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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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Sony KV-36XBR800 like keystone pix, bad purity also.
The CRT, & yoke seems ok because if I put a small magnet near the
little coils on the pin correction pcb, the pix is near perfect. The four corners are out of purity a bit, & overall convergence is bad throughout pix, & pix is rounded on top & bottom, but height, & width is ok. The CRT is fine, I'm thinking the drive board is bad, or more likely, not getting correction pulses, or voltages from the main board. Didn't have time to check. Any tips on this? And a service manual? Thanks, Dani. |
#2
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Sony KV-36XBR800 like keystone pix, bad purity also.
I cannot tell you the exact components in your TV, or any TV without
actualy troubleshooting it in detail. With the service manual and a detailed understanding of how the electronics of the TV works, and the proper instrumentation it is possible to troubleshoot the set. Some very common causes are electrolytic caps in the scan and pin amp drive ciruits. These caps can be checked by using an ESR meter, or shot-gunning it by changing them all. On more rare occasions it can be semiconductors or other type of support components in the pin and scan drive areas. On more rare occasions I have seen deflection yokes and or the horizontal output transformer (flyback) cause problems. I have also seen, but very rare, a damaged shadowmask in the CRT cause pin and purity errors. What you are doing with the magnet is offsetting some of the scan distortions. This will cause other distortions to appear when trying this. In a properly working set, small magnets of the proper spec are used around the CRT and yoke area for some pin, convergence, and purity correction. This type of adjustment requires very good skill from a lot of practice. Considering the age of your set, I would not be encouraged to invest a lot of money and time in to it. Jerry G. On Nov 29, 1:48*pm, Dani wrote: The CRT, & yoke seems ok because if I put a small magnet near the little coils on the pin correction pcb, the pix is near perfect. The four corners are out of purity a bit, & overall convergence is bad throughout pix, & pix is rounded on top & bottom, but height, & width is ok. The CRT is fine, I'm thinking the drive board is bad, or more likely, not getting correction pulses, or voltages from the main board. Didn't have time to check. Any tips on this? And a service manual? Thanks, Dani. |
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