Date: 11 Feb 90 06:27:32 GMT
From: philmtl!philabs!briar.philips.com!rfc@uunet.uu.net  (Robert Casey)
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@NYNET
  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 @ VE3JF


          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
                                                           last
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