1960 SERVICE MANUAL
SERVICE NOTES
1. When replacing parts or circuit boards, clamp the lead wires around the terminals
before soldering.
2. When replacing a high wattage resistor ( >0.5 W metal oxide film resistor) in the
circuit board, keep the resistor about 1 cm (1/2") away from the circuit board.
3. Keep wires away from high voltage or high temperature components.
4. Keep wires in their original positions so as to minimize inteference.
SAFETY TEST
Before returning a serviced monitor to the customer, a thorough safety test must be
performed to verify that the monitor is safe to operate without danger of shock.
Always perform an AC current leakage check on the exposed metallic parts, such as
screw heads, as follows:
1. Plug the AC line cord directly into a rated AC. Do not use a Line Isolation
Transformer during this check).
2. Use an AC voltmeter having at least 5000 ohms per volt sensitivity as follows:
Connect a 1500 ohms 10 watt resistor, paralleled by a 0.15mfd, AC type capacitor
between a known good earth ground (such as a water pipe or conduit etc.) and the
exposed metallic part simultaneously. Measure the AC voltage across the
combination of 1500 ohms resistor and 0.15mfd capacitor.
3. Reverse the AC plug at the AC outlet and repeat the steps for AC voltage
measurements for each exposed metallic part.
4. Voltage measured must not exceed 0.3 volts RMS. This corresponds to 0.2
milli-amps AC. Any value exceeding this limit constitutes a potential shock hazard
and must be corrected immediately.
To good earth ground
To exposed metallic
/ Part
1500 ohm
10 watt
5
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