies of the schematics and PCB because the small dimension of the composants.
I removed the cable from J1002 and connected another to a wattmeter.
I found particaly 5 to 7 watts output unless in 6m.Following the scematic i found that there is two pair of diodes acting as a swith between the HF lpf and 6m bpf.
There is also a low level command coming from the PLL board to proper filter to function.