Heathkit SB-220

Heathkit SB-220 and SB-221 essential mod - Modifications to avoid damage when 3-500Z tubes fail.

SB-220 SB-221 Heathkit Amplifiers - SB-220 or SB-221 Heathkit Amp Using Eimac's 3-500Z - K0GKD

Improving Heathkit SB-220 - Circuit Improvements for the Heath SB-220 Amplifier

Heathkit SB-220 - The Heathkit SB-220, two 3-500Z, amplifier made a notable impact in the world of amateur radio when it debuted in 1975. Resources and modifications

2 kW HF Amplifier Rebuild - Heathkit SB-220 amplifier repaired at W8UM

SB-220 Mods - Heathkit SB-220 Amplifier modification by KE5YA

Adding 160 meters to the Heathkit SB-220 - There will be radical changes to this Heathlit SB-220. There will be the addition of 160 meters along with many other circuit and design changes.

SB-220 Repairs and Modifications - Heathkit SB 220 mods, replacing the Zener ZD1, replacing the plate-voltage voltage divider, adding a keying circuit for solid state transceivers

Heathkit SB-220 Meter Repair - Repairt a Heathkit SB-220 Linear Amplifier with a bad Plate Voltage meter