my tv brand cyberlux model TVR7CX-21US does not turn on
Another thing when I unplug and plug in and turn on the TV the screech it makes is the standby circuit
OKAY. Make some measurements on the secondary voltages of the source and comment. The noise may be due to the cutting of the source by a short circuit in the High voltage part. Try the TSH and Diodes in the Fly Back sector
the only voltage I have in the secondary is 10v in the c161 of the audio stage according to the diagram
To see if the AT stage is not the problem, lift the end of the R470 = 1.2 ohms 2 W from the side that goes to Pin 4 of the Fly back, and at that loose end of the R you connect a 60 or 75 W with the other pole to ground. It has to turn on with 110 V. if the source works
It would be good if you got a 60W lamp because of the doubts that the source is cutting for a lot of consumption. Otherwise, you can use a 200 ohms 60 Watts wire resistor.
I have already indicated everything that can be done. You just have to do what you still lack from what I was telling you.
I measured the values and they are not the ones that you indicated to me approach the diodes 3v
Chassis PH08K-N22.pdf [207.66kb] Here I am sending the circuit source to guide you better. The cap. You had to have changed it before starting the TV. I hope the regulator has not been affected again. Chassis PH08KX-N35-Fuente.png [351.06kb] Before connecting the TV try and / or change the items marked in the following file.
Hence I send the complete circuit of the TV so you can better guide Fuente.png [424.79kb]
Then I measured with the diode test tester (If the PIP sounds better), continuity from the 220V cable, through the fuse and reaching the diode bridge, to chap. Filter
Between the Positive of the filter and chassis there should be 300 V. See if it has an NCT Resistance, the R901 between the junction of the cathodes of the bridge diodes and the positive of the filter. bridge it and measure.
Then you have some element of the primary source in short circuit. It can be the FET V901 = 2SK3116 and / or the Regulator N901 = TDA16846. measure them and from now on, do not bridge the resistance.
So it may be that the circuit I have is not the same, but surely that is short. After taking it out, I also measured some surrounding parts as well.
Check if you have the chassis number on the board (Above or below) and tell me if I can get a more accurate circuit.
It is also important that you change the cap. electrolytic associated to the regulator because sometimes it burns when they are dry
I already replaced it but try to turn on the standby LED makes a noise and it goes out and to try again to turn it on I must unplug and plug it in again
Measure with the tester in diode measurement. You must mark on one side between 600 and 700 and on the other nothing
I wanted to comment that in my country the voltage of the outlet is 110v not 220v at all, so I don't have 300v in the cap if not half
There I sent you the complete TV circuit so you can guide yourself better. File Name: Chassis PH08K-N22.pdf [207.66kb]
It would be good if you got a 60W lamp because of the doubts that the source is cutting for a lot of consumption.
So if you have already done all the tests and changes that I have indicated, it only remains to test the elements associated with the optocoupler if you changed it. Example: Transistor V553 = C1815; Zener VD560 = 6.3V - VD581 = 5.2V; the voltage setting preset RP551 = 2K; and elements associated with them