Philips 42PFL9803 - chassis Q529 - two blinks - shot FDS8884 FETs on main board - typical fault

The Philips 8000/9000 series from around 2010 are my favorites after the Panasonic NeoPlasmas. This one came in with the two blink code. The seller said it suddenly switched itself off and never came back alive.

Just look at this. Two fans and four decent speakers. Only one adhesive tape, the rest is done with clips. The power supply is built for eternity. Back in those days, TVs used to have a protective shield in front of the panel and the frame was rock solid. The golden age of LCD TVs.

Ok, service manual readily available at elektrotanya.com. The Philips manuals from those days are enormously detailed. They even explain the DC/DC regulator circuitry. Real engineering pride. They always give me good confidence to attempt any repair, even on board level. First thing to do with a dead Philips is to activate the SDM (service default mode). This is done by shorting the SDM point on the main board to ground:

The device will ignore a number of checks and keep running. Also, it will morse an extended error code via the stand-by LED. In my case it was 1 long - 8 short, which means code 18. Let's look it up:

Aha, so next task was to locate the DC supply circuitry on the main (SSB) board and measure. I found a broken fuse:

I measured the FETs right next to it and found 7U05 to be dead short. It was the 1.2V DC supply. All the FETs are FDS8884. Didn't have those in stock, but I had a number of FDS8880, which are from the same family, but can handle more current. After removing the FET I also did an A-B check on the two identical PWM chips on the underside and found nothing alarming. So the PWM chip could still be ok.

Now, for testing I connected a fuse holder with a 4A fuse and started the device. Klack klack - dead - blinking. The fuse blew again! Was I a little to hasty this time?

The FET was shorted again. Why? Because I was sloppy and did not properly check 7U06, which wasn't dead short but almost. This so-called 'lower FET' goes to ground and 7U05 goes to 12V plus. Therefore, this sucker killed my new FET by pulling it to ground.

Now this got me thinking again: if 7U05 goes short, which is connected to 12V and is feeding directly into the 1.2V line, 12 volts are hitting the processor! Even for a short period of time, this could be fatal for main processor's core. I also did some research on the net and that did not lift my spirits, either. In a number of forums I found a couple of similar cases with no good ending.

With mixed feelings, I replaced both FETs this time. I connected the board to my bench supply, limiting the current to 500mA. I first connected the 1.2V line directly and it only pulled much less than that. Chances were high that the processor was still good.

Then I connected the 12V feed. The DC/DC regulator came up ok and the board pulled a constant current around 550mA. Nice.

Back in the TV, I still kept the 12V feed connected to the bench supply. The TV wouldn't come up unless I raised the current limit to 1600mA.

But that did the trick. It was working again! I was lucky. No ICs fried. A cheap repair.

Hallo Frau Johansson!

This TV confirmed my opinion about the 8/9er series. Brilliant image! Totally even backlight, crisp colors, very high contrast. Like all LCD TVs I've seen, it does not match the natural colors of a Panasonic NeoPlasma. The viewing angle is a little critical, too. The colors quickly wash out viewed slightly from the top. Like many LED LCDs, it emphasizes reds a little. The software does offer a custom white balance, which does help somewhat.

The sound is powerful, homogeneous and spacey, thanks to four proper wide-band speakers.

Epilogue

I was lucky++. Later I found the following warning note in the manual:

And this:

These guys know their stuff!

I should have checked the FETs first. In my case, the fuse blew and they were inactive, anyway. But if they had produced over-voltage without blowing the fuse, I definitely would have fried the main processor. The main board is not available anywhere, not even in the most exotic countries.
Always fully read the fucking manuals!

As this TV had some mileage, I also had a look at the power supply's solder joints. None of them showed any signs of aging. As a precaution I re-soldered all FETs and diodes. All heavy and hot parts are mounted in rivets, the heat sinks are ridiculously over-sized. They get a little more than hand-warm at best.

A great machine. However, it seems to have trouble with the DC/DC stage sometimes and according to some voices on the net, it may fry its processor.

So what about the three blinks error code?

The same model was on eBay at the time, with a three blink error code. According to the manual, this means 12V supply failure. Your first instinct would focus on the power supply. But, from what I know now, I'd suspect an identical failure, albeit with no open fuse. The DC/DC stage might produce heavy over-voltage and there is nothing the protection circuitry can do about it except cutting the 12V supply. The warnings from the manual have to be taken very seriously. The question is: did the ICs survive the attack or not?

