Philips 241B4LPCS/00 Service Manual page 81

241 4L LC
3. Lead-free product identification
You can identif lead-free product b Philips-lead-free lo o on PCB.
4. Lead-free product repair instruction
4.1 Use onl lead-free Solder Allo 0622 149 00106(1.2mm SAC305) or 0622 14900108(1.0mm SAC305).
Remark For lead free solderin material please visit www.alphametals.com website for details. This is recommended b Philips.
4.2 Use onl ade uate solder tools applicable for lead-free solderin -tin. The solder tool must be able to reach at least a solder-temperature of 400 to
stabili e the ad usted temperature at the solder-tip and to e chan e solder-tips for different applications.
Small Passives/Actives to be removed with thermal twee ers
Automated s stem for IC and BGA repair (Microscope Camera Beam split optics Computer Pro rammer Heat controllers Vacuum s stem Laser
pointer) Solder Hand-Tool (Ad ustable in temperature hei ht Temperature shall be held constant Fle ible tips)
4.3 Ad ust our solder tool so that a temperature around 360 -380 is reached and stabili ed at the solder oint.
Heatin -time of the solder- oint should not e ceed 4 sec. Avoid temperatures above 400 otherwise wear-out of tips will rise drasticall and flu -fluid will
be destro ed. Corrosion of Tool-Spikes can be avoided when usin SAC305 and a temperature of less than 400.
4.4 Mi of lead-free solder-tin/parts with leaded solderin -tin/parts is possible but not recommended. If not to avoid clean carefull the solder- oint from old
tin and re-solder with new tin.
4.5 Use onl ori inal spare-parts listed in the Service-Manuals. Standard-material (consumables) can also be purchased at e ternal companies.
4.6 Special information for lead-free BGA-ICs this ICs will be delivered in so-called dr -packa in to protect the IC a ainst moisture and with lead-free
lo o on it. This packa in ma onl be opened shortl before it is used (soldered). Otherwise the bod of the IC ets wet inside and durin the heatin
time the structure of the IC will be destro ed due to hi h (steam-) pressure. If the packa in was opened before usa e the IC has to be heated up for
some hours (around 90 ) for dr in (Take attention for ESD-protection )
5. Rework on BGA (Ball Grid Arra ) ICs
General
Althou h (LF)BGA assembl ields are ver hi h there ma still be a re uirement for component rework. B rework we mean the process of removin
the component from the PWB and replacin it with a new component. If an (LF) BGA is removed from a P WB the solder balls of the component are
deformed drasticall so the removed (LF)BGA has to be discarded.
Device Removal
As is the case with an component that it is essential when removin an (LF) BGA the board tracks solder lands or surroundin components are not
dama ed. To remove an (LF)BGA the board must be uniforml heated to a temperature close to the reflow solderin temperature. A uniform temperature
reduces the chance of warpin the PWB.
To do this we recommend that the board is heated until it is certain that all the oints are molten. Then carefull pull the component off the board with a
vacuum no le. For the appropriate temperature profiles see the IC data sheet.
Area Preparation
When the component has been removed the vacant IC area must be cleaned before replacin the (LF) BGA. Removin an IC often leaves var in
amounts of solder on the mountin lands. This e cessive solder can be removed with either a solder sucker or solder wick. The remainin flu can be
removed with a brush and cleanin a ent. After the board is properl cleaned and inspected appl flu on the solder lands and on the connection balls of
the (LF)BGA
Note Do not appl solder paste as this has shown to result in problems durin re-solderin .
Device Replacement
The last step in the repair process is to solder the new component on the board. Ideall the (LF) BGA should be ali ned under a microscope or
ma nif in lass. If this is not possible tr to ali n the (LF)BGA with an board markers. To reflow the solder appl a temperature profile accordin to
the IC data sheet. So as not to dama e nei hbourin components it ma be necessar to reduce some temperatures and times.
More Information
For more information on how to handle BGA devices visit this URL http //www.at ourservice.ce.philips.com (needs subscription). After lo in select
Ma a ine then o to Workshop Information. Here ou will find Information on how to deal with BGA-ICs.