Philips 47PFL7422D - Dim on left side (different than other thread)

[DLinkOZ]

I have a 47" Philips - 47PFL7422D. It would turn on and within a minute go extremely dim and flicker. Found both caps in both inverters (master and slave) were popped, so I replaced all four of them this morning. Powerd up and things are a bit strange:

It was bright as it should be on the right side, still dim on the left. After a few minutes, the right side went dim but there was no flicker. I unplugged the left (from the front, slave) output to the CCFL and the right side went back to a normal brightness. It has enough light output to actually light the left quite well on its own. I've let it play off the DVR for many hours now, and it's been solid.

I went back just recently, and plugged the left (slave) side back in (output to CCFL). Entire panel immediately went dim. Unplugged and it returned to how it was (right bright, left dim). Any ideas what would cause this behavior?

[tom66]

Re: Philips 47PFL7422D - Dim on left side (different than other thread)

If you look at the rear of the chassis in a dark room, you should see several holes which glow when the TV is running. Is the slave side noticeably dimmer than the master?

[DLinkOZ]

Re: Philips 47PFL7422D - Dim on left side (different than other thread)

Well, it's dimmer in the holes now because the slave is disconnected and the master side light is bleeding over (that's the extent of lighting on the slave side). If I connect the slave side, the master side goes quite a bit dimmer. Or did I misunderstand your question?

[tom66]

Re: Philips 47PFL7422D - Dim on left side (different than other thread)

No, you didn't misunderstand me. I misread your post and missed that.

Do you have a digital voltmeter / multimeter?

Where did you source the replacement caps from?

[DLinkOZ]

Re: Philips 47PFL7422D - Dim on left side (different than other thread)

I do have a meter, yes. The caps came from a local electronics supply store.

[tom66]

Re: Philips 47PFL7422D - Dim on left side (different than other thread)

Local electronics supply store is usually a big indicator of non-low-ESR capacitors which the inverters require to function correctly. The bulged ones may have actually briefly been better! Any chance you could take a picture of these capacitors so we can get an idea of the manufacturer and series?

We highly suggest buying caps from digikey.com or from the Badcaps.net store, as both provide the right parts, whereas typical store bought caps are not up to the job. Even if the worked first time, they would fail in short order (a year at the longest in a high stress environment.)

[DLinkOZ]

Re: Philips 47PFL7422D - Dim on left side (different than other thread)

Is there any reasonable way to test that? I can place an order, but would have a better warm fuzzy feeling if I could somehow determine that it was the likely cause. Such as, could I determine that proper voltage is being output to the ccfl?

Now that I snap a pic of the cap, I see immediately that it's an 85 degree part (the bin was labeled 105, my fault for not checking more closely). But I can't imagine that would play directly into it with the back off and immediately upon power up. Though it could lend itself to gauging the quality of the part.

[tom66]

Re: Philips 47PFL7422D - Dim on left side (different than other thread)

Those capacitors are certainly not suitable. Lelon capacitors are among the worst, cheapest crap you can buy. They are 85°C rated; originals would have been around 105~130°C. The temperature rating itself doesn't factor much into performance, only life. But, almost nobody, and certainly not Lelon makes low ESR capacitors in 85°C ratings.

What is the capacitance and voltage rating of them? We need to find you some suitable replacements.

You can't measure the CCFL output with a conventional DMM. Typically around 1500~2000V in operation and 3000~4000V to start the tubes at high frequency (>10kHz.) Your DMM will be roasted alive.

Without an oscilloscope there's little you can do to check how the capacitor is functioning (supply rail decoupling can't be checked), but going from your symptoms of a working TV which failed after some time and one which is constantly dim or not working, then it sounds like the only variable which has changed -- the capacitors -- is at fault.

One thing you can verify is the 24V of the power supply and see if that is stable, as there may also be bad capacitors on that.

[DLinkOZ]

Re: Philips 47PFL7422D - Dim on left side (different than other thread)

Here are the original caps

[tom66]

Re: Philips 47PFL7422D - Dim on left side (different than other thread)

These:
http://www.digikey.com/product-detai...6CT-ND/3072276
will be fine. Add $2.50 postage.

Badcaps.net does not carry 680uF 35V unfortunately.

[DLinkOZ]

Re: Philips 47PFL7422D - Dim on left side (different than other thread)

Yeah, I noticed that when I checked (wanted to try and give back for the help). But digikey order submitted, and I'll report back after I get them installed.

[cashkennedy]

Re: Philips 47PFL7422D - Dim on left side (different than other thread)

When you installed the new lelon caps did you make sure to be very careful the match the capacitance, and be very careful to match the + and - pins on the caps to the markings on the board. And you need to make sure none of the solder for each pin is able to touch / should be a clear seperation between the solder clump around each pin.

Its very possibly if one cap was different then what the bin said it had, that it could be a completely different capacitance too.

I personally think you have another issue other then using the wrong type of cap, like a short on 1 inverter, possibly caused by putting in a cap backwards, although youd expect that to cause the whole inverter to blow a fuse. Have you checked the inverter fuses with your multimeter?

[DLinkOZ]

Re: Philips 47PFL7422D - Dim on left side (different than other thread)

Values are the same (except for the temp, which didn't match the bin and my fault for not validating). Also, 100% sure I got the polarity correct and did not bridge any solder joints. I did verify capacitance and voltage per cap as I soldered, so they were all the same.

[DLinkOZ]

Re: Philips 47PFL7422D - Dim on left side (different than other thread)

I'll be smurfed! The fuse is actually bad (no continuity). So the question is - does it make sense that with a blown fuse, plugging in the slave CCFL would bring down the master side? And the age-old question: is the fuse blown the problem, or a symptom (what caused the fuse to blow, same thing that caused the caps to pop or was it the caps popping)?

[DLinkOZ]

Re: Philips 47PFL7422D - Dim on left side (different than other thread)

Success! I swapped out the fuse, so lucky and random that I had another 10a ceramic on-hand. The set is now 100% lit up. I'll still change the caps when they come in, they already shipped (digi-key doesn't mess around with shipping!).

[DLinkOZ]

Re: Philips 47PFL7422D - Dim on left side (different than other thread)

New caps arrived. While installing them won't solve any immediate problems (since there aren't any at this point), they will provide longevity to the set. Again, thanks to both of you for the assistance!

[nomoresonys]

Re: Philips 47PFL7422D - Dim on left side (different than other thread)

having similar problem, can you tell me where the 10a ceramic fuse is located, is it on the slave board or power or main, thanks.

[DLinkOZ]

Re: Philips 47PFL7422D - Dim on left side (different than other thread)

Sorry for getting back to this so late, but it was on the slave board.

[maiden790]

Re: Philips 47PFL7422D - Dim on left side (different than other thread)

Where can I buy the new fuse??