Intercom problem

[highspark]

Intercom not working on electric gates installation. 2 seperate gates with 2 intercoms in parallel and one phone operating from the 2 comms.

Comms are fed from 240v - 12v PCB/transformer. On the out side of the transformer is 0v 12v ac and another that is 0v +12v dc.

Fed from 0v 12v ac terminals is the light which highlights the name card. I got this working by changing the fuse/bulb.

However from the 0v +12v dc this goes straight to the intercom panel. But the panel itself is not working. Usually the bell/button is alight wen working and buzzes when pushed this isn't happening on either.

When testing across 0v +12v do I get no voltage???? Is this correct or should I be getting 12v? If this is the case is the transformer nackered?

 

[sedgy34]

You need some power there for the light to work
Post make,&model,& pics

 

[highspark]

I know that but in the +12v dc terminals across +12v and 0v I'm getting no voltage - not working, is it because I am getting no voltage across the terminals???? I.e transformer is nackered

On the otherside for the name card light feed 12v and 0v ac I'm getting the 12v - is working

 

[telectrix]

are you sure you set your meter for dc when measuring the dc volts? this 12v dc must come off the tx then be rectified. could be a prob with the rectification circuit. possible fuse?

 

[highspark]

There is no fuse on the dc side (out). It just goes straight into the intercom. Baffled by it

 

[highspark]

Also I have the fluke t50 it does ac and dc

 

[sedgy34]

Connect onto the 12v you have got there that will prove your transformer

You couldtry a battery

 

[UNG]

Have you disconnected the outgoing circuit before testing the 12VDC

Have you checked the continuity of the cables and also for any shorts, I have found vermin damage when these systems die usually chewed cables

Have to agree with Telectrix that a fuse or possibly a thermal trip is protecting the transformer and or rectification circuit and needs to cool and reset other than that use the test instrument on your face most equipment that fails that has no protection usually has caused burning that you can smell

 

[highspark]

No have not disconnected circuits whilst testing for DC voltage. Would this matter?

I'm basically stuck on saying to customer renew whole system or let me carry on fault finding.

The system is around 8 years old and although parts are still scarcely available the company has now been taken over by another and parts can't be bought direct from them. So will be hard to get replacement transformer and also at what cost? Is it best just to replace for me and customer?

The problem I have is both intercoms are linked but fed separately from the same transformer. The customer tells me they both went at exactly the same time and it was around the time of a big freeze.

Considering both went at exactly the same time I'm looking at the power point/ transformer as being the problem...

Should I be getting 12v dc across my probes in normal use on the outside of the transformer. If so I'm not getting it and this must be part of the problem???

 

[jumpin jax]

Just buy a multi voltage transformer, cut plug off ,wire in, done 240v to DC Transformer

 

[123brez]

had a similar problem with an interlock unit try disconnecting all outputs and work your way back. will be something stupid

 

[i=p/u]

maybe only get 12v output when button is pushed.....

 

[UNG]

I would hope the customer has had this fixed by now this thread is six months old

 

[bigbaddave]

Either that or still sleeping in the car