Sharp r-8580 manual Procedure Letter

R-8680

PROCEDURE

LETTER

TEST PROCEDURES (CONT’D)

COMPONENT TEST

3.Water container should be one (1) litre beaker made of Pyrex glass and its diameter approxi- mately 12 cm.

4.Room temperature should be around 20 “C.

5.Power supply voltage should be specification voltage.

POWER TRANSFORMER TEST

DISCHARGE THE HIGH VOLTAGE CAPACITOR BEFORE TOUCHING ANY OVEN COMPO- NENTS OR WIRING.

Disconnect the primary input terminals and measure the resistance of the transformer with an ohmmeter. Check for continuity of the coils with an ohmmeter. On the R x 1 scale, the resistance of the primary coil should be approx. 1.6 ohm and the resistance of the high voltage coil should be approximately 74 ohms; the resistance of the filament coil should be less than 1 ohm.

(HIGH VOLTAGES ARE PRESENT TO HIGH VOLTAGE TERMINAL, SO DO NOT ATTEMPT TO MEASURE THE FILAMENT AND HIGH VOLTAGE.)

C HIGH VOLTAGE RECTIFIER AND RECTIFIER TEST

DISCHARGE THE HIGH VOLTAGE CAPACITOR BEFORE TOUCHING ANY OVEN COMPO- NENTS OR WIRING.

HIGH VOLTAGE RECTIFIER TEST

Isolate the high voltage rectifier from the circuit. Using the highest ohm scale of the meter read the resistance across the terminals and observe, reverse the leads to the high voltage rectifier terminals and observe meter reading. If a short is indicated in both directions, or if an infinite resistance is read in both directions, the high voltage rectifier is probably defective and should be replaced.

RECTIFIER TEST

Isolate the rectifier from the circuit. Using the highest ohm scale of the meter, read the resistance across the terminals, reverse the leads to the rectifier terminals and observe meter reading. If an infinite resistance is read in both directions, the rectifier is good.

If a short is indicated in either direction, the one is probably defective and should be replaced.

D HIGH VOLTAGE CAPACITOR TEST

DISCHARGE THE HIGH VOLTAGE CAPACITOR BEFORE TOUCHING ANY OVEN COMPO- NENTS OR WIRING.

If the capacitor is open, no high voltage will be available to the magnetron. Disconnect input leads and check for short or open, between the terminals using an ohmmeter.

Checking with a high ohm scale, if the high voltage capacitor is normal, the meter will indicate

continuity	for	a short	time	and	should indicate	approximately	IOM R	once the capacitor is
charged.	If the	above	is not	the	case, check the	capacitoi’with	an ohmmeter	to see if it is shorted
between the terminals. If it is shorted, replace the capacitor.
								(RD82603U)
E					SWITCH	TEST

Isolate the switch and check the contacts by using an ohmmeter using the following table. If improper operation is indicated, make the necessary switch adjustment or replacement.

			Table:	Switch	Connection
Connection		Common Terminal-Normally		Open	Terminal	Common Terminal-Normally Close Terminal
Operation		(COM)		(NO)		(COW	(NC)
Plunger	released	Open	circuit			Close	circuit
Plunger	pushed	Closed	circuit			Open	circuit
							(RD82701U)

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