I just answer to this quite old topic.
What kind of IPAD ?
To do simple:
1) if it's an IPAD WIFI + Cellular then that's right that there is basically one resistor to remove (resistor R1506 for example in IPAD Air) . Then after reassembling the Ipad, when you power it on, it automatically enters in DFU mode and you will have to connect it to Itune on a computer and restor it using the firmware dedicated to your model WIFI only . Also after all is done, don't forget to turn off the automatic firmware update in your Ipad's settings.
2) if it's an IPAD WIFI only: sorry ! no real way. It's been reported that unsoldering the Nand and changing it by a new one you will find on site like Alliexpress and then, restoring the Ipad would work, but I have some doubts.
I see on Ebay so many Ipad sold as not working only because the are Icloud Locked! how is this possible?
Prior any transcation with a seller, ask him to give you the IMEI or serial number printed on the back of the machine and check with https://www.icloud.com/activationlock/
If the seller doesn't want to give you the serial number , then go away!
If the seller "doesn't know" -in case of Icloud-lock - the password , then go away!