January 22, 1976 SB-200 Bulletin No: 1 KW Linear Amplifier SB-200-1 Meter Switch Lugs Shorting To Bottom Cover The meter switch supplied in the kit may have long lugs on the switch, which can result in shorting of lugs 6 and 7 of the switch to the bottom cover. Shorting lug 6 of the switch to the bottom cover will cause the antenna relay to close when the meter switch is in the "grid" position, and release in the "plate" position. Shorting of lug 7 to the bottom cover will cause antenna relay closure in any position of the meter switch. These switch lugs should be bent to prevent shorting. ------------------------------------------------------------------------------------------------------------------ February 3, 1976 SB-200 Bulletin No: 1 KW Linear Amplifier SB-200-2 Replacement Fan Blades The PN 266-21 fan blade is no longer available. The PN 266-900 blade will be used as a replacement. When using the new blade, the set screw must also be changed. ------------------------------------------------------------------------------------------------------------------- December 5, 1977 SB-200 Bulletin No: 1 KW Linear Amplifier SB-200-3 Difficulty in Mounting Capacitor ++++Information not available at this time++++ ------------------------------------------------------------------------------------------------------------------- May 15, 1979 SB-200 Bulletin No: 1 KW Linear Amplifier SB-200-4 Sheet Metal Screws Will Not Tighten If the perforated covers will not secure properly due to enlarged sheet metal holes, install a 6-32 speednut [PN 252-22] over the lip and surrounding hold. The 6-32 X 3/8" sheet metal screw [PN 250-8] will then tighten securely. Using the speednuts does not noticeably degrade the products' shielding capabilities. ----------------------------------------------------------------------------------------------------------------- January 21, 1980 SB-200 Bulletin No: 1 KW Linear Amplifier SB-200-5 Apparent Self-Oscillation When Used with Kenwood Transceivers ++++Information not available at this time++++ ------------------------------------------------------------------------------------------------------------------ February 7, 1980 SB-200 Bulletin No: 1 KW Linear Amplifier SB-200-6 Presetting the Loading Capacitor ++++Information not available at this time++++ ----------------------------------------------------------------------------------------------------------------- March 7, 1980 SB-200 Bulletin No: 1 KW Linear Amplifier SB-200-7 Interfacing the Linear to Kenwood Exciters ++++Information not available at this time++++ ------------------------------------------------------------------------------------------------------------------ September 2, 1980 SB-200 Bulletin No: 1 KW Linear Amplifier SB-200-8 RFC3 Overheats and Circuit Breakers Trip ++++Information not available at this time++++ ------------------------------------------------------------------------------------------------------------------ April 6, 1984 SB-200 Bulletin No: 1 KW Linear Amplifier SB-200-9 Interfacing The Linear To Kenwood Exciters The ALC voltage to Kenwood transceivers and transmitters should not exceed -8 volts. To Ensure the proper voltage to the Kenwood, add: An 8 volt zener diode [PN 56-621] across the ALC connector on the back of the amplifier. Connect the banded end of the diode to the ground lug. Adding a control in the ALC line (as instructed in previous bulletins) to control the level of ALC voltage doesn't always work. This control loads the ALC line so much that very little ALC voltage is developed, resulting in the exiter overdriving the linear, In units which have the control installed and the operation is still unsatisfactory, return the ALC circuit to its original design and install the zener diode. ------------------------------------------------------------------------------------------------------------------- March 31, 1988 SB-200 Bulletin No: 1 KW Linear Amplifier SB-200-10 Variable Load Capacitor [PN 26-97] NLA The #26-97 load capacitor used at C28 in the earlier SB-200 Linear Amplifiers are no longer available from our vendors. A #26-160 variable capacitor is now used as a replacement. Installing the new capacitor requires drilling new mounting holes in the chassis and rerouting the wiring. When Heath Parts Replacement receives an order for the #26-97 capacitor, they'll send the #26-160 capacitor and an instruction sheet [PN 597-4951] to tell the customer how to install the capacitor. -------------------------------------------------------------------------------------------------------------------