Elenco 3 1/2 Digit Cap. / Trans. Kit - Manual (Page 21)

ASSEMBLE THE FOLLOWING COMPONENTS TO THE PC BOARD
-20-
IC Socket 14-pin
IC3 - LM324 Op-Amp IC
(see Figure M)
R45 - 150
Ω
1% 1/4W Res.
(brn-green-blk-blk-brn)
(see Figure I)
VR3 - 200
Ω
Pot
R47 - 11k
Ω
1% 1/4W Res.
(brn-brn-blk-red-brn)
(see Figure I)
R46 - 76.8k
Ω
1% 1/4W Res.
(violet-blue-gray-red-brn)
(see Figure I)
C14 - .01
μ
F (103) Mylar Cap.
R48 - 160k
Ω
1% 1/4W Res.
(brn-blue-black-orange-brn)
(see Figure I)
C15 - .01
μ
F (103) Mylar Cap.
D6 - 1N4001 Diode
D7 - 1N4001 Diode
(see Figure O)
R29 - 10
Ω
1% 1/4W Res.
(brn-blk-blk-gold-brn)
(see Figure I)
R24 - 900k
Ω
1% 1/4W Res.
(white-black-black-org-brown)
(see Figure I)
R25 - 90k
Ω
1% 1/4W Res.
(white-black-black-red-brown)
(see Figure I)
R26 - 9k
Ω
1% 1/4W Res.
(white-black-black-brn-brn)
(see Figure I)
R27 - 900
Ω
1% 1/4W Res.
(white-blk-blk-blk-brown)
(see Figure I)
R28 - 90
Ω
1% 1/4W Res.
(white-blk-blk-gold-brown)
(see Figure I)
h
FE
- Sockets - Install
these with no more than
0.4” of height from the PC
board to the top of the
sockets. Otherwise, the top
case will not fit together
properly with the bottom
case.
R49 - 220k
Ω
5% 1/4W Res.
R50 - 220k
Ω
5% 1/4W Res.
(red-red-yellow-gold)
(see Figure I)
D8 - 1N4001 Diode
D9 - 1N4001 Diode
(see Figure O)
Top Legend Side
Bottom Legend Side
Figure P
R43 - 4.3k
Ω
1% 1/4W Res.
(yellow-orange-blk-brn-brn)
(see Figure I)
R42 - 1.91k
Ω
1% 1/4W Res.
(brn-white-brn-brn-brn)
(see Figure I)
R40 - 39k
Ω
1% 1/4W Res.
R41 - 39k
Ω
1% 1/4W Res.
(orange-white-blk-red-brn)
(see Figure I)
R44 - 10k
Ω
1% 1/4W Res.
(brn-blk-blk-red-brn)
(see Figure P)
C13 - .01
μ
F (103) Mylar Cap.
C12 - .01
μ
F (103) Mylar Cap.
Figure O
Stand diode on end. Mount with
band as shown on the top legend.
D9
D8
D6
D7
Lay resistor flat against the PC
board.
0.4”
-15-
r Insert the four input sockets into the PC board
holes and then solder the sockets in place.
Apply enough heat to allow the solder to flow
around the input sockets (see Figure J). r Attach the LCD to the PC board using the two
2.5 x 8mm screws. Use the two top mounting
hole and lightly tighten the screws. The screws
will be removed to assemble the next section.
Voltage Test
1. Place the top label over the knob and turn the
range selector knob to the 20V position.
2. Connect the 9V battery to the battery snap
3. Connect the test leads (red lead to V
Ω
CAP and
black to COM). Turn the meter on by pressing the
power switch.
4. Using another meter of known accuracy,
measure a DC voltage less than 20V (such as a
9 volt battery). You will calibrate the kit meter by
measuring the same voltage source and
adjusting VR1 until the kit meter reads the same
as the accurate meter. When the two meters
agree, the voltage circuit is calibrated. Turn the
meter off and continue to the Current Test.
If the tests are not working, check components
R10 – R23, R30 – R33, VR1, and the transistor T2.
Current Test
1. Turn the range selector knob to the 200
μ
A
position.
2. Connect the test leads (red lead to
μ
A/mA and
black to COM).
3. Connect the kit meter and another meter of
known accuracy in series. Set the both meters in
the 200
μ
A position. Construct a circuit for a DC
current (for example 9V and a 47k
Ω
resistor for
190
μ
A) and measure the circuit. Both meters
should have close to the same readings. Check
the other DC current (2mA - 200mA) scales.
20A Scale
The 20A scale requires a circuit of 1 - 20 amps.
If the meter reads a higher current, resolder the
shunt wire so there is less space between the
shunt wire and the PC board. If the meter reads
a lower current, resolder the shunt wire so there
is more space.
If the meters do not agree, check the parts just
added. Do not readjust VR1 for this will change the
voltage reading set in step 1. If the tests are not
working, check for cold solder joints and part values.
4. Turn the meter off and remove the battery, top label,
and test leads DO NOT PROCEED TO SECTION C
WITHOUT YOUR INSTRUCTOR’S APPROVAL .
5. Remove two display mounting screws and
display by unscrewing the two mounting screws.
Testing Procedure
Bottom Legend Side
Figure J
Input Sockets
Socket
Solder
Figure K
2.5 x 7.5
Screws