Help identifying a SMS component - picture inside

[Bicurico]

Hi,

The attached picture is shows part of the circuit that drives a small FullHD TFT monitor.

I believe that the IC in the red circle I painted may be defective - actually the board drives two monitors and the pictured part of the circuit is symmetrical to the other side, where I am pretty sure this IC is broken.

I need help identifying what it is and where to get a substitute.

Thanks,
Vitor

[Toasty]

Need the 1st digit or number.

?Nd5

T

[Bicurico]

I have a hard time reading it myself! The picture was taken with extra light and a Canon EOS 550D to get more zoom.

I will try to find a magnifying glass. Should have bought a USB microscope a long time ago - are the cheap ones (around 20 Euro/Dollar) any good?

Thanks. Will post the missing number ASAP.

Regards,
Vitor

[Toasty]

I use a 10x jewelers loupe and a bright LED flashlight in most cases.  You just have to get the correct spot working with both the light and viewing angle.

T

[Bicurico]

Here 4 further shoots, but none makes it easy to read.

Is it "8Nds5" or, flipping the image 180 degrees, "JPN8"?

The IC is not flat. It has a buldge in the centre, as if it was some kind of wrapped coil.

Thanks,
Vitor

[Toasty]

I would try all the combinations with "datasheet" after it in Google. i.e., JPN8 datasheet

Can you get a shot of the whole board?

You said this was symmetrical to the other side.  Is there a matching coil and IC like this?

What is the brand & model number of the monitor?

T

[Bicurico]

It is a Black Magic Design SmartView Duo monitor, used in broadcasting: https://www.blackmagicdesign.com/products/smartview

As a side notet: Black Magic Design is a HUGE company in the Broadcasting world, but I believe they are unknown to most people outside broadcasting. I was at IBC (https://www.ibc.org/) once and visited their booth. It was huge and full of... magic! Incredible how they are so unknown outside there niche. They have all these little devices that makes you wonder how it is possible...

Anyway, the device has two FullHD TFT screens and neither turns on. The PCB itself is working, LED's go on, the USB port makes Windows try to install a driver, the RJ45 ports react to a cable being inserted.

I just received this device to attempt repair. The "other side" of the PCB, with symetrical components for the second screen is in bad shape, as the proprietor of the device tried to dessolder (unsuccessfully) the 220 inductor, thinking that it was resonsible for the fault (I don't think so).

Unfortunatly it is a multi layer board, all with BGA or SMD devices and no test points, no documentation, nothing.

The two TFT modules are GLUED to the support case and hence I cannot see their OEM brand, unless I try to unglue them, which will probably break or at least bend them.

The power pin on the TFT flatcable (pin 1) goes up to the 220 inductor, which is not interrupted, either (the undamaged one).

Because the IC I am asking in this thread for, looks odd by not being flat and somehow linked to pin 1 of the flat cable (power), I want to take a look at its datasheet.

Regards,
Vitor

[Toasty]

It's not flat because it's blown.

If there is an identical circuit on the other side, you'd have to get to see it for proper identification numbers.

T

BTW: That's a sweet looking unit!

[Bicurico]

That's my thoughts exactly.

I think this might be some kind of fuse or switch related with the power supply of the TFT.

The equal IC on the other side is damaged from the inductor removal attempt and is not readable at all.

By the way, where could I source the 200 inductor of same quality?

Regards,
Vitor

[PA0PBZ]

LM3405 (SPNB)

[Toasty]

Nice! 

[Bicurico]

@PA0PBZ: WOW!!! Thank you very much! You are totally correct. This makes full sense as the trace goes directly into the power supply of the TFT illumination LED's.
@ALL: Thanks for the help and interest.

And the good news is that I used the "old" trick of holding a bright light against the TFT's and they are actually working. It is just the LED's that are not turned on, thus no background light.

I am pretty sure that replacing the destroyed shielded inductor labeled "220" and the two LM3405 bring this device back to life.

