ah) HW-101 and SB-10x Service Bulletins
This section contains a compendium of service bulletins for the HW-101, SB-100, SB-
101 and SB-102 transceivers. The HW-101 is included due to the large number of 
similarities between the HW-101 and SB-10x series of transceivers.
ah.1. HW-101 Service Bulletins
ah.1.1. HW-101-1: VFO Drift
FEBRUARY 11, 1971
HW-101 BULLETIN NO: SSB TRANSCEIVER  HW-101-1
The vfo coil has been changed to improve the drift problem experienced in many units.  
The old coil [PN 40-810] should be replaced by the new coil [PN 40-1976] whenever a 
unit displays excessive drift.  This has been made a permanent change in all future 
production.
ah.1.2. HW-101-2: Repeated Heterodyne Oscillator Tube Failure Inadequate 
USB-LSB Frequency Shift
SEPTEMBER 14, 1972
HW-101 BULLETIN NO: SSB TRANSCEIVER HW-101-2
Change:  R-212 from 220 Ohm to 330 Ohm 1/2 watt resistor [PN 1-4].  
Lack of VFO shift range can be corrected by changing the value of the FET source 
resistor. Change:  R-947 from 470 Ohm to 1000 Ohm [PN 1-9].
ah.1.3. HW-101-3: Carrier Null Control Failure
FEBRUARY 16, 1973
HW-101 BULLETIN NO: SSB TRANSCEIVER HW-101-3
Recently an improved mounting method was devised for the [PN 10-147] controls in kit 
models SB-102, SB-401 and HW-101.  Current production utilizes a fiber washer for 
greater clearance and the case of the control is grounded by a separate wire.  We are 
anxious to know if this will reduce the failure rate.  Please make note of any change, 
good or bad, and keep us posted.
ah.1.4. HW-101-4: Low Output on 40 Meters
OCTOBER 29, 1973
HW-101 BULLETIN NO: SSB TRANSCEIVER HW-101-4
HW-101 Service Bulletins Page 136