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Old 01-22-2018, 03:54 PM   #21
Truncatedhose
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Default Re: Samsung PN60F8500AFXZA, can't determine X or Y failure

Quote:
Originally Posted by tom66 View Post
You are getting shut down event if Vs and Va are good then die. Ctrl board switches them off to stop fire/electrocution in case of panel fault (crack, etc.) or failed sustain board.

There are a number of things that can cause this.

Usully the control board LED is blinking 5 seconds on 2 seconds off, which is DRV_RESET state, i.e. something is not right with something on the panel or controller boards and the control board has pulled the plug.

If your LED is blinking once a second and STAYS blinking once a second, disregard this as your control board is running normally, and most likely it is main board that is bad and not sending video. You can try checking this by doing test pattern mode by jumpering pins 3-4 of the block on the control board.

Your set has integrated control board, but the principle is similar, the hardware is copy-pasted onto the main board and behaves as a separate part essentially.

Bad X or Y board - not shorted, but bad in some way.
Bad buffer board shorting Vsch voltage and bringing -Vsc down with it.
Bad panel, crack or lost gas.
Bad control board firmware.

You can rule out bad buffer board by checking for shorts.
Similarly bad panel - check for cracks around the WHOLE panel.
Bad control board firmware is rare. Often LED on control board will blink a pattern distinct from 5-2 bliks.

If you have an oscilloscope, you can check the X/Y waveforms on power up, but if you are not familiar with what the waveforms should look like, you may be stuck here...So you would have to replace one of the two boards and see what happens.
Thank you, Tom66! I have ordered a YSUS and will see what happens. I appreciate your breakdown of possibilities, especially. Yes, I looked over the panel and couldn't find any cracks. The buffers had no shorts, etc. I will let everyone know if the YSUS does it.
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Old 02-07-2018, 05:22 PM   #22
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Default Re: Samsung PN60F8500AFXZA, can't determine X or Y failure

Tried the Y-Main, but no change. Ordered an X-Main. We'll see what happens with that.
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Old 02-08-2018, 04:39 AM   #23
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Default Re: Samsung PN60F8500AFXZA, can't determine X or Y failure

replace the 3 10uf 50 volt ceramic caps (blue) next to the transformer on the y-sus board
Had the same issue fixed
voltages come up on the y and z them drop
see the following
http://www.avsforum.com/forum/167-pl...turning-6.html

Last edited by chrismurphy; 02-08-2018 at 04:42 AM..
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Old 02-08-2018, 08:02 PM   #24
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Default Re: Samsung PN60F8500AFXZA, can't determine X or Y failure

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Originally Posted by chrismurphy View Post
replace the 3 10uf 50 volt ceramic caps (blue) next to the transformer on the y-sus board
Had the same issue fixed
voltages come up on the y and z them drop
see the following
http://www.avsforum.com/forum/167-pl...turning-6.html
Maybe i was too quick but the board is not quite the same as mine but look for a 30uf /50 volt cap or caps next the the small transformer lower center to the right could still be your problem, especially if the y ans z come up and then drop off
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Old 02-12-2018, 11:03 AM   #25
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Default Re: Samsung PN60F8500AFXZA, can't determine X or Y failure

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Originally Posted by chrismurphy View Post
Maybe i was too quick but the board is not quite the same as mine but look for a 30uf /50 volt cap or caps next the the small transformer lower center to the right could still be your problem, especially if the y ans z come up and then drop off
Thank you, I am aware of that common issue with some boards, but the whole Y-Main was just replaced and there was no change.
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Old 02-13-2018, 07:27 AM   #26
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Default Re: Samsung PN60F8500AFXZA, can't determine X or Y failure

I have a power and main board for ps64f8500 dont know if they are the same . These boards are brand new ,newver used
https://www.gumtree.com.au/s-ad/morp...ard/1162670751
https://www.gumtree.com.au/s-ad/morp...ply/1162627073
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Old 02-15-2018, 02:50 PM   #27
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Default Re: Samsung PN60F8500AFXZA, can't determine X or Y failure

