R-22AMM (serv.man5). Function Of Important Components - Sharp Home Appliance Service Manual (repair manual)

r-22amm (serv.man5) service manual
Model
R-22AMM (serv.man5)
Pages
2 Few pages! See other manuals at the bottom of the first or last page.
Size
106.51 KB
Type
PDF
Document
Service Manual
Brand
Device
Home Appliance / Microwave Oven / Function Of Important Components
File
r-22amm-sm5.pdf
Date

Read Sharp R-22AMM (serv.man5) Service Manual online

R22AMM
5 – 1
R22AMM
Service Manual
 
CHAPTER 5. 
FUNCTION OF IMPORTANT COMPONENTS
[1] DOOR OPEN MECHANISM
1. The door release lever is pulled.
2. The upper latch head is lifted up by the linked door release lever.
3. The head lever is lifted up by the door release lever.
4. The joint lever is lifted up by the head lever.
5. The lower latch head is lifted up by the joint lever.
6. Now both latch heads are lifted up, so they can be released from
the latch hook.
7. Now the door can be opened.
Figure D-1. Door Open Mechanism
[2] SWITCHES
1. INTERLOCK SWITCHES (SW1 & SW2) AND STOP
SWITCH (SW5)
1. When the oven door is closed, the contacts COM-NO must be
closed.
2. When the oven door is opened, the contacts COM-NO must be
opened.
2. MONITOR SWITCHES (SW3 & SW4)
The monitor switches (SW3, SW4) are activated (the contacts opened)
the upper latch head and switch lever A while the door is closed. The
switch (SW3 or SW4) is intended to render the oven inoperative by
means of blowing the fuse (F1 F10A or F2 F10A) when the contacts of
the interlock switch (SW1 or SW2) fail to open when the door is
opened.
Function
1. When the door is opened, the monitor switches SW3 +SW4 con-
tacts close (to the ON condition) due to their being normally closed.
At this time the interlock switch (SW1+SW2) are in the OFF condi-
tion (contacts open) due to their being normally open contact
switches.
2. As the door goes to a closed position, the monitor switches
SW3+SW4 contacts are opened and interlock switch (SW1+SW2)
contacts are closed (On opening the door, each of these switches
operate inversely.)
3. If the door is opened and the interlock switch SW1 (or SW2) con-
tacts fail to open, the fuse F1 F10A (or F2 F10A) blows simulta-
neously with closing of the monitor switch (SW3 or SW4) contacts.
CAUTION: BEFORE REPLACING A BLOWN FUSE (F1 F10A OR F2
F10A) TEST THE INTERLOCK SWITCH (SW1 OR SW2)
AND MONITOR SWITCHE (SW3 OR SW4) FOR PROPER
OPERATION. (REFER TO CHAPTER “TEST PROCE-
DURE”).
[3] NOISE FILTER
The noise filter assembly prevents radio frequency interference that
might flow back in the power circuit.
[4] FUSES
1. FUSES F10A 250V (F1, F2)
1. If the wire harness or electrical components are shortcircuited, this
fuse blows to prevent an electric shock or fire hazard.
2. The fuse F10A (F1 or F2) also blows when interlock switch (SW1 or
SW2) remains closed with the oven door open and when the moni-
tor switches (SW3 or SW4) closes.
2. WEAK POINT A017 (F3)
If the wire harness or electrical components make a shortcircuit, this
weak point F3 blows to prevent an electric shock or fire hazard.
3. WEAK POINT (FFS-GA014)
If the oven lamp, touch control transformer or control unit make a
shortcircuit, this weak point blows to prevent an electric shock or fire
hazard.
4. HIGH VOLTAGE FUSES (F4, F5)
The high voltage fuse blows when the high voltage rectifier or the mag-
netron is shorted.
5. MAGNETRON TEMPERATURE FUSES (TF1, TF2)
The temperature fuses (TF1, TF2) located on the top of the upper and
lower waveguide, are designed to prevent damage to the magnetrons
(MG1, MG2). If an over heated condition develops in the tube due to
blower motor failure, obstructed air ducts, dirty or blocked air intake,
etc., the circuit to the magnetrons are interrupted. Under normal oper-
ation, the temperature fuses remains closed. However, when abnor-
mally high temperatures are generated within the magnetrons, the
temperature fuses will open at 150
°C causing the microwave energy
to stop. The defective temperature fuses must be replaced with new
rated ones.
6. EXHAUST TEMPERATURE FUSE (TF3)
The temperature fuse (TF3), located on the side of the exhaust duct
assembly, is designed to prevent damage to the oven by fire. If the
food load is overcooked, by either error in cook time or defect in the
control unit, the temperature fuse will open. Under normal operation,
the oven temperature fuse remains closed. However, when abnormally
high temperatures are generated within the oven cavity, the oven tem-
perature fuse will open at 120
°C, causing the oven to shut down. The
defective temperature fuse must be replaced with new rated one.
Latch head
SW4: Monitor switch
(Oven side)
SW3: Monitor switch
Latch hook
SW1: Interlock switch
SW2: Interlock switch
(Oven side)
SW5: Stop switch
Latch head
Joint lever
Door release
lever
Head lever
R22AMM
5 – 2
[5] THERMISTORS
1. EXHAUST OVEN THERMISTOR (TH3)
The thermistor is a negative temperature coefficient type. The temper-
ature in the exhaust duct is detected through the resistance of the ther-
mistor. 
If the temperature is high, the control panel will display “EE7” and the
oven will stop to avoid overheating and catching fire. 
If the thermistor is open, the control panel will display “EE6” and the
oven will stop.
2. MAGNETRON THERMISTORS (TH1, TH2)
The thermistor is a negative temperature coefficient type. The air tem-
perature around the magnetron is detected through the resistance of
the thermistor.
If the temperature is high, the control panel will display “EE17” and the
oven will stop to protect the lower magnetron against overheat.
If the magnetron thermistor is open, the control panel will display
“EE16” and the oven will stop.
If the magnetron thermistor is short, the control panel will display
“EE19” and the oven will stop.
[6] MOTORS
1. BLOWER MOTOR (BM)
The blower motor (BM) drives a blade which draws external cool air
into the oven. This cool air is directed through the air vanes surround-
ing the magnetrons and cools the magnetrons. This air is channelled
through the oven cavity to remove steam and vapours given off from
the heating foods. It is then exhausted through the exhausting air
vents at the oven cavity.
2. ANTENNA MOTORS (SM)
The upper and lower antenna motors (SM) drive stirrer antennas.
[7] OVEN LAMP
The oven cavity light illuminates the interior of the oven so that food
being cooked can be examined visually through the door window with-
out having to open the door. The oven lamp is on during the cooking
cycle and idle condition.
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Here you can read online and download Sharp R-22AMM (serv.man5) Service Manual in PDF. R-22AMM (serv.man5) service manual will guide through the process and help you recover, restore, fix, disassemble and repair Sharp R-22AMM (serv.man5) Microwave Oven. Information contained in service manuals typically includes schematics / circuit diagrams, wiring diagrams, block diagrams, printed wiring boards, exploded views, parts list, disassembly / assembly, pcb.