Hi, I found 2 of my CCFL drivers shorted Q6 & Q7, problem is they are SMD transistors, and they only have 4 letters written on top DK QA. I replaced them with a DK QM I had, it worked for about 24 hours but looks to me they went bad again, I can't find how to read this letters(manufacturer code), on the other hand I think the transformer is probaly shorted too. Where can I find any information on this board, a schematic or a clue on the name of this 2 transistors?
One and a half year later I know the solution :-). It is 2SC4672... sure!. DKQ* is in my Jaeger SMD-Decoder book (10.000 SMD - Demiconductor - Codes)
Common problem with inverter PCB. Caused by the damaged or loose 100nF (or some same value)
Succes. For me it is working.
This is not a solution but I am just surprised that you have the EXACT same fault as me. I've done some searching on datasheetcatalog website and apparently the letters DK mean it is a BCX42 PNP Silicon AF and Switching Transistor (For general AF applications High breakdown voltage) however the datasheet for this device is a 3 pin smd not a 4 pin so I'm not sure that it is correct.
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Hello Edwin Ortiz---My tv had the red blinking light on the power board and i found a tiny 3amp subminiture fuse listed as F2 on the printed board. It fooled me because it did not look like any fuse i've ever seen. Anyhow the fuse was open and the problem was the two transistor listed as Q6 and Q7 on the power board.The transistors are a brand from fairchild with a part # FQPF9N50CF . They cost $1.60 each and i got them from Mouser Electronics out of texas (www.mouser.com )
On power board check F2 minifuse and transistors Q6 and Q7---make sure that you use so heat sink compound on the new transistors or they wont last long. You can reach me at email@example.com for more detail on how to fix. good luck--jim--
In the Polaroid FLH-3701, the fuse is located on the power supply board, next to the AC power connector. It is a small black cylinder. It is labelled F1. Value is 5 amp, 250 volts.
A fuse does not blow for no reason. Most commonly a fuse will fail because of a short someplace on the board. I have this same TV. The fuse blew. The reason was transistor Q6 had shorted. There are two identical paired transistors on the output side. Q6 and Q7. They are both Infineon 11N60C3 MOSFET transistors. Check those for a short. There may be a burnt smell.
More commonly, this TV will fail because of bad capacitors on the power supply board.
This could be caused by a few things. First, be sure the capacitors you used are low ESR. You can't use capacitors from Radio Shack, they can damage the electronics. Second, on the bottom of the power supply board you will find 4 transistors, they may be blown out. Check them with a multimeter or transistor checker. If the transistors are blown, we carry them is stock if you need them. Contact us at: firstname.lastname@example.org if you need any additional help.
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Besides those transistors, you may also fine the large capacitor
adjacent to the transformer gone too, Possibly the transformer may be
bad too ?
Also the 924s used at least two style boards.
Got the same problem for a N3250. I'm not an electronic engineer and will attempt to fix my TV. Therefore I got the FSP2123F02 ($49.75)and now they have a harness 4WT0062302GP ($8.90) that will do a quick plug and play and will avoid any solder of the pins. That is my understanding can anyone corroborate this procedure. By the way I got both products from electronica-usa.com
I repaired it on June 28th with the lsit of parts above
More deatil information here (of the problem)
List of photos
A) new Power supply on TV B) new Power supply and new 12 pin connector (plug and play) C) old board D) TV picture in HD
If the monitors use seperate plug in power supply EG 12 to 24volts it could be that at fault.
Or it could be the invertor at fault.
I have had some success repairing invertors if you can use A meter remove invertor Panels & check accross the coils with meter set to ohms all the coils should read identical chances are you will find one set of windings either dead short or open circuit. This will be the faulty coil hopefully as your monitors are all the same make the coils will be the same.
Carefully desolder faulty coil & fit one that reads good from a doner board.
Look for any SMD type fuses & check or replace them & thats it I have done quite a few now using this method.
Give it a go.