Okay, X-Main (BN96-25208A) fixed the set. Thanks to all who helped. I guess there's nothing to take away from this other than with that error code on the main board (indicating an X or Y failure according to the service manual), you can start with the X board and if that doesn't fix it, then try the Y board. (If nothing obvious checks bad on either one as in this case).
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Old 02-15-2018, 03:27 PM   #28
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Default Re: Samsung PN60F8500AFXZA, can't determine X or Y failure

Glad to hear. These sets can be very hard to diagnose without an oscilloscope.

I am wanting to check the UART output on a set with a failure. On a D450 set it didn't reveal much interesting, but maybe the newer sets will report the cause of the DRV_RESET condition.
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Old 10-19-2018, 08:27 AM   #29
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Default Re: Samsung PN60F8500AFXZA, can't determine X or Y failure

I have a power supply board BN44-00603A from a PN64F8500 Plasma tv that had a shorted fet at location QX854. I replaced the fet but noticed that on the backside of the board, there is a burnt resistor at location RX813 that I can't identify due to its burnt condition. Can anyone who might have a service manual or another power supply board look and tell me what the value or marking is on that resistor? Thanks in advance!
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Old 12-26-2018, 08:19 PM   #30
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Default Re: Samsung PN60F8500AFXZA, can't determine X or Y failure

Hi Nick and anyone else who would like to weigh in:

As per your post #15, I've done the following on my PN60F8500

"Short PS-on to ground and VS on to standby and check all output voltage."

When jumpered, My power supply voltages rise up close to or above spec, but then immediately drop again. they fluctuate like this about three times, then remain off.

When not jumpered but connected, powersupply continues to supply mainboard power (so sound but no picture).

I assume this means something is wrong with the VA/VS circuits. I have checked and repaired any cold solder joints (didn't find much compared to what I've seen on other TVS in the past, this TV has low hours.)

Replacements are rare if able to be found at all, and as I'm in Canada the repair service shipping is prohibitive.

Do you or anyone else know which components regularly fail on this PS? Nothing is shorted and the fuses are good, but something looks like it's leaking down or out of spec. Any thoughts?
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Old 12-31-2018, 03:20 PM   #31
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Default Re: Samsung PN60F8500AFXZA, can't determine X or Y failure

I just want to confirm this but nothing else was connected to the power supply correct?

All wires and connectors going to the main board, Y-sustain, and or other boards were all removed when the jump was done correct?

If so, then your power supply does seem to be at fault, and per the last post 15 you are referencing, please read the details of the post to fix your board.

If not, then please try again with the power supply board isolated from the rest of the TV set.

Good luck.
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Old 12-31-2018, 04:21 PM   #32
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Default Re: Samsung PN60F8500AFXZA, can't determine X or Y failure

Thanks Nick,

I have reflowed everything as per post 15, and the tests are done with the board completely isolated before jumpering. When you repair these boards, do you common reflow them or do you find you need to replace parts too?
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Old 01-01-2019, 10:53 AM   #33
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Default Re: Samsung PN60F8500AFXZA, can't determine X or Y failure

Most often the damage is obvious such as needing to reflow the board and replace shorted transistors. Often the traces to burn up all the way instead of the more simple cracked solder joints that can be simply reflowed, and so we will need to rewire the trace to the transistors. We almost never see small surface mount component failure with this specific model such as diodes, surface mount transistors, or IC's. Simply go with your meter across the transistors that are mounted on the heatsinks and check them all for shorts. Of course if you have any voltage left in them even if it is half a volt, it will show you a false short, so make sure you don't have any more voltage going through those.
Check both of the heatsinks on the cold side of the board, and you should find your problem.
We have occasionally seen 1 resistor also fail on these, this would be a small surface mount component on the back side of the board which burns up and actually physically burns the board, so when that occurs its easy to spot as you can usually see it visually on the front side.
If you could take a picture of the front side of the board, I can tell you if that resistor burned up or not.
I know what I just said doesn't make much sense, but once we have a picture it will make more sense.
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Old 01-01-2019, 01:41 PM   #34
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Default Re: Samsung PN60F8500AFXZA, can't determine X or Y failure

