Heathkit SB-10 Series Troubleshooting Manual page 7

ab)If the dial pointer is to the right of the "5" marking, loosen the dial pointer
drive arm mounting screws and move the dial pointer drive arm base down until
the dial pointer is at the "5" marking. Retighten the screws....................................71
ab.1.1.Dial Calibration........................................................................................................................................... 71
ab.1.2.Re-engaging the Main Tuning Pulley.........................................................................................................71
ab.1.3.Drag When Rotating Main Tuning Knob.....................................................................................................73
ab.1.4.Circular Dial Wobble................................................................................................................................... 74
ab.1.5.Spiral Groove Nylon Follower Replacement...............................................................................................75
ab.1.6.Zero Set Dial Mechanism and Pulley.........................................................................................................76
ab.1.7.Repairing the Center Hub........................................................................................................................... 78
ab.2.Knob Inlays................................................................................................................... 80
ab.3.PA Load Capacitor Remove and Replace...................................................................81
ab.4.Function Switch (A.C. Switch).....................................................................................82
ab.4.1.Finding a Replacement AC Switch.............................................................................................................82
ab.4.2.Replacing the AF Gain with a Control Having an AC Switch......................................................................82
ab.4.3.Modifying the Failed Switch with a Microswitch..........................................................................................82
ac)Modifications.............................................................................................................84
ac.1.Conversion to Low-Z Headphones:.............................................................................85
ac.2.Improved CW Operation:..............................................................................................86
ac.3.Transmit Improvements...............................................................................................88
ac.4.Receive Improvements.................................................................................................90
ac.5.BFO Level to Product Detector....................................................................................90
ac.6.I.F. Filter Passband Improvements..............................................................................92
ac.7.Stabilizing Meter Zero Settings....................................................................................94
ac.8.Antenna Connector......................................................................................................96
ac.8.1.BNC Connector........................................................................................................................................... 96
ac.8.2.SO-239 Connector...................................................................................................................................... 96
ac.8.3.SO-239 to RCA Male Adapter....................................................................................................................97
ac.9.SB-100 CW Filter Modification.....................................................................................98
ac.10.Using an External VFO for Split Frequency Operation..........................................100
ad)Heathkit Filters........................................................................................................101
ad.1. Heathkit Filter Measurements...................................................................................102
ad.2.SSB Filter 404-200 Circuit..........................................................................................104
ad.3.SSB Filter 404-283 Circuit..........................................................................................105
ae)Printed Circuit Boards (PCBs)..............................................................................107
HW & SB Series Manual Page 7