Date: 11 Feb 90 06:27:32 GMT
From: philmtl!philabs!briar.philips.com!rfc
Subject: FT101E mods so you can use USA final tubes
copied from packet:
Msg# TSF Size #Rd Date/Time MsgID From To
17464 BF 2446 1 0131/0304 44022_VE3JF VE3OSN MODS
Sb:Final Mods - Yaesu FT 101E
PACKET BID:44022_VE3JF
Here's an old modification that's been around for a few years. I had
occasion to use it recently myself, so it may be of value to someone
else I am not sure of its origin, I may have picked it out of an old
QST. Anyway, it works.
73 -Bob- VE3OSN
REPLACING FINALS IN FT101E TRANSCEIVERS
---------------------------------------
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 circuit.
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.
2352z, 1886
Note:I haven't tried this, proceed at your own risk WA2ISE
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SOURCE: The QRZ Windows Ham Radio CDROM
