Need help in buying eMMC Module for rock 5b+

#23

Ok, that means now I will prepare 5b + board with PCB cleaner and then putting solder balls on eMMC module and get it or place solder balls on 5b+ board then heat it and once they melt place eMMC module onto it. Finally using hot-air gun heat and dry the eMMC module till it settles a little. After that cool it for how long ideally it gets cooled??? I know it looks very silly to you, but you know I am trying it for the first time and I want to minimise error as little as possible and make it easier for me to succeed in reballing and get eMMC support for my 5b+…

Thanks for your support buddy

#24

no, pcb cleaner is used to clean flux, which is needed for soldering,
If board was used normally just blow some air to not have any dust there, paint eMMC pads with flux

If You really need to do that,
most comes with them ready to install,
probably You will not do that better for first time,

If You need to reball module, place it on holder, preheat, add flux, mix tin, use solder wick to remove tin, then pcb cleaner, flux, add solder balls (or solder paste) via stencil, then heat and stencil remove, yet another cleaning. Some prefer to remove stencil before heat, this depends on materials (sometimes everything sticks to stencil), without it You can easily blow balls away.

If I understand You correctly, You want to put tin on both sides?
No, You should have them only on eMMC and flux on Rock pcb.
Board should be preheated first to not add too much temperature difference (this can brake something),
Preheat below tin melt point, then add chip, position it and add temp to melt balls under chip.

Yes, this one is correct. You should see when it settles and additionally You can touch it with some tool to get sure that it floats on both sides and balls are on pads.
What You want to dry? You missed cleaning flux at the end, if You using ipa then hot air helps indeed to get everything dry, but flux should be removed with some cleaning pads, without that it will just move somewhere on pcb eventually causing corrosion.

Just leave it for few minutes,

Practice on something else to be sure.
You can get all nuc with same pads for eMMC for few bucks. You can try on on any electronics to remove and resolder some elements. You can buy for few bucks PCB rulers to get PCB with solder pads to practice.
As I mentioned - You can easily get eMMC with solder balls and this makes whole process much easier for first time. Practice on something and You will quickly know is it worth to risk, still You can find profesional service near You.

#25

Thanks for your motivation and detailed instructions. I have ordered all the necessary parts today. I will see when they are there I will try. I am getting the eMMC which is already balled, I confirmed it with the seller. As you said I will try to follow your steps and wait for the results.

One last doubt I have, how sure are you that the eMMC is properly connected with the PCB board through the solder balls? You cannot see if all the balls are in contact with the underlying board right ? What if only one ball fails to align properly and doesn’t make contact then you have bad luck and the eMMC needs to be recalled and the whole procedure needs to be repeated right ??? It’s just a trial and error I guess…
It would have been much easier if the radxa team had sold the PCB with eMMC module rather than we doing it. The eMMC module costs 8€ for 32gb and the rest parts to solder is costing me around 30€😞 …what a shame… But there is no other option right.

#26

eMMC location surrounded here by some ports and eMMC layout with huge margin will not let You see anything. All You can check is the gap between pcb and chip, should be equal for all sides,
Take a look at RAM chip and SoC, those have pads near edge of chip so You can inspect those, You can see solder balls if they are connected each other and on their places. If You did not position chip with offset it should drag chip to perfect place.

Flux helps You to connect solder balls and pads. If You only position chip correctly and there was no obvious dirt on pads everything should be fine. Try to solder something with and without flux and You will quickly know the difference :slight_smile:
If something is wrong indeed You need to start over. Clean both sides, reball chip try again. You have few attempts per chip, overheating can damage it.

As I said other option is to get professional bga service near You, not that expensive :slight_smile:

#27

Hi Dominik, my ordered products related to eMMC and it’s soldering to PCB are in transit and next week I will be receiving them.

I ordered eMMC which is preballed. When I receive it, I will just clean the rock 5b+ eMMC slot with a fluid which removes dust and preheat it. After that just apply flux to eMMC preballed surface, place it exactly onto eMMC slot and heat it with hot air gun at around 230°c ?

How long does it take for the eMMC to get soldered onto PCB ? After leaving it for 2-3minutes to cool things up I will finally clean the area again with the cleaning fluid (ipa) to wipe off the flux. Then I am done theoretically right ?
I hope I will do it exactly and get good result.

Thanks :pray:

#28

Great :slight_smile:

eMMC pads on PCB, You should not have slot on Rock 5B+
if You did not touched that area there is no need to clean pads with liquid before soldering, dust will stick to board when You can just easily blow some air on that area and use simple brush to remove dust
flux should be applied to PCB, not chip, it’s just easier to do that on flat area with pads instead of balls,

This is temperature where tin starts to float, but usually PCB and chip spread temperature around so You need bit more to get this temp under the chip. I would start with something around 260 and see if tin start to melt, you can see that on near elements.

If You preheat board it’s usually few second to something under minute, This depends on temperature, airflow and pcb itself.

Yes :slight_smile:

1 Like
#29

nvme很便宜,为什么一定要使用emmc?

#30

Pls use English as official communication language here. What are you trying to say ???

#31

Because m.2/pcie it’s not always available to use.
Let’s say You build NAS and You need 10G networking as well as sata HBA card, both m.2 in use and still there need to be something to boot up system. eMMC is still way better option than sd card. I really appreciate having that in ROCK 5B.

@Manu_B - don’t be angry, just right click on that text and select “translate to english”, quick and easy.