Replacing the Y-MAIN or Y-SUSTAIN Board in Philips 42PF9630A/#&

If the image looks normal but misshapen then the Sustain and buffer boards are functional - their role is strictly to transform the image data into direct commands for pixels from the plasma panel.
The shape, size and aspect of the image is encoded in the image data which is determined by the processor on the mainboard which also stores the firmware and the commands, and is used to do the diagnostics. So either the processor is failing and the mainboard will have to be replaced or the image data get corrupted - check the data cables between the mainboard and the sustain boards. If the cables are good then replace the mainboard
http://www.partstore.com/Part/Royal+Philips+Electronics/Philips/42PF9630A/Royal+Philips+Electronics/Philips/996500038481/New.aspx

Hi.

As such boards are cheap and fail quite easily (both the two sustain and the buffers) Philips service manuals are more oriented at board swapping then at proper testing. In this particular case the buffer boards fail very easily because of a bad soldering to IC. The short will regularly blow the main sustain board.

To start when a main sustain (e.g. Ysus) is fried the TV will go in protect mode with the led flashing in standby. One test is done disconnecting the Sus board (with power off) and restarting the TV. If TV does not go in protect, then the sustain board was good.

If there is no protection:

The first thing to check on a main sustain board is the fuse. If the fuse has blown the IC is probably fried.I believe fuse is F5004. Check for swollen capacitors that may have blown. Test the FET. That is the core of the board as it is the power amplifier.


Here the service manual:PHILIPS_SM_15540.pdf - Right Click "Save Target As"

Here a more useful service manual. Check and follow troubleshooting diagrams in manual.

Here some troubleshooting from users.

Note:if buffer board was shorted, then the main sustain board is usually faulty.

Regards.

Ginko

Hello,

Problem is in either power supply or the Y-Sustain board.

The Y-Sustain is a relatively large board out of which go connections to the side of the display; it's therefore closer to either the left or the right side of the display, has at least one rather large heat sink on it and fat power cables connecting it to the main power supply.

Often there are fuses on that board - one or more. Check those.

if they are blown you can try to replace them, but expect them to blow again - usually the whole board needs to be replaced.

often that *needs* to be done in a service center as there are some adjustments to be made after replacement; don't know about this particular TV model.

Hope this helpout........

Let a trained tech work on this, to begin, when you replace the Y-sustain board, you should also replace the Z-sustain board otherwise you will have problems

X or Y sustain boards need servicing or replacement............

Are there any blown caps on the PSB-power supply board. Most sets have sammy boards and they used very shotty caps. If there are no visual clues being a poped cap at the top (X) they simply often do vaporize and dry out. The YSUS-Main and the 2 Y buffer boards control the picture OSD-on screen display. Your not getting any of that. So power supply is where you start first. The YBU-upper and the YBL-lower control the upper and lower OSD the Ysus main control both of them. Usually if you have one in the door you have to replace all 3. But not always. If you were to replace any of the boards I would replace the YSUS-Main, or get the board reworked at a pc repair shop that does board level test and repai. Its more cost effective.

Best Regards and Semper Fi

last time I had seen these syptoms on Philips plasma it was bad panel. Replace tv panel is too expensive to replace.

The Z sustain module blew it's transistors. It may have been initiated by the Y sustain board going bad. I always replace both at the same time so as not to waste $250. You will find a Y sus board will run you between $250 to $350 and a Z sus is a little cheaper. I wouldn't replace one without the other. Let me know if this helps.

first thing to do is determine if there is a blink code as that gives a direction for t/s. regardless, what you should do first is offload the y main and x main sustain boards from power supply one at a time as there is a common issue where these boards can cause load on power supply and if voltages come up with either one offloaded that board should be replaced before proceeding. if y main is the issue there is an upper and lower buffer board to left of that board and also should be replaced at same time as 3 boards complete a circuit and replacing one could cause damage to others.

7 blink error on that model is 8.6 volt error and generally caused by y main board. disconnect y main from power supply and if tv does not shut down and vs voltage comes up (test point on power supply) replace y main and both y upper and lower buffer boards as replacing one without other two could cause additional failures