Need help identifying value of this bad SMD cap.

[keeney123]

Re: Need help identifying value of this bad SMD cap.

So is this a transistor with a NPN or PNP or is is a FET with S,D,G? it would seem to be a NPN but are you measuring in circuit because the Collector to emitter should be open either way.

[Spork Schivago]

Re: Need help identifying value of this bad SMD cap.

overoad?????

Yeah, overload. On my multimeter, it just means the reading was too high for my multimeter to read. For example, if there's infinite resistance, it'll show a message OL because the resistance is too high for the multimeter to read. If I have just one probe hooked to a resistor and the other probe floating in the air, I'll get an OL. Or if there's a cut in the trace and I'm trying to measure the continuity on opposites sides of the cut, I'll get an OL.

[stj]

Re: Need help identifying value of this bad SMD cap.

overoad?????

[Spork Schivago]

Re: Need help identifying value of this bad SMD cap.

So black on D (C) (the collector) to red on S (E) (the emitter) equals 0.624V but should actually say Overload, among a few other pins, right? Does that mean it's not a transistor or does that mean the transistor is bad as well as the cap?

[stj]

Re: Need help identifying value of this bad SMD cap.

diode test shows voltdrop.
one way should show nothing, the other way is usually 400-600mv for a regular diode or 100-200mv for a schottky

[Spork Schivago]

Re: Need help identifying value of this bad SMD cap.

too bad i cant make out the writing in those foto's
i refuse to believe that a meter with true-rms and a serial interface is lacking a diode test.

I was going to post clear pictures to show you! If you didn't say that, I probably would of never looked at the Ohm dial and would of never of saw the Diode symbol! I'm such a freaking idiot! Thanks!

[Spork Schivago]

Re: Need help identifying value of this bad SMD cap.

Omg, there is away! I'm so stupid. For some reason, I was thinking a transistor testing feature. I've own this thing since middle school or early high school (back in the 90's). I was looking at the dial for Ohms and it shows the Ohm symbol, a diode symbol and an auditory bell symbol. When it's switched to Ohm, if I hit the DC / AC button, it switches from resistance mode to diode mode to auditory resistance mode! I am such an idiot!

So how do I understand the results? I put it in Diode test mode and measure
Black on D (C) to Red on G (B) = 0.617 V
Black on D (C) to Red on S (E) = 0.716 V
Black on G (B) to Red on S (E) = Overload

Red on D (C) to Black on S (E) = 0.624V
Red on D (C) to Black on G (B) = Overload
Red on G (B) to Black on S (E) = 0.617V

I'm pretty sure I know what ruined the capacitor there. It was a terrible thing but I had a headache real bad (I'm on medication now for them which is helping) and some website wasn't working correctly and I accidently picked up the mouse and hit it really hard on the table out of anger. I should of never of done that but I don't think something broke and shorted out the capacitor or anything. I think it was me hitting it hard on the table because right after that, it stopped working. I appreciate the help guys.

[keeney123]

Re: Need help identifying value of this bad SMD cap.

Looks like someone needs a new meter for Christmas.

[stj]

Re: Need help identifying value of this bad SMD cap.

too bad i cant make out the writing in those foto's
i refuse to believe that a meter with true-rms and a serial interface is lacking a diode test.

[budm]

Re: Need help identifying value of this bad SMD cap.

The Ohms mode so far showing it is not shorted out, you need diode mode to test the PN junctions.

[Spork Schivago]

Re: Need help identifying value of this bad SMD cap.

In Ohm mode though, with black probe on D (C), I get
D (C) -> G (B) = 20 Megaohms, slowly counting down
D (C) -> S (E) = 60 KOhms, slowly counting down

With red probe on D (C), I get
D (C) - G (B): 0.43 Megaohms, slowly counting up
D (C) - S (E): 143.2 KOhms, but it was higher, jumping around a bit, and finally stayed at 143.2 KOhms.

With black probe on G (B) and red probe on S (E), I get 0.403 Megaohms.
With red probe on G (B) and black probe on S (E), I get 28.75 Megaohms, slowly counting down.

