Powertech MP3090/Manson SPS9400

[raistlin119]

Good morning, I have used the powertech MP3090 also sold as the Manon SPS9400 successfully for many many years.

Went to switch it on the other day and nada, nothing, the unit won't power on.

The fuse is fine.

Could I get some guidance as to what to look for?  All the tracks look fine, no burn marks and none of the caps are bulging.

Here's a generic pic of the unit.

Thanks!

[Manul]

I would say it is not very common for SMPS to fail so silently and calmly. Does AC really come to the main board (I assume PT1 and PT2)?

[coromonadalix]

maybe some "startup"  electrolytic  capacitors near the pwm ic


Schematic
https://eevblog.com/files/SPS9400_ServiceManual.pdf

do you have a voltage on the cathode of d2  in the section of u1

you psu has a small power supply section to feed the other one, its called auxilary power supply, its in the section D1 thru D6, it feeds the displays and the main power supply section. 

You have a Dave eevblog video #272