Can I ask for one last bit of advise: I know it is a shielded inductor and it says 220 on top of it. But searching on eBay, I did not find any similar component.

Any suggestion?

Regards,
Vitor

[Toasty]

What's the dimensions of it in mm?  I'm finding a good number, but they may not apply to Portugal...

220 = 22µH

http://www.ebay.com/itm/121064167231

http://www.ebay.com/itm/292174581910

T

[Bicurico]

Hi,

I just found one pretty similar. Unfortunately it comes from China, so I will be waiting around 3 weeks:

http://www.ebay.com/itm/10-PCS-DS1207-220M-22uH-22-uH-12x12x7MM-Shielded-SMD-Power-Inductors/121997876480

Again, thanks for the help!

Also ordered this:

http://www.ebay.com/itm/1PCS-LM3405XMKX-IC-LED-DRVR-CONST-TSOT23-6-3405-LM3405/192083033898

Hopefully that will do the trick.

Cheers,
Vitor

[Toasty]

Excellent!

Just an FYI for you and everyone that buys parts from eBay via China.  If you need multiple parts from an eBay seller in China, always ask if they can get the other parts.

Take your purchase here as an example.  Had you asked the one that had the inductor if they had or could get the IC, they might of been able to do so.  It's a very organised market, even though it looks totally helter-skelter to an outsider.  The buy/sell/trade/barter with one another all day.  If Wang Chao doesn't have it, Li Xia might. Plus he knows that Zhang, Wang Min, & Wang Xiu just got a bunch the other day.  Or, that seller could have a pile that they hadn't listed yet.  Sometimes it takes them no more than walking next door.  It is insane (to us)!

Feedback (and pics) when you get this fixed, please

T

[Bicurico]

Will do - in around 1 month... China shipping is free but slowwwwww!

Vitor

[Bicurico]

Hi,

As promised, here my report back.

1) Replaced the LM3405: was a nut job, because these IC's are so tiny! Desoldered the broken ones with hot air station, but that was complicated because there were even smaller SMD components pretty close to it. One of the broken LM3405 had suffered from the previous inductor removal attempt (not done by myself) and one short trace to a capacitor was not OK. I was able to bridge it with some solder directly.

2) Inductor 220: there ws only the plastic remains, but I was not able to desolder it. I would have had to heat it too much with the hot air station, considering the many tiniest SMD resistors and capacitors fitted only few millimeters from it. Too risky, they might have been flown away by the hot air. Also, the Chinese replacement 220 is higher than the original and there would not have been enough space, after screwing the backplates together. I resorted to a dirty trick: I soldered small wires to the remains of the original inductor and glued the new one to the backplate.

3) I had to connect PIN 4 and 5 of the LM3405, because the pulsed signal for brightness level was missing. This is an option explained in the datasheet, but the drawback is that one cannot change brightness anymore. Not a big deal, I guess. I think that the IC responsible for the pulsed signal must have gotten broken, too, when the original fault happened.

4) A tiny SMD component (size under 1mm) was broken/missing. I think it was a resistor, maybe a diode. I just risked it and shorted the two pins with a bit of solder. No chance replacing that component: I did not know what it was, where to get it and no means of soldering it, due to impractical size.

All this to say, that the device is up and running again. Only drawback is a slightly blue taint on the left screen, when looked from an angle and the missing backlight brightness regulation. Still, I am pretty happy that it worked out. This is actually not just a device with two screens to show SDI pictures in HD: it is actually a digital video scope!

Attached some pictures of the repaired device.

I know I could try to get the brightness regulation working, as well (done via Linux/Windows software). But I am afraid that the board has suffered already too much. Better leave it as it is.

Again, thanks for the help in identifying the LM3405!

Regards,
Vitor

[mrf245]

If you buy compoments in ebay from "ShenZhen, Guangdong", China, its normally convenient to ask sellers to hele you buy a list of what you want even if some parts not in their listed.  Maybe sometimes price is not so reasonable (a bit high).
For example, buy LM3405, you can ask for buy 22uH together.