and two
35mm
nuts.
4.
Refer to Fig.
75.
Mount the
LM3OQ
regulator and
heat sink on the PCB, using the hardware called
-
3
.
out in step 3.
Graymark
r8commends
the use of
heat sink compound on the surfaces of the
’
voltage regulators and heat sinks where they
4
.
contact each other. Be sure that the larger
machine screws
(35mm
diameter) are
us8d
to
-
5
.
fasten the
IC
and heat sink to the PCB. If you use
the smaller 3mm diameter screws for this
purpose, it is possible for the heat sink to short
to the
IC
leads.
5.
Solder the regulator leads to
the
PCB. Cut off any
excess lead length.
+5
VOLT
REGUMTOR
TEST
1.
Conn8ct
th8 808 power plug to a power outlet.
2.
Turn th8 808 power switch ON, wait 1
s8cond
-
6
.
and turn it
OFETouch
the components that were
installed in the construction steps that were just
completed. If any of these components are
warm, there is
sumething
wrong. Check the PCB
and components carefully, and consult with your
instructor if necessary.
Repeat
step 2, leaving
the
power ON for 5
s8conds
this time.
Rep8at
step 2 again, this time leaving the power
ON for 15
seconds.
If none of the components heated up in the
previous steps, power up the
808
again.
Measure the dc voltage between* test points
TPi
9 and
TP7.TPlQ
should
be
positive, and the
voltage should
be
between 4.6 and 5.4
Volts.
This range of voltages allows for the specified
output voltage tolerance (4.7 to 5.3 Volts), plus
approximately 2
%
measurement error.
lf
the
voltage is not in this range, check your work
carefully, and consult with your instructor if
n8cessarym
Turn OFF the 808 power switch and remove the
power plug from the power outlet.
FIG.
75
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