Heathkit SB-10 Series Troubleshooting Manual page 171

5. Check all edges of the final enclosures for proper grounding to the main chassis.
6. Check the hardware for the side rails to be sure a good ground is being provided.
7. Be sure that all the ground clips on the coil cover are making good contact with the
switch shields.
8. Check the soldering of the switch shields to the center pins of tube sockets V6, V7,
V10 & V11.
9. Check the ground leads from the switch board & shields, to be sure they are going to
ground foil & not to the preselector capacitor foil pods on the RF driver board.
10. Check for broken or shorted pigtails on each of the shielded cables in the unit.
11. Check RFC801 & L901 for any signs of deterioration or physical damage, (burn
spots). If apparent replace the part.
12. Improper adjustment of the Het. Osc. coils could cause improper mixing action,
resulting in the final operating at a different frequency appearing as instability.
13. Change driver & final tubes then re-neutralize per manual instructions.
14. Check driver tube shield to be sure that it has a good ground contact with the
socket spring clip.
15. Check for a good ground between the front panel & chassis.
16. Check the SWR of the antenna system at the frequency of operation. Should be
below 2:1.
17. Check the antenna coax for leakage, poor connectors & broken shield
connections.18. Is the transmitter properly grounded?
19. Be sure all shields & tube shields are installed.
20. Realign using a properly terminated 50 ohm non-reactive dummy load.
NOTE: This does not include a light bulb.
21. Check for normal Het. Osc. test-point voltage.
22. Check for proper LMO injection voltage 1.0-1.5 VRF.
23. Check for a high AC ripple content in the LV-B+, HV-B+ and bias voltages from the
power supply.
SB-101 Service Bulletins Page 171