Samsung UN60H7150AF Burned IC

[tvfixer007]

TV won't power on. When I unplugged the main board the back lights come on and stay on. Was able to test power supply voltages with main board removed they all looked within margin. I spotted burned (IC206) on the main board but can't find a schematic for this TV.

Was wondering if I should just order a new IC and cross my fingers? Or that something else is the cause for the IC to fry?

[petehall347]

Re: Samsung UN60H7150AF Burned IC

you need to be checking everything connected to it ..without a schematic its not so easy .. only things to short are semi conductors and the occasional capacitor .
you could take an educated guess and look up the data sheet for the ic . looks like a z3015pi1

[tvfixer007]

Re: Samsung UN60H7150AF Burned IC

Okay thanks. I found the data sheet for it. Will post back when I find anything else wrong.

[budm]

Re: Samsung UN60H7150AF Burned IC

http://www.aosmd.com/search?pn=AOZ3015

[saddle_au]

Re: Samsung UN60H7150AF Burned IC

Check the input voltages before replacing it. Anything above 18v-20v frys that chip. Its supposed to be good for 3A. The output voltage for this circuit will be,

(R2003+R2004+R2005)*0.8/(R2003+R2004)

If you measure those, you can work out what voltage this circuit is supposed to be generating.

[CapLeaker]

Re: Samsung UN60H7150AF Burned IC

I'd be checking th buck regulator's output to GND. If there is a low resistance, either remove that dc to dc buck converter or the inductor beside it and check for a short to GND again.

[tvfixer007]

Re: Samsung UN60H7150AF Burned IC

I get no reading for buck output to ground. However I found low resistance on D207 and the 4 caps to it's left. I didn't know if it would be safe to power it up and test the voltages?

[Diah]

Re: Samsung UN60H7150AF Burned IC

I get no reading for buck output to ground. However I found low resistance on D207 and the 4 caps to it's left. I didn't know if it would be safe to power it up and test the voltages?

any reading and this burn IC still on board are useless. must be out from the board first then test around in general this regulator should it had zinner diode in circuit i cant find it on board.. it may the ZC2009 fly out by heat !!!

[budm]

Re: Samsung UN60H7150AF Burned IC

I get no reading for buck output to ground. However I found low resistance on D207 and the 4 caps to it's left. I didn't know if it would be safe to power it up and test the voltages?

That does not make sense for you to not see at the output low resistance reading to GND since the CATHODE of D207 (Anode connected to GND) is connected to the VOut pin 8 of the IC. D207 looks to clamping diode to protect the circuit in case the internal MOSFET Q1 of the IC shorted out.

[saddle_au]

Re: Samsung UN60H7150AF Burned IC

Suck the chip off and measure it separately. This fault may also have been caused by something upstream or a short in the inductor (shorted turn) or shorted fly back diode. measure the output resistance to ground with the chip out to see if the load is also causing a problem.

[tvfixer007]

Re: Samsung UN60H7150AF Burned IC

That does not make sense for you to not see at the output low resistance reading to GND since the CATHODE of D207 (Anode connected to GND) is connected to the VOut pin 8 of the IC. D207 looks to clamping diode to protect the circuit in case the internal MOSFET Q1 of the IC shorted out.

Sorry about that I was thinking pin 4 was pin 8.

[tvfixer007]

Re: Samsung UN60H7150AF Burned IC

Suck the chip off and measure it separately. This fault may also have been caused by something upstream or a short in the inductor (shorted turn) or shorted fly back diode. measure the output resistance to ground with the chip out to see if the load is also causing a problem.

Couldn't remove the chip.

[budm]

Re: Samsung UN60H7150AF Burned IC

There is bare pad on the bottom of the IC (see IC spec sheet) to transfer the heat to the copper pad on the board so it will take quite a bit of heat to remove the IC.
Cut the legs off the IC first will help.

[dick_barton]

Re: Samsung UN60H7150AF Burned IC

Run solder on all 4 pins on both sides of the IC and move your iron between each side until the solder is molten on both sides then lift the chip off the board.

[saddle_au]

Re: Samsung UN60H7150AF Burned IC

If the chip is soldered underneath and you snip the legs, unless you have a very sharp zero cut angle pointy pair of snips, you risk lifting the pads during the snipping. Heating the board from the top or underneath also risks lifting pads and tracks.

Run a blob of solder down each side of the chip leaving a gap between the plastic and solder. Do this until all four legs of each side is just one mass of solder. Joining all four legs makes the legs and pads more rigid. Use your snips now or better a sharpie (Stanley blade here) and cut the legs off on the edge of the chip, then melt and remove the four legs in one go. You will be left with a legless plastic blob that you can physically attack without hurting the pads. Snip the top off until you see silicon, then cover it in solder, it should lift away.

Sometimes its not solder underneath, but glue. Twisting the legless plastic blob also releases it.

[petehall347]

Re: Samsung UN60H7150AF Burned IC

use a heat gun or chip quick might do it .

[tvfixer007]

Re: Samsung UN60H7150AF Burned IC

I tried soldering iron first no success. Lost my heat gun. Tried to cut pins off but scalped a few traces.

[tvfixer007]

Re: Samsung UN60H7150AF Burned IC

any reading and this burn IC still on board are useless. must be out from the board first then test around in general this regulator should it had zinner diode in circuit i cant find it on board.. it may the ZC2009 fly out by heat !!!

I looked at this board on a few sites which ZC2009 and ZC2004 are not present on these boards.

[tvfixer007]

Re: Samsung UN60H7150AF Burned IC

I tested D207 out of circuit and it's shorted.

[budm]

Re: Samsung UN60H7150AF Burned IC

Yep, that is why the IC burnt up, Q1 was feeding that shorted out D207, the protection (Vout sense pin) did not act fast enough to turn off Q1.