Any Help to id these two parts?

White cylinder a transformer?

Black part on four legs? has a voltage drop across it from 100V ac to about 48V ac. What to know if it is working correctly and whether I need to replace it.

Thanks in advance.

 

The white cylinder is probably a bifilar common-mode rejection transformer.
The black square thing is a bridge rectifier. Measure the AC input voltage and the DC output voltage.

 

thankyou
I will do some reading in these parts.