Samsung UE46D6200 - double image, ghost image - thin black horizontal line - panel defect

A friend sent me a picture of his Samsung and asked me if I could repair it. It suffered from double images in the upper half and a thin horizontal line on the lower third of the screen. He said that the line appeared first and the double images came later.

My first rule of TV repairs says: horizontal, irregular structures or single black lines are panel faults. They are caused by defects in the gate drivers, which are partially or fully shorted.

Knowing about the disastrous quality of the Samsung D series - I see a defect D with panel fault almost every week on eBay or eBay classifieds -  I had no doubt about it that this was yet another panel fault. I picked the TV up and took the opportunity for some investigation. Maybe it was a bonding problem and I could fix it with a hack.

The Samsung panel had no Y- (gate driver) boards and thus, no bonding on the left or right side to the panel. The only connection to the panel is made on the bottom of the screen, which drives both, the gate- and datalines.

The bonds and driver chips did not respond to any pressure or bending. They seemed ok. I also unplugged the two connectors to the TCON-board one after another to see if one side has the fault. Nope. The double image would not go away, regardless of what I did.

The problem with this type of panel are the gate drivers, which are inside the panel. On the glass, to be more specific. The semiconductors are sitting on the glass substrate. Absolutely no chance to repair.

So, this was a hopeless case. I removed all the boards, which had no fault, and dumped the rest. I also kept the nice thick plexiglass light guide sheet from the panel, this might come in handy some time.

My friend bought a nice Panasonic, which I recommended to him. I hope (and expect) that this one will last longer than the Samsung crap, which ran for ridiculous 3 1/2 years. Unless Panasonic bought panels from Samsung :-o

If you like to learn a lot about how LCD panels work, I recommend Ken Liew's ebook LCD/LED Screen Panel Repair Guide. It is a large, yet sometimes chaotic and hard to read - Asian English :-) - collection of tips and tricks on panel repair, written by an experienced practitioner. He spends some time explaining the cause of double images and suggests pretty wild hacks to revive the TVs, albeit with some loss in image quality.

The Asian repair guys generally tend to dig much more into the devices.

Toshiba 42SL738G - switches itself off - loose screws and potentially bad solder joints on power supply board

A friend got this TV from eBay classifieds. The seller said that after about 1h the TV would switch itself off.

A TV switching itself off when it is warm has either a problem with cold solder joints or some semiconductor is flawed. I didn't waste time waiting for that event and opened the set right away. First thing I noticed was the fragile plastic case. Not impressed.

Toshiba did not use any adhesive tapes here, applause for that! However, the power and logic board (the green in the center) were so ill-fitted to the chassis that they bent. Look at that:

Jesus, Toshiba! Seeing this directed my attention to the power board, which might have had a problem with cold solder joints. I did not see any obvious cracks on the joints of the FETs and diodes, nevertheless I re-soldered all of them, just to be safe.

None of the FETs and diodes had rivets in their solder joints. Boooh! This is very cheap and prone to fail eventually.

I also noticed that all screws besides the one of the backlight board were loose. This can cause problems when a ground screw is affected. It can even kill a TV (see Panasonic Plasma loose screws)

After tightening everything up, I let the TV run for half a day and a couple of evenings and it was flawless. At least electrically. The image suffered from the "dirty screen symptom". Look at the vertical, regular streaks:

They appear in regular distances, yet in alternating intensity. First I thought there was dirt in the panel, like it tends to accumulate in panels with CCT backlight, due to electrostatic charge and heat. However, in an edge-lit LCD TV there is neither of that. After some research I realized that this seems to be a well-known issue among all brands. The reason is the hunt for ever more contrast and dark blacks, which require aggressive filtering. If the filter foils in the panel do not perfectly align, those patterns appear.

This TV is a mixed bag. The image is quite ok, but suffers from the dirty screen symptom. The sound is very thin. The overall build quality is mediocre.

Considering the cheap price my friend got it for and the 0€ repair, this doesn't matter much.

Sony KDL-26EX555 - stuck in ageing mode - white screen shows TMP, TIM - TV is bricked

A friend brought me this Sony, which he got from eBay classifieds. In the ad, the owner said it had no sound. Well, that's not at all what I found.

The set would start up, flash the normal image and then show a white screen with two numbers: a temperature TMP and a countdown TIM. This is the so-called ageing mode, which can only be activated via the service mode.

