The 6.3V and 12.6V connections look to be correct, but I think you have made a mistake with the 250/0/250V connections.
According to the diagram on the transformer, the yellow '250' and the green '0' wires should be connected together and go to the '0' terminal on the PCB. The yellow '0' goes to one of the 250v connections on the PCB and the remaining green '250' will go to the other PCB connection.
But to make sure, I would suggest before you wire up the PCB, connect the leads to a three way 'chocolate terminal block' and using a multimeter set to 1000V AC, measure the voltage across the unpaired yellow and green wires. If all is wired correctly you should get a reading of 500V.
That's made the order of the wiring very clear. I'll be very careful with the wiring and test as suggested.
Thank you again for taking the time to explain, and thank you to the good folks at AOS who make friendly communities like these happen, it really is appreciated by those less knowledgeable people like myself!
Hi T, sorry for late reply, Mail went to spam..
On my transformer it’s the green 250v green 0v orange 250v the wires do not match the colours on the label. The yellow is not used the orange is 250v
Many thanks, Karl, for getting back to me. Much appreciated.
I hate to do this but may I ask for another piece of advice? I've attached here a pic (PIC1.jpg) of the actual transformer I'm using (in principle it's the same as the stock image I used previously). If I wire up as you suggest 250V blue/0V blue/250V black (PIC2.jpg) I get a reading of 263V AC on the blue and 104V on the black. But if I wire up as Barry suggested using all four of the blue and black wires (PIC3.jpeg) I get 263V AC both left and right.
Where I have the problem (well two really!) is that my multimeter AC readings are coming out a bit high overall ... instead of 6.3V I get 7.1V, 12.6V reads 13.5V and 250V reads 263V. Is that normal or should I look into buying a new multimeter?
My main problem is that when wiring up to the PCB using choc terminal blocks to do a quick test prior to soldering a deep hum comes from the PCB mainly at the 6.3V connection area and the zener diodes there get super hot and start to smoke!!! especially the two circled in green on PIC4.jpeg.
Is there something I'm obviously doing wrong that comes to mind or would you suggest I strip the PCB back and re-solder the components to see if that fixes things? I realise it's difficult to diagnose without physically seeing the PCB etc so no worries if you are unable to suggest anything, you guys have already been a great help! And hope you're enjoying the Bank Holiday!
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