Guide
How To Repair Without Schematics : Try This Method PART
How To Repair Without Schematics : Try This Method PART 2
#Repair #Schematics #Method #PART
“Learn Electronics Repair”
Most of the time we have no schematics but we need to fix stuff. Here is another method which will help you to repair stuff.
source
To see the full content, share this page by clicking one of the buttons below |
Check the FB, pin 9. If the lower resistor was open (I know – why would that happen) FB would float the the battery voltage and the chip would think it's charged.
Looks like a dumb battery to me, but still try to charge it manually by applying voltage to the disconnected battery, then to the output of that coil and watch the current on the PSU in both cases.
Heya. lovvvvvvvvvvvvvve to see this trouble shooting it could be a rabbit hole but I would love to see how to back wurds re-ingeneer this pcb and maybe we can learn something from it
Try the battery circuit. Maybe that one is messed up. New – never ever worked =))
Definitely chipquik for something like that, a lot quicker, no need for hot air at all, except where there's a thermal pad underneath like I just saw doh…. ah well 🙂
At this stage I would pull and test all the parts in that area, including the mosfet. They are all common off-the-shelf parts so just remove and test them. You might find an open resistor or maybe the mosfet is not working correctly. From what I've seen the mosfet must be driving the chip. If the chip isn't working either the mosfet is bad or the chip is fake, or a smd resistor/cap is out of specification.
Edit: Also, I checked previous vid and you seem to have missed checking that the chip is alive. Pin 6 is a 5V LDO output. Check for 5V on pin 6. If 5V is present the chip is working and the fault is elsewhere. If 5V is not present then the chip is not running or is fake. You can also check pin 4 which is another output for the Charge State Indicator.
@andygardiner6526 You win the best drama queen of the day award..
I'm assuming that usb is for charging a device from the battery . Is that connected to the chip ?
There are PCB holders available you can get. However, clamping the board with wooden clothes pins with lead weights (for RC aircraft) attached, work well to hold the PCB in place too.
People face a lot of problems the batteries may it be the computer or mobile they should all be of standard size for etch category of batteries for Amh or mah .
Hi Rich. My first thought is to check that the solder blob on the bottom didn't short to one of the pins…
Wow❤
Hi mate, why you just changed the chip without invistigating what was the issue with it?
pin 8 seems temperature detect pin-and needs to be between 80% and 45% of vdd(pin1,2) according to datasheet. hard to see from the video where its connected. Is the white wire of the battery providing the temp data? also you can try to isolate pin 8 and grounding it by removing R24 and shorting R25..to bypass temperature sensing to see if there is some issue with the battery internal temp sensing?
I’d be very interested to see the voltages on the pins of the chip after you’ve replaced it.
I’m still doing it via a magnifier but looking to upgrade
❤
Hi richard can i give you trick just use pliers and twis it the smd capacitors comes right off.
I watch your videos a lot and they are very informative. I have over 50 years experience in this industry. I still get a lot from YouTube. I see you remove components and I shout at the screen as knowing a better way. See you taking off those capacitors I always use the 2 iron method. Mrsolderfix channel has some great tips (no pun intended) on SMD rework techniques.
Why you don't check the battery? The Bms board in the battery pack is probably not allowing the battery to charge as the cells may be not balanced or fuse blown etc.? Or there is a fuse in the battery board? Look on some sorin videos of him repairing battery. You are fixed on the board and the fault could be the battery itself or even the charger not providing enough current…….. Give it a try and thank me later🙋♂️
are you sure you dont have a fake chip ???? as it does come from ali !!!
There is a Polish video "Dockin d fine + problem charging" https://www.youtube.com/watch?v=OkxC3EfAAt8 Any problem with PCB behind the charging port? Anyone speak Polish?
Did you try your thermal imaging camera. I recently found a faulty schottky diode with this and the Li-ion charger is now working again. D6?
I made my self a hot plate, I can use it to populate PCBs. But what I do when I want to remove components from a PCB is set it a little below the melting point of the solder or delicate components, this brings the area to a good temperature, then when I use hot air, I only need to use the hot air briefly to melt the solder.
Right-handed, what is that? I have two hands, I use both of them. 😉
for the caps use hot tweezers easy and quick
TEMP & Vset / VDD? D7? Batt signal as mentioned by @DumahBrazorf?
A tip. To stop your boards flapping around like a demented chicken a spot or two of blu-tak will stick the board to the mat just enough to stop it moving sideways. If necessary a bigger lump can add some mass to the board, hold it inclined or whatever. Just have a walnut sized piece stuck to a convenient upright above your bench and replace it when it gets too hairy!
Have a look at the switching frequency and check against the datasheet. Use your bench PSU to simulate the battery rather than trying to discharge the real one. AC/DC voltages etc, check all the components around the chip once more. How many layers just 2 ? has the chip got an 'enable' pin ?.. Dunno…just a couple of things I might look at. See you in part 3 !….cheers
Maybe checking the inductor is worth it?
Love your videos and i learn a lot from you. had a similar issue with Anker bluetooth speaker and had to do this-I would disconnect the battery and charge it up with a bench supply at around 0.8C so each cell is 3.7v and the total pack voltage is 11.1v. as the battery pack voltage is less than 10.8v or 3.6v per cell the chip might not want to charge it as its below the threshold. once the pack is 11.1v and balanced.. hopefully the chip will charge the pack.