- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
check your b+ first. if your tv has no 125 volts your tv will not turn on check your horizontal transistor located in the side of the flyback transformer unsolder the collector then try to power on your tv check your high voltage at the collector without the collector of the horizontal transistor.
Are you talking about the LV power supply or the HV power supply? The terminology your using is related to the horiz drive circuit. Have you checked the B+ off the regulator which should be about 120v or, it will on the pc bd for the correct voltage. Do you have sound? If you do then you will have to use use your scope to see if you have proper drive at the base of the Horizontal Output Transistor. Then we can go from there. Oh, by the way I can tell by the voltage readings you stated both of those transistors of turned off.
verify your b+ voltage on collector of horizontal output transistor 7405 and if 130 volts is missing or way off go to power supply circuit and verify voltage on pin 14 of ic 7511 and if there is not approx 150 volts present should replace that ic and startup capacitor 2511 and opto isolator 7513. if 130 volts is present on collector of 7405 then scope signal on 7404 and if not clean signal replace micro processor
how is the 200 volt supply to the video output transistors??
measure the collector voltage of the video output transistors with the crt board on and off the crt. if voltage goes up when crt board is off then crt shorted
If the output transistor is good you need to measure the voltage at the collector to see if it has the needed voltage to operate,is also important to check the conections in the horizontal driver transformer and also measure the volts at the collector of the horizontal driver transistor,before you check any voltages check for loose conections and overheated areas,after everything is nice and solid then you can check for volts,be careful while measuring voltages and try not to touch anything with your bare hands while the set is on.Let us know how it goes or if you need more information.
The voltage might be low because is being loaded down,open the collector of the output transistor and measure the voltage again,if it goes up to 130 or the voltage is suppose to have you might be looking at a bad output transformer(flyback)there are other parts that can cause the loaded down voltage,the yoke can be one and capacitors in the deflection circuit,check to see if one of this caps is overheated (bubble)or cook,Be carefull if you open the collector when you measure the voltage,If you can try measuring the voltage somewhere else.Lets Us know if you need meore help.