Hi. Can anyone tell me what this is, how to test it and what equivalent part can be used. The part number doesn't come up when searched. It is on a circuit board from an old movie projector. Thanks.

 

Hi. Can anyone tell me what this is, how to test it and what equivalent part can be used. The part number doesn't come up when searched. It is on a circuit board from an old movie projector. Thanks.

Welcome to AAC!

It is called a bridge rectifier. They are commonly available and not very expensive.
You can use a DMM in diode mode to verify each of the four diodes.

Connect the red lead of the DMM to one ~ pin and the black lead to the + pin. You should see a reading around .500. The exact number is not critical.
Move the red lead to the other ~ pin and same should happen.

Next connect the red lead to the - pin and the black lead to one ~ pin. The same should happen.
Move the black lead to the other ~ pin and the same should happen.

 

Thanks for the reply MrChips. What do the numbers represent? Thanks.

 

What do the numbers represent?

It could be a house marked part.

 

Thanks for the reply MrChips. What do the numbers represent? Thanks.

The number represents the diode forward voltage for a given test current. It should read about 500mV or .500V.
Any value from .400 to .700 would be expected.

If you reverse the polarity of the test current, i.e. switch the red and black leads you should see 0L, meaning that it is very high resistance. This is normal. A working diode should conduct current in one direction and not in the reverse direction.

 

Thanks again. The next problem is finding 1 that has the - then AC the +then AC. They all seem to have the ACs between the - and +.

 

Nope, it converts AC into rectified DC. the ~ markings are the AC input side and the +/- markings are the DC output.

 

The next problem is finding 1 that has the - then AC the +then AC. They all seem to have the ACs between the - and +.

You can wire individual diodes to get the correct pin order, or you can make a "swizzle" board to change the order of connections on a standard part.

 

Have you determined that the bridge rectifier is bad and needs replacing?

You can build your own bridge with four diodes.

 

There are bridge rectifiers with "non-standard" pinouts, to match what you have, like the VS-2KBB40 series (-, ~,+,~) rated 400V at 1.9A.
Make sure those parts do NOT have a "R" at the end of the part number as that makes it back to the -,~,~,+ pinout.
Not sure if yours is surface mounted or not, with those tab like pins. However, a pin based rectifier can still work.

 

Thanks everyone for your help. I have now found 1 on elements14. Cheers all.