Small Width In Hitachi CRT TV
Customer sent to me this 21″ Hitachi with the complaint of small width display (squeezed display at both left and right side)….see the above photo. For your information, if the display width is small, usually is due to less B+ voltage to the flyback transformer or the safety capacitor value already decreased.
If the problem is small width display with curve inward at both side, it can be due to shorted modulation diode but it can also be due to less B+ voltage or both.
As you know one of my procedures in troubleshooting a circuit board is to use visual inspection first before I use my meters to check on the voltage and components. Visual inspection can see bulged capacitor, broken wire and traces, burnt components (ex black mark at the side of IC or even pinhole on top of IC), dry joints and etc.
In the above case I found the B+ voltage capacitor that was bulged and the value was 100uf 200volt.
Replacing the only capacitor solved the small width display problem.
Conclusion- It was quite easy to solve this problem. Assuming after the replacement of the capacitor and the display is still small then I will proceed to check on the safety capacitor or even the modulation diode. If you want to be good in CRT TV Repair you can check out on Humphrey’s CRT TV Repair ebook here.
This article was prepared for you by Suranga Bandara who owns an Electronics repair shop in Anuradapura, Sri Lanka.
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