Hours wasted due to SMPS

[bernardgreen]

This happened to a friend last week.

He had designed an electronic circuit, mostly analogue, and was testing the prototype PCB when he found spurious analogue signals, something was un-expectedly oscillating. No matter what he tried the problem remained.

It was the soldering iron. A 24 volt temperature controlled iron. Unknown to him the transformer in the soldering iron's base station that regulated the heat in the iron was an SMPS. ( Switch Mode Power Supply ). Radiated electrical noise from the soldering iron and / ir it's base station was affecting the electronics.

 

[jj4091]

It's amazing what will give off RFI.

 

[JohnW2]

It was the soldering iron. A 24 volt temperature controlled iron. Unknown to him the transformer in the soldering iron's base station that regulated the heat in the iron was an SMPS. ( Switch Mode Power Supply ). Radiated electrical noise from the soldering iron and / ir it's base station was affecting the electronics.

Frustrating though it must have been, in one sense that soldering iron PSU probably did your friend a good service - since, had it not been there, he would not have realised (so soon) that the circuit he was designing was so susceptible to external interference!

Kind Regards, John

 

[bernardgreen]

He was fully aware of the need to protect the unit from RFI. The PCB layout has taken that into account and the unit's rejection of RFI meets the accepted standards. This he has verified by testing.

The amount of near field wide band RFI from the soldering iron's SMPS is far in excess of what would be acceptable.

 

[ban-all-sheds]

So now he is knowingly causing interference is he going to stop using it?

 

[bernardgreen]

So now he is knowingly causing interference is he going to stop using it?

He has aleady smashed the SMPS beyond repair. It was one he had not used before.

 

[ban-all-sheds]

He has aleady smashed the SMPS beyond repair.

In a rage, or as a calm, considered, action?

 

[bernardgreen]

Calm and considered, though I wonder why you need that information.

 

[ban-all-sheds]

I don't.