I'm working on a faulty electronic microscope, I have replaced all faulty components on the power board but AC power is not getting into the bridge rectifier and the metal frame of the microscope is also given shocks. Any help?

 

Photo of the board please.
A schematic of the board would be a big help.
What make/model is the microscope?

 

Start by checking the mains supply from the plug to the transformer, and post pictures please....

 

the metal frame of the microscope is also given shocks.

I think this should be your main concern right now. By finding out why you are getting shocked, you might find your rectifier problem.

 

I'm working on a faulty electronic microscope, I have replaced all faulty components on the power board but AC power is not getting into the bridge rectifier and the metal frame of the microscope is also given shocks. Any help?

The metal frame giving shocks would generally be indicative of a grounding problem. Not sure how South African Ghana power distribution works but I would imagine 220/240 Volt a Neutral and a Ground. I would start by measuring metal case to a known good ground and seeing what you have and what is creating the shocks.

Ron

 

I think this should be your main concern right now. By finding out why you are getting shocked, you might find your rectifier problem.

It is a 110V power which was accidentally plugged into a 220V outlet. I'm using a stepdown transformer now and facing that challenge. If I measure the voltage across the resistor before the first AC foot of the bridge rectifier, I get the 110V. But if I measure both AC foot of the Bridge diode, there is no voltage

 

The metal frame giving shocks would generally be indicative of a grounding problem. Not sure how South African Ghana power distribution works but I would imagine 220/240 Volt a Neutral and a Ground. I would start by measuring metal case to a known good ground and seeing what you have and what is creating the shocks.

Ron

Is 220/240V, basically a grounding problem and don't know what actually is causing that? Could it be the cause why power is not getting to the bridge rectifier?

 

If I measure the voltage across the resistor before the first AC foot of the bridge rectifier, I get the 110V. But if I measure both AC foot of the Bridge diode, there is no voltage

Post a schematic and indicate where you're taking measurements.

 

It is a 110V power which was accidentally plugged into a 220V outlet. I'm using a stepdown transformer now and facing that challenge. If I measure the voltage across the resistor before the first AC foot of the bridge rectifier, I get the 110V. But if I measure both AC foot of the Bridge diode, there is no voltage

So there you go, your resistor is Open Circuit!

 

Thank you very much, issue solved.


But does any one knows the equivalent of the zener diode YS2100 or has a data sheet on that