Augustica
®
T e c h n o l o g i e s
Page 5 of 7
A
SSEMBLY
Cleanliness is essential. Before soldering, be sure to clean both sides the PCB with 70%
to 90% isopropyl alcohol. Do not use dull looking solder. Solder should shine. If it does
not shine, first clean away the outer oxidation with some steel wool or a copper-scouring
pad. If the resistor leads look in the least gray, clean away the oxidation with either steel
wool or a wire sniper’s sharp edges. Admittedly, with new resistors and a fresh PCB,
such metal dulling is rare, but if the parts have sat in your closet for a year or two, then
expect a good amount of oxidation to have developed.
Be consistent in orienting the resistors, capacitors and diodes. Keep nominal information
on a resistor's or capacitor's body flowing from the left side to the right side as you face
the resistor or the capacitor straight on. This will pay dividends later, if you need to locate
and de-solder a resistor, a capacitor, or a diode placed in a wrong location. Because the
board is double sided, with traces and pads on each side, it is easier to solder the resistors
from their topside. As the PCB is overbuilt, it is difficult to remove an incorrectly placed
part. Be sure to confirm all the electrolytic capacitor orientations, as a reversed polarized
capacitor can easily vent (or even explode) when presented with high-voltage. Confirm
trice, solder once.
Start with assembly of the high B-plus DC voltage bus of the power supply and first
attach the MOSFET transistor IC1 to its heatsink. This transistor is extremely sensitive to
electric static, therefore, you must use ESD safe soldering station and you also must ware
an ESD bracelet. Once you attached the MOSFET transistor to its heatsink, you can insert
heatsink leads and the MOSFET transistor leads into the PCB. Solder the leads of the
MOSFET transistor to the PCB. At this point do not solder the heatsink's leads to the
PCB - you will do it later.
Second, solder the rectifying bridge D1-D4 and capacitors C11, C12, C13, and C14. Pay
attention to the polarity of the rectifying bridge D1-D4. Solder terminal block K2.
Connect a transformer or variac to the terminal block K2 and slowly bring voltage to 220
Volt AC. Measure the high B-plus DC voltage produced by the rectifying bridge D1-D4.
If you applied 220 Volt AC to the rectifying bridge, after rectification you should obtain
about 320 Volt DC without any load.
Third, solder diodes D5 and D6 and then solder resistors R24 and R25 followed by
capacitors C15, C16, C17, C18, C19 and C20. Now solder red LED D7 and resistors R26
and R27. Connect a transformer or variac to the terminal block K2 again and slowly bring
voltage to 220 Volt AC. Measure the high B-plus DC voltage produced by the high
voltage bus of the power supply as a whole. If you applied 220 Volt AC to the terminal
block K2, the power supply should deliver about 320 Volt DC without any load. Measure
AC component that is present in the DC voltage after it is regulated and filtered by the
MOSFET transistor IC1. The AC component of the high B-plus DC voltage should
fluctuate between 2 millivolts and 20 millivolts AC. If your measurements show
