Monitor resolution changing when changing power sources of power supply

[ron2456]

My monitor resolution changed when I switched power sources. Usually I keep my power supply on an UPS but today I decided to test it on city power.
But when I plugged into city power the monitor resolution lowered to somewhat 800x600 and the adapter gave warning about out of range signal.
The connection is like City Power>Surge Protection> UPS > PSU>Monitor= Resolution OK(1366x768)
But when
Power>Surge Protection> PSU>Monitor= Resolution Lowers to 800x600. Is this normal?

My monitor is connected via a active hdmi to vga adapter to my motherboard.
Cpu, gpu etc in signature.
Monitor is LG HD, forgot model number.


EDIT: Found the problem, it was a faulty Adapter.

 

[cin19]

Because you found the problem, I closed this thread. If you want to reopen it PM me. Thanks.