Problem with panasonic ct27g5b, flyback transformer secondary volts too high changed str58041 but power supply only make whining sound when turned on

There is no need to rewire the internal of the heater!
Just bring in the electrical supply to the heater, it can be either 120 or 240 volts.
If the heater you have is like the picture associated with your post, then all then have to do is change the supplied plug from 240 to 120. It comes pre set for 240. That plug is inside the cabinet.

If any other brand, then you need to change the wires at the transformer of the heater. All heaters need to be supplied with primary voltage: 120 or 240. Then the control system is supplied with secondary voltage out of the transformer. The secondary voltage is no more than 28 volts. and these wires are normally colored as blue or yellow.

Secondary power is already wired within the heater. NO need to change where they are. You will only need to deal with the Primary wiring.

There are many varieties of transformers that transform high primary voltage to a low secondary voltage of 28 volts. and these transformers have many wires: primary & secondary.
I will try to make this easy to understand.

If you have a Gas Heater Transformer with these colors:

• Red
• Black
• White
• Green

Or...

• Red
• White with Red Stripe
• Black
• White with Black Stripe
• Green

These are Dual Voltage Transformers, you can bring in either 120 Volts or 240 Volts

If you bring in only 120 Volts...
1st example:
The Red wire will not be used! Hot wire to the Black, and the Neutral/Common, to the white wire. Green to ground.

2nd example:
Connect the Red wire with the White with Red Stripe together and connect these to the incoming Neutral/Common wire, normally White.
Connect the Black Wire with the White with Black Stripe to your incoming Hot Wire, which is normally Black.
Green to ground

If you bring in 240 Volts...
1st example.
1 Hot wire to the Red, the Other Hot wire to the Black, and White wire is not used. Green to ground

2nd Example:
Wire nut the two Striped wires together. then one incoming Hot wire to the Black, the other incoming Hot wire to Red.
Green to ground

Or This is only a Low voltage - 120 Volts Only

• Black
• White
• Green

Or either any of these combinations...

• 2 Blacks w/Green
• 2 Reds w/Green
• 1 Black, 1 Red w/green

This type will only be a high voltage, 240 volts only
Picture below is what a transformer looks like and it is where your incoming supply wires go. The smaller leads with the spade connections will go to a specific location & is the 'Secondary" .

Good Luck

Check the all the large capacitors or coils

Ur flyback transformer it have cold soldier or is dead.U also could have prob. with ur power ic inverter board too.

Replacing a flyback is not something I would suggest for anyone with no electronics experience. Second, lets see where the noise is coming from first. Take off the back and listen to the noise. The flyback will be at one end of the large red wires that go to the tubes. Sometimes the connection at the tube is not 100% and the noise comes from there. BE CAREFUL - there are high voltages going through this red wire that can be dangerous even with the set UNPLUGGED!! IF the noise is coming from the connection at the tube, with the set unplugged, carefully turn the rubber cap back and forth touching only the rubber part with one hand. Put the other hand in you pocket while doing this.

If the noise comes from the flyback side, if you can solder, again with the set unplugged, try resoldering the pins on the transformers. That may resolve the problem.

Keep me posted.
Dan

From your description it seems that when the high voltage comes up there is a fault detected by the uPC, and the power supply is put in to the protect mode. This can be from many problems such as the flyback transformer failing, or a defective component(s) in the secondary supply from the flyback, or the CRT itself having a failure.

On many of these sets, there is an HV multiplier that is part of the flyback assembly. This HV multiplier is usually where the fault occures more so than the internal windings of the flyback. But, they come as one molded assembly.

Most often, I have seen this fault from the flyback transformer or the CRT.

This has nothing to do with anything you connected to the set. This problem would have occured anyways.

Jerry G.

TV's use high voltage to generate the stream of electrons traveling across the picture tube hitting the screen and lighting it up (thus the name Cathode Ray Tube). It takes about 25,000 volts to do this. In normal air, it takes about 1000 volts to jump an inch of air, so the high voltage transformer needs to have good insulation. It generates the voltage through a technique of charging the transformer's magnetic field with a low voltage of about 140 volts then letting it go where upon it flys back out the high voltage side at much high levels (Thus the common name flyback). A most common failure in a CRT type TV is for the insulation to crack in this transformer which is a unique component for each model of TV and leak out the current overstressing the circuit driving it. You can liken it to a little bolt of lightning getting loose in the circuit and has the same sound on a smaller scale.
It would be well to replace your flyback transformer before it gets worse and blows up something else as well. Best done by a professional used to handling high voltage. The picture tube can retain voltage even when the TV is unplugged for some time, and replacing the anode lead (the big red one) can be dangerous.
Hope Ya Fix It!

Check for a high voltage power supply section of your TV set...
Especially in flyback transformer.Be careful to do so because the output voltage of the flyback transformer is almost thousand volts.

your problem is in flyback or high voltage section failure.

• check horizontal output transistor
• check fly back transformer.
• check for supply to horizontal section as high voltage from power supply may create such problem
• as this failure is due high voltage section so it is better to take skilled technician help.
• good luck.

hi Buddah! heres the solution for the high pitch sound on to your Panasonic TV,,just check if there are some SHORTED RECTIFIER DIODE on the power supply section,

Yep i can tell you what it is. The High pitched sound is the power supply soound when its overloaded and thats because the Horizontal output transistors shorted and this happened because of the flyback transformer went bad and /or the horizontal driver coil right off the secondary of the horizontal driver transformer and then the other side of this coil connects to the base of the horizontal output transistor. The part transformer cost about 35 to 45 bucks to the dealer and the transistor cost about 15 bucks. the total repair job cost about 175 to 225.00 after all said and done and some shops even may charge more ad there labopr rates may be higher. Good Luck