Ah.4.9.Sb-102-9: Oscillations Or Low Drive; Ah.4.10.Sb-102-10: Self Oscillations Occurring After Installation Of Steel Comb Brackets; Ah.4.11.Sb-102-14: Relays Remain Energized After Transmit Condition - Heathkit SB-10 Series Troubleshooting Manual

NOTE: Take adequate steps to eliminate any possible contact with B+ or B+ shorts to
chassis after disconnecting wire & resistor.
ah.4.9. SB-102-9: Oscillations or Low Drive
December 18, 1974
SB-102
Loose boards cause sporadic self oscillations & unstable RF conditions, particularly at
the high [15 & 10 meter] bands. The comb brackets which have been used are
aluminum & could not be soldered. Steel brackets are now available [PN 204-2096] &
should be used whenever encountered in the field. Both the switch shields & the driver
boards should be soldered to these brackets.
This change helps to increase grid drive as well as increase stability.
ah.4.10. SB-102-10: Self Oscillations Occurring After Installation of Steel Comb
Brackets
May 2, 1975
SB-102
It has been found that in a number of units, self oscillations are still occurring after
installation of both steel comb brackets [PN 204-2096].
To correct the condition, the screws around the RF driver board must be tightened
securely. Also, the lock washers between the circuit board & chassis must be installed,
otherwise a good ground is not assured.
Retightening screws which are already snug will also cause these oscillations to
disappear in units where it is a problem.
ah.4.11. SB-102-14: Relays Remain Energized After Transmit Condition
June 5, 1978
SB-102
After keying the transceiver with PTT for thirty to forty seconds, a positive voltage in
excess of 10 volts appears at the control grid, pin 9 of V12, thus keeping the relays
energized.
- To correct the problem, replace V12 [PN 411-124].
IEC brand tubes have been found defective in several cases, but other brands may also
cause this problem.
SB-102 Service Bulletins
Bulletin No:SSB Transceiver
Bulletin No: SSB Transceiver
Bulletin No: SSB Transceiver
SB-102-9
SB-102-10
SB-102-14
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