Philips 170X7FB/00 Service Manual page 85

3. Lead-free product identification
You can identify lead-free product by Philips-lead-free logo on PCB.
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4. Lead-free product repair instruction
4.1 Use only lead-free Solder Alloy 0622 149 00106(1.2mm SAC305) or 0622 149
00108(1.0mm SAC305).
Remark: For lead free soldering material, please visit
details. This is recommended by Philips.
4.2 Use only adequate solder tools applicable for lead-free soldering-tin. The solder tool must be able to reach at least a
solder-temperature of 400 , to stabilize the adjusted temperature at the solder-tip and to exchange solder-tips for different
applications.
Small Passives/Actives to be removed with thermal tweezers
Automated system for IC and BGA repair (Microscope, Camera, Beam split optics, Computer, Programmer, Heat
controllers, Vacuum system, Laser pointer)
Solder Hand-Tool (Adjustable in temperature height, Temperature shall be held constant,
Flexible tips)
4.3 Adjust your solder tool so that a temperature around 360 -380
Heating-time of the solder-joint should not exceed ~ 4 sec. Avoid temperatures above 400
rise drastically and flux-fluid will be destroyed.
Corrosion of Tool-Spikes can be avoided when using SAC305 and a temperature of less than 400 .
4.4 Mix of lead-free solder-tin/parts with leaded soldering-tin/parts is possible but not recommended. If not to avoid clean
carefully the solder-joint from old tin and re-solder with new tin.
4.5 Use only original spare-parts listed in the Service-Manuals. Standard-material
(consumables) can also be purchased at external companies.
4.6 Special information for lead-free BGA-ICs: this ICs will be delivered in so-called
dry-packaging to protect the IC against moisture and with lead-free logo on it. This
packaging may only be opened shortly before it is used (soldered). Otherwise the
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body of the IC gets wet inside and during the heating time the structure of the IC
will be destroyed due to high (steam-)pressure. If the packaging was opened before
usage the IC has to be heated up for some hours (around 90 ) for drying (Take
attention for ESD-protection!)
5. Rework on BGA (Ball Grid Array) ICs
General
Although (LF)BGA assembly yields are very high, there may still be a requirement for component rework. By rework, we
mean the process of removing the component from the PWB and replacing it with a new component. If an (LF)BGA is
removed from a PWB, the solder balls of the component are deformed drastically so the removed (LF)BGA has to be
discarded.
Device Removal
As is the case with any component that, it is essential when removing an (LF)BGA, the board, tracks, solder lands, or
surrounding components are not damaged. To remove an (LF)BGA, the board must be uniformly heated to a temperature
close to the reflow soldering temperature. A uniform temperature reduces the chance of warping the PWB.
To do this, we recommend that the board is heated until it is certain that all the joints are molten. Then carefully pull the
component off the board with a vacuum nozzle. 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 replacing the (LF)BGA.
Removing an IC often leaves varying amounts of solder on the mounting lands. This excessive solder can be removed with
either a solder sucker or solder wick. The remaining flux can be removed with a brush and cleaning agent. After the board
is properly cleaned and inspected, apply flux on the solder lands and on the connection balls of the(LF)BGA
Note: Do not apply solder paste, as this has shown to result in problems during re-soldering.
Device Replacement
The last step in the repair process is to solder the new component on the board. Ideally, the (LF)BGA should be
aligned under a microscope or magnifying glass. If this is not possible, try to align the (LF)BGA with any board markers.
To reflow the solder, apply a temperature profile according to the IC data sheet. So as not to damage neighbouring
components, it may be necessary to reduce some temperatures and times.
More Information
For more information on how to handle BGA devices, visit this URL:
subscription). After login, select Magazine , then go to Workshop Information . Here you will find Information on how
.to deal with BGA-ICs.
Repair Tips
www.alphametals.com
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website for
is reached and stabilized at the solder joint.
otherwise wear-out of tips will
http://www.atyourservice.ce.philips.com
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