Door bell

[pushkins]

Both the front and rear door bells stopped working at the same time, doesn't appear to be any disconnected wires so this leads me to think it's the transformer, how do i test the transformer ?

[mrcaptainbob]

transformer check...

A volt meter....

[HayZee518]

low voltage transformer

Is your transformer mounted through one of the knockouts in your panelbox?
or is it mounted into one of your junction box knockout holes?
In either case 120 volts on the wires and 16 or 24 volts on the secondary terminal screws.
MrcaptBob is correct. A cheap multimeter is the easiest means to test.

[pushkins]

It's in a crawl space about 20" tall, where else would you put it....somewhere easy ?..

[HayZee518]

door bell

That opens up a can of worms.
In a crawl space it could be anywhere.
Knob n tube wiring, it could be connected to the two parallel wires running down the joist space.
It might be connected to a piece of romex with just wirenuts [no box of any type]
To test.
Well, the pushbutton at either place front or back is an open circuit.
with the multimeter set on AC volts, 20 or 200 volt range, if you go across the pushbutton's contacts and you read a voltage, then the transformer is working.
One side of the transformer is common to both chimes. A common terminal on the chime marked "C"
The other side is common to both push buttons through a spliced connection.
Each push button's return to the chimes has one wire for the front and one for the back solenoid.
I'll draw you a diagram.

[korean1]

you'll need to cover all your basis'.
1. make sure the push buttons are good and working.
2. look at the door bell box itself and make sure all wiring and parts are in working order.
3. locate and verify transf. working.

example: Friends bell was not working. problems: push button was slammed and held down which caused the bell itself to over heat and the solenoid to melt into the plastic housing. Thus causing the bell to not sound. Thus causing the transformer to short out.
So sometimes it can be just one item.
And sometimes it can be more than you bargained for.
Sounds like though the worst part is the crawlspace.