Collins Service Bulletin Index
MODEL |
SB/SIL# |
DESCRIPTION |
| KWM-1 | SB 1A | Improvement in calibrator operation |
| SB 1B | Spurious output of KWM-1 | |
| SB 1C | Transient in speaker when switching from receive to transmit | |
| SB 1D | Hum in speaker when AF gain control is advanced in CW operation | |
| SB 1E | "Tweets" in audio output caused by DC power supply | |
| KWM-2/2A | SIL 1-75 | Overcome instability caused by aging |
| SIL 2-75 | Extended operating range | |
| SIL 2-3-60 | VFO oscillator drift | |
| SB 1 | Not Issued | |
| SB 2 | Add Vox relay time constant control | |
| SB 3 | Correlation between frequencies on different bands | |
| SB 4 | Improvement of ALC action and elimination of ALC overshoot | |
| SB 5 Revised | To improve transmit-receive exciter tuning coincidence | |
| SB 6 | To eliminate delay in operation when switching from transmit to receive function | |
| SB 7 Reissue | Replacement of K2 and K4 with plastic encased plug-in type relays | |
| SB 8A | Eliminate AGC overshoot on noise pulses and provide dual time-constant action | |
| SB 8B | Change source of delay bias to AGC rectifier | |
| SB 8C | Add delayed-decay (hang) AGC to the RF amplifier | |
| SB 9 Revision 2 | Convert KWM-2 To KKK-2A | |
| SB 10 | Eliminate VHF parasitic oscillations in tone oscillator | |
| 30L-1 | SB 1 Revision | Wiring change required before conversion from 115 To 230 volt operation is made, use of 8-ampere line fuses, and correction to instruction book drawings |
| SB 2 | Backward deflection of ALC meter | |
| SB 3A | To lower operating temperature of PA tubes | |
| SB 3B | To eliminate pilot light fluctuation with RF excitation | |
| SB 4 | Operation from 230 VAC power source | |
| 30S-1 | SIL 10-14-59 | Loading of the 30S-1 amplifier |
| SIL 2-15-60 | "What's Watt With SSBVI" | |
| SB 1 | To increase operating life of PA tube | |
| SB 2 | Prevent intermittent dropout of plate overload relay | |
| SB 3 | Reduce excessive ALC control | |
| 32S-1/2 | SIL 7-28-59 | Use of transmitter as CW exciter for AM mode |
| SIL 2-3-60 | VFO oscillator drift | |
| SIL 1-75 | Overcome instability caused by aging | |
| SB 1 | Improve VOX operation | |
| SB 2 | Improve carrier suppression | |
| SB 3 | Add VOX relay time constant control | |
| SB 4A | To improve CW operation (Supersedes SB 4) | |
| 32S-3/3A | SIL 2-75 | Extended operating range |
| SB 1 Revision | Improve VOX circuit to eliminate intermittent dropout, and improve operation of first audio amplifier | |
| SB 2 | Removal of audio distortion | |
| SB 3 | Not Issued | |
| SB 4 | Replaced by SB1 Revision | |
| SB 5 | Replaced by SB1 Revision | |
| SB 6 | Replaced by SB1 Revision | |
| SB 7 Revision 2 | Converts 32S-3 To 32S-3A | |
| 51S-1 | SIL 7-63 | Reduced hum in audio output with use of 28-volt DC power supply |
| SB 1 | Suppression of unwanted oscillations In low level audio output lines and allow use of wiring configuration | |
| SB 2 Revision 2 | Replace transformers T14 and T15 with mechanical filter | |
| SB 3 Revision | Improve sensitivity of lower bands | |
| SB 4 | Addition of dial lock assembly ly | |
| SB 5A | Converts 51S-1A/1AF to 51S-1/1F | |
| SB 5B | Converts 51S1/1F to 51S-1A/1AF | |
| SB 6 | Provision for high-speed receiver muting and recovery | |
| SB 7 | Reduce 500-khz spurious response | |
| 55G 1 | SB 1 | Increase current handling capacity of 115-volt input fuse |
| 62S-1 | SB 1 | Improvement in operation of ALC circuit |
| 75S-1/2 | SIL 2-75 | Extended operating range |
| SIL 2-3-60 | VFO oscillator drift | |
| 75S-3/3A | SIL 2-75 | Extended operating range |
| SB 1 | To eliminate BFO parasitic oscillations | |
| SB 2 | To minimize background hum level | |
| 75S-3B/3C | SIL 2-75 | Extended operating range |
| SB I | Improved performance | |
| SB 2 | Second mixer plate circuit improvement | |
| SB 3 Revision 2 | Convert the 75S-3B to 75S-3C | |
| 516E-1 | SB 1 | Modification for use with positive ground |
| 516E-2 | SB 1 | Add bleeder resistor to +260 vdc line to |
| 516 F-2 | SIL 1-76 | Prevent fuse blowing caused by arcing in the vacuum tube rectifiers |
| PM-2 | SB 1 Revision | Extension of design specifications for |
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