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SPX900 Transformer


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Im just clearing through a shelf of broken gear and have come across a SPX900 with a open primary winding on the mains transformer.

I cant see a thermal fuse in it, and need to know the secondary voltages in order to find a suitable replacement.

There seems to be 2 windings on the secondary, one centre tapped and one not.


Does anyone have a SPX900 that they could meter the secondarys on?


Yamaha have been extremely unhelpful in the aquisition of a replacement transformer.. have been waiting over 2 years for the part to become available now.



George Puttock

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You might have to fit 2 transformers - as you will need to produce +/- 15 volts for the audio stages and a 5 volt rail for the digital department, unless you are lucky enough to find a transformer with all the secondary windings. Check the voltage regulators to see if the above assumed voltages are correct.


If so - you might look for a 15 - 0 - 15 VAC and 0 - 6 VAC windings, which should give plenty of margin for the voltage regulator IC's after rectification and smoothing.

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