Samsung 226BW blur

[POM_MJ]

Hi, I've a Samsung 226BW with colors blur problem, see pictures attached.

1. caps on IPboard already replace with Panasonic FM, UCC LXZ and Rubycon ZLH
2. all CCFLs backlight are good (I tested by disconnect the Panel connector, then powered ON, the screen is fully white.)
3. all voltages are good on both IPboard and logic board, included 5V for panel when switched ON.
4. the problem is, when power ON without signal cable connected, the box "Analog" / "Digital" would appear,
then the box "Check Signal Cable" show and moving around the screen with blurry colors.

Does anyone has found problem like this before?
Is this problem came from Panel or logic board?
Panel part number is M220Z1-L01
(I suspect the logic board, but I can't find an identical board for test. )
please advise.

[pedro]

Re: Samsung 226BW blur

Hi, I've a Samsung 226BW with colors blur problem, see pictures attached.

Does anyone has found problem like this before?
Is this problem came from Panel or logic board?
Panel part number is M220Z1-L01
(I suspect the logic board, but I can't find an identical board for test. )
please advise.

I'm assuming that all your replacement work and components were good. My guess is that you will find there is ripple on at least one of the supply rails resulting in unwanted signal modulation, and I expect it will be at switcher frequency.

Using a CRO, I'd start at the display board and work back through the video board. If you don't have access to a CRO you can sometimes fudge it by using your multimeter on its most sensitive AC volage scale but some require a DC-blocking cap in series to remove the rail DC voltage from the meter input.

If ripple is present in any significant amount it points to:
(a) inadequate filtering by caps (revisit cap replacement)
(b) incorrect switcher frequency? (check switching controller data sheet)
(c) other faulty component - now that is broad I know.

But hey, it's a Samsung. Anything's possible ....

[POM_MJ]

Re: Samsung 226BW blur

Thankyou for reply.
I'm quite good in electronics repair and soldering skills.

I've an oscilloscope at my workplace, I will borrow to check the signals by follow your suggestions.
update informations and better pictures will post later.

[POM_MJ]

Re: Samsung 226BW blur

Here are better pictures.

I've used oscilloscope to measure all voltages ripple, none of them found.

When I supply 14V to the logic board, X710 osscilated sinewave properly at 14.318MHz just 2-3 seconds then waveform distorted.
This could be GM5822 damaged?

[Agent24]

Re: Samsung 226BW blur

I've used oscilloscope to measure all voltages ripple, none of them found.

When I supply 14V to the logic board, X710 osscilated sinewave properly at 14.318MHz just 2-3 seconds then waveform distorted.
This could be GM5822 damaged?

Do you mean you found no ripple or you found no voltage at all?

What is X710? I can't find it in the schematic... Maybe it is faulty?

(Also, I believe when checking crystals etc you can cause the oscillation to be altered by the probe?) - someone else confirm this please!

[PlainBill]

Re: Samsung 226BW blur

Do you mean you found no ripple or you found no voltage at all?

What is X710? I can't find it in the schematic... Maybe it is faulty?

(Also, I believe when checking crystals etc you can cause the oscillation to be altered by the probe?) - someone else confirm this please!

X710 is shown at the left end of the bottom of IC310, the GM5822.

Yes, a scope probe can distort the waveform, but I would expect the distortion to start at once, not 2-3 seconds later.

POM_MJ, did you check both sides of X710? I believe only one side would be susceptible to loading by the scope probe.

PlainBill

[POM_MJ]

Re: Samsung 226BW blur

Do you mean you found no ripple or you found no voltage at all?

What is X710? I can't find it in the schematic... Maybe it is faulty?

(Also, I believe when checking crystals etc you can cause the oscillation to be altered by the probe?) - someone else confirm this please!

sorry for my english.
I mean found no ripple at all voltages, 5V,5Vpanel,3.3V,1.8V.
X710 connected to pin 200-201 of the GM5822 positioned as PlainBill told.

X710 is shown at the left end of the bottom of IC310, the GM5822.

Yes, a scope probe can distort the waveform, but I would expect the distortion to start at once, not 2-3 seconds later.

POM_MJ, did you check both sides of X710? I believe only one side would be susceptible to loading by the scope probe.

PlainBill

Thankyou Bill,
Pin 200 (XTAL) = No waveform (or very small)
Pin 201 (TCLK) = Sinewave 14.318MHz, but distorted after 2-3 seconds.
too hard to take the waveform's pictures, I will try.

[PlainBill]

Re: Samsung 226BW blur

sorry for my english.
I mean found no ripple at all voltages, 5V,5Vpanel,3.3V,1.8V.
X710 connected to pin 200-201 of the GM5822 positioned as PlainBill told.



Thankyou Bill,
Pin 200 (XTAL) = No waveform (or very small)
Pin 201 (TCLK) = Sinewave 14.318MHz, but distorted after 2-3 seconds.
too hard to take the waveform's pictures, I will try.

I don't think a picture of the waveform would help.

TCLK would be the output, XTAL the input. The loading of a scope probe on TCLK should have very little effect.

I agree with your conclusion - the GM5822 is probably defective. You could try replacing the crystal and C365, C366, C373 and C374, but I doubt that would solve the problem.

