Working with high voltages (110V/220V)
can be lethal. Work at your own risk. Soldering irons
are hot. Use caution.
1. Cutter Pliers
2. Long Nose Pliers
3. Soldering iron (adjustable temperature preferred),
or 25-30W soldering iron. (Do not use 100W soldering
4. Solder lead (60/40 or equivalent)
Step-by-Step Assembly Instructions:
If you bought the kit, all the onboard
PCB parts are already included, sorted, and labeled for
your convenience. Click here to order the PSU-4448 KIT.
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1. Solder components from the smallest/shortest
to the biggest/tallest component in that order. This
makes assembly easier.
2. Do not use too much solder lead. Use
just enough to make a good connection. The
PCB is plated-through hole, and molten solder lead will
flow into the hole to ensure a good connection. You don't
need globs of solder to make a good connection.
3. Work slowly and carefully, especially
if this is your first time. Double-check parts before
soldering them. It's easier to solder something in, that
to desolder them out (if you make a mistake).
4. If you make a mistake solder a part
in the PCB (example, wrong location, or wrong orientation/placement),
you will need a desoldering tool to suck the solder out
from the board. Even then, the part may not easily
get out. The easiest thing to do is to "sacrifice" the
part, cut the leads, use a long nose pliers to hold the
lead, heat the pad while pulling the leads out. Then
use a desoldering tool to open the hole. So as I said,
double check parts before committing to solder them.
Solder all resistors, and diodes to the
(2pcs) 220 ohms - RED-RED-BROWN
(1pc) 8.2K (8K2) - GRY-RED-RED
(1pc) 7.5K (7K5) - VIOLET-GRN-RED =
this is marked on the PCB as 7.68K
Note the orientation of the (4) diodes
on the board. The white band should all be on top.
Next, solder the 0.1uf capacitor. You may
need to open up the legs of the capacitors a bit to fit
in the holes.
They'll go into the PCB looking
Next, solder the bridge rectifier
W02G. Note the orientation of
the component and where the flat side is pointing.
Next, solder the (4) electrolytic capacitors.
(2pcs) of 10uf and (2pcs) of 1uf. You will need
to open up the legs of the 1uf a little bit to go into
This is what your PCB board should look
like at this point of the assembly. Note the capacitors.
Next, solder the (2) LM317 regulators to
the board. For aesthetics, make sure they're the same
height when you solder them. Also, note the orientation.
The flat side (heatsink mounting part) should be facing
towards the outside of the PCB.
The only thing remaining to do now is solder
the (2) big electrolytic capacitors.
TIP: The capacitors are snap-in type. So
when you put place them on the PCB, do a twisting motion.
When you solder the capacitor, the (-) leg of the capacitor
is tied to the ground plane of the PCB. The PCB copper
can suck the heat out of your soldering iron. So make
sure to bump up the temperature of your soldering iron
Solder AC1 and AC2 terminals of the board
to the SECONDARY windings of your power transformer. Apply
power to your power transformer, and measure that you're
getting 44V and 48V DC at the output of the PSU board.
Note: You may not measure EXACTLY get 44
and 48V due to component tolerances. But if it's of by
a few millivolts, you'd be fine. If you're measuring
something like 0V or 60V or higher, something is wrong
and most probably you have a short somewhere.
If everything checks out, then attach a
heatsink to each voltage regulator. I recommend you use
TO-220 insulators/spacers so there is no electrical connection
between the heatsink and the regulator. You can
also use TWO SEPARATE heatsinks, one for each regulator.
Just make sure the two heatsinks DO NOT touch each other.