Hi! Good morning Sir Jestine Yong. I’m a follower of your article and i read a some of your book. Sir I just want to ask question on 1 of my for repair item. I repaired a tv model Sharp 21v-fw650s. The problem is discoloration display. I check the following.
- Crt board all the components are good.
- I resoldered all the component and wire connections.
- I checked the connection on the main board and component as well all are ok.
- I resoldered it also.
- I checked the flyback connection and resolder it also.
- I checked the degaussed wire and connection are ok also.
- After Check everything i found nothing wrong.
When I powered on the discoloration is still there. I used my demagnetizer to degaussed the crt. After that the picture was ok. I observed it for 1 hour everything was fine. When I switch off for about 3-5 min. and switch on again still the picture was fine and i observed again for about 30 min. still fine. I switch off again for 15 -20 min. and power on again. The discoloration problem comes again. I used this method of testing for many times but the discoloration problem still there. I have used again my demagnetizer again it again. I was thinking maybe the picture tube is the problem. Sir Jestine Yong what do you think is the problem of this tv. Please help me and give some advice.
Thank you very much and more power to you.
Try check the posistor circuit to see if there is any dry joints . If Ok then direct replace the posistor and retest. If problem still the same this could be the problem of tube. Sometimes a dry joints in certain pins of the vertical output ic may cause such problem also. If you have the Blue ring tester you can also check for any partial shorted winding in the degaussing coil