Modifications for the Yaesu
FL-2100
19-07-1998 FL-2100B 12 meter
modification
If you do not mind losing 10 meters on your FL2100B,
this quick mod should have you up and running on 12 meters with near full power
output.
Place the FL2100B on its side with the LOADING control nearest
the surface that the amp is setting on. Make sure that the amp has been UNPLUGED
and that the PLATE VOLTAGE has dissipated before you proceed. Remove the screws
that hold the bottom cover on and remove the bottom cover of the amp.
Set
the BANDSWITCH to : 10
Set the PLATE CONTROL to : 9
Set the LOADING
CONTROL to: Fully counter-clockwise
Disconnect the 850 volt red wire that
leads from the transformer to the DIODE BOARD (located right behind the TRANS -
OPERATE switch. Install a SWR bridge between the EXCITER and the FL2100B. Tune
your HF rig to 24.950. Turn the FL2100B on and place the amp in the OPERATE
MODE. Excite the the AMP with an AM signal, enough so that you can calibrate
(set) your SWR meter. Place your SWR meter in the REV position and read the SWR.
While in the TX mode, tune L206 (located near the GROUNDING WINGNUT just inside
of the amp chasis) untill you achive your lowest SWR reading. You have just
completed the retuning proceedure of the 10 meter ANTENNA INPUT COIL.
If
you would like to operate both 10 meters and 12 meters, you may want to tune
L206 on a frequency between your operating fre-quencys on 10 and
12.
Re-solder the 850 volt red wire (with the AMP off and un-pluged).
Re-assemble the AMP and enjoy INCREASED POWER OUTPUT on 12
METERS.