# Transformer pri winding

I need to know how find the correct wires on a transformer with multi pri taps. I have a transformer that can work on PRI 120vac, 220vac and 250vac. There was a switch to select the proper input voltage but the switch was removed and now I am stuck. I would like to know what to do to get the transformer working on 220/250 vac. The colour of the wires that goes in on pri side from main is:

ORANGE
WHITE
BLUE
RED
BROWN
YELLOW

I hope this could help in a way. The transformer is in an audio amp. The transformer is a TAMRADIO. I don't find any data about it. I'll appreciate help. Thanks

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One way to find out is to measure resistance between wires. If there is indeed an common and three taps you should measure $\dfrac{220}{120}$ the resistance between 220V and common, compared to the resistance between 120V and common. So look for ratios $\dfrac{220}{120}$, $\dfrac{250}{120}$ and $\dfrac{250}{220}$. If you measure a relatively small resistance between pins, you're probably measuring between 220V and 250V.