Can anyone help me identify this component please?

Thread Starter

berni29

Joined Apr 6, 2021
10
Hi There

I'm a first time poster here so hello! As usual its a cry for help :)

I am attempting to repair the brushless motor from my (expensive dead) drill and have identified a blown component. With my limited knowledge it seems to be an SMD inverter, marked 7739 J428 1329. Pictures below!

Just to add this board lives inside of the motor.

If I can get this drill going again it will be a significant personal victory haha. Any guidance gratefully received.

All the best

Berni
 

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Thread Starter

berni29

Joined Apr 6, 2021
10
Hi

That would be a cheap drill if I lived in the US! I am UK based. Really though I would like to fix this one.

Tks

Berni
 

Tonyr1084

Joined Sep 24, 2015
5,807
It COULD be an IGBT (Insulated Gate Bi-polar Transistor). We would have to be able to see the numbers to know for sure. But it could also be a MOSFET. Being it's a metal body I'd lean toward IGBT.
 

Thread Starter

berni29

Joined Apr 6, 2021
10
It COULD be an IGBT (Insulated Gate Bi-polar Transistor). We would have to be able to see the numbers to know for sure. But it could also be a MOSFET. Being it's a metal body I'd lean toward IGBT.
Hi Tony

Thank you very much. The only numbers on it are 7739 J428 1329 each block written on a separate line. There is an upside down triangle with a line next to it on the component will try to get a close up although it may be difficult.

Does that help?

Many thanks again

Berni
 

Yaakov

Joined Jan 27, 2019
2,362

Thread Starter

berni29

Joined Apr 6, 2021
10

Thread Starter

berni29

Joined Apr 6, 2021
10
Hello again, just to build on my obvious ignorance, but how do you mount this component if it is surface mount, but the contacts are under the actual component?

Tks!

Berni
 

Thread Starter

berni29

Joined Apr 6, 2021
10
Hi

Just by way of completeness here are the actual instructions for replacing this type of device........

To replace a DirectFET device: Note: If you usually bake to remove residual moisture before rework, insert your normal procedure here. 1. Heat the site to approximately 100°C (150°C for lead-free assembly) using the substrate heating stage. Note: Pb devices are qualified for a maximum reflow peak temperature of 230°C (260°C for PbF devices). To avoid overheating the device or substrate, adjust the settings on your equipment to achieve a maximum air temperature of 300°C. 2. Lower the placement arm to bring the de-soldering tool into contact with the device. When the device and the solder interconnects reach reflow temperature, lift the placement arm to remove the device from the substrate. Discard the device. 3. Clear residual solder from the site using a bladetype de-soldering tool and de-soldering braid. Clear residual flux using a flux-reducing agent. Take care in cleaning the site: damage to the solder-resist may produce undesirable results. 4. When the site is ready, apply new solder paste with a micro-stencil and squeegee. 5. Position a new device on the vacuum tip of the placement head and lower the placement arm until the device is in contact with the solder paste. 6. Switch off the vacuum on the placement head and retract the placement arm, leaving the device in place. 7. Heat the site to approximately 100°C (150°C for lead-free assembly) using the substrate heating stage. 8. Use the de-soldering tool to heat both device and solder interconnects to reflow temperature, waiting until all the solder has reflowed. 9. Retract the arm, leaving the device in place. Cool as quickly as possible.

Tks

Berni
 
Hi

Just by way of completeness here are the actual instructions for replacing this type of device........

To replace a DirectFET device: Note: If you usually bake to remove residual moisture before rework, insert your normal procedure here. 1. Heat the site to approximately 100°C (150°C for lead-free assembly) using the substrate heating stage. Note: Pb devices are qualified for a maximum reflow peak temperature of 230°C (260°C for PbF devices). To avoid overheating the device or substrate, adjust the settings on your equipment to achieve a maximum air temperature of 300°C. 2. Lower the placement arm to bring the de-soldering tool into contact with the device. When the device and the solder interconnects reach reflow temperature, lift the placement arm to remove the device from the substrate. Discard the device. 3. Clear residual solder from the site using a bladetype de-soldering tool and de-soldering braid. Clear residual flux using a flux-reducing agent. Take care in cleaning the site: damage to the solder-resist may produce undesirable results. 4. When the site is ready, apply new solder paste with a micro-stencil and squeegee. 5. Position a new device on the vacuum tip of the placement head and lower the placement arm until the device is in contact with the solder paste. 6. Switch off the vacuum on the placement head and retract the placement arm, leaving the device in place. 7. Heat the site to approximately 100°C (150°C for lead-free assembly) using the substrate heating stage. 8. Use the de-soldering tool to heat both device and solder interconnects to reflow temperature, waiting until all the solder has reflowed. 9. Retract the arm, leaving the device in place. Cool as quickly as possible.

Tks

Berni
Make it as easy on yourself as you can. I would recommend using ChipQuick (OEM part#: SMD291), and solder flux. Brush the flux onto the pads after the component is removed. Then brush a *very tiny* amount of ChipQuick across the pads (don't worry if there is inter-connect). Set the new component on the pads and heat it with a hotplate underneath, and hot air reflow (I've even used hair dryers in my early days with smt). As soon as the solder beads up, goes shiny, remove the hot air, turn the hot-plate off, and let it sit. Absolutely do NOT move it throughout this process until it is cool and fixed. The flux will help the solder bead to the pads and separate so long as you didn't put too much down.

Youtube has great videos on techniques to do this without stenciling.

IMHO.
 

Thread Starter

berni29

Joined Apr 6, 2021
10
Hello

Thank you very much for your advice. Sounds much better. I will do as you suggest. By the way, do you think it is likely that other components may have been damaged when the fault event occurred? Its probably not possible to know. gotta change it and see!

Thanks again

Berni
 

Thread Starter

berni29

Joined Apr 6, 2021
10
Hello again.

Update time.... I got the blown component off, and this is the state of the board. The board is attached to the motor and does not look like it wants to come off easily. How do I repair this damage? Is it even repairable. I do have a microscope if I need to do any very precise work. Just not much track record with this sort of thing.....

Thanks again!

BerniIMG_6826.jpgIMG_6823.jpgIMG_6820.jpgIMG_6825.jpg
 
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