Overheating Chip - Vizio M320SL 32" LED TV

[SgtRock]

Greetings EEVBees:

--This Vizio M320SL 32" LED TV works normally for about 10 minutes then gets the vertical stripes. Having removed the back cover, I notice that the heat sink on the main board tends to get quite hot unless I put a fan on it. I do not want to run the TV in the abnormal condition, as I am afraid of further damage. With the back off and a fan blowing just a little air on it, the heat sink stays cool to the touch, and the TV operates normally. Any advice would be appreciated.

"There are two possible outcomes: If the result confirms the hypothesis, then you've made a measurement. If the result is contrary to the hypothesis, then you've made a discovery."
Enrico Fermi 1901 1954

Best Regards
Clear Ether

[SeanB]

Redo the thermal compound and look to see if you can get a bigger heatsink. Probably this chip is at the high end of the power envelope ( on die leakage currents) so gets hotter.  If they had a heatsink you can bet they put the minimal size one on.

[SgtRock]

Greetings EEVBees:

--As I recall the fellow from Canada asked me where I got the TV and if it might have had a fan originally. This TV was purchased for me from eBay by a neighbor, and has never had a fan. My last resort would be to cut a hole in the case and add a fan.

--Sean, thanks for the advice. I have about 20 pounds of old heat sinks, from which I am likely to be able to modify something to get an increased foot print, mass, and perhaps a simdgeon of height. I also plan to polish the underside of the new heatsink. I have ordered some Arctic Silver MX-4 thermal compound. Do you know of anything better? I really wish I was set up to do Lost Wax Casting in Copper. It is easy enough, except for melting the copper.

--Final question; Could failing capacitor(s) be somehow responsible for the overheating?

"I have had my results for a long time: but I do not yet now how I am to arrive at them."
Carl Friedrich Gauss 1777 1855
 
Best Regards
Clear Ether

[tom66]

My guess would be leaded solder on the processor  failing. Adding a fan will only delay the inevitable failure.

[SgtRock]

Dear Tom:

--Damn! I was rather afraid that might be the problem. I shall proceed with any and all low cost repair attempts and report back. ShopJimmy is selling a repair kit for all three boards for $88 plus shipping, see below link.

http://www.shopjimmy.com/vizio-m320sl-led-tv-repair-parts-kit-version-1.htm

--It seems unlikely that the kit would include the chip in question, nay? If anyone has any idea what is included in such a kit, please advise. I will not be calling SJ until such time as I am ready to consider purchasing one. At present I could also buy a guaranteed used board on eBay, for $95, but by the time I decide I need one it is likely to be gone, but I will probably be able find smashed screen units cheaply for the foreseeable future.

--I realize you said leaded, but did you possibly mean unleaded? I have heard far more about tin whiskers from unleaded solder taking out BGAs (which I assume this is) than high heat melting the (lower melting temp) leaded solder balls. Also, could you (or anyone) please tell me if a reflow is likely to buy me any delay in the inevitable?

--As always, thanks for the outstanding help.

"In the heat of battle, my father wove a tapestry of obscenity that as far as we know, is still hanging in space over Lake Michigan."
Ralphie Parker

Best Regards
Clear Ether

[tom66]

Yeah, unleaded/lead-free solder. So many processors/SoCs on LCD and plasma TVs failing. Main reason is a lot less R&D expense in stopping such failures from occurring. The problem also happened to PS3 and Xbox 360. Really, lead-free solder has brought so many problems. It's surely led to more waste than before...

[SgtRock]

Greetings EEVBees:

--I took some temperature readings using a Fluke 87V and thermocouple of the heatsink on the mainboard of the Vizio M320SL, all with the back removed.

1) With no added cooling whatsoever, the temp increased over 43 minutes to 52C, at which point the the display started to flicker to the striped pattern, and the TV was shut down, and allowed to cool.

2) An ordinary household fan on low was directed at the back of the TV from a few feet away, and the temp increased over 11 minutes to a stable reading of 38C. Display remained normal, and TV was switched off and allowed to cool.

3) A junk box Hanano Ball ball bearing fan, 51mm X 51mm X 6mm was modified. A ring terminal was soldered the ground lead and a small piece of paper clip on the hot. The paper clip piece fits well into one of the 12V slots on the PS input plug. The fan was installed, see pictures and the temp rose to 34C over 11 minutes, and was then left on for 8 hours with no problems.

--I am still waiting for the ARCTIC COOLING MX-4 Thermal Compound, to arrive, at which time I will, uninstall the main board, remove the heatsink, clean the old compound off, and identify and take pictures of the the BGA Chip (if possible). Then the face of the heatsink will be polished to a mirror finish by rubbing it on a sheet of glass with jeweler's rouge, thermal compound will be carefully reapplied, the heatsink and main board will be reinstalled and, and the temperature tests will be repeated, with and without the fan.

--Conclusions: I am assuming that the die temp must get way above the 52C measured at the heatsink, in order for the chip to go crazy, and so the heatsink and compound may not be doing a good job of sinking the heat, so replacing the compound may solve the problem, but probably not, In any case the new tests should be interesting. There is about zero clearance to install the back on the TV with the fan installed, so I may, carefully cut a hole for it. Tom66 has said it is likely that the chip will inevitably fail. When it does I will consider replacing the board, or reballing the chip, perhaps with a new one, if obtainable. I really like this TV and I plan on getting another one, as I already have a spare stand.

"Imitation is the sincerest form of television."
Fred Allen 1894 - 1956

Best Regards
Clear Ether

[SgtRock]

Greetings EEVBees:

--Well, there has been a little progress, or regress, depending on how you look at it on this Vizio M320SL 32" LED TV repair. Tom66 pointed out that the ARM Chip, marked MEDIATEK ARM, MT5396CFJ, 1203-BTAH, ETNAY642, was likely to eventually fail permanently, and I thought that Tom was probably correct. So this is what I have done so far. I managed to obtain from ShopJimmy a repair kit consisting of all boards,  and all cables, with a 180 day guarantee, for $92.05 US. See the attached sticker, which must have come from a new or low mileage unit with a broken screen or a similar situation.

--From looking on eBay, I found that the Main Board alone was going for about the same money, so I judged it to be a resonable investment, as I plan to buy another of these if possible. See the attached picture for the price of the three larger boards alone for $230 plus shipping.

--So it was working with the fan, but I would have had to cut a hole in the back, and even then it was unlikely to last. So, into the breech I stepped. I decided to remove the heat sink, identify the chip, remove the thermal compound, and replace it with Arctic MX-4, recommended here as the best. I tried gingerly to remove the heatsink by prying and twisting but no go. I then tried heat and managed to get it to release at about 100C. As you can see by the attached pictures, Vizio used a quicky rubber pad which had a very poor thermal connection to the chip and the heatsink. Also the heat sink was held down by loose plastic clips instead of screws. In any case, I applied the MX-4 and re-installed. The TV at first was showing the dreaded stripe pattern and now will not turn on at all, by any means. So now I have in mind to check the standby voltage, and all of the PS voltages and all voltage regulators. Any pointers would be appreciated. Once I have a better idea of what is wrong, I will proceed to try any necessary repairs, in order to get back to just the stripe problem.

--I know it seems that I am going the long way around the barn but I, am trying to learn something, just as much as I am, just trying to solve the problem at hand. So, once I am pretty sure I have the problem confined to the Main Board, I will try, blowing high pressure air under the ARM Chip on the theory that it might remove any of the Unleaded Solder Tin Whiskers, just for fun. I then will try to do a reball of the original chip, protecting the rest of the board with aluminum foil. I already have a heat gun, a Hakko 851 Rework Station (see picture), and a toaster oven for preheating, but I am thinking of getting one of the larger plate warmers and trying it. I still need to get a couple of items before proceeding, including, hopefully a wider and slightly taller heatsink, and figuring out how to screw it down, if possible, without creating a short. This is a long term project, and I will report back from time to time, as it progresses.

Any and all advice would be sincerely appreciated. I noticed that several of the screws holding the Main Board to the chassis were rather loose, and I was wondering if that could have contributed to the overheating ARM. And, does anyone know where to get a new MEDIATEK ARM, MT5396CFJ, 1203-BTAH, ETNAY642 Chip?

--If all else fails, hopefully I will be able to just install the new boards, and Bobs your uncle.

"If it weren't for Philo T. Farnsworth, inventor of television, we'd still be eating frozen radio dinners."
Johnny Carson 1925 - 1992

Best Regards
Clear Ether

[SgtRock]

Greetins EEVBees:

--Here is the latest progress, so far. BGA reballing is just like Brain Surgery. See one, do one, teach one. Seriously, I may indeed not succeed, but I will give it a try. I did find a source for the correct ARM chip, I believe), for $15.26, see link below, and picture at bottom. I probably will not buy one unless the original one ist kaput.

http://www.aliexpress.com/item/MT5396CUFJ-BGA-in-stock/710249126.html?tracelog=back_to_detail_b

--To uninstall and reinstall the ARM Chip, I plan to acquire a vintage Sunbeam Electric Frying Pan for preheating. I will make sure of the thermal profile ramp up and down to 150C, by using a thermocouple. As far as I can tell, a little slower is fine, it is just quick that causes problems. I will use a Heat Gun to reach 220C for removal, and 200 for reflow. And I will be installing a larger heatsink, cut, milled, and drilled. to fit, I judge, that I can go a couple of millimeters thicker, a couple of inches longer, and an inch or so wider, with the heatsink. And, I will try to get it screwed down without shorting or warping the Main Board.

--And, below is a video of a BGA reball, done with an absolute minimum of kit. This is the approach I intend to take.



--I just need to add the following items to my tool kit before I can start. I will report back is a 6 weeks or so, with pictures.
Vacuum Tweezers
Aluminum Tape (for shielding)
SunBeam 1/4" thick Electric Frying Pan, 12" X 12", I believe Lady Ada uses one of these.
Universal Stencil of the appropriate pitch
Leaded BGA Balls of the appropriate size
Amtek BGA Flux
Flux Brush
ESD Pad with Wrist Strap
A 90x90x12 Heatsink, to be modified to fit.

--As usual, any and all advice is gratefully considered.

--P.S. Last but not least, reballing an iPhone using just plain solder, amazing. See below link.



"What you will observe is a vast wasteland" (Head of FCC Referring to TV Programming, 1961.)
Newton N.Minnow 1926 -

[NiHaoMike]

If you can find the datasheet for the panel, you can probably find a driver board that will be compatible for much less than trying to repair the existing one. (Or for real fun, use a FPGA board with HDMI in!) You might be able to find a discarded monitor or TV with a bad panel and use the driver board from that.

[SgtRock]

Dear NHM:

--Thanks for the good advice. But without very exact instructions I lack the knowledge and experience to do what you advocate, which sounds like a lot of fun though. You missed my earlier post, wherein  I explain that I already have purchased a complete kit containing all boards and cables from Shop Jimmy.

--The reason I am going to the rather minor expense (~~$70) of setting up and doing a full on reball is for learning purposes, as it comes up time and again with various chips in Laptops, Phones, TVs, Monitors and what have you. Also, like the Toshiba Satellite Laptops, and MicroSoft X-Boxes, many of the Vizio LED HDTVs are known to have this particular weakness and even a new Main Board (with the dreaded Lead-Free solder balls, and the inevitable tin whiskers), will often not last long. I can tell by looking at the layout and construction of this TV that it is very well designed, but that the Unleaded Solder Ball, has proved to be, in fact a fatal error. So I am trying to improve my skill set to solve a generic problem.

--In the last year I have benched all of my 22" monitors and am now using larger sizes of discarded or eBay junker TVs for monitors, after repairing. Good 1080P TVs tend to have just as good a picture as the monitors and are much easier to find in the largest sizes. This allows me to sit far from the display, and by using a wireless keyboard/mouse, alows much greater comfort, for lo the many hours, I am at the bench.

-All of that being said, I was wondering if you would care to tell us more about your approach or perhaps point to somewhere it has been done. I looked for the data sheet to the LG LC320EAU LED 1080P display, but could not locate. If anyone knows where to find it please post.

--Thanks again for the help, even if it was mostly over my head. I am more of a part swapper, and I lack real world EE knowledge, but am always willing to learn.

"Before I came here I was confused about this subject. Having listened to your lecture I am still confused. But on a higher level."
Enrico Fermi 1901 1954

Best Regards
Clear Ether

[SgtRock]

Greetings EEVBees:

--The new Main Board from Shop Jimmy is working perfectly.

--I was able to buy a new Mediatek BGA ARM MT5396CUFJ from Alibaba for $15.36 shipping included. They informed me that they do not have any source for data sheets as they are removing the chips from old equipment, and that they are lead free. Hopefully they have already cleaned off the the old solder, so that they are tin free as well. According to the Alibaba the chip has an operating temperature of 105, and uses 66300 Watts, which I assume means 66 Watts In any case, I will continue, subject to finances, to procure all that I need to do a reball, and we shall see. From my research it would appear that Kingbo is the best flux for reball projects.

"Television has raised writing to a new low."
Szmuel Gelbfisz - Samuel Goldfish - Samuel Goldwyn
1879 - 1974

Best Regards
Clear Ether