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Panasonic TX-P50VT30B - 7 Flash issue.

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Turnip:
Hi folks,

Have one in where I get initial Green flashes then 7 Red flashes, no picture or sound.

Any thoughts ?  - Thanks -  Chris

downunder:

Hi Chris,

Code 7 is the SC board (Y-sus), or SU/SD boards (buffers). If you read a short across the 2 pin plug SC2, you have a short on the SC board,
usually a number of FETs.

Alternatively, disconnect the SU/SD boards totally from the SC so that there is no longer any electrical connection to the SC board. Leave the SU/SD
connected to the panel ie don't disconnect the brown flexies that go to the panel.

On the buffer side of the SC, locate a small 2 pin socket SC50 and short out the 2 pins. Power the TV on. If still code 7, the SC is faulty. If the TV powers up to a solid green LED, SC is OK but one or both of the buffers are cactus. See how you go to this point.

Bruce

Turnip:
Thanks Bruce,

Seems I've got a few duff Fets on the SC board. Note a repair kit on Ebay for £20 or a working board for £150.

Wondered if the buffers K.O. the SC (Seen no signs of burning on the buffers - £35 pair)

Replacing the Fets looks straight forward but seems the kit also contains a chip or two, what do you think ? - Thanks - Chris.

downunder:
Hi Chris,

Kits are a bit iffey and often result in repeat failure. Suspect some of the FETs are clones and not ridgey-dig. I've always gone for board replacement but

they may be getting a bit scarce. Usually the buffers are OK. The metal pads under the larger screws that bolt the buffers to the SC are the floating

earth. An analogue meter (because it reacts faster than a digital one) on ohms is best.

Probe on floating earth, then run the other probe along the contacts of flexies that connect to the panel. Reads like a diode, so select

meter polarity for the high reading. All flexie contacts should read high. If not, one or more buffer chips are shorted.             

The SC often fails because of poor earthing between the board and the metal panel back at the mounting screws. Look for signs of arcing at these points

if you remove the SC and take remedial action. Pana supply screws with star washers now but I'm sure you'll figure out a solution.

Bruce

Turnip:
Hi Bruce, thanks a lot.

Cust has donated the set as panel repair dubious (Judging by on line observations where half an hour is pretty good 'till the Fets go phut again)

Checked buffers as suggested - seem OK, so worth having a go as not much to lose and fun if it works -  Chris

Had a look at those fixing screw earths under the panel and found several dubious - Star washers for me.

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