audio power transformer schematic question

Thread Starter

spuddo

Joined May 2, 2013
45
Hi
The attached is a power supply schematic of a Pioneer A-656 amp.
I am wiring it up for 240 volt operation.
Using pins 2 & 5 as the primary connections.
In the schematic it shows pin 4 , connected direct to neutral , with what appears to be a fuse ?
I have not seen this symbol before.
Any thoughts.
Thanks for listening.

Screenshot_2021-05-13 Pioneer-A-656-II-Service-Manual pdf.png
 

nsaspook

Joined Aug 27, 2009
8,382
My guess would be a transformer fusible link or thermal overload symbol meaning it should always be in the power circuit. I would suspect a move of the wire from 3 to 5 while leaving the other wire at 4 would be the proper way to go. Lots of Japanese equipment had tap provisions for 200VAC 50/60Hz operation on the power transformer that might not be on the English versions of the drawings.

Schematic-wiring.jpg
 
Last edited:

Thread Starter

spuddo

Joined May 2, 2013
45
Hi
The attached is a power supply schematic of a Pioneer A-656 amp.
I am wiring it up for 240 volt operation.
Using pins 2 & 5 as the primary connections.
In the schematic it shows pin 4 , connected direct to neutral , with what appears to be a fuse ?
I have not seen this symbol before.
Any thoughts.
Thanks for listening.

View attachment 238193
[/QUOT
My guess would be a transformer fusible link or thermal overload symbol meaning it should always be in the power circuit. I would suspect a move of the wire from 3 to 5 while leaving the other wire at 4 would be the proper way to go. Lots of Japanese equipment had tap provisions for 200VAC 50/60Hz operation on the power transformer that might not be on the English versions of the drawings.

View attachment 238194
Thanks for your reply , could not find that symbol (fuse in circle) , but make sense now.
As you say , i should connect neutral to pin 4 and active to pin 5.
Best regards.
 
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