Neutralizing finals

[Charles Seitz]

This should help.  It came from an official service bulletin for the SB-101
but notice there are also references to the
HW-101.

---  CHAS  WA2DYA

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                                        May 23, 1974
SB-101
      Bulletin No.
SSB Transceiver
SB-101-6

                       Alternate Method of Neutralizing The Final Amplifiers

1.   Disconect final plates & screen grid.***
2.   Turn unit on.
3.   Rotate the BAND switch to 28.5.
4.   Place the VTVM RF probe in the ANTENNA connector.**
5.   Set the FUNCTION switch to TUNE.
6.   Rotate the LEVEL control fully clockwise.
7.   Adjust the PRESELECTOR control for a maximum reading on the VTVM.
8.   Adjust the FINAL control for a maximum indication on the VTVM, with the
LOAD control set at the 50 ohm position.
9.   Using an insulated screwdriver, adjust neutralizing capacitor for a
MINIMUM indication on the VTVM.
10.  Readjust the neutralizing capacitor for a minimum indication on the
VTVM.
11.  Turn the FUNCTION switch to the off position.
12.  Discharge high voltage power supply capacitors.
13.  Reconnect final plates & screen grid.
**VTVM & RF probe will be needed.
***To remove screen voltage in SB-100, SB-101, HW-100 & HW-101 disconnect
R920 (100 ohm resistor) from buss wire between pins of V8 & V9.  In the
SB-102 removal of accessory plug is all that's required.  To remove high
voltage in SB-100, SB-101 & SB-102 disconnect red wire at lug 4 (in
Sb-100 lug 3) of terminal strip BK that goes to grommet BL.  In HW100 &
HW101 disconnect red wire going to lug 1 of RF choke in final cage.

NOTE:  Take adequate steps to eliminate any possible contact with B+ or
B+ shorts to chassis after disconnecting wire & resistor.
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