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TUCoPS :: Radio :: ft101e_1.txt

Yaesu FT-101E mods

        There will come a time when the finals in your
FT101E will need replacing.  These transceivers were
originally equipped with 6JS6C tubes manufactured by NEC. 
This tube's properties are slightly different from the 6JS6C
tubes available today from American tube manufacturers.  By
the way, don't bother looking for tubes made by NEC.  They
got out of the business several years ago.
        In order to use the "American" variety 6JS6's, a
simple modification to the neutralization circuit must be
made to the final section of the transceiver.
        The modification consists of replacing the fixed
value 100 pf 1000 VDC mica capacitor with a 10 pf 1000 VDC
mica capacitor.  This capacitor, C125, is in series with the
10 pf variable neutralizing capacitor off of the plate
        If this modification has not already been completed
on your rig, be sure to use a mica or silver mica of at
least 1000 VDC.  Do not substitute a different type, because
the heat in the final compartment will change the value, and
your tubes will fail prematurely.  Also, be very careful to
keep all leads short and in exactly the same orientation as
the original capacitor.
        Before reneutralizing, open the variable
neutralizing capacitor all the way to minimum engagement and
follow the neutralizing instructions in the manual.  While
dipping the plate, remember to adjust the neutralizing
capacitor for equal value meter reading peaks (IC position)
on both sides of the dip when tuning the "Plate" control.
see files ft101e and ft101e.1 - request them from server

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