For the Toshiba 288X8M TV, after turning on, the upper part of the screen image is stretched, and the lower part is severely compressed.
Analysis and Maintenance: A preliminary judgment indicates poor field linearity. The cause of a field linearity fault is usually due to performance issues with feedback components in the field linearity or field scanning circuit. First, check the field linearity components such as R304, R307, R323, C315, and C316, all of which are normal. Therefore, it is determined that the fault lies in the field linearity negative feedback circuit. The sawtooth wave current from the field output circuit generates a signal voltage on resistor R323, which is fed back through C317, R304, and R307 to pin 32 of IC501 (TA8616N), forming an AC negative feedback signal voltage. Focus on checking components C317, R304, and R307. Upon inspection, it was found that capacitor C317 had lost its capacitance.
Handling Method: After replacing C317, the image returns to normal.