iPad Air 1 Drains Battery Fast

[Shrimply Pibbles]

Hi Guys I have an iPad Air 1 that came into our general repair for a new battery due to a dead battery the guys changed the battery twice and both batteries only last around 3 hours playing Youtube videos at full volume/brightness and quality (normally 7 ish).
I figured it's probably a partial short? as it lost 15% while completely off.
I have done a visual inspection and everything seems normal.
I have diode tested the lines leading to the battery which also seem fine (No OL, Low or High readings)
I have also tested line around Nand and Pmic and they all seem relatively normal (nothing stands out)

I do not have a known good board so i don't know for sure tho.

I then went back to the battery lines and followed them along and got a low reading after one of the MOSFETs (0.156) I'm unsure of the line as zxw does not list the name but looks lick VC Main (just a guess).
I have attached a photo of the line.

Could this be the line causing the issue?
If so how do I find the culprit I'm guessing faulty Cap? (The same as full short? inject voltage and heat check?)
If this is not a problem line and reading is normal as I know 0.156 can be a normal reading where do I go from here? is there any known trouble spots I should check.
Also if I connect this to dc and power off am I rite in thinking if there was a partial short you would see a small constant draw on the amps?

As always thanks in advance

[Jessa_the_Professa]

You need a known good to be sure, but that sounds like a normal vccmain reading for Air. I would assume you are more likely to have a partial short on a tristar line like 3v3acc or a partial short within the pmic because that has a mechanism for failure due to charger damage

[Shrimply Pibbles]

Thanks Jessa_the_professa i checked that line and the rails around it and they all seem normal. I will keep probing and set a "Fuck It" alarm for 2 hours and call it quits after that

[Jessa_the_Professa]

I would change tristar and if not solved then you have no mechanism for how this device could come to have a hardware defect, so then completely open-ended. Changing tristar is indicated because you do have a mechanism for a common fault that could cause this problem