Build Your Own SLA/SLS

Hi all.
This is my first post ,up until now I appreciated the amazing advice and help given by members.Here is my issue.I have been running mu Little RP for almost a year now primarily for making jewelry prototypes and I must say that it is absolutely fantastic for this job .It runs like a thoroughbred racehorse that is until recently .This is what it has started to do.During a print the machine will stop sometimes after around 30% and sometimes around fifty or 80% and this stoppage is not constant.When I say stopping I mean the plate stops rising after the exposure ,so I end up with a large flat surface across the print zone.If I trash the job and start again every thing will work fine , but the break down will be in a different place.
I have tried new jobs ,reinstalling CW and all .The unit is on a stable bench top and a good environment and I am at a loss to know what to do.Any advice will be very much appreciated.

The usual suspects:

check your power supply

check and re-seat your cables particularly the endstop cable

swap out your usb cable, change the usb connector you are using

put some airflow on your controller board

check the windows power settings: control panel > power options > change plan settings > change advanced power settings
usb select suspend setting should be disabled

Thanks for the suggestions.
I gave everything a clean ,a check over .Then started a test run , now the intermittent issue has grown .I now have no lift of lowering the projector is working the lamp well and think I might have to get some replacement parts off Brad.Any other alternatives will be greatly accepted.

I had similar failures due to power supply spikes from other equipment turning off or on the same mains distribution board. Fix was to unplug the other equipment and depower everything for ~ 1 minute to reset.

Hi all,
Thank you all for the advice .
I systematically worked through all the "usual suspects" and in the end replaced an ad shield unit.
Plugged it in made a test run and then am printing again .Runs like a rocket.This is a great little printer ,I am using it to print jewelery which it does very well.
Thanks again for the help.