Yamaha rx-v463 not powering on

I know it's a old unit but I have a yamaha rx-v463 av receiver, after being left unplugged for a month , I tried turning it on but have no signs of life .
No screen no relay click when power button is pushed, won't start in protect mode.

Have checked fuse inside that's fine but I'm only getting 5v before and after fuse before it goes to transformer surely that's not enough?

Have read a few things online about other models have a dogey c405 capacitor on the standby board , but from what I can see this model doesn't have one . It has a c4051 on the schematic but I'm unsure if that's related

I'm armed with a soldiering iron and a multimeter
If anyone can point me In a direction of where to go from here please it would be much appreciated