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DNA 250 not charging


Riccs
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Hello!

My name is Riccardo and i have an old DNA250 board that i am trying to recover.

The board i think is working ok, it is 5 years old but there are no problems in escribe. I bought a new lipo, 3S 11.1V 1300mAh and 14,43Wh but connecting it to he pc or to a power brick it is not charging. I assume the USB port works fine because eScribe connects to the DNA, and the T-Plug connections works too because the battery gets readed on too. I checked the Fuse continuity and it's 0.0 so the fuse is good.

What can i test with the multimeter to see where is the problem?

Many thanks in advance!

With Battery .png

Screenshot 2022-11-19 at 15.40.49.png

IMG_2461.jpg

IMG_2462.jpg

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Hello!

Thank you both for your quick replies!

I went into a shop and we have welded again the micro usb port but with no luck! The port connections are all good but the situation on device monitor is still the same and the battery still doesnt charge.

I will attach the battery section on Mod.

Using the multimeter tester, which part of the board do you recommend I check to see where the charge is interrupted?

Thank you!

Screenshot 2022-11-19 at 20.02.49.png

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That 24 pin (6 pins on each side) square chip right above the USB is the Battery Management IC and is a BQ76925 I think. It controls charging and battery management functions. But if the firmware has it set to not charge, it won't.

But I would try an earlier firmware version before I would even be thinking of replacing that chip. I hadn't heard any newer firmware incompatibly problems with older board revisions, but who knows. And you can check this in seconds.

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Update:

I downgraded to an earlier firmware version (from sp6 to sp5) and ACTUALLY something changed but still not working. Now from the total 0.0000 of usb power and usb current we are at 0.015 (max) W of USB Power and 0.002 A of USB Current but the charge is still dropping.

Do you have more information about the Power managment chip or where to find the codes so i can search it online if its the problem? 

Also, is there a datasheet with electronic schematic that i can consult? 

Thanks!

Screenshot 2022-11-19 at 21.50.02.png

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For the specs of the chip, you're gonna have to Google like I would. It's manufactured by Texas Instruments btw.

Everyone I know, if they suspect the chip is faulty, they just swap it out with a known good one. It always seems to work.

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I saw online that there are many types of that chip. I think i can see  BQ76925 TI [something unreadable] AXH4 on it but i am not sure. 

What do you think about the new values of USB power and current? Do you think it could be something other than the chip? 

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Does it fire?
Have you tried different cables?

Plug it in, and let it sit for a minute. The board does not start charging immediately after being plugged in. Down in the bottom left hand corner (Device Manager) where you see stealth, locked ....... you'll also see charging (if it is).

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17 minutes ago, Riccs said:

I saw online that there are many types of that chip. I think i can see  BQ76925 TI [something unreadable] AXH4 on it but i am not sure. 

What do you think about the new values of USB power and current? Do you think it could be something other than the chip? 

The AXH4 stuff is version, lot, etc numbers. So those are not important as far as replacement.

The new values of USB power and current is what I would expect from the older firmware. And yes, I do think it is a failed chip.

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You want the square (not rectangle) BQ76925 24 pin IC. You are very unlikely find a RGER or a RGET after it. Since that was just for that particular production run. And that one the charging failed! So why would you want one from the same production run? As another one from the same run may likely fail the same fate.

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I admit to having the same doubt as you, but unfortunately I cannot find any information about a BQ76925 24 pin chip (square) that is not RGER or RGET..

Also i really want to work so at least i want to be sure about which of the two i need to order..

 

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