Sharp R-21JV-F Service Manual page 25

1. Employing lead-free solder
The "Main PWB" of this model employs lead-free solder. This is indicated by the "LF" symbol printed on the PWB and in the
service manual. The suffix letter indicates the alloy type of the solder.
Example:
2. Using lead-free wire solder
When repairing a PWB with the "LF" symbol, only lead-free solder should be used. (Using normal tin/lead alloy solder may
result in cold soldered joints and damage to printed patterns.)
As the melting point of lead-free solder is approximately 40˚C higher than tin/lead alloy solder, it is recommend that a dedicated
bit is used, and that the iron temperature is adjusted accordingly.
3. Soldering
As the melting point of lead-free solder (Sn-Ag-Cu) is higher and has poorer wettability, (flow), to prevent damage to the land
of the PWB, extreme care should be taken not to leave the bit in contact with the PWB for an extended period of time. Remove
the bit as soon as a good flow is achieved. The high content of tin in lead free solder will cause premature corrosion of the
bit. To reduce wear on the bit, reduce the temperature or turn off the iron when it is not required.
Leaving different types of solder on the bit will cause contamination of the different alloys, which will alter their characteristics,
making good soldering more difficult. It will be necessary to clean and replace bits more often when using lead-free solder.
To reduce bit wear, care should be taken to clean the bit thoroughly after each use.
PROCEDURE FOR CHECKING/CLEARING SERVICE COUNTS OF MICROWAVE OVEN
The following procedure enables the servicer to obtain the total
using times (cook cycles) since the microwave oven is pur-
chased and the total operation time (hours) since the micro-
wave oven is purchased. The maximum capacity of the total
using is 999,999 times, and the maximum capacity of total
operation time is 999,999 hours.
1) Practice for checking total using times (Ex. 345678 times).
... Flashing /
PAD DISPLAY
(Door close)
CHECK
CHECK #1 82 68
(user total count)
#2
SIGNAL
SIGNAL
DOUBLE 34 56
QUANTITY
(service total count upper figure)
3456XX
1 (No 1)
(after 1 sec.) 34 56
(service total count upper figure)
2 (No 2)
(after 1 sec.)
(service total count lower figure)
CHECK
PRECAUTIONS FOR USING LEAD-FREE SOLDER
Sn-Ag-Cu
Indicates lead-free solder of tin, silver and copper.
... 0.1sec BUZZER
INDICATOR PHONE
.
.
. CHECK No.
CHECK
1 No.
2 No.
78
.
2) Practice for checking total operation time (Ex. 4567 hours).
PAD
(Door close)
CHECK
CHECK #1
(user total count)
#2
SIGNAL
SIGNAL
DOUBLE
QUANTITY
(service total count upper figure)
3456XX
9 (No 9)
(after 1 sec.)
(Total operation time upper figure)
0 (No 0)
(after 1 sec.)
(Total operation time lower figure)
CHECK
23
... Flashing / ... 0.1sec BUZZER
DISPLAY INDICATOR PHONE
.
.
. CHECK No.
82 68 CHECK
34 56
9 No.
45
0 No.
67
.
R-21HT-F
R-21JV-F