31 Troubleshooting

3-2. GENERAL. When troubleshooting, use all of the aids included in this handbook: block diagram (figure 3-1), overall schematic (figure 3-3), amplifier schematic (figure 5-10), illustrations of components (figures 1-4, 1-5, and 3-2), stage (as shown in schematic, figure 3-3). Make all capacitor checks with capacitor analyzer, if available. Always disconnect capacitors before making tests; otherwise the readings will be affected by a possible shunt circuit. Replace any capacitor which shows a deviation of 20 percent or more.

Figure 3—1. Block Diagram of C—3 Console with PR—40 Tone Cabinet

and the trouble shooting chart (reference paragraph 3-28). Before starting an elaborate test procedure, make a thorough visual inspection to locate the fault. Check for defective wiring, drops of solder, faulty connections, open resistors and capacitors, jammed tone wheels, etc.

3-3. TUBE TESTING. When the trouble is traced to a specific stage, test tubes in that stage. If tubes are satisfactory, make a point-to-point voltage check in accordance with paragraph 3-4.

3-4. VOLTAGE AND RESISTANCE MEASUREMENTS. Make voltage and resistance measurements on the individual components of the

Switch Assembly

3-5. RESISTORS. Resistors used in Hammond Organs are marked with the standard EIA (Electronic Industries Association) color code, as shown in Table II. In this code, the body color or first color ring (starting from the outside edge) indicates the first digit of the resistor value. The second ring denotes the second digit, aad the third ring represents the number of zeros after the second digit. Thus a resistor marked with brown, green,- and yellow rings (in that order) would have a value of 150,000 ohms. Gold and silver rings represent percentage tolerance, gold indicating 5 percent tolerance and silver indicating 10 percent tolerance. Replace

Hammond Organ Schematics

INDICATOR

INDICATOR

BLACK SIGNAL

YELLOW

SHIELD (GND) GREY

A.C. POWER

INDICATOR

A.C. POWER

6 POLE PLUG

A.C. POWER

6 POLE PLUG

rep Signal

BROWN _

INDICATOR

black signal

YELLOW SHIELD (GND)

GR6Y A.C. POWER

6 POLE. RECEPTACLE

6 CONDUCTOR CONSOLE-TO-CABINET CASLE

INDICATOR

BLACK

INDICATOR

BLACK

GROUND

5 POLE PLUG

INDICATOR

BLACK

SIGNAL NO CONNECTION

INDICATOR

BLACK

SIGNAL NO CONNECTION

a.c. power

GROUND

5 POLE PLUG

6 POLE RECEPTACLE

S CONDUCTOR CABINET-TO-CABINET,CONSOLE-TO-CABINET,OR AMPHFIER-TO-AMPL'FlER COUPLING CABLE WOt CATO R INDICATOR

GREEN-YELLOW TR. SIGNAL

GREEN-YELLOW TR. SIGNAL

GREEN-RED TR. 51GNAL

no connection

GREEN-RED TR. 51GNAL

no connection

GROUND GROUND

j POLE PLUS 5 POLE PLUG

3 CONDUCTOR CAftlNET-TO-CA8lNET OR| AMPLIF1ER-TO-AMPLIFIER SIGNAL CABLE

INDICATOR

GREEN-RED TR.

SIGNAL

NO CONNECTION

GREEN-RED TR.

SIGNAL

NO CONNECTION

INDICATOR

STANDARD ATTACHMENT PLUG FOR CONNECTION TO A.C. OUTLET

6 pole receptacle

2 CONDUCTOR AMPLIFIER POWER CORQ

INDICATOR

indicator

BLACK (SHIELDED) SIGNAL

INDICATOR

BLACK (SHIELDED) SIGNAL

A.C. POWER

BLUE A.C. POWER

NO CONNECTION

A.C. POWER

BLUE A.C. POWER

NO CONNECTION

a.c. power

OLACK (SHIELDED) SIGNAL

YELLOW 5H!ELD(6ND)

7 pole pl,ug

6 POLE RECEPTACLE

6 CONDUCTOR RE VE RBERATION-P RE AMPLIFIER-TP-POWER-AMPLIFIER COUPLING CAftLE

ALL VIEWS SHOW BACK OR CABLE SIDE OF CONNECTOR

Figure 2—2. Cable Connectors

resistors differing by as much as 30 percent from their rated values.

TABLE ÍI - RESISTOR COLOR CODE

O-Black

4-Yellow

1-Brown

5-Green

2-Red

6-Blue

8-Gray

3-Orange

7-Violet

9-White

3-6. COIL MEASUREMENTS. For the DC (direct current) resistance value of chokes and audio transformers, refer to the appropriate circuit diagram. An open winding in the choke or transformer will be indicated by no ohm-meter indication. Check the power and filament transformers by comparing their measured voltage with the voltages given in the circuit diagram. All voltage values are given for a 117-volt (or 234-volt) AC input. If the input voltage varies, a corresponding change will be noted.

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