I recently got a hold of a Sinclair QL that unfortunatelly seems to have some issues starting up

I googled this issue a bit and found some suggestions to remove/replace the 8301 chip and see if that would help, but once I opened up the QL to do that I found out that this particular device had its memory upgraded at some point by piggy-backing RAM chips on top of the original ones. The RAM upgrade looks quite failure prone due to all the extra bits of wiring, but since the device locks-up at the blank white screen, is it the 8301 chip that´s the most likely culprit?
Any ideas of how to proceed in order to resurrect this QL would be appreciated.
Thanks in advance.