Elenco Resistor Substitution Box - Manual (Page 7)

-6-
r Installation of Knobs without an Ohmmeter
If an ohmmeter is not available, turn both switches
so that the wiper contact is in the position shown in
Figure 5. Start with switch SW1, follow the copper
run on the PC board from the lug in contact with the
wiper to the 470
Ω (R7) resistor, to be sure that the
switch is set in the proper position. Align the knob
on the SW1 (
Ω) switch to the 470 position, push the
knob onto the shaft. Follow the same procedure for
switch SW2 (K
Ω), except follow the copper run to
the 6.8K
Ω (R13) resistor. Align the knob on the
SW2 (K
Ω) switch to the 6.8 position.
TESTING THE CIRCUIT
SCHEMATIC DIAGRAM
SW1
Ω POSITION
Value Position Meter Reading
10
Ω
22
Ω
47 Ω
100
Ω
220
Ω
330
Ω
470 Ω
680
Ω
1000
Ω
2200 Ω
3300 Ω
4700
Ω
SW2 K
Ω POSITION
Value Position Meter Reading
6.8K
Ω
10K
Ω
22K Ω
33K
Ω
47K
Ω
68K
Ω
100K Ω
220K
Ω
330K
Ω
470K Ω
680K Ω
1M
Ω
Figure 5
Wiper Contact
Lug PC Board
The following test is to be made with your meter to determine that the resistors are in their correct circuit
positions. The resistors used in your circuit are gold banded with a tolerance of +5%. That means that a 10k
Ω
resistor could measure between 9,500
Ω and 10,500Ω and be correct. Each of the 24 resistance value positions
will be tested and recorded in the chart below.