PCB Where did I go wrong?

[rsjsouza]

One thing I would do is connect the transformer to one of your empty spare boards and see what happens. If the PCB house made a boo boo in the fabrication, it would be evidenced by the transformer overheating with no parts inserted.

I would then add a pair of diodes, connect and test; then the other pair, connect and test and so on.

[Spuddevans]

Try connecting just one of the secondary windings to the PCB (ie not the two windings in series, leave the other winding un-connected) and see if it still heats up.

Did you measure the AC current flowing through the PCB?

Tim

[Cubdriver]

On the photo of the diodes only board, I see only one input terminal block installed.  How are you connecting the transformer to the board?  Perhaps a photo showing the connections would be helpful.

-Pat

[rsjsouza]

On the photo of the diodes only board, I see only one input terminal block installed.  How are you connecting the transformer to the board?  Perhaps a photo showing the connections would be helpful.

That is a good point. If you are connecting both wires of the transformer to "AC1" they will be shorted according to your drawings. You should have both "AC1" and "AC2" populated to connect the transformer.

[goldfinger]

All,

Firstly want to say a big thank you to everyone who offered advice and help. I've found the issue there is a defect on some of the boards under neath near the ac entry with some bubbling now it's only very small but it looks like gnd plane might have defect to ac net. Which explains why it happens on entry! Thanks all really appreciate everyone's time and help.

Awesome!!!


Sent from my 486 IBM WIN 3.1x Desktop...

[goldfinger]

On the photo of the diodes only board, I see only one input terminal block installed.  How are you connecting the transformer to the board?  Perhaps a photo showing the connections would be helpful.

-Pat

Yeh I installed one and realized the tinned wire on the smaller transfomer was small enough gauge just to sit in hole mate snug to test so didn't bother

[neil t]

All,

Firstly want to say a big thank you to everyone who offered advice and help. I've found the issue there is a defect on some of the boards under neath near the ac entry with some bubbling now it's only very small but it looks like gnd plane might have defect to ac net. Which explains why it happens on entry! Thanks all really appreciate everyone's time and help.

Awesome!!!


Sent from my 486 IBM WIN 3.1x Desktop...

Excellent, congratulations, who doesn't enjoy a good sluthing moment, I think there was a number of guys  trying to lead you to that conclusion. It seemed so obvious from this side. but highlights to all of us the need for due diligence when fault finding ie: the need to start from the source or origins and follow a logical path, as head banging as it can be the absolute thrill of finding a fault and subsequent satisfaction of gained knowledge. excellent stuff which is one of the reasons I joined this forum.

regards Neil

[goldfinger]

All,

Firstly want to say a big thank you to everyone who offered advice and help. I've found the issue there is a defect on some of the boards under neath near the ac entry with some bubbling now it's only very small but it looks like gnd plane might have defect to ac net. Which explains why it happens on entry! Thanks all really appreciate everyone's time and help.

Awesome!!!


Sent from my 486 IBM WIN 3.1x Desktop...

Excellent, congratulations, who doesn't enjoy a good sluthing moment, I think there was a number of guys  trying to lead you to that conclusion. It seemed so obvious from this side. but highlights to all of us the need for due diligence when fault finding ie: the need to start from the source or origins and follow a logical path, as head banging as it can be the absolute thrill of finding a fault and subsequent satisfaction of gained knowledge. excellent stuff which is one of the reasons I joined this forum.

regards Neil

Very true Neil, and thanks for your help! As much as a pain in the butt it is/was at least I know now how to fix!!!

Thanks again to you and everyone else for their help and feedback!!!




Sent from my 486 IBM WIN 3.1x Desktop...

[Cubdriver]

Excellent!  Happy to hear that you've found the problem.   

I hope you can correct the issue with a bit of exacto knife surgery.

-Pat