©2008 Hamtronics, Inc.; Hilton NY; USA. All rights reserved. Hamtronics is a registered trademark. Revised: 6/3/10
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may vary widely with setup; but levels given
are useful as a general guide.
REPAIRS.
If you need to unsolder and replace any
components, be careful not to damage the
plated through holes on the pc board. Do not
drill out any holes. If you need to remove sol-
der, use a solder sucker or solder wick. A
toothpick or dental probe can be used with
care to open up a hole.
If you need to replace a surface mount ic,
first be very sure it is damaged. Then, care-
fully cut each lead off the case with fine nose
cutters. Once the case is removed, individual
leads can be unsoldered and the board can be
cleaned up. Carefully position the new ic, and
tack solder the two opposite corner leads be-
fore any other leads are soldered. This allows
you to melt the solder and reposition the ic if
necessary. Once you are sure, the remaining
leads can be soldered. If you get a solder
short between leads, use a solder sucker or
solder wick to remove the excess solder.
If it becomes necessary to replace output
transistor Q6, you must unsolder the three
leads first from under the board. Then, care-
fully melt the solder holding the can to the top
of the board. This requires a very hot iron or a
hot air tool, and care must be taken to avoid
damaging the board. Once the transistor is
removed, a vacuum solder sucker can be used
to clean the excess solder off the ground
plane. Install the new output transistor flat
against the board, and solder the leads on the
bottom of the board. Then, solder the bottom
of the metal can to the pcb ground plane with
a continuous bead of solder flowing around
the can. (Soldering the can to the ground
plane is necessary to provide a low impedance
emitter ground and heatsinking; the transistor
is designed to be installed this way).
