Sweet Sammy PN50C7000

**DXseekerMO** · 12-05-2018, 12:15 AM

Re: Sweet Sammy PN50C7000

Bump

**Biruslapio** · 12-05-2018, 04:09 AM

Re: Sweet Sammy PN50C7000

You probably replaced everything that wasn't the problem,i don't know if this model supports this but you can take X-main out of the equation by:
Unplugging it from the power supply and taking out the panel connectors.
Removing X-main board from TV and you can leave the panel connected to the secondary X board.
The screen will still work but grainy and purple tint,just do it for testing purposes and if that was the problem you will se samsung logo,menus etc.
Since you have no display on screen but it still lights up i say it's YSUS problem,logic board or C-boards,make sure to insert the LVDS cable properly.
Check the Voltages produced by Y-SUS board,I'm not familiar with this TV but on images i see VSCAN and VSCH checkpoints,if they are correct look at your VA voltage and if it reaches C-boards(large heatsink at the bottom of TV),because it's common to have no display because address buffers do not receive voltage or a problem with flat cables/connections.

**Michale32086** · 12-05-2018, 06:53 AM

Re: Sweet Sammy PN50C7000

Originally posted by Biruslapio

You probably replaced everything that wasn't the problem,

Story of my life..

i don't know if this model supports this but you can take X-main out of the equation by:
Unplugging it from the power supply and taking out the panel connectors.
Removing X-main board from TV and you can leave the panel connected to the secondary X board.
The screen will still work but grainy and purple tint,just do it for testing purposes and if that was the problem you will se samsung logo,menus etc.
Since you have no display on screen but it still lights up i say it's YSUS problem,logic board or C-boards,make sure to insert the LVDS cable properly.
Check the Voltages produced by Y-SUS board,I'm not familiar with this TV but on images i see VSCAN and VSCH checkpoints,if they are correct look at your VA voltage and if it reaches C-boards(large heatsink at the bottom of TV),because it's common to have no display because address buffers do not receive voltage or a problem with flat cables/connections.

Awesome info... I have a dental this morning, but I'll jump on this right when I get back..

Many thanx...

**bman4** · 12-05-2018, 07:19 AM

Re: Sweet Sammy PN50C7000

Be carfull and not to plug Boards in unless vs is under 10v. Look at toms quick guide to samsung repar.

**Michale32086** · 12-05-2018, 08:43 AM

Re: Sweet Sammy PN50C7000

OK I am back...

Here's a pic of the X-SUS area...

From what you wrote, I am guessing I unplug the X-SUS board from the red marked areas and physically remove it from the TV...

The green marked areas can remain plugged in..

Is that an accurate assessment??

Attached Files

**Michale32086** · 12-05-2018, 08:44 AM

Re: Sweet Sammy PN50C7000

Originally posted by bman4

Be carfull and not to plug Boards in unless vs is under 10v. Look at toms quick guide to samsung repar.

Thanx for the heads up.. Much appreciated..

**Michale32086** · 12-05-2018, 09:04 AM

Re: Sweet Sammy PN50C7000

After reading and re-reading your post, I figured I understood it all right..

So I went ahead and powered up...

With the X-SUS pulled completely out of the equation, I don't get ANY flash on the screen at all. Completely dead on the screen..

I get a solid and steady 212V on VS and 55V on VA...

So, I am assuming we're talking a bad Y-SUS???

EDIT: OK, hold that thought for a second. I think I need to redo the test...

**Michale32086** · 12-05-2018, 09:22 AM

Re: Sweet Sammy PN50C7000

OK..

Turns out with the X-SUS board installed, the screen does flash bright for a second or two and then dims a little, but it's still lit.. I even see a few sparklies here and there..

But nothing is displayed..

With the X-SUS pulled out of the TV, the screen is completely dead.. No flash no bright no nuttin'...

So, indicates the Y-SUS or the buffers??

**Biruslapio** · 12-05-2018, 09:50 AM

Re: Sweet Sammy PN50C7000

This is what a X-MAIN(or Z-SUS as in this video is a LG plasma) failure looks like, sparkles are also X-MAIN related if you can post a picture of the panel while it's on.

EXAMPLE video

Since the screen works for only 20 seconds there is a problem with SUS boards.

Do you have sound from inputs?
Does the LED on logic board blink or do anything?

These are your X and Y boards, circled in red are points you should check.
Post your VSCAN,15V,VSCH on Y board and VE on X while the panel is ON, i think you measure them from checkpoint to ground except for VScan,which should have it's own reference. VE is 86V, VScan/VSC -190 according to what i've found.
Here's why i circled those resistors,in my experience with LG plasmas they tend to open when IGBT go boom,don't know with samsung,wait for the board to be totally discharged before servicing.
All of them are 1 OHM,some in parallel,should read 0.33 to 1 OHM.Also i circled the fuses,make sure they are good.
Forget this purple squares on ysus image,it was already like this when i got it.

