Samsung HPT5054, HUGE PAIN IN THE ASS

[Truncatedhose]

I can post pictures of the boards if you want, but this is such a common TV with these problems. I've been reading all the threads here about this model, trying to find a solution, but no luck.

I have the classic no screen/no picture symptom and I've already replaced the Y-SUS and the upper Y buffer (both confirmed bad), but still have the same symptom. I would suspect I got a bad board, but my VS and VA are perfect, so how could the buffers or Y-SUS be bad? The Z-SUS doesn't have any blown fuses, and again, if it was bad, wouldn't my voltages be down? ANY HELP PLEASE?

[johns1mj]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

I believe I am going through a similar situation. Did you double check your board numbers. If a revision is different or from a different model they may not work in your tv.
1) do you have the start up chime?
2) what happens 30 seconds after start up? Do your voltages stay the same?
3) Do you get a response from the buttons/remote? Can you get sound from another source?
4) If the above checks fine did you check the screen with a flash light to see if the back lights are the problem and not the screen? (picture but very dark due to no back lights)
5) on start up do the back lights flash? Disconnect the the ribbon to the logic board and what happens?

[Truncatedhose]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

I believe I am going through a similar situation. Did you double check your board numbers. If a revision is different or from a different model they may not work in your tv.
1) do you have the start up chime?
2) what happens 30 seconds after start up? Do your voltages stay the same?
3) Do you get a response from the buttons/remote? Can you get sound from another source?
4) If the above checks fine did you check the screen with a flash light to see if the back lights are the problem and not the screen? (picture but very dark due to no back lights)
5) on start up do the back lights flash? Disconnect the the ribbon to the logic board and what happens?

Thanks for the reply. The boards are correct. The voltages stay the same after 30 seconds. I will try to check for audio. What do you mean by backlight? Plasmas don't have a backlight...?

[ReeceyBurger123]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

Plug the set in and switch on, is there a green Led on the Ymain lit up solid ?

[ReeceyBurger123]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

I believe I am going through a similar situation. Did you double check your board numbers. If a revision is different or from a different model they may not work in your tv.
1) do you have the start up chime?
2) what happens 30 seconds after start up? Do your voltages stay the same?
3) Do you get a response from the buttons/remote? Can you get sound from another source?
4) If the above checks fine did you check the screen with a flash light to see if the back lights are the problem and not the screen? (picture but very dark due to no back lights)
5) on start up do the back lights flash? Disconnect the the ribbon to the logic board and what happens?

Plasma dont have backlight, they have low level prime to keep the gases ironized which is known black glow from the screen when full black if not image is written to it.

[Truncatedhose]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

Plug the set in and switch on, is there a green Led on the Ymain lit up solid ?

Yes, it is solid.

But I have to say, the VE is 15 volts and doesn't come up if I unplug that plug from the power supply. There was another thread on here with the exact same issue with the same set, but it never resolved.

[Truncatedhose]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

Okay, a development...a BIG DEVELOPMENT and one mystery uncovered or solved? This service manual and the panel label MUST be wrong. If the VE is supposed to be 96 volts, then why is there a 25v electrolytic first in line on the trace? I think 15 volts is correct and the manual and panel are wrong. VE is usually a low voltage supply anyway. I think I'm going to shotgun the logic board and hope that fixes it.

[ReeceyBurger123]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

The Ymain smp has shutdown which is why the Led is lit up. Also the 25v cap is for the 15v decoupling for the smp controllers which use that. Also have you checked the transistors for short circuits ?

[tw2005]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

Okay, a development...a BIG DEVELOPMENT and one mystery uncovered or solved? This service manual and the panel label MUST be wrong. If the VE is supposed to be 96 volts, then why is there a 25v electrolytic first in line on the trace? I think 15 volts is correct and the manual and panel are wrong. VE is usually a low voltage supply anyway. I think I'm going to shotgun the logic board and hope that fixes it.

So , you're looking at the Xmain and at the power connector what are the labels?

Vs, Gnd, Vcc ? Vcc is 15V Ve test point on the xmain should be as per the panel sticker. I see a trace going from Vcc through a small green fuse into C4712 680uF 25V cap

[martino]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

did you try the test mode?

[Truncatedhose]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

The Ymain smp has shutdown which is why the Led is lit up. Also the 25v cap is for the 15v decoupling for the smp controllers which use that. Also have you checked the transistors for short circuits ?

Okay, so you're saying the green led solid on the YMAIN is indicating the YMAIN has shutdown? And are you saying to check the transistors on the YMAIN or on the Power Supply board? Also, if there were shorted transistors, how would there still be full VS and VA voltage?

[Truncatedhose]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

So , you're looking at the Xmain and at the power connector what are the labels?

Vs, Gnd, Vcc ? Vcc is 15V Ve test point on the xmain should be as per the panel sticker. I see a trace going from Vcc through a small green fuse into C4712 680uF 25V cap

Okay so on the power supply, the plug for the power cable going to the ZSUS (Xmain as you call it) is:

VS
VS
RTN
RTN
VE

and then the same cable plug on the ZSUS (Xmain) says:

VS
VS
G
G
VCC

So on the power supply side they call it VE and on the ZSUS side they call it VCC.

The cap I was referring to is CX821, which is the first component in the power supply board connected to the trace going to the VE pin of that plug. That cap is 220ufd 25v, that's why I was saying 95v for VE doesn't seem possible with a 25v cap like that.

[tw2005]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

Okay so on the power supply, the plug for the power cable going to the ZSUS (Xmain as you call it) is:

VS
VS
RTN
RTN
VE

and then the same cable plug on the ZSUS (Xmain) says:

VS
VS
G
G
VCC

So on the power supply side they call it VE and on the ZSUS side they call it VCC.

The cap I was referring to is CX821, which is the first component in the power supply board connected to the trace going to the VE pin of that plug. That cap is 220ufd 25v, that's why I was saying 95v for VE doesn't seem possible with a 25v cap like that.

Ok, you're looking at the PSU side, Does not look like Ve to me, Vg.

Vg is 15V, confusing yes and tiny to read but Ve is generated on the xmain and shoud be as per the sticker

[Truncatedhose]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

Ok, you're looking at the PSU side, Does not look like Ve to me, Vg.

Vg is 15V, confusing yes and tiny to read but Ve is generated on the xmain and shoud be as per the sticker

I looked again, and it definitely says VE. I'm confused now. =) What should I do?

[ReeceyBurger123]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

Ve is on the Xmain and should be about 98v, the test point is labeled near the fuse at the top.

[Truncatedhose]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

Okay, so you're saying the green led solid on the YMAIN is indicating the YMAIN has shutdown? And are you saying to check the transistors on the YMAIN or on the Power Supply board? Also, if there were shorted transistors, how would there still be full VS and VA voltage?

Reeceyburger, are you there?

[ReeceyBurger123]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

I

[Truncatedhose]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

Damn! I was wrong! IT DOES say Vg! The lower case g looks like an upper case E. What the HELL? My mistake. So, the VE test point on the ZSUS (Xmain) is 107 volts. So now what? Reeceyburger, what transistors were you talking about testing? And can you please help me troubleshoot this?

[ReeceyBurger123]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

Psu will have Vg. Y main is failed, I have the same set here to fix same issue Will be doing video on it. Theres 5 transistors on the lower smaller Ymain heatsink that normally fail test them.

[ReeceyBurger123]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

Heres an image of one I did last night, added fan to the heatsink with the commonly failing fets which you should test.