It makes sense. I'll get a picture in a bit. This power supply is in very nice shape though. When I went over it looking for cold solder joints I couldn't even find any... but given the jumpering tests I'm 100% sure it's the PS. It's a low hour TV too. I'll give it one more try with a magnifiying glass and upload some pictures in an hour or two.

-Jeff
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Old 01-01-2019, 09:07 PM   #35
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Default Re: Samsung PN60F8500AFXZA, can't determine X or Y failure

I've never uploaded pictures before, so this is my first go with resizing etc. I can take better pictures tomorrow in natural light.

I realize the bottom lug is damaged... I'll own up to that but it's just the corner of the PS.
Attached Images
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File Type: jpg tl.jpg (964.8 KB, 12 views)
File Type: jpg tm.jpg (1.15 MB, 12 views)
File Type: jpg tr.jpg (1.24 MB, 13 views)
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Old 01-01-2019, 09:23 PM   #36
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Default Re: Samsung PN60F8500AFXZA, can't determine X or Y failure

If you are going to check your power supply without the Y and X boards connected you need to have a load on the Vs supply of the power supply, you can use 2 60watt incandescent lamps in series between Vs and ground. without a load the OVP circuit will shut down the power supply
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Old 01-01-2019, 10:58 PM   #37
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Default Re: Samsung PN60F8500AFXZA, can't determine X or Y failure

Do you know if that is something specific to this model? I've not experienced that in other Samsung plasma models of similar production year.
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Old 01-02-2019, 06:41 AM   #38
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Default Re: Samsung PN60F8500AFXZA, can't determine X or Y failure

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Originally Posted by jjanssen7 View Post
Do you know if that is something specific to this model? I've not experienced that in other Samsung plasma models of similar production year.
I've encountered it on a few sets but I think it's not an issue on these newer Samsung sets. Reason being that the Y-main and X-main actually go to very low load levels under dark picture levels so it would be untenable to have the PSU shut down every time!
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Old 01-03-2019, 05:51 AM   #39
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Default Re: Samsung PN60F8500AFXZA, can't determine X or Y failure

So this one is still being very fussy. When the PS is disconnected from everything and jumpered as per post 15, VA comes up to the midf 50's (v) and then once the VA shuts off (1/2 second?), goes back down until the VA "resets" and tries to bring the VA back up to spec. it does this cycle about 4 or 5 times and then does not attempt to bring the VA up again.

As soon as jumpered, the rest of the board always stays on as expedted... tested as 405 across the main caps, 15v and 5.3v line stays up too. It's just the VS and VA that cycles and then shuts down.

This may be a clue of what's going on: Once, on the bench (and out of the TV) VA came up to 54v and stayed there. VS could be adjusted as normal, but the VA could only be adjusted (using the trim pots) up to 54v. Is is possible that something is pulling down (slightly) the VA line upon startup and therefore 99% of the time VA and VS won't settle at near specs and remain on?

Keep in mind this is still with the board disconnected. The board has been reflowed, and I'm pretty proficient with a soldering iron so I'm (rather) confidant there are no cold solder issues (anymore). If there ever were, they were very minor.

Thoughts on what I should look for next? Does the 54v ceiling for the VA no matter how the trim pot is adjusted mean anything?

Last edited by jjanssen7; 01-03-2019 at 05:52 AM..
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Old 01-03-2019, 09:24 PM   #40
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Default Re: Samsung PN60F8500AFXZA, can't determine X or Y failure

You won't get proper voltages without a load on the Vs
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