i have a PCB that is powered up by 9v adapter...when disconnected from PCB the Adapter gives all 9volts but as i connect it to my PCB the voltage drops to 0.4volts(measured from pcb main inlet conections)....need help why is it happening??

 

Hello,

It sound like there is a short on the PCB.
Are all solder connections nice and clean?

Bertus

 

Your PCB is trying to draw more current than the adaptor is capable of supplying either because of the design of the PCB or because of a constructional fault.
I cannot say more without details of the adaptor and the PCB schematic and construction.

 

yup every component looks good...how to find a hidden shorted component??

Your PCB is trying to draw more current than the adaptor is capable of supplying either because of the design of the PCB or because of a constructional fault.
I cannot say more without details of the adaptor and the PCB schematic and construction.

Should i change Adapter??

 

Should i change Adapter??

How much current can the adaptor provide?
How much current does your PCB need?

 

Hello,

Can you post some sharp photos of the PCB's component and trace side?
Also do you have the schematic and detail of the adapter?

Bertus

 

i dont have it with me right now but i will post tomorrow...thnx for ur kind help...will contact tomorrow

How much current can the adaptor provide?
How much current does your PCB need?

the adapter has the reading printed on it but how come i know about the pcb??

 

Connect your ammeter and figure out how much current the PCB is drawing. Compare that number against what the PCB should reasonably draw. This will help you to determine whether your PCB is drawing too much, or if you your power supply is failing or under sized.