I have replaced the LA7841 vertical output ic and got the unit back up and going again, but the ic is getting too hot and vertical linearity is not good. The top part of the picture is fine, but the very bottom is a little compressed. Possibly yoke short? I did find some bad caps in vertical section and it did correct some of the problems. Just wondering if anyone has run into this before on this series of set?
Rob: You probably missed a cap or two.... re-check your work. If you suspect the yoke you should ring-test it. electricitym
How do you ring test a vertical yoke? Every one that I have ever tested has no more than 4 rings with either of 3 Sencore units that I have. I have never found this to be an effective way of evaluating vertical yokes. How do you do it?
If a yoke is working and the problem is linearity, the problem is almost always going to be a bad cap.
Leonard
Leonard: If you ring-test a yoke with a shorted turn and compare the results with a good yoke you can see the difference immediately...... a yoke with a shorted turn will have lower amplitude rings and be quite obvious when compared to a good yoke. I always keep a good yoke handy in my junk box for this reason. electricitym . .
I think it's the vertical yoke that has a parallel resistor that has to be taken out-of-circuit before an accurate ring test is possible.
Tom
Thanks for all the help on the vertical problem, I seem to be finding a lot of dried up caps. I think where unit was located, it didn`t have much ventilation and it had alot of dust. Rob
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.