PlainBill

[POM_MJ]

Re: Samsung 226BW blur

I don't think a picture of the waveform would help.

TCLK would be the output, XTAL the input. The loading of a scope probe on TCLK should have very little effect.

I agree with your conclusion - the GM5822 is probably defective. You could try replacing the crystal and C365, C366, C373 and C374, but I doubt that would solve the problem.

PlainBill

Replaced X710, C373, C374, has no affect.

I have a working Samsung 2232GW, I will use their boards to test 226BW's panel.
hope the panel is still good, then I could find GENESIS GM5822 for replacement.

[Agent24]

Re: Samsung 226BW blur

Well, looks like someone is selling them right here: http://cgi.ebay.com/GM5822H-LF-IC-/110460310863

Hopefully that IC is the faulty one!

Hope you've got the skills\tools to replace it too.. lol

[POM_MJ]

Re: Samsung 226BW blur

Well, looks like someone is selling them right here: http://cgi.ebay.com/GM5822H-LF-IC-/110460310863

Hopefully that IC is the faulty one!

Hope you've got the skills\tools to replace it too.. lol

Thankyou Agent24.
I've hotair SMD rework station, but I'm not sure about my skills to replace the chip too.

[jsog]

Re: Samsung 226BW blur

It's a microcontroller, which would likely need firmware programming (requiring hardware, software, and a good firmware image).

There are a few places online selling that whole BN41-00807A board. Whether any of them are trustworthy, don't know.

[POM_MJ]

Re: Samsung 226BW blur

It's a microcontroller, which would likely need firmware programming (requiring hardware, software, and a good firmware image).

There are a few places online selling that whole BN41-00807A board. Whether any of them are trustworthy, don't know.

I guess, the firmware stored in SPI flash memory on board (IC313 : MX25L4005M2C-15G), may be corrupted.
tomorrow I will check the 226BW's panel with 2232GW boards.
from their service manual, they're used same panel.

[PlainBill]

Re: Samsung 226BW blur

I guess, the firmware stored in SPI flash memory on board (IC313 : MX25L4005M2C-15G), may be corrupted.
tomorrow I will check the 226BW's panel with 2232GW boards.
from their service manual, they're used same panel.

If it were only a matter of display problems I would agree that it could be corrupted flash memory. That does not explain the distortion you observed on the crystal drive line.

PlainBill

[POM_MJ]

Re: Samsung 226BW blur

test the 226BW's boards with the 2232GW's panel (M220EW01 V2) working fine.
test the 2232GW's boards with the 226BW's panel (M220Z1-L01) not working, the screen display full of vertical lines with randomly colors.

now, I'll focus on the M220Z1 panel PCB.

Where should I start looking? or Do I need to buy a new panel?

[PlainBill]

Re: Samsung 226BW blur

test the 226BW's boards with the 2232GW's panel (M220EW01 V2) working fine.
test the 2232GW's boards with the 226BW's panel (M220Z1-L01) not working, the screen display full of vertical lines with randomly colors.

now, I'll focus on the M220Z1 panel PCB.

Where should I start looking? or Do I need to buy a new panel?

Good job of troubleshooting, you have at least localized it to one subassembly. Also, good use of the pink foam in the first picture.

There are a limited number of things to test on the panel board. First, see if pressure on the bonds of the flex conductor (the amber plastic material) to the panel board has any effect. These are the regions labeled DR1, DR2, DR3, etc. The flex conductor also is bonded to the glass LCD panel, so try compressing the panel at the edge slightly.

The components in the second picture of the panel board (U1, U9, etc) are also suspects. They generate the voltages the panel needs. And of course, U2 is the main decoder.

Even if I have mentioned it already, the excellent pictures makes this much easier for me. I appreciate it.

PlainBill

[Agent24]

Re: Samsung 226BW blur

What effect does the working panel have on X710's waveform??

Maybe it's not necessary to know, but it seems like it would be interesting.

[POM_MJ]

Re: Samsung 226BW blur

Good job of troubleshooting, you have at least localized it to one subassembly. Also, good use of the pink foam in the first picture.

There are a limited number of things to test on the panel board. First, see if pressure on the bonds of the flex conductor (the amber plastic material) to the panel board has any effect. These are the regions labeled DR1, DR2, DR3, etc. The flex conductor also is bonded to the glass LCD panel, so try compressing the panel at the edge slightly.

The components in the second picture of the panel board (U1, U9, etc) are also suspects. They generate the voltages the panel needs. And of course, U2 is the main decoder.

Even if I have mentioned it already, the excellent pictures makes this much easier for me. I appreciate it.

PlainBill

U1 seem to be AZ1117-2.5, 2.5V 1A low dropout linear regulator.
I will use the oscilloscope to check voltages and ripples on the panel's PCB.

What effect does the working panel have on X710's waveform??
Maybe it's not necessary to know, but it seems like it would be interesting.

Sorry, I've forget to check the waveform at X710 TCLK with the panel M220EW01.

[0burn0]

Re: Samsung 226BW blur

Can You tell me what parts Q4,Q5 and U5 are
I cant see labels on them

[selldoor]

Re: Samsung 226BW blur

This thread is 3 years old!!! try cleaning yours with IPA - Have they burnt up?

POst a picture of them close up in the position where they are on the board