harbach-electronics ss-221 User Manual
3
This completes the installation of the SS-221 “So ft Sta rt” module. Before putting the case back
onto the cha ssis, it would be w ise to che ck the operation. NOTE: MAKE SURE THE "SAFTY
BRASS SPRING INT ERLO CK" IS NOT GROUNDED BEFORE PLUGING INTO AN AC OUTLET.
FAILURE TO DO THIS WILL SHORT CIRCUIT THE HIGH VOLTAGE SUPPLY TO GROUND
onto the cha ssis, it would be w ise to che ck the operation. NOTE: MAKE SURE THE "SAFTY
BRASS SPRING INT ERLO CK" 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 am plifier 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 v oltage. Afte r 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.
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 v oltage. Afte r 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
(419) 945-2359
PARTS LIST
BR1
FULL-W AVE BRIDGE (1A 400 PIV)
D1 & D2
1N4005 (1A 600 PIV)
K1 & K2
SPDT 12A 48VDC
R1 & R2
20
Ω
10W
(240VAC)
R1 & R2
R1 & R2
10
Ω
10W
(120 VAC)
R3
R3
3000
Ω
2W 5%
Z1 & Z2
200V MOV
Z3
390V MOV