Changhong TV common disease maintenance experience set - Home Appliances

Brand AVX TPSE226M035R0125 Low impedance tantalum capacitor AVX 22

Electronic scale crystal oscillator 3.2*2.5mm 3225 16M (16.000MHZ) 12PF 10PPM 20PPM 30PPM

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1. For the LA7688N decoding block in Changhong series, the shutdown issue was resolved by removing the Y board (viewing board) VD611 and VD612, and soldering a 4148 diode back to the positive side of VD613 and the negative pole of VD617.

2. In the case of Changhong 29A18, the line size was not full, with only 75-85V from the main power supply. After checking, the performance of VD520 was poor, so RU2 was replaced.

3. For Changhong CK56B2, the field vibration occurred at pin 33 of TA7698 integrated block, where the VCC voltage was about 4V instead of 8.6V. The fault was traced to an open circuit in components like the push tube or transformer.

4. In Changhong 2939FD, the upper retrace line had issues, and after entering the "S" bus, it returned to ABK--ENABLE normally. When the fault occurred, brightness became bright.

5. In Changhong N2918, there was only a blue background without picture when AV input was used. After repeated investigations, the comb filter was found faulty and re-welded. It was estimated that the capacitance had leakage. Note: Removing the button socket caused the channel to flip automatically.

6. In Changhong C2589, black lines appeared in the upper part, and the linearity was poor. After heating and checking, C329 (471K polyester capacitor) was found bad and replaced.

7. In Changhong C2191, a "zi" sound occurred and the TV did not work. After unplugging the deflection coil, the line C voltage was normal. Investigation showed that C428 (1UF/250V) was short-circuited and replaced.

8. In Changhong C2992, the image's upper part was jagged. After checking, the field supply capacitor C825 (35V/1000UF) was normal.

9. In Changhong G2125, the upper half of the length was investigated, and R402 (120K) resistance was found open. Replacing it restored normal operation.

10. In Changhong 2118FA (A6 movement), VD514 (4148) was open. The main power supply was normal when using a dummy load. However, the tube burned after 2 seconds when the load was applied.

11. In Changhong C2919PK color TV, there was a power indication, but no second boot. The line output load (7) foot VD408 (RU4Z) was short-circuited, and replacing it solved the problem.

12. In Changhong G2132 (K), the machine had a power indication but did not boot. The line was not heated during the second boot. Using a dummy load, the main load was 130V, which was normal. After multiple checks, the line deflection coil was found short-circuited. This is a common failure in this model.

13. In Changhong R2916N (same as R2518N), the line center shifted right by 3 cm, and no characters were visible. AV also had no picture. Checking D403 and D404 on pin 9 of the line pulse high voltage package showed they were short-circuited. Replacing D404 (5.1V) fixed the issue. The negative end of D403 should normally read 0.7V.

14. In Changhong 25K18 (using LA7841 field block), the upper part of the display would compress, while the lower part was thin. Checking C301 (1000P) showed it was bad, and replacing it resolved the issue.

15. In Changhong G29K36, a bright line appeared on the screen. Checking N30 (LA7841) showed it was faulty. At the same time, the voltage regulator tube VD302 (1Z75) should be checked, as a short circuit could burn out the LA7841.

16. In Changhong 25N16, the map was compressed by 10 cm and rolled up. C302 and 10N capacitors were found bad.

17. In Changhong C2919PK, (1) the upper retrace line was not dark, and C318 (35V/220UF) was replaced. (2) The upper retrace line had no underfield, and C305 (50V/1UF) was replaced.

18. In Changhong C2919PS, there were stripes (like unsynchronized lines), and the "black" sound (blue background off) occurred. The comb circuit was found faulty.

19. In Changhong C2588A, a rare compression failure occurred, and replacing C317 (2.2UF) fixed the issue.

20. In Changhong C2169, the "M" red character fault was due to entering debug mode. If the remote control cannot be turned off, pressing an unused button between “SYS1/SRC” and “AN-SEL” on the K1L remote control would turn the red character green and eliminate the issue when the remote was turned off. If the fault remained, the remote needed replacement.

21. In Changhong C2169 and similar models, the TV started in "AV" state. This indicated a change in the working program, usually due to memory or external circuit failure, and replacing the components resolved the issue.

22. In Changhong R2518AE (D), the machine had instructions but couldn't start twice (with a "support" sound). The tube was burned. After checking, the line frequency 15625 went to the tube, sometimes the TV could be turned on but with left-side raster compression and drawing. Multiple investigations found the VD431 (1N4148) diode defective.

23. In Changhong C2588PS, a small amount of retrace line was present in the upper part. After repeated checks, it was not C320, but the field blanking was bad (go to visual release). R321 (2.2K) and similar resistors were checked.

