Tobishi dead CRT TV repaired
Tobishi is China made CRT TV and in my country not many people own CRT TV any more. This customer insisted that I repair this one because he wanted to give it to his friend as a gift. It was a dead CRT TV.
It was a dirty one but after cleaning I was able to see what inside this TV set. The main fuse was intact and the 400 volts was reaching the main capacitor. I checked for any voltage reading on the secondary side of the power supply. All the readings were very low. It seems like we have a problem either in the primary or the secondary sections of the power supply.
After checking all the primary suspected component and found all of them are function within factory specification. I moved my search to the secondary section of the power supply and I was not shocked to see that almost all the capacitors in that section were giving me a very high ESR reading.
I am sure you can tell which one I replaced because they all look shinning and nice. To my surprise, that did not bring this CRT TV to life.
All the voltage readings at the secondary section of the power supply are back to being steady and normal. That was the result of the replacement of these bad capacitors. I was reading, 145 volts which goes directly to the horizontal output transistor. I could read the 12, 42 and 5 volts there but that did not bring this TV back to life for some reason. According to these reading, the TV should be on but it was not.
I did more checking at the fly back area but all of them checked ok. All the capacitors checked ok as well. What was causing this TV not to come on? I asked myself that question so many times. I decided to leave it for a while, take a break then come back to work on it.
I have seen this kind of problem before and I think I have solved this problem by trying to power up this TV with a remote control. I pushed the power button on the remote control and wow, the TV came on displaying a very nice picture with nice colors.
This article was prepared for you by Waleed Rishmawi, one of our ‘Master Authors’ and currently working in the Bethlehem area of Palestine repairing electrical and electronic equipment. Please give a support by clicking on the social buttons below. Your feedback on the post is welcome. Please leave it in the comments.
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