Samsung PS50C7000YFXXY powerboard

[maxvalutech]

This set has standby and sound but at switch on the Va Vs immediately shut down from their respective voltages. Low voltages remain on. Same happens with y and z connectors removed. Looks like protection comes in straight away
Tested all diodes and fuses nothing obvious seen on the board BN44-00333A or LJ44-00185A. The screen is blotchy on outside due to using water to clean it according to owner ???!!!! Will put up pic of board later but anyone have comment on this meanwhile?

[maxvalutech]

Re: Samsung PS50C7000YFXXY powerboard

Have had the board out and checked as much as I can but problem remains. Seems to me that as Vs Va come up then the feed circuit is ok but as the 2 x 180uf caps immediately discharge its either them or perhaps det circuit problem. Dont have 180uf would it be ok to test with 150uf or 220uf ? Pics herewith

[maxvalutech]

Re: Samsung PS50C7000YFXXY powerboard

This set looks to be about 5yrs old in manufacture owner said it was a bit over 3yrs since they bought it new. In another recent thread a post says that recent Samsung plasma sets have the Vs Va shut down if the respective boards y and z (x) are not connected. If this is so for this set then my conclusions re power board problem are shot. Any comment or info appreciated thanks.

[maxvalutech]

Re: Samsung PS50C7000YFXXY powerboard

Well getting nowhere with powerboard so removed heavy metalcover from over logic board.Noted green light flash sequence of about 5 sec on then 2 off which didnt seem right. Disconnected power feed and ribbon cable to logic - now green light flashing about every second which is normal. Seems the problem is with Y side main and or buffer - opt for the main.Cant find any obvious problem and no idea on tests other than fuses and resistors which all ok. Caps look ok too. Pic herewith for any comment.

[Andrew F. Ali]

Re: Samsung PS50C7000YFXXY powerboard

Samsung PLASMA SMPS Self Test Method. Try this out.
You would need to make a test-light---Two (2) 100W 220V light bulbs connected in series.
Step 1: Disconnected all the connectors to PSU board, except the AC input connector.
Step 2: Use two short wires, on connector CN807 connect pin-1 (STBY5V, Standby 5V) to pin-2 (VS_ON) and connect another wire from CN807 pin-4 (PS_ON) to pin-5 (RTN, this is GND).
Step 3: Connect the Light Bulbs to the Vs voltage output pin and the chassis GND.
Step 4: Power on the AC supply to PSU board. If all the voltages output normally, the Light Bulb will light-up. Measure the Va voltage.
* Check the output voltages are the same as the marking number voltage values. If all same voltages, that’s mean this PSU board is OK.

Your Connector ID No. and Pin Nos. may be different. Just look for the names of the pins I mentioned here.....Good Luck.

Notes:
1) If the method above does not work with your Plasma TV Power Supply (PSU), you may try to switch their connection, for example:
 If the original connection is PS_ON connect to standby 5V and the VS_ON is connect to ground (GND), we can switch the connection, like connect the PS_ON to GND, and the VS_ON connect to standby 5V.
 Make sure that the connection is connecting to the right pin/s!
2) You can use the manual method. The manually method is try to find out the Standby Voltage (STBY5V), PS_ON signal and VS_ON signal pins. Using the above method to connect the pin/s and also connect the Light Bulb tool for testing.

[maxvalutech]

Re: Samsung PS50C7000YFXXY powerboard

Thanks for that useful information. Problem now is after taking out the y main for a check over when I replaced it and plugged in the TV to power outlet it automatically started and then immediately shut down. Now no sign of Vs Va but low voltages on all the time! Left it overnight but does the same thing every time power is connected. The joys of techdom!!

[ozzy214]

Re: Samsung PS50C7000YFXXY powerboard

Thanks for that useful information. Problem now is after taking out the y main for a check over when I replaced it and plugged in the TV to power outlet it automatically started and then immediately shut down. Now no sign of Vs Va but low voltages on all the time! Left it overnight but does the same thing every time power is connected. The joys of techdom!!

Then somethign is shorting out the y main. Check that you didnt accidentally leaving something between board and chassis shorting it!!

[maxvalutech]

Re: Samsung PS50C7000YFXXY powerboard

Am waiting on y-sus from UK. Meanwhile my research has found that blink 5sec on 2 off does indicate problem with that board and normal logic board blink is one per second. Codes changed 2010. Should have researched fully earlier and not jump to conclusions based on previous results with similar faults.

[tw2005]

Re: Samsung PS50C7000YFXXY powerboard

Am waiting on y-sus from UK. Meanwhile my research has found that blink 5sec on 2 off does indicate problem with that board and normal logic board blink is one per second. Codes changed 2010. Should have researched fully earlier and not jump to conclusions based on previous results with similar faults.

I would think the fault is likely to be with the sustains or buffers, and 5 on 2 off is typical of what happens when in protection.

[maxvalutech]

Re: Samsung PS50C7000YFXXY powerboard

Final update (I hope) as the set is up and running again. But at first the new y sus didn't seem to work as the vs va turned straight off again so I removed it and the buffer board which I was checking for faults when I noticed a slight moisture coating which seemed a bit oily on top rear of that board. Decided to look at the rubbery sticky pad on chassis which the board rests on and sure enough pressing it showed up a small amount of oily wet discharge - gave all a good clean then reassembled and voila all good. The set has been in my garage for at least 5 weeks and all in dry area so these tacky strips may be the source of various shorts!!

[Rusty Brown]

Re: Samsung PS50C7000YFXXY powerboard

RE: To do self test on SMPS Board: BN 44-00333A

Connector CN801 (SMPS to Main Board) - The pin 1 is 15 V STBY

To do the self test on this board, do I have to connect this pin (15 V STBY) to VS-ON (pin 2 on CN802/connector: SMPS to logic board) or do I have supply 5 volts to VS-ON pin.

Standby voltage is normally 5 volts on these boards. On BN 44-00333A it is 15 volts. Is this correct?

Thank you.

Samsung PLASMA SMPS Self Test Method. Try this out.
You would need to make a test-light---Two (2) 100W 220V light bulbs connected in series.
Step 1: Disconnected all the connectors to PSU board, except the AC input connector.
Step 2: Use two short wires, on connector CN807 connect pin-1 (STBY5V, Standby 5V) to pin-2 (VS_ON) and connect another wire from CN807 pin-4 (PS_ON) to pin-5 (RTN, this is GND).
Step 3: Connect the Light Bulbs to the Vs voltage output pin and the chassis GND.
Step 4: Power on the AC supply to PSU board. If all the voltages output normally, the Light Bulb will light-up. Measure the Va voltage.
* Check the output voltages are the same as the marking number voltage values. If all same voltages, that's mean this PSU board is OK.

Your Connector ID No. and Pin Nos. may be different. Just look for the names of the pins I mentioned here.....Good Luck.

Notes:
1) If the method above does not work with your Plasma TV Power Supply (PSU), you may try to switch their connection, for example:
 If the original connection is PS_ON connect to standby 5V and the VS_ON is connect to ground (GND), we can switch the connection, like connect the PS_ON to GND, and the VS_ON connect to standby 5V.
 Make sure that the connection is connecting to the right pin/s!
2) You can use the manual method. The manually method is try to find out the Standby Voltage (STBY5V), PS_ON signal and VS_ON signal pins. Using the above method to connect the pin/s and also connect the Light Bulb tool for testing.