Need help with a Diode issue.

[92vig]

So I have been having an idle surge issue in my DSM. I cracked the case open and saw that one of the capacitors was leaking (typical on DSM's) So I was checking all of them out and noticed this big black piece that has a burn mark in it...hmmm, looks like a very important diode.

Hmmm, looks like someone had replaced the caps before....hmmm, that looks a lot like a soldering iron touched the fucker and melted the plastic.

So the question is, is it still good to use or does it need to be replaced? It was working in the car like this but I don't want anything to happen when I can clearly replace the damn thing since the ECU is apart.

How do I test a diode to see if it is still good?

[F22HB]

lol you gotta be kidding me. This is something I thought I'd never see. Bad caps y0

[92vig]

Oh, AND you want to know what's even funnier?

So I have been fixing so many things wrong with this car....and I took the throttle body off to replace the shaft seals since I am changing out a lot of gaskets...

And they INSTALLED THE SHAFT BACKWARDS. The divets for the screws for the butterfly plate face toward the passengers side....they installed the fucking thing to face toward the drivers side. Wow, easy way for the screws to get sucked into the intake manifold...dumbfucks.

And yes, leaking capacitors is common on almost every single DSM. Change them out if you don't know when they're been changed, pretty much.

Still doesn't answer my question about the diode though.

[F22HB]

Might be worth replacing, I'm sure you could pick a replacement up from radioshack or something and solder it in pretty easy.

[92vig]

I just have no clue what size I need....1A 100UA? Pff, is there a way to test it and tell? No idea...

[mj213]

http://www.allaboutcircuits.com/vol_3/chpt_3/2.html

[ryaniskingofyou]

diode? if you can get ahold of a DMM (digital multimeter), just test the resistance across it. should have a diode setting on the multimeter, looks like an arrow with a horizontal line at the tip. the resisitance should be like 700 ohms one direction (+ or - 150 ohms or so), and a few thousand ohms with the leads on the other direction. if the resistance is low as hell, its a shorted diode, if its super fucking high then its open. if either of those is the case, just desolder it and replace it and you should be good. thats an odd lookin diode though.
im excited to actually get to use some of my new knowledge ive learned since ive been in electricians school with the navy

[HondaB18]

You can easily replace that, much easier than SMD. The part number/part specs are usually printed on the part. Diodes are really cheap at your local Radio Shack (if they carry the one you are looking for). For that piece of mind.

diode? if you can get ahold of a DMM (digital multimeter), just test the resistance across it. should have a diode setting on the multimeter, looks like an arrow with a horizontal line at the tip. the resisitance should be like 700 ohms one direction (+ or - 150 ohms or so), and a few thousand ohms with the leads on the other direction. if the resistance is low as hell, its a shorted diode, if its super fucking high then its open. if either of those is the case, just desolder it and replace it and you should be good. thats an odd lookin diode though.
im excited to actually get to use some of my new knowledge ive learned since ive been in electricians school with the navy

What is odd about that diode? How do you know what the resistance is without knowing the specs of the diode?

[92vig]

You can easily replace that, much easier than SMD. The part number/part specs are usually printed on the part. Diodes are really cheap at your local Radio Shack (if they carry the one you are looking for). For that piece of mind.

Yea, the only thing is, that diode says 930 S on it....nothing about the specs.

What is odd about that diode? How do you know what the resistance is without knowing the specs of the diode?

x2

[92vig]

So I tested it with my multimeter...I put it on that diode setting (arrow with a VERTICAL line, LOL). One way it has nothing, the other way it is at 450 or so. Which should be typical of a diode since it controls current only in one direction, right?

I'm assuming since it reads whatever and not open, it is good....??

[HondaB18]

So I tested it with my multimeter...I put it on that diode setting (arrow with a VERTICAL line, LOL). One way it has nothing, the other way it is at 450 or so. Which should be typical of a diode since it controls current only in one direction, right?

I'm assuming since it reads whatever and not open, it is good....??

It controls current in one direction only to a certain amount.

Yes.

Does not apply to your situation but there are tons of different types of diodes. I think I see others but in SMT form on the PCB.

[92vig]

Will have to just put the shit back in the car and see what happens.

[ryaniskingofyou]

Hondab18, I guess I'm saying it looks odd because I'm thinking of what a resistor looks like. I'm so used to looking at schematics that the actual thing throws me off haha. a diode is made of p and n type semi conductor material, joined together in the middle forming a junction. The resistance of that region (the potential hill) is about 700 ohms ideally when the diode is forward biased (operating.) If you take a resistance reading across that junction with the leads backwards, its upwards of 2000k ohms. 450 should be about right though, that's not shorted by any means. I'm not sure what to tell you, I'm only a couple months into school

[92vig]

Well I will just put the ECU back into the car and see how it goes...if it doesn't work, I'll replace the piece.