ah.4. SB-102 Service Bulletins
ah.4.1. SB-102-1: Meter Zeroing
November 25, 1970
SB-102 Bulletin No.SSB Transceiver SB-102-1
Original 10-147 control tolerance not sufficient to allow zeroing in all units. This part is
being re-specified to a closer tolerance. In the meantime, any field problems regarding
zeroing of the meter can be corrected as follows:
Change: R-107 from 100K Ohm to 82K Ohm [PN 1-159].
ah.4.2. SB-102-2: Repeated Heterodyne Oscillator Tube Failure
September 14, 1972
SB-102 Bulletin No.SSB Transceiver SB-102-2
Change: R-212 from 220 Ohm to 330 Ohm 1/2 Watt resister [PN 1-4].
ah.4.3. SB-102-3: Low Grid Drive - Alignment Problems
March 23, 1973
SB-102 Bulletin No.SSB Transceiver SB-102-3
This has been related to the differences [internal electrode capacitance] between Tung-
Sol & RCA 6146's. Purchasing has ceased buying Tung-Sol tubes; all new stock since
late 1972 will be RCA's which give better performance. In addition, an additional
alignment sequence is being put into the manuals which insures adequate grid drive --
previous tune-up was done in receive only where the peaks were broader than required
for transmitter tuning. The new procedure uses the receiver sequence to get in the "ball
park"; the added sequence peaks for maximum grid drive.
The following modifications to the manual will help avoid the many questions:
PAGE 103: 8th step, right column, last two sentences:
Then turn the meter switch to GRID [grid current]. The meter should have some up-
scale indication. The meter may read as much as full scale -- this is normal.
PAGE 104: left column #2:
Turn the meter switch to GRID & adjust the MIC/CW LEVEL control for a grid current
reading, just enough so a peak may be seen when making the adjustment in the next
step.
PAGE 104: Right Column #4 - will be deleted.
SB-102 Service Bulletins Page 175
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