guys need some help with my air compressor, anyone able to help or offer adivce

It's a ingersoll Rand 3 cylinder compressor( unsure of exact type )

Start's and run's fine, Builds up air pressure at the receiver tank as tested by the release of air at the drain valve ( 1st photo). However there is no air being released at the outlets to the larger air receiver ( 2nd photo . There air pressure gauge on the side is so faded its unreadable so i plan on replacing it. There is air pressure at the join's before the pressure gauge, however nothing afterwards.

At the back of the pressure gauge is a blue box, Is this some sort of pressure switch? or pressure release diaphragm.(photo 3) right hand gauge in photo the blue box to the bottom of the photo. if so can this stop air pressure being released to the outputs. If so is there a specific type i need to replace it or ideas. Compressed air reaches that line to the bottom of it, but not past it

Hope this makes sense as i am new to air compressors, and just unsure of a few things. Plus local companies cost a fortune to come out and have a look

 

Holy **** that's an old one!

Looks like the control air pressure switch for turning the compressor on or off etc. You can test it with a multi meter or just check the compressor is shutting off at the correct pressure.

You need to. Change the dials for ones you can read to find out what is going on, but it sounds to melike you could have a blocked non. Return valve or similar