Philips 20PFL4122/93 Service Manual page 5

Use only lead-free soldering tin Philips SAC305 with
order code 06622 149 00106.If lead-free solder paste
is required please contact the manufacturer of your
soldering equipment.In general,use of solder paste
within workshops should be avioded because paste is not
easy to store and to handle.
Use only adequate solder tools applicable for lead-free
soldering tin.The solder tool must be able:
-To reach a solder-tip temperature of at least 400 C.
-To stabilise the adjusted temerature at the solder-tip
-To exchange solder-tips for different applications.
Adjust your solder tool so that a temperature of around
360 C -380 C is reached and stablilised at the solder joint.
Heating time of the solder-joint should not exceed~4sec.
Aviod temperatures above 400 C,otherwise wear-out of tips
will increase drastically and flux-fluid will be destroyed.
To aviod wear-out of tips,switch"off" unused equipment or
reduce heat.
Mix of lead-free soldering tim/parts with leaded soldering
tin/parts is possible but PHILIPS recommends strongly to
avoid mixed regimes.If this cannot be avoided,carefully
clear the solder-joint from old tin and re-solder with new
tin.
Use only original spare -parts listed in the Service-Manuals.
Not listed standed material(commodities)has to be purchased
at external companies.
For sets produced before 1.1.2005,containing leaded
soldering tin and components,all needed spare parts will
be available till the end of the service period.For the
repair of such sets nothing changes
In case of doubt whether the board is lead-free or not(or
with mixed technologies),you can use the following method:
Always use the highest temperature to solder,when using
SAC305(see also instructions below).
De-solder thoroughly(clean solder joints to avoid mix of
two alloys).
2.3.4 Alternative BOM identification
In September 2005,Philips CE introduced a change in the way
the serial number(or production number,see Figure 2-1)is
composed.From this data on,the third digit in the serial number
(example:AG2B0335000005) indicates the number of the
2. Safety Instructions,Warnings and Notes
Alternativ BOM(bill of Materials used for producing the sepcific
model of TV set).It is possible that the same TV model on the
market is produced with e.g. Two different types of displays,
coming from two different O.E.M.s.
By looking at the third digit of the serial number,the serivce
technician can see if there is more than one type of B.O.M. Used
in theproduction of the TV set he is working with.He can used in
the Commercial type Version Number of the TV set
(e.g.20PFL4122/93),after which a screen will appear that gives
information about the number of alternative B.O.M.s used.
If the third digit of serial nuber contains the number 1(example:
AG1B0335000001),then there is only one B.O.M. Version of the
TV set on the market.If tje third digit is a 2(example:
AG2B033500001),then there are two different B.O.M.s.
Information about this is important for ordering the correct spare
parts!
For the third digit,the number 1....9 and the characters A.....Z can
be used,so in total:9 plus 26=35 different B.O.M.s can be indicated
by the third digit of the serial number.
2.3.5 Board Level repair(BLR) or Component Level Repair(CLR)
If a board is defective,consult your repair procedure to decide if
the board has to be exchanged or if it should be repaired on
component level.
If your repair procedure says the board should be exchanged
completely,do not solder on the degective board.Otherwise,it
cannot be returned to the O.E.M. Supplier for back charging!
2.3.6 Practical Service precautions
It makes sense to avoid exposure to electrical shock.
While some sources are expected to have a possible dangerous
impact,others of quite high potential are of limited current and are
sometimes held in less regard.
Always respect voltages.While some may not be dangerous in
themselves,they can cause unexpected reactions that are best
avoided.Before reaching into a powered TV set,it is best to test
the high voltage insulation.It is easy to do,and is a good service
precaution.
TPS 1.0A LA 5