Help figuring out what replacement power transformer I need

dazaa

Member
2014-10-05 8:20 am
For a marantz 3300 pre amp. Unfortunately the primary winding is open circuit. The schematic doesn't show the voltages coming out of the transformer but it does show that + and - 13.5v should be coming out of the power supply board after the rectifier, does give some indication of the value of the secondary windings of the transformer?
 

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dazaa

Member
2014-10-05 8:20 am
So to put that in simple terms, I need a replacement transformer with a secondary winding voltage of between 15-18v? Since the pilot lamp is powered from the transformer would it be possible to find a replacement which also has a secondary tap of a few volts for the pilot lamp? If not would it be sensible to wire an Led from the switched outlets on the back at 240v? Or use a tiny separate transformer (space is not an issue) to power the lamp?
 
You need 15- 18 V each side of center tap so it means 30V - 36Volts ..

Most of the time catalog gives total voltage and a note to indicate that there is a center tap... it looks like this ... 36V ct

You can also look at the nameplate of the unit power consumption is usually written there
 
Often in Europe a centre tapped transformer is written as 15-0-15. You will more likely find transformers with two identical secondary windings, so 2x15V. You can connect these two windings to form a centre tap arrangement.

Its unlikely you'll find a transformer with the winding for the pilot light... consider replacing the bulb with an LED, which you can power from any DC voltage available.