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I've been looking for 115v primary 9v secondary 3.2va power rating PCB transformer and couldn't find any to replace the one that was fried. All I find is dual one, instead for example 4 pins it has 8 pins, and 220v once.

Could I use 220v primary 9v seconday 3.2va even the input is 110v? It's for coffee machine Saeco.

Can I use the dual output and just use one pin?

Here is a picture of a transformer I need (size and shape) enter image description here

Thank you

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  • \$\begingroup\$ Try to find a 220V -> 18V transformer. If you connect 110V to the primary, you should get 9V on the secondary. \$\endgroup\$ – Pentium100 May 20 '16 at 13:17
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schematic

simulate this circuit – Schematic created using CircuitLab

Figure 1. Double-primary, double-secondary wiring options.

The twin 110 V primary type transformer can be configured as shown in Figure 1 (a) and (b) to work on either 220 V or 110 V wiring. Just ensure that the transformer VA rating matches or exceeds that which is replacing - and given that the original burnt out "exceeds" would be better.

You may have to stand it off the board and connect with flying leads.

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A 220:9 transformer with 110 input will only be capable of about 1/2 the 220V rated VA. The 220V, 8-pin transformer needs to have the two primaries connected in parallel to get the full VA rating. Using just 2-pins will give 1/2 VA.

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It is quite possible that you have identified a suitable FUNCTIONAL replacement transformer. However, since you did not actually identify it, we can't confirm whether is is really suitable.

There are many such transformers with "split windings". So, for example, you can connect the two primary windings in parallel for 110V or in series for 220V. And in a similar manner the two secondary windings can be used either in parallel (for half voltage, double current) or in series (for double voltage, half current), etc.

However, it sounds like your replacement transformer won't be a PHYSICAL replacement because it doesn't have the same "pinout" or even the same number of pins. And of course the exact size and spacing of the pins is also likely to be a mis-match. In that case, you could hot-glue the transformer upside-down and run wires from the pins down to the board pads, etc.

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