Yamaha A760 supply problem

[Vrystaat]

Goodday all,
I am looking for a Triac replacement for a Smor5g42, It is part of an X drive like Carver is using in their power supplies, I think it is a 500mA jobbie.
Help appreciated !
Regards
Jan

 

[madis64]

Have you already found the replacement or are you still looking?

 

[Vrystaat]

Hallo madis64, no thank you I've got it sorted. The one winding in the the transformer of the Yamaha a-760 were damaged, I took it out and put in another transformer without the power control board, works fine now. 😉
👍

 

[madis64]

no thank you I've got it sorted.

Good 🙂

The one winding in the the transformer of the Yamaha a-760 were damaged, I took it out and put in another transformer without the power control board,

I also replaced the (fully functional) PSU on my 760 because I did not like what I saw in the measurement results (noise and THD wise).
So I ordered a custom toroid transformer to get 50V DC and also moved the rectifier and power supply capacitors from the main board to the PSU section (like e.g.in A-700):

Measurement results before and after show improvement both in noise and THD. THD improvement I would attribute to removal of the "cycle-interrupted" power supply rails, 100 Hz noise reduction should come from the rectifier and power supply caps location and wiring changes.

So I have one full original A-760 power supply now for which I probably will have no use in the future (except as a component donor in a rare case I would meet another A-760 or A-960 on my desk). If anybody is interested, send me a message.

 

[Vrystaat]

I still have to replace the filter caps. They heat up in minutes and pulls the rail voltage down.
Regards
Jan

 

[madis64]

I still have to replace the filter caps.

I used these as replacement (but I placed them on another board - the dimensions should fit into the original place but I am not sure about lead spacing):

https://uk.farnell.com/kemet/alc70a103cf063/cap-10000uf-63v-alu-elec-snap/dp/2950144