Haier HG-9041 Tablet Fix / Repair

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So I got a Haier tablet in the Fuko 10 and it wouldn’t power on,

It had an issue with not powering on or taking a charge however it would power on and stay on while power was connected.

Then I got another one in Fuko 11, and it works perfectly! Now I felt brave enough to open the old one and see what’s wrong with it.

I started by using a pretty dull razor blade around the seam that is visible around the edge near the top (screen side). I gently pried until i can see it starting to open just a little, then I moved around the whole thing doing that. It came open surprisingly easy. There were only two speakers attached to the back that can be pulled out.

After looking at it for a while and checking that the ribbon cables were all secure, I started by checking voltage on the battery. My multi-meter said it has about 0.010v in it. So that’s not good. I know lithium batteries take damage when completely drained. But I decided to see if the charging circuit was working at all and connected power while checking battery power in circuit. Nothing.

I didn’t have a clue what was wrong and assumed it must be some problem that would require a lot more work to determine and I didn’t feel like all that. I got a little careless and just decided to apply power directly to the battery. But I didn’t know how much power, though I assumed 3.7v. I was right according to this website.

So I took one of my 18650 lithium batteries and connected it in parallel with the tablet battery for a few seconds and then checked the voltage on the tablet battery again. The voltage went up by maybe 100ma. So that was good news. I decided to give the tablet power again and see if the battery starts to get a charge this time. Surprisingly it was! It was getting about 3.2v.

I put it all back together and it’s still working. Charged it to 100% and allowed it to drain to 33% just sitting there in sleep mode. Took about 18 hours to do so. I think that’s a bit too fast for sleep, but I haven’t done the same test on the new tablet yet. However I wouldn’t be surprised if the battery has taken some permanent damage from the full discharge.

TLDR: Battery not taking a charge. I applied 3.7v to the battery for a few seconds.

Just wanted to let you guys know in case there are some out there with this tablet that would like to get it working and happens to have the same problem with it. I hope it helps.

Be careful with lithium batteries though, they can be dangerous.