hole in SB cabinet

Emil Dular WD4SCZ at AOL.COM
Thu Mar 18 19:14:27 EDT 2010


I don't see why it wouldn't.  You don't have the Molex plug but if you can 
disconnect the plates and screen grid the rest of steps should work fine.

I normally use an oscilliscope to measure the RF output. Another method that 
will work in a pinch is connect a short lead to the antenna connection and 
use the S-meter of a good receiver tuned to 28.5.  Peak the drive and load, 
then adjust the neutralization cap for minimum S-reading.




----- Original Message ----- 
From: "Robert Myers" <rsmyers at rogers.com>


> Hi,
>
> Would this work for a SB-401 transmitter?
>
> Thanks,
> -- Rob VE3JQL

>                        May 23, 1974
> SB-102                                          Bulletin No:
> SSB Transceiver                                 SB-102-8
>
>         Alternate Method of Neutralizing The Final Amplifiers
>
> NOTE:  Be sure unit is off and power supply high voltage capacitors are
> discharged.
>
> 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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