Harbach Electronics SS-100 User Manual

SS-100 UNIVERSAL “SOFT START” INSTALLATION INSTRUCTIONS

PARTS S UPPLIED WIT H THIS KIT:

(1) SS-100 “Soft Start” Circuit B oard Asse mbly

It is not p ossible to g ive exact instal la tion instruc tions for the Universal “Soft Start” module because I
ha ve neither the schematic nor the physical layout of your specific amplifier. I can give you enough
information, together with the schematic of the Universal “Soft Start”, to help you install this module.

Please examine the SS-100 module. N ote that there are letters on the foil side that designate the
leads to be connected. The “C” and “D” le ad s will be co nn ec ted to th e sw itche d p ow er inpu t. The “A” and
“B” leads will be connected to the load. A RED wire between pads “C” and “D” (user supplied) is connected
to the neutral or return of the input power line. Refer to the schematic below. The module will be mounted
using silicone adhesive relay side to the chassis.

The overa ll ope ration is qu ite simpl e. W hen the pow er switch in turned ON , 240 volts is ap plied to
the load through a 20Ω 10W resistor in each side of the line. The voltage at the load is measured by the
diode connected to pad “A”. As the filter capacitors and other components charge or stabilize in current
drain, the voltage at pad “A” rises. When this voltage reaches approximately 90 volts, the two relays are
activated, shorting out the 20Ω resis tors. Now the power circuit is back to its full power state and the soft
start circuit is locked out of operation.

120-VOLT OPERATION

If this circuit is to be installed in equipment operating from 120-volt AC power lines, a modification
must be made. The 20Ω 10W resistors must be changed to 10Ω 10W . These resistors are readily available
at any electronic store. However, if the soft start is used with equipment running on less than 120 volts, the
resistors probably do not need to be changed.

NOTE: If only one sid e of th e inpu t pow er line is s witch ed, be su re tha t th e sw itched lea d is
on the “C to A” side of the soft star t circuit.

PARTS LIST

D1 1N4005 (1A 600 PIV)
K1 & K2 SPDT 12A 48VDC
R1 & R2 20Ω 10W
(240VAC)
R1 & R2 10Ω 10W
(120 VAC)
R3 2400Ω 2W 5%
C1 & C2 100µF 63VDC

HARBACH ELECTRONICS

Jeff Weinberg – W8CQ

468 County Road 620

Polk, OH 44866-9711

[phone]

htt p://ww w.harbachelect ronics.com

info@harbachelect roni cs. com

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