Toshiba TX79 Series User Manual page 33

(1) Lead insertion hole intervals on the printed circuit board should match the lead pitch of the
device precisely.
(2) If lead insertion hole intervals on the printed circuit board do not precisely match the lead
pitch of the device, do not attempt to forcibly insert devices by pressing on them or by pulling
on their leads.
(3) For the minimum clearance specification between a device and a
printed circuit board, refer to the relevant device's datasheet and
databook. If necessary, achieve the required clearance by forming
the device's leads appropriately. Do not use the spacers which are
used to raise devices above the surface of the printed circuit board
during soldering to achieve clearance. These spacers normally
continue to expand due to heat, even after the solder has begun to solidify; this applies severe
stress to the device.
(4) Observe the following precautions when forming the leads of a device prior to mounting.
•
Use a tool or jig to secure the lead at its base (where the lead meets the device package) while
bending so as to avoid mechanical stress to the device. Also avoid bending or stretching device
leads repeatedly.
•
Be careful not to damage the lead during lead forming.
•
Follow any other precautions described in the individual datasheets and databooks for each
device and package type.
3.5.2 Socket mounting
(1) When socket mounting devices on a printed circuit board, use sockets which match the
inserted device's package.
(2) Use sockets whose contacts have the appropriate contact pressure. If the contact pressure is
insufficient, the socket may not make a perfect contact when the device is repeatedly inserted
and removed; if the pressure is excessively high, the device leads may be bent or damaged
when they are inserted into or removed from the socket.
(3) When soldering sockets to the printed circuit board, use sockets whose construction prevents
flux from penetrating into the contacts or which allows flux to be completely cleaned off.
(4) Make sure the coating agent applied to the printed circuit board for moisture-proofing
purposes does not stick to the socket contacts.
(5) If the device leads are severely bent by a socket as it is inserted or removed and you wish to
repair the leads so as to continue using the device, make sure that this lead correction is only
performed once. Do not use devices whose leads have been corrected more than once.
(6) If the printed circuit board with the devices mounted on it will be subjected to vibration from
external sources, use sockets which have a strong contact pressure so as to prevent the
sockets and devices from vibrating relative to one another.
3.5.3 Soldering temperature profile
The soldering temperature and heating time vary from device to device. Therefore, when
specifying the mounting conditions, refer to the individual datasheets and databooks for the
devices used.
3 General Safety Precautions and Usage Considerations
3-12