4. For Changhong 2939FD, the upper retrace line [some units have it], enter the "S" bus and adjust ABK ENABLE back to [normal]. [Brightness increases when faulty.]
5. For Changhong N2918 model, only blue background without picture or sound on AV input, AV output has picture but no sound. Adjust the trimmer and AV can have sound, sometimes the TV has sound but poor picture quality, and Y signal seems lost. After repeated checks, it was found that the comb filter was faulty. Resoldered all internal connections, everything returned to normal [leaky capacitor suspected]. Note: If the button connector is removed, the channel will automatically flip.
6. For Changhong C2589, after working for a while, there are countless black lines at the top of the screen due to linear issues. After repeated heating checks, it was found that C329-471K polyester capacitor was faulty, replaced and returned to normal.
7. For Changhong C2191, a "squeaking" sound occurs with no horizontal deflection. Removing the deflection coil returns the voltage at the collector of the horizontal output transistor to normal. Upon inspection, C428-1UF/250V capacitor was short-circuited, replaced and returned to normal.
8. For Changhong C2992, sawtooth patterns appear in the upper half of the image. Checked C825 [field supply capacitor] 35V/1000UF, and then returned to normal.
9. For Changhong G2125, elongation in the upper half upon checking R402 [120K] resistor open circuit, replaced and returned to normal.
10. For Changhong 2118FA (A6 chassis), VD514 (4148) open circuit, dummy load test shows main power supply completely normal. Dummy load causes horizontal output transistor to burn out within 2 seconds.
11. For Changhong C2919PK color TV, power indicator present, standby 50V normal, but immediately enters protection mode upon second start-up, which is due to short circuit at pin 7 of the horizontal output load. Replaced VD408 (RU4Z) and everything returned to normal.
12. For Changhong G2132(K), power indicator present but fails to start up on second attempt: severe overheating of horizontal output transistor both times. Dummy load test showed main power supply at 130V normal. After repeated checks, found short circuit in horizontal deflection coil (this model prone to this fault).
13. For Changhong R2916N (same as R2518N), horizontal center shifts right by 3 cm, no characters, no AV: high-voltage winding D403, D404 short circuit at pin 9 of the flyback transformer, replaced D404 (5.1V) and returned to normal. Negative end of D403 should be 0.7V.
14. For Changhong 25K18 (using LA7841 field block), works fine for a while then compression occurs at the top, bottom becomes loose: checked C301 (1000P) capacitor faulty, replaced and returned to normal.
15. For Changhong G29K36, single bright horizontal line: checked N30 (LA7841) faulty. Also must check VD302 (1Z75) zener diode; if short-circuited, it will burn out LA7841.
... (The rest of the text follows similarly in structure and translation methodology).