Hafler DH-200, Assembly And Operating Instructions Manual

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Wiring the Kit Mechanical Assembly
If any components are unfamiliar to you, checking the
pictorial diagram should quickly identify them. Or, the quan­
tities, and the process of elimination as you check the parts
list, will help. The pictorial diagram is necessarily distorted
to some extent for clarity, so that you can trace every wire in
a single overall view for verification as you work. You may
wish to check off on the diagram as you solder each location.
To "prepare" a wire means to cut the designated length
from the coil of that color, and strip about 1/4" of insulation
from each end. The wire supplied in the kit is #18, so you
can set adjustable wire-strippers accordingly. The
transformer leads are #16 or 18, and the line cord is #18.
Be careful that you do not nick the wire when you strip it
(that can happen more easily if you do not use wire strippers)
for that weakens it. The wire supplied in this kit is "bonded
stranded," which provides exceptional flexibility with resis­
tance to breakage for easier use.
Whenever a connection is to be soldered, the instructions
will so state, or indicate by the symbol (S). If more than one
wire is to be soldered to the same point, they will be indi­
cated by (S-2), (S-4), etc. If soldering is not called for, other
connections have yet to be made to that terminal. They
would be more difficult if the connection was already
soldered. Every connection in the kit will be soldered when
it is complete. After soldering a connection, it is best to clip
off any excess lead length to minimize the possibility of a
short circuit (as on switch lugs, where terminals are very
close together), and for neatness.
Be sure that uninsulated wires cannot touch adjacent ter­
minals or the chassis metalwork.
The symbol (#) indicates a connection is to be made to
that point. When a lug number is specified without (#), it is
simply a locating reference.
When the instructions call for twisting two or three wires
together, the length of wire indicated anticipates a fairly
tight, uniform twist by hand, of three full turns every two in­
ches. If you find the wires too short, loosening the twist will
gain some needed length.
Handle the circuit boards carefully. They represent a ma­
jor part of the kit cost. Stand-up components, such as transis­
tors, should be checked when you install the module, to be
sure all leads are separated.
All of the active circuitry is contained on the PC-6 board,
which has been carefully tested to assure that it meets every
specification. Only the interconnection of power supply ele­
ments is left to the builder. Take the time to be accurate and
neat, and you can be sure that your completed amplifier will
meet the performance of a factory assembled unit, and can
continue to perform properly for years to come. Check your
work, and make sure the entire step has been completed
before placing a check mark in the space provided, and con­
tinuing on to the next step.
KEP nuts have been supplied as a convenience. These
have lockwashers attached, and the lockwasher always goes
onto the screw first. If the sheet metal screws have hex heads,
you may find it easier to first start them with a regular
screwdriver, to set the thread, and then use the more con­
venient nut driver, if one is available.
1 • When you unpack your kit, you will find that the
transformer, large capacitors, and the output assem­
blies have been temporarily fastened to the chassis for
safe shipment. Disengage these, and include this hard­
ware with the rest when you check off the components
against the parts list in the back of the manual. We
recommend this check-off to be sure you have every­
thing, and to enable you to identify any unfamiliar
items by comparing them with the pictorial diagram.
An egg carton is ideal for keeping hardware items sepa­
rated.
A "set" of hardware includes one screw and one KEP nut
(with its attached lockwasher). Always install the lockwasher
side of the nut first. If the size of the hardware is not
specified, use the #6 size. The smallest size is #4 and #10
the largest. Always insert the screw from the outside of the
chassis.
It will simplify matters if you first separate the #4 nuts from
the #6 nuts, which have the same outside dimensions. A #4
screw will pass through a #6 nut, aiding identification.
2 • Select the four rubber feet, four sets of hardware, and
the chassis. Insert each screw through a foot so that the
head is recessed, and install the feet on the outside at
each corner hole.
3 • Select the two red output terminals. Install them in the
sequence shown below, in the two center holes R2 and
R3 at the rear of the chassis. Before you fully tighten
the first nut, unscrew the cap to expose the hole drilled
through the threaded shaft. Connection of loudspeaker
wires will be easier if these holes are positioned ver­
tically. A nail through the hole will keep it positioned
while the hardware is tightened. Each connecting lug
should point downward before the last nut is secured.
Be sure both nuts on each terminal are tight, as they
are difficult to reach when the amplifier is completed.
4 • Select the two black output terminals and install them
on either side of the red ones, at B l and B4. Be sure the
shaft holes are vertical, the lugs point downward, and
each nut is tight.
5 • Select the two round fuse holders, and two each 1/2"
rubber washers, lockwashers and nuts. First install the
rubber washer on the holder, so it will be outside the
chassis, and then fasten the fuse holders at L F and RF,
with the tip lugs pointing away from each other, toward
the edge of the chassis.
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