In ageing mode, the power LED blinks continuously and the TV will not go to normal stand-by anymore. The remote control has no effect on anything, neither do the switches on the side of the case.

This is a screenshot from a video I took. The normal image flashed very quickly, no chance to take a normal shot.

After that, it looked like this:

I browsed the net and it seems that this happened to quite a few people with other Sony TV models. Either they inadvertently pressed some keys on the remote or the TV suddenly was in that state when it booted. One suggestion was to press the Analog/Digital button on the remote. Didn't work.

This looks like a software bug. The device is bricked. It is impossible to get out of the aging mode without the means they have at the factory.

There are two choices:

• Look for a local Sony service, who may have the means to unbrick the TV
• Buy a used main board (# 1-884-958-21). I only found some for the EX553, which has no sat receiver. 20 british pounds. Not so bad, may be cheaper than the Sony service.

I'll let my friend decide.

In the meantime, Sony support suggested pressing the Up key on the remote together with the On/Off button on the TV. Nonsense. Another suggestion was to press the Menu key on the TV for longer while plugging in. Also nonsense. They don't have a clue!

Sony Service Manuals used to be better

The service manual of this TV has some nice color images for assembling and disassembling, and some block diagrams, which explain things on a high level. But no schematics for anything. What happened to Sony? I am disappointed.

Panasonic Plasma TX-P50STW50 - 7 blink error code - Z-sustain board TNPA5524 defekt

It was about time to fix a Panasonic Plasma TV, my favorites! I recommended this one to a friend, who was looking for a 50 inch. It was listed on eBay. The seller had observed the 7 blink code. My friend got it for 200€.

A look inside:

Panasonic finally picked up the idea to install a woofer speaker with its own cabinet. The TV also sports WiFi and Bluetooth for the 3D glasses. My GT30 has none of that. 

The first check in a 7 blink Pana goes to the SC board (Y-sustain). It had no short on the supply line and none of the semiconductors measured suspicious. According to the service manual, on this model, the 7 blink can also be caused  by the SS board (Z-sustain). And lo and behold, this one had a short on the supply line.

A closer look revealed shorts on the following semiconductors:

As the IGBT transistors are working in parallel, I unsoldered them and measured them individually. As it turned out, only three of the 30F132 IGBT transistors were dead. Both from the center and the one in the middle of the group of three.

Anyways, a new board was necessary. The plasma TVs of the previous generation used the 30F131, which has a lower current pulse capability. I could not cannibalize my spare SS board.

My favorite supplier flattvparts.co.uk had one board left. Now, you need to be very careful here, because there are many versions of the TNPA5524 board around, which all look similar, but they aren't equal. 

Check this label:

There are RFUU, REUU, RHUU (and probably more) types around. Each has a different configuration of transistors and coolers.

The new board fixed the TV. I found brownish areas on the old board, a sign of high temperatures. To improve cooling, I unsoldered all coolers from the old board and put them in the areas where the most heat seemed to build up. I also measured the temperatures. I put a bigger cooler on the transistors, where one maybe had been the reason for the failure.

On the SC board, I put the same cooler on four transistors, which seemed to heat up more than average.

Evangeline Lilly was beaming into the room. An image only the best plasma TVs are capable of. Just compare it to the Philips LCD I fixed recently: Lilly on LCD. The difference in color spectrum is striking.

This is a brilliant TV. The picture is awesome and finally, also the sound has become acceptable. The ST series misses more fine-grained image adjustments, but the available modes work very well right out of the box.

Here is the list of the high power semiconductors:

SC only

D RFUH25 (SC)

D DAF30A (SC)

T DG301 (SC)

T 30F131 (SC) can be substituted with F132

T R5007 (SC)

T RJP6304 (SC)

SS only

T DG302 (SS)

T RCJ200 (SS)

T RCJ220 (SS)

SC & SS

D RFUH20 (SC, SS)

T 30F132 (SC, SS)

T 45F132 (SC, SS)

Sony micro HiFi system CMT-G2NiP - not starting - defect voltage regulator toko 73400 and shorted capacitor

I took this micro receiver home on new years eve. It belongs to my friend's neighbor. Coming home at 2:30am, I could not resist to check it out. The device wouldn't start. A click, standby red and then nothing.

