4 replies to this topic

[mark]

Is it possible to check the diodes while they are still soldered to the board?

 

I have an Omni HO board and want to check to make sure all diodes are working before I proceed with my build.

 

Thanks,

 

Mark

[drrufo]

Just use a voltmeter and makes sure to check the orientation. The black lead the should be on the end with the stripe.They  should be close to the nominal value. In all of mine they should be over 500.

 

John Andersen

[Ramcatlarry]

These use bridge rectifiers, so no line. Using the bridges instead of single diodes makes the controller polarity neutral.  A visual inspection should never show ANY cracks or solder leakage.  I have seen shorted out ones that have whole sections blown out, otherwise they are hard to hurt.

 

Use voltage on the white lead and check for smooth continuity across the wiper bands with a meter.  You are looking for no dead spot and smooth increase in voltage to full.

[SpeedyNH]

there's always the diode check selection in the Ohms area on some inexpensive meters. this will put a small current through the device and tell you the Voltage drop across it, which should be about six tenths per diode.  

 

oddly enough, most cheap DMMs have the black lead positive in the Ohms range. so if you get nothing, swap the leads.

Speedy

[mark]

Well I tested out the omni board last night and all of the bridge diodes are good. Now on to building my John Cukras replica controller.