Tried to fix vibrator now screen has stopped working

I bought an iPhone 5 with a non-working touchscreen and was pleased with myself when I managed to fix it by reseating and cleaning the digitiser and LCD cables. The screen and touch worked great but there was evidence of past water damage and the vibrator and compass were will not working.

I purchased a new vibrator but this didn't fix the issue so I thought I'd try reseating and cleaning the vibrator / switch cable at the end next to the LCD etc cables.

I powered the phone down, removed the front, and disconnected the end of the switch cable. I sprayed a few drops of isoproyl on the cable and the logic board connector and brushed them both lightly with a soft toothbrush (the technique I used successfully on the digitiser cable). When I reconnected the switch cable and powered the phone back on I found that the screen was no longer working - there was a block pattern. Neither did the touch appear to be working as touching the screen didn't prevent the backlight from turning off after a few seconds.

After quite a few iterations of reconnecting switch, LCD, and digitiser cables the screen was completely black except for the backlight. I reassembled the phone just to test it this way and now even the backlight appears to no longer be working. Previously when the screen showed blocks I could call the phone from another and it would ring, now there is no ringing. Connecting the phone to iTunes however works normally.

Can anyone please help? I'm gutted as I got the phone carrier unlocked and it was almost good to go.

Thanks.