Achme 200W Switching Power Supply AM630BS20S Fault

[TomFortune]

Hi guys,
I have a Shuttle PC that runs on a Achme 200W Switching Power Supply AM630BS20S. Yesterday i went to turn the pc on and nothing happened, i immediately thought it could be the power supply so tested it with a power supply meter. As i first thought there is no power to any of the board and therefore i decided to remove the metal cover to investigate. Upon opening the cover i noticed that there were three 10v 1000uf capacitors that had blown and therefore i decided to replace them. Whilst replacing these capacitors i noticed that the transformer in the middle of the board had blown the legs off of its body. Luckily i had a replacement transformer from a old identical power supply (the old power supply had a wiring harness short). On the casing of the transformer it was printed TOP222Y which when googled stated that it is a AC to DC transformer! is this correct? After further research i found that the circuit board had a fuse covered in black heat shrink which i have also replaced. Upon doing all this, i hoped it would work but unfortunately there is only a slight humming sound coming from the output side of the board. I am unsure as to where to go from here any help would be much appreciated
Many Thanks
Tom

[stj]

Re: Achme 200W Switching Power Supply AM630BS20S Fault

it's not a transformer, it's a psu chip.

anyway, top's use a starting capacitor.
you need to find an replace a small capacitor near the top, it will be 10uf to 100uf usually.

it dries up inside and then the top wont start.
look at the attachement

[TomFortune]

Re: Achme 200W Switching Power Supply AM630BS20S Fault

it's not a transformer, it's a psu chip.

anyway, top's use a starting capacitor.
you need to find an replace a small capacitor near the top, it will be 10uf to 100uf usually.

it dries up inside and then the top wont start.
look at the attachement

Hi stj,
thanks for the quick reply ive just replaced the capacitor i think you mean't it was 10uf and 50v but it still wont fully turn on as small pulses can be heard. any other ideas??
Many Thanks
Tom

[stj]

Re: Achme 200W Switching Power Supply AM630BS20S Fault

small pulses may indicate a short on the output.

if you have a meter, check any diodes to see if any are shorted.