Collins Service Bulletins and Service Information Letters for the KWM-1/2/2A and S-Line Series of Amateur Equipment
Collins Service Bulletins and Service Information Letters
For the KWM‑1/2/2A and S‑Line Series of Amateur Equipment
Legend: SB = Service Bulletin SIL = Service Information Letter
| Model | SB/SIL # | Description |
|---|---|---|
| KWM‑1 | SB 1A | Improvement in calibrator operation |
| KWM‑1 | SB 1B | Spurious output of KWM‑1 |
| KWM‑1 | SB 1C | Transient in speaker when switching from receive to transmit |
| KWM‑1 | SB 1D | Hum in speaker when AF gain control is advanced in CW operation |
| KWM‑1 | SB 1E | “Tweets” in audio output caused by DC power supply |
| KWM‑2/2A | Comp List | KWM‑2 component list |
| 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< |