[iMore Question]

I placed the logic board in another iphone but the phone still draining battery means the problem is in the logic board which part exactly shall I replace

[Ledsteplin]

Welcome to iMore! You might have better luck contacting iFixit.com.

[Just_Me_D]

I placed the logic board in another iphone but the phone still draining battery means the problem is in the logic board which part exactly shall I replace

If you restored from a backup to the other iPhone after you placed the logic board in it then you may have restored the problem. A rogue app and/or setting can drain a battery quickly even when not in use. With that in mind, I recommend you set up the device as new if the above applies.

[cuttheredwire]

My general advice is thus:

Delete the Facebook app.
Disable background spp refresh.
Turn off Bluetooth if you don't use it.
Reduce your brightness.
Check the battery section.

[Ledsteplin]

My general advice is thus:

Delete the Facebook app.
Disable background spp refresh.
Turn off Bluetooth if you don't use it.
Reduce your brightness.
Check the battery section.

Background App Refresh is a good thing. It saves more battery than it uses. It helps apps run in the background more efficiently.