Sansui au-11000 transformer

[quadmatrix82]

Hello Sansui experts I have a Sansui au-11000 with a shorted transformer can I subsitute with a au-9900 transformer ?

 

[Hyperion]

Unfortunately the power transformers for these two models are different, I think the secondary voltages are higher for the AU-11000.

 

[quadmatrix82]

Thanks Hyperion such a shame

 

[Hyperion]

10Vac difference on the low current winding and 12Vac difference on the high current winding, - too big a difference to ignore.

 

[Tom B]

Are you sure that the transformer is shorted? That unit uses what appears to be a torriodial core transformer (Round Case). If you measure the primary, many times they ohms reading is very low, appearing as a shorted winding. Transformers usually short and then open if they fail, and that is pretty rare unless someone replaced the fuse with the wrong value. A good indicator of a "Bad" transformer is a strong burnt smell by the openings.

Have you tried removing all of the secondary fuses, and attempting power on, looking for AC voltage on the secondary?

 

[quadmatrix82]

Definitely shorted runs very hot wrong fuse was in there too such a shame

 

[slimecity]

Definitely shorted runs very hot wrong fuse was in there too such a shame

So the trafo itself is getting hot?

Have you tried doing what Tom B suggested?

 

[ConradH]

Definitely do what Tom B suggests. If it really is shorted, I'm guessing the short would be the primary winding as it usually has the smaller wire. I've had some success getting a suitable transformer in terms of size and power, then adding my own windings on top of the primary to get the voltages I need. Easier with lower voltages. I think there are a few places that will custom wind, so a bad transformer isn't the end of the world if you value the piece.

 

[Tom B]

Definitely shorted runs very hot wrong fuse was in there too such a shame

Does the transformer still get hot when all of the secondary fuses are removed?
Are the AC voltages correct with the secondary fuses removed?

 

[quadmatrix82]

hi all yes it still gets hot with the secondary fuses removed - burning hot! its definitely shorted the yellow wires get 0 volts. i'll see if i can find a suitable replacement

 

[Tom B]

Very strange as it seems to be a secondary short at the leads of the yellow wires, but would expect the fuse to pop, of the primary to open. Agree that its bad.

 

[Hyperion]

We will never know what abuse that transformer has been through, a short on the yellow 30Vac low current winding before the fuses?