I'm trying to replace a PT in a Proton 1100 preamp (aka NAD 1150). This unit was left on all summer, in a hot garage, in Atlanta, and the design supposedly pushed the PT pretty hot to begin with, so I'm not surprised it went bad. It blows fuses instantly with mains power applied and all secondaries disconnected. It's not $$ but I like it and have had for quite a while.
It has dual secondaries - one set is center tapped (I believe) and supplies ~24v (? -for a ~30v rail), the other set supplies 6v for the power LED. I can't really tell much about it, there's no labels on it other than a part number, and since it's bad, I can't measure what it's actually producing, but those are what the schematic calls for. Does anyone know of a drop-in or close equivalent? - I realize that there are other ways to get that supply, but I'd like to stick to the original preamp design and not have dual PTs, cut sheet metal, etc.
Pic of xrmr in situ, attached, schematic at link HERE.
It has dual secondaries - one set is center tapped (I believe) and supplies ~24v (? -for a ~30v rail), the other set supplies 6v for the power LED. I can't really tell much about it, there's no labels on it other than a part number, and since it's bad, I can't measure what it's actually producing, but those are what the schematic calls for. Does anyone know of a drop-in or close equivalent? - I realize that there are other ways to get that supply, but I'd like to stick to the original preamp design and not have dual PTs, cut sheet metal, etc.
Pic of xrmr in situ, attached, schematic at link HERE.
Attachments
I have considered that. I've used a Guy up in Maine for several projects before and he's first-rate. Service manual (in the link above) has almost zero info about the transformer, just a part number and a description of the operating voltages afterthe regulation block.
That information about voltages is enough for a competent repair man to do the winding.
But those rarely fail, so you must try to trace what caused the failure, before connecting another transformer.
But those rarely fail, so you must try to trace what caused the failure, before connecting another transformer.
If the 6V winding is only for an LED, just use a 24VCT transformer and change the LED dropping resistor?
EDIT: NVM - I see in the schematic it's a 6V lamp.
EDIT: NVM - I see in the schematic it's a 6V lamp.