I have a RCA 32" model F32444. when i plug it in a high pitch chirp comes from the circut board and none of the controls work. Is it time for a new plasma? Thanks
A high pitched chirp is a sign that you have a short on the load of your power supply. I just finished repairing one of these sets and it had a shorted horizontal output transistor and a bad flyback transformer.
Posted on Jan 12, 2007
Hello,Hack!
The flyback for this TV is available from:
Surburban Electronic,Suitland,Md, 20746
Phone: 1-800-341-5353
Part# GEN257805 @ 18.95
Horizontal Output transistor: 2SC5148 @ 1.98.
If you're experienced at changing parts this is not too difficult to do.FIRST, MAKE SURE YOU HAVE IT UNPLUGGED!!!!!
You have to remove the main circuit board and use solder wick to remove these parts.
You need to be careful when unhooking the big red wire going into the top of the picture tube
since it may have a charge stored in it. Use a jumper cable with a screw driver hooked to one end. Clip one end of the jumper to the gound wire on the outside of the tube and push the blade of the screw driver under the rubber cup where the red lead goes into the tube. If any charge is there you'll hear a "snap". This should discharge any voltage stored up in the tube.
There are several cables connected to the circuit board. You need to remember where they plug. You might want to draw a picture of where
they plug to the circuit board.
Once you've got everything installed,double check all the cables that you unhooked. Make sure all grounds are connected. This is very important.
When you're sure everything is connected correctly you may power up the set. If you don't hear the squeal like you did before, then it'll probably come on. If the screen is dark you need to turn up the screen control which is located on the transformer you just replaced. It's the bottom one. The top one is the focus control. You need to watch the screen while making these adjustments.
This FLYBACK is a generic. It seems that it is difficult to get one from RCA. I think they want us to just throw their sets away and buy a new one.
I hope this information will help you!
Good luck and be careful!
Stargazer
Hello!
The transformer is a different color but will physically fit right into the holes in the circuit board. All connections are the same.
The transistor is identical to the original transistor.It is a black plastic case transistor with just 3 leads to connect. Like most transistors.The 2SC5148 is written right on the transistor.
Good luck !
Stargazer
Hello,Hack !
Sorry I didn't tell you where the transistor is located.
I forget the reference number but it is located near the flyback transformer. It is on about 2" X 2 1/2" piece of aluminum which stands up and the transistor is held to the aluminum by a black flat spring clip. YOU can see the number when you remove the spring clip. You un-hook one end of this clip and swing it out of the way or remove it to release the transistor. It would be a good idea to put a little heat sink compound between the transistor and aluminum to make a good thermal connection between the transistor and the aluminum heat sink.When you put it back. It is important to clamp the transistor to the aluminum (heat sink) to keep the transistor from getting too hot and destroying itself.The three leads go through the circuit board. You turn over the board to use solder wick to remove the solder from the leads.
Also there is a black "L" shaped plastic bar which clips to the top of the fly back to help stabilize it on the circuit board. You need to remove this to get the flyback off the board.Of course you un-solder the flyback's leads first.
At each end of this "bar" is a twist lock sticking up through it. Just use a pair of pliers to untwist the tabs at each end so that this 'bar' can be pulled up from the fly back and circuit board.
If I can help you in any way, let me know!
Stargazer
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How hard is it to replace, where can i get one and how much would it cost. thanks
gazer... my electronic background is limited... Will the transistor be a direct replacement.. meaning color for color so i can identify it? the transformer will probably look the same...Right? I have a friend with steady hands... sounds easy enough.. and it sounds like your pretty confident that this is the problem.. i think its worth a try. THANKS!!!
where on the circuit board is the transistor... all of them have #'s, none are described as the horizontal output one. I dont have a wiring digram. Most have a 4 digit code next to them. THANKS AGAIN
I replaced the HOT and the fly-back transformer using generic parts. My TV now turns on but has horizontal lines across the screen...Turning the adjusting screw on the fly-back transformer counter clockwise makes it come in the best, and clockwise loses the picture completely. Ends up going to a blue screen. Any suggestion???
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