lcd only working outside the frame?

Hi

I don't do many HTC, I mainly do iphone/samsung.

Anyway, done a screen replacement and gave the phone back, a couple of days later, the phone has come back to me because the screen is not working.

I've reseated the cables, cleaned with 99% isopropyl. And still no joy.

So, I took the screen out, and inspected for any damage, which I could not find! So I hooked everything up minus the frame, so it's just the lcd, board, sister board, and main flex cable. Held the battery in place, and with my 8th hand, switched the phone on.....and it works.

Now, I've put both pieces of that cloth type tape where they should, be, so something must be touching somewhere. So wondering if anyone else here with any more knowledge with these HTC knows of any issues like this?

Thanks