Sharp R-230HW User Manual

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R-203HW

R-220HW

R-230HW

OPERATION

DESCRIPTION OF OPERATING SEQUENCE

The following is a description of component functions during

oven operation.

OFF CONDITION

Closing the door activates door sensing switch and second-

ary interlock switch. (In this condition, the monitor switch

contacts are opened.)

When oven is plugged in, 120 volts A.C. is supplied to the

control unit. (Figure O-1).

1. The display will show flashing "88:88".

2. To set any program or set the clock, touch the STOP/

CLEAR pad. The display will clear, and " : " will appear.

COOKING CONDITION

Program desired cooking time by touching the NUMBER

pads. And program the power level by touching the POWER

LEVEL pad.

When the START pad is touched, the following operations

occur:

1. The contacts of the relays are closed and components

connected to the relays are turned on as follows.

(For details, refer to Figure O-2)

RELAY CONNECTED COMPONENTS

RY-1 oven lamp/turntable motor/fan motor

RY-2 power transformer

2. 120 volts A.C. is supplied to the primary winding of the

power transformer and is converted to about 3.35 volts

A.C. output on the filament winding, and approximately

2000 volts A.C. on the high voltage winding.

3. The filament winding voltage heats the magnetron

filament and the H.V. winding voltage is sent to a voltage

doubler circuit.

4. The microwave energy produced by the magnetron is

channelled through the waveguide into the cavity feed-

box, and then into the cavity where the food is placed to

be cooked.

5. Upon completion of the cooking time, the power

transformer, oven lamp, etc. are turned off, and the

generation of microwave energy is stopped. The oven

will revert to the OFF condition.

6. When the door is opened during a cook cycle, monitor

switch, door sensing switch, secondary interlock switch

and primary interlock relay are activated with the following

results. The circuits to the oven lamp, turntable motor,

the cooling fan motor, and the high voltage components

are de-energized, and the digital read-out displays the

time still remaining in the cook cycle when the door was

opened.

7. The monitor switch is electrically monitoring the operation

of the secondary interlock switch and primary interlock

relay (RY2) and is mechanically associated with the door

so that it will function in the following sequence.

(1) When the door opens from the closed position, the

secondary interlock switch, door sensing switch and

primary interlock relay (RY2) open their contacts. Then

the monitor switch contacts close.

(2) When the door is closed from the open position, the

monitor switch contacts open first. Then the contacts

of the secondary interlock switch and door sensing

switch close.

If the secondary interlock switch and primary interlock relay

(RY2) fail with the contacts closed when the door is opened,

the closing of the monitor switch contacts will form a short

circuit through the C/T fuse, primary interlock relay (RY2)

and secondary interlock switch, causing the C/T fuse to

blow.

POWER LEVEL COOKING

When Variable Cooking Power is programmed, the 120

volts A.C. is supplied to the power transformer intermittently

through the contacts of relay (RY-2) which is operated by

the control unit within a 32 second time base. Microwave

power operation is as follows:

VARI-MODE ON TIME OFF TIME

P-HI (100% power) 32 sec. 0 sec.

P-90 (approx. 90% power) 30 sec. 2 sec.

P-80 (approx. 80% power) 26 sec. 6 sec.

P-70 (approx. 70% power) 24 sec. 8 sec.

P-60 (approx. 60% power) 22 sec. 10 sec.

P-50 (approx. 50% power) 18 sec. 14 sec.

P-40 (approx. 40% power) 16 sec. 16 sec.

P-30 (approx. 30% power) 12 sec. 20 sec.

P-20 (approx. 20% power) 8 sec. 24 sec.

P-10 (approx. 10% power) 6 sec. 26 sec.

P-0 (0% power) 0 sec. 32 sec.

Note: The ON/OFF time ratio does not correspond with

the percentage of microwave power, because

approx. 3 seconds are needed for heating of the

magnetron filament.

POWER OUTPUT REDUCTION

If the oven is set for more than 20 minutes at 80, 90 or 100%

power level, after the first 20 minutes the power level will

automatically adjust itself to 70% power to avoid overcook-

ing.

Questions and Answers:

A
Alicia BrownAug 19, 2025
What to do if my Sharp R-230HW Microwave Oven produces little or no heat?
- T
  Timothy MichaelAug 19, 2025
  If your Sharp Microwave Oven appears to be running, but the food is not cooking or is only partially cooked, you should check or replace the power transformer.
R
Rachel StevensAug 21, 2025
What to do if my Sharp R-230HW isn't defrosting food properly?
- C
  Christine MaddoxAug 21, 2025
  If your Sharp Microwave Oven goes into DEFROST mode but the food is not defrosting well, you should check or replace the control unit or relay.
A
Amanda CooperAug 25, 2025
Why is my Sharp R-230HW heating food unevenly?
- J
  Julie HillAug 25, 2025
  If your Sharp Microwave Oven is cooking food unevenly, you should check or replace the magnetron.