User Guide

3
This completes the installation of the SS-221 “Soft Start” module. Before putting the case back
onto the chassis, it would be wise to check the operation. NOTE: MAKE SURE THE "SAFTY
BRASS SPRING INTERLOCK" IS NOT GROUNDED BEFORE PLUGING INTO AN AC OUTLET.
FAILURE TO DO THIS WILL SHORT CIRCUIT THE HIGH VOLTAGE SUPPLY TO GROUND
AND DAMMAGE WILL RESULT IF POWER IS APPLIED! To do this, right the amplifier and plug
it in and place the multi-meter switch to the “HV” position. With the power selector switch in the
“CW” position, turn the amplifier on. Observe the plate voltage. After about one half second, it
should read its normal reading. You will hardly notice any difference in the operation of your SB-
220, but you will know it is very well protected from voltage transients and high inrush currents.
SS-221 “SOFT START” MODULE
HARBACH ELECTRONICS
Jeff Weinberg – W8CQ
468 County Road 620
Polk, OH 44866-9711
[phone]
http://www.harbachelectronics.com
[e-mail]
PARTS LIST
BR1 FULL-WAVE BRIDGE (1A 400 PIV)
D1 & D2 1N4005 (1A 600 PIV)
K1 & K2 SPDT 12A 48VDC
R1 & R2 20Ω 10W
(240VAC)
R1 & R2 10Ω 10W
(120 VAC)
R3 3000Ω 2W 5%
Z1 & Z2 200V MOV
Z3 390V MOV