[Spork Schivago]

Re: Need help identifying value of this bad SMD cap.

Test in Diode mode both directions of the probes.

My DMM doesn't have a Diode mode Budm. It's a very old Craftsman True RMS DMM. It's Craftsman True RMS AutoRanging Digital Multimeter, 82357

Here's a link to the one I have:
http://www.machine--tools.com/By-Typ...ter-82357.ASPX

[budm]

Re: Need help identifying value of this bad SMD cap.

Test in Diode mode both directions of the probes.

[Spork Schivago]

Re: Need help identifying value of this bad SMD cap.

Pulled the little tiny resistor and measured it at 393 Ohm. I'm guessing it's supposed to be a 400 ohm resistor. Gonna try getting it back on. It's really, really, really tiny. Never played with suuuuchhhh a small resistor. There'd be no way to hand solder it because of how small it is. Even the tip on my micro soldering iron is a lot bigger than this whole resistor. The pads I can barely see. Gotta use a magnifying glass.

[Spork Schivago]

Re: Need help identifying value of this bad SMD cap.

Is it possible that there's more than just two layers here? I use my needle probes and I put them on that hole next to the bad cap. Then, on the other side, I've tried every hole around there and I can't get any readings at all. But if I have one of my probes on that hole and test the continuity to a capacitor or resistor, I get continuity. Really high resistance though, like .405 Megaohms. So I'm certain my needle probes are small enough to get into the hole...

[Spork Schivago]

Re: Need help identifying value of this bad SMD cap.

Since it is in parallel with the resistor then it is not a coupling cap to block DC due to the fact that the resistor will let the current flow through.
Did you check the value of the resistor?
How about the pictures of the whole board?
That device can be Transistor or MOSFET, did you do the Diode test to find out if it is PNP, NPN, etc?

I did check the value of the resistor, but on-board. I can remove it and test it out of circuit. On-board (which probably didn't get me an accurate reading) showed it to be around 400 ohm. I will post pictures of the whole board, front and back, in a little bit.

How do I do the Diode test to find out of it's PNP, NPN, etc? I've measured the continuity between the various pins. If we call the very top pin (the one all by itself), pin 1, and the bottom left pin, pin 2 and the bottom right pin, pin 3, these are the readings I get when I have (B stands for black probe, R for red probe. Black probe is hooked to COM, red probe is hooked to ohm):

[FONT="Times New Roman"]
B R
1 - 2: 20 Megaohms, slowly counting down
1 - 3: 60 KOhms, slowly counting down
2 - 3: 0.403 Megaohms

R B
1 - 2: 0.43 Megaohms, slowly counting up
1 - 3: 143.2 KOhms, but it was higher, jumping around a bit, and finally stayed there
2 - 3: 28.75 Megaohms, slowly counting down.
[/FONT]

Pictures are uploaded now. Once my wife gets home (around 3:00 - 3:00pm today), I can have her hold a light and try to get better pictures with better lighting. Let me know if you need those. I can also zoom in on different parts and take better pictures there.

[budm]

Re: Need help identifying value of this bad SMD cap.

It looks like some type of ceramic capacitor.

It is MLCC.

[keeney123]

Re: Need help identifying value of this bad SMD cap.

It looks like some type of ceramic capacitor.

[budm]

Re: Need help identifying value of this bad SMD cap.

Since it is in parallel with the resistor then it is not a coupling cap to block DC due to the fact that the resistor will let the current flow through.
Did you check the value of the resistor?
How about the pictures of the whole board?
That device can be Transistor or MOSFET, did you do the Diode test to find out if it is PNP, NPN, etc?

[Spork Schivago]

Re: Need help identifying value of this bad SMD cap.

If it is a coupling capacitor, that means it blocks the DC but allows the AC to go through. Would that be used for the wireless transmissions? I know coupling caps are used with audio circuits a lot to block the DC so you don't get the hiss and crackling and stuff, right?