ah.2. SB-100 Service Bulletins
ah.2.1. SB-100-1: Diode Leakage in The SB-100, SB-101, HW-100
May 23, 1974
SB-100 Bulletin No:SSB Transceiver SB-100-1
The silicon diodes used in the SB100 & SB101 are standard power diodes rated at
500PIV & 750MA. For each condition described, the diodes should be replaced with an
equal value to maintain proper operation.
Diodes D902 & D903, when leaky, will have an effect on ALC indication. The ALC
indication will be normal for the first half hour to an hour. Then the meter indication will
start dropping off until there is very little indication.
D101, when leaky or defective, will cause slow or no receiver recovery after transmitting
for any period of time.
D905, under leaky conditions, will cause very slow or no receiver recovery and false
meter indications. The meter will kick up scale & slowly drift down to zero.
D201 will result in a decrease in VOX sensitivity to the point where the VOX circuit will
not be activated. It can also result in increasing VOX delay, causing the relay to stay in
the transmit condition.
ah.2.2. SB-100-2: Alternate Method of Neutralizing the Final Amplifiers
May 23, 1974
SB-100 Bulletin No:SSB Transceiver SB-100-2
NOTE: Be sure unit is off and power supply high voltage capacitors are discharged.
Disconnect final plates & screen grid.***
1. Turn unit on.
2. Rotate the BAND switch to 28.5.
3. Place the VTVM RF probe in the ANTENNA connector.**
4. Set the FUNCTION switch to TUNE.
5. Rotate the LEVEL control fully clockwise.
6. Adjust the PRESELECTOR control for a maximum reading on the VTVM.
7. Adjust the FINAL control for a maximum indication on the VTVM, with the LOAD
control set at the 50 ohm position.
SB-100 Service Bulletins Page 161
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