Relay buzzing after transformer change?

[BabuBinks]

Ideal 4180 Paper Gulilotine stopped working. Changed fuse in the 230v > 24v transformer. A relay started buzzing on the PCB upstream. Thought it was a damaged relay so I replaced it for like.

Tested output on transformer and was only outputting 8v. Replaced the transformer for like also. Output is 31v and relay still buzzing.

What I'm confused about is that the relays on the PCB are DC but the old transformer and new transformer both output AC, how did the old transformer work as it was manufactured like this? There is nothing between the transformer and PCB to change the current.

The PCB is rectangular with a relay on either side with 3 capacitors in the middle. Between the relays and the edge of the board there are two diodes on each side.

Images below are the old Transformer next to the new transformer and the PCB

Any help would be appreciated.

 

[Harald Kapp]

The AC output of the transformer is most likely rectified and filtered. There is a componnet labeled K6, barely visible in the first image. Can you supply a photo of this component? It might be the rectifier. The capacitors C5, C6 and C7 are most likely filter capacitors to smooth the AC ripple on the DC voltage after the rectifier.
A humming relay is indicative of too much AC ontent on the supposed DC supply voltage. The culprit here is often the filter capacitors which tend to dry out and lose capacity over time. You do have a multimeter, I suppose. Check the voltage across these capacitors with the multimeter in AC voltage setting. If the meter indictaes more than about 1-2 V AC, these capacitors are surely compromised and need to be replaced. Replacement should have the same capacity and the same or higher voltage rating. Size is not important as long as the replacements fit the available space.

 

[Martaine2005]

There are AC relays as well.
Can you show a photo of the text on your relays?.

 

[Harald Kapp]

It says 24 V DC:

 

[Martaine2005]

My bad. That was in the OPs first photo, I didn’t zoom in.
Thanks @Harald Kapp

 

[bertus]

Hello,

What is the text on the old black relays?

Bertus

 

[BabuBinks]

Ive replaced all the capacitors for new. They are all receiving 30v AC. Relay still buzzing, What is my next step?

 

[bertus]

Hello,

Can you post pictures of the top and bottom of the full board?
The capacitors should not have AC on them.

Bertus