Diode Test

[bushido]

Hello guys. Been going through your board for the last week or so, figured I'd get my feet wet, so to speak.
Got a quick question for y'all.
Why can you not check the diodes cr14104, 05, and 06 on the pc board? Even with one end off the board I get a bad reading, but when I take them right off the board, they check out fine, and are fine. But, you can test cr14108 properly right on the board, no problem.
Anybody know why this is?

[skinerd]

Because there are other componets that are in circuit with them and you will be reading through them too....

[bushido]

Yeah, sort of figured thats what it was. Thanx for the come back though skinerd.

[Wotan]

You can test a diode with one of the leads disconnected from the circuit… Using your multi-meter on the continuity/diode range and one of the leads de-soldered, put the negative (black) test-lead on the side of the diode with the stripe and positive (red) lead on the other side of the diode. The meter should read about 0.6 Volts. If you reverse the test-leads, the meter should read “OL” or open. If the meter reads “OL” both ways or 0 Volts both ways, the diode is pooched.

I know it works because I just tried it on an RCA420 5 minutes ago! :D

Wotan

[skinerd]

Wotan,
by pulling one leg out of circuit that is effectively testing the component out of circuit, if it has only two legs,
if it has three, you need to pull two of them, to effectively be out of circuit.

[Wotan]

Skinerd,

Totally agree with you, 100%... But ater all, we were only talking about a diode, right? ;)

W

[skinerd]

Yes, but I wanted to make it clear to anyone else that just by pulling one leg was not enough if the component has more than 2 legs.