Attached Files

**Michale32086** · 12-05-2018, 10:23 AM

Re: Sweet Sammy PN50C7000

OK, just confirmed...

When the X-SUS is in, the screen "comes on" for about 30-40 seconds.. The longer the TV has sat unpowered, the longer the screen stays on...

Unfortunately, it's not a very obvious brightness.. I have to do it in a darkened room to even notice that it's "on"... So I can't get any pics of it..

I don't get any sound from audio.. No Sammy Tones or anything..

The LED on the Control Board blinks on/off every second..

On the Y-SUS Board, VSCAN is -189v, 15v_VSCAN is -134v and VSCH is 89v

Attached Files

**Michale32086** · 12-05-2018, 10:32 AM

Re: Sweet Sammy PN50C7000

On the X-SUS, VE is74v..

I should also note that, when the TV is powered up, the buttons to turn on and off do not work.. The power LED blinks when pressed, but the TV can't be turned off either by the button or by the remote..

That usually indicates a bad MAIN Board, but that was just replaced...

**DXseekerMO** · 12-05-2018, 10:33 AM

Re: Sweet Sammy PN50C7000

One bump 12h ago and look at all the replies. Sweet!

**Michale32086** · 12-05-2018, 10:38 AM

Re: Sweet Sammy PN50C7000

Originally posted by DXseekerMO

One bump 12h ago and look at all the replies. Sweet!

Yea, thanx for that..

**Biruslapio** · 12-05-2018, 11:13 AM

Re: Sweet Sammy PN50C7000

I'm at a loss,the voltages are there,you mentioned 76V for VE,is it within the panel spec?
How about the resistors and fuses?
Are you sure this main board you bought is ok?
Don't miss out on screws,they need to be tight on SUS boards,they help a lot with grounding,and don't mix them with longer screws as they will pierce through the panel.
I don't know if this samsung series lets you power only certain boards,some TVs will refuse to boot without everything in order.
Try to power only the main board,disconnect X and Y from power supply. On main board only leave speakers and the remote sensor/keyboard,does it respond?

**Michale32086** · 12-05-2018, 12:17 PM

Re: Sweet Sammy PN50C7000

Attached is the spec sticker..

VE on the X-SUS is 73v... On the sticker it says VE is suppose to be 83v but VE2 (which I can't find) is supposed to be 73v...

All fuses are good and there are no burnt/blown caps or resistors..

It was a used Main Board, so I spose it could be bad...

Powered it up with just the Main Board and the Power PCB... Nothing on the display, but the power LED blinked like normal...

Gonna grab the old Power PCB and see if that produces any different result..

**Michale32086** · 12-05-2018, 12:26 PM

Re: Sweet Sammy PN50C7000

Ooops forgot the sticker...

Put the old Power PCB on there.. No change in results..

VSCH voltage was -39 instead of +89

Attached Files

**Michale32086** · 12-05-2018, 12:39 PM

Re: Sweet Sammy PN50C7000

OK Just was re-checking the Main Video board..

While connectors and component placement is identical, this board is for a PN58C8000YFXZA and I have the PN50C7000....

Could that be the issue???

Attached Files

**Biruslapio** · 12-05-2018, 01:18 PM

Re: Sweet Sammy PN50C7000

This is a main board for C8000 series,i didn't find any info on this 58 inch model,but they probably communicate differently with the logic board.
I'm not an expert and you're in need of one,I've had a PL63C7000 with a PL50C7000 main and it worked fine.
For now use your original main.
With only main board the TV seems to respond OK then?
https://www.badcaps.net/forum/showthread.php?t=73365 look at this thread that is parallel to yours but same TV series,my next checkpoint would be on buffer boards,then X-main and Y-SUS IGBTs and MOSfets,so do that,check output buffer ICs,i'm not suspecting them because the panel lasts quite a while before shutdown,and generally when it's a buffer board Y-sus enters protection mode immediately or gets shorted.

**Michale32086** · 12-05-2018, 01:26 PM

Re: Sweet Sammy PN50C7000

Thanks for all the help.. I found a Y-SUS and buffer set for a great deal.. Gonna see if that helps anything...

I'll check out that threat for any clues..

Thanx again.. I'll follow up when the Y-SUS/Buffers get here..

Sweet Sammy PN50C7000

Sweet Sammy PN50C7000

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