B.2.Resistance And Voltage Checks - Heathkit SB-10 Series Troubleshooting Manual

If the meter was removed from the front panel, reinstall it before reinstalling the panel (it's
easier to get to the lower mounting screws while the panel is out)
If the LMO dial was removed, reinstall it before replacing the front panel
Make sure the LMO tuning shaft and bushing positioned loosely on the metal ring of the
circular dial before reinstalling the front panel.
Make sure the zero set shaft and pulley are installed on the zero set dial and positioned to
line up with the hole in the escutcheon.
Reinstall the main dial escutcheon on the front panel
Reinstall the front panel and all knobs except for the large tuning knob.
Reconnect the meter leads
Adjust the LMO tuning shaft/pinch roller for proper operation of the circular dial and tighten
the large nut on the shaft bushing. Install the large tuning knob on the LMO shaft.
b.2. Resistance and Voltage Checks
Note: Perform the visual inspection and resistance checks before applying power
for the first time.
Perform resistance check and log (on spreadsheet) measured values. Note any that
resistance values that are out of tolerance (+/- 20% or more) and replace as
required.
Note: if resistor R701 (1K on the driver grid switch board) or R940 (100 ohm
running between the switch boards) is burned or open, the tab on the
bandswitch closest to the bottom shield cover may be touching the lug on
the bandswitch causing a short. Bend the lug on the switch away down so it
doesn't contact the cover plate. This problem can also manifest itself after
the cover plate has been removed and reinstalled for any reason. Problems
with either resistor will show up in the resistance measurements for the V6
and V7 plate values. (see Service Bulletin HW-101-37)
Apply power gradually using a Variac controlled supply. Watch for any unusual behavior
such as smoke or burnt smells.
Check that all pilot lights function and replace as required (pilot lights may be in series with
tube filaments and burned out bulbs can upset the filament voltages).
With full voltages applied, check and log (on spreadsheet) measured voltages. Note any
voltages that are out of tolerance.
Check the receive function on all bands using either the built-in calibrator, antenna, or
signal generator. Note any issues or anomalies.
General Inspection and Restoration Checklist revised 12/17/2021 Page 23