24. In Changhong C3419PS, a 5 cm retrace line was present in the upper part (normal amplitude). Checking C318 showed it was bad, and replacing it restored normal function.

25. In Changhong R2518AE, the tube was always burning. Checking the capacity of C436 and C435RO, if it was a blue CBB81 type, it needed to be replaced. After changing the capacitor and the tube, everything worked normally.

26. In Changhong 2938FD, there was no sound. No 16V was detected. Checking 872 (0.27/0.5W) resistance showed it was open. Replacing it with 1W/0.33 made it normal.

27. In Changhong R2519N, the machine automatically shut down and sometimes failed to boot. R820 (0.15 ohm) deteriorated to 0.5 ohms or more, and replacing it restored normal function.

28. In Changhong 2518FN series, the upper length was too long, the lower side was compressed, and the bottom had 3-4 cm of no light. This was caused by C306 (4700/25V).

29. In Changhong R2519N (using TDA6103Q for viewing), the brightness was slightly brighter because the ABL circuit R421 (100K) increased. If the boot was bright, it became a bright line; opening RX19 (220K) would fix it.

30. In Changhong D2962A, there was no sound, no line, and the capacitor C461 (7200P/1500V) was degraded (including 5100P). Replacing it resolved the issue.

31. In Changhong G2536, the search did not save the table, the blue background was closed, and fine-tuning could be saved. The AV map flipped. Checking the CPU at 36 feet showed C022 (101N) was bad. Normally, 36 feet should have 3.5-4.5V.

32. In Changhong T2981 and T2982, the map difference was due to a problem with the antenna input amplifier box. Cross-line tuning and antenna input box could help.

33. In Changhong SF2915, there was a power indication, but it could not boot. Checking the CPU (N100) showed 3.3V was only 2V. Replacing the power supply part V871 (C2688L) restored normal function.

34. In Changhong 2588K, the line burned, and the new line-changing tube had low pressure. Checking the C472 (7200P/1600V) capacitor on the pillow board showed it was bad, and replacing it restored normal function.

35. In Changhong C2919PK, after a few minutes, some channels ran, and automatic search might not complete. Checking the middle of the main box showed 1160 was bad.

36. In Changhong C2919PS, the TV ran irregularly (normal picture-in-picture). Cracks were found at the main high-frequency head pin, and re-soldering fixed the issue.

37. In Changhong 2118FA, the tube V432 (D1651) burned. Checking the power supply and capacitance showed they were normal. Then checking the VD441 (RM11C diode) on the deflection circuit showed it was short-circuited.

38. In Changhong G2125, there were instructions, but it could not boot. Checking the 18V power supply showed a short circuit. Because V832 (D400-E) was bad, D834 and D835, R824 were burned. Replacing them restored normal function.

39. In Changhong SF2551, three faults occurred. After replacing N801 (STR-F6454), VD830, VD808, and V801 (C2655), it worked normally.

40. In Changhong C3419PD, there was a lack of Y signal. Checking the clarity enhancement box showed it was bad, and short-circuiting 1-3 feet could provide emergency troubleshooting.

41. In Changhong H29D80, the sound was bad, and only a "black" sound was heard. Z608{L6.5C} was bad. Replacing it restored normal function.

42. In Changhong G2985 (B), the line width distortion had a 1CM difference left and right. R931 (0.5W 15 ohms) was increased to 150 ohms, and replacing it fixed the issue.

43. In Changhong C2152 (KV), the LA7680 small signal was normal, and the TV automatically turned on after a few minutes. Changing C563 (35V/330UF) capacitor resolved the issue. Wood grain interference could be addressed by checking C562.

44. In Changhong T2982, there was a power indication, but no boot. Diode VD408 (RU4Z) was bad, and replacing it restored normal function.

45. In Changhong C3419PD, the standby was normal, but starting burned C4706 adjustment tube. The 400V/560UF capacitor was bad. (The boot was accompanied by a "click" sound.)

46. In Changhong C3419PK, the main power supply was 115V, but only 100V. R868 270K/1W was open, causing sound size issues.

47. In the Changhong HP series rear projection power supply improvement, R888/270K/1W was changed to 470K/1W; between VC801 (2) (3) feet and 0.22UF/250V capacitor, there was a "吱" sound and interference (channel 1).

Two:

1. When overhauling the 21" color TV fault produced by the A6 movement, or repairing the TDA7496 without the sound failure, connect the CRT, the left and right speakers of the main channel and the main board to the screen.

2. For individual models of color TVs, there are more snowflake points in the signal receiving areas, and there are noise problems. You can take one of the two ends of the front intermediate frequency amplifier circuit V101 "E" pole resistor R115. Capacitance resolution, the reference value is 0.01UF.

3. A6 movement of various types of color TV production when the black and white image display is normal, after the color saturation is opened, the full screen green screen failure