After some poking around I found that a voltage regulator on the processor/main board was getting very hot. It is a Toko 73400 and it did not produce any reasonable voltage at its output. I measured the output line against ground and it was short. Then I lifted the output pin and measured again. The short was on the IC. The plus line had no short. At least that was what I thought I had measured then...

Ordered 10pcs for little money from Aliexpress. Almost a month later, the chips arrived.

The chip had not been soldered to the pad properly. I applied solder to the pad with the iron and reflowed a new chip with hot air.

With great expectations I started the device. Nothing. Damned.

Measured again. There was still a short! It couldn't be the new regulator. More likely, I screwed up my first measurement. I started unplugging the many connectors one after another. It turned out that one connector was linking M-GND to GND. That shorted the regulator output to GND. There was a short between M-GND and the +7V line on the main board. M-GND had no connection to GND unless this connector was plugged in. I poked around to find something and after a while I hit the large black e-cap you see on the left side. It had the same reading against M-GND on both pins. This sucker did not look suspicious at all. No buldge. The ESR reading was good, because it had a short!
Ahhh, measurements...sometimes they are your enemy :-/

It was cheap crap of a brand I had never seen before. Shame on you, Sony! I replaced it with a decent Nippon Chemicon. This fault will never appear again!

The receiver is working all right again. Fixed for 3€ parts. In a repair shop, they would have swapped the whole processor board for a lot more bucks, if at all.

I am not entirely sure whether my first assessment of the regulator defect was right. Well, not much time and money wasted and a new one can't hurt, as it had to withstand a short. Now I have a batch of 9 adjustable, robust 1A, 1.3-12V low drop voltage regulators left. They might come in handy sometime.

Philips 37PFL9604/H12 - distorted colors / solarization - AS15F chip defect on TCON board

Same procedure as last year, Miss Sophie!

A colleague asked me to fix his TV. From the symptoms he described, I was pretty sure this would be another AS15F chip case. Philips TVs of the generation 2008/2009 will all break after about 6 years it seems. The AUO TCON boards have this built-in bug.

This image is typical for a mild AS15 failure. Shimmering magenta colors where they shouldn't be.

This is what it should look like. The boot image is actually an excellent test for gamma failures. I wish it would stay longer for testing. Any aberration in the blue gradients to other colors is a clear sign of gamma problems (the magenta stripes of the moiré patterns don't exist in reality).

Let's have a look into the machine:

The 9er series has nice features like big speakers and built-in WLAN. The back cover is removable without loosing the stand screws (that's extremely rare), and the TCON is not buried under the stand. Nice one, very serviceable.

So here it is, the blue trouble child. The AS15 is in the upper right corner.

On the heater plate with 160°C and with the hot air gun at 420°C, the chip comes off easily.

The first attempt was almost successful. The image didn't look 100% right. It was difficult to pin down its faults. Some dark areas in some scenes where too bright. Other scenes looked perfect. In other words: some gamma value had to be wrong. How can this be? It is not unusual that new AS15 chips don't work perfectly. I swapped the chip again and this time it looked good.

Here are the VGAMMA measurements of the first chip and the second chip in brackets. As you can see, the first chip isn't completely broken, but he second is much more continuous, even though there are a few jumps in it.

v1: 15.17 (15.2)
v2: 15.09 (15.12)
v3: 9.5 (10.24)
v4: 8.5 (9.55)
v5: 8.4 (9.24)
v6: 5.9 (7.08)
v7: 5.85 (7.0)
v8: 5 (6.25)
v9: 5 (6.2)
v10: 3.75 (4.6)
v11: 3.57 (4.4)
v12: 3.13 (3.9)
v13: 0.280 (0.333)
v14: 0.235 (0.271)

It is a mystery to me how some of the chips work in such a distorted way. I always handle them the same, therefore I am pretty sure it isn't my fault. Some work, some just don't.

Et voilà. Everything is back to normal. Frau Johansson was not available today, so I kindly asked Miss Evangeline Lilly for a test.

This TV is able to produce very dark blacks. I think it has a special filter layer in the panel. The orange and yellow tones are a little weak, but I am a spoiled plasma viewer :-)

The sound is the best I have ever heard in any TV thanks to the proper two-way stereo speakers, which live in their own, closed compartment.

Due to high-quality parts everywhere I could not find any suspicious capacitor. All made in Japan and good for many more years.

The higher series Philips from 2008-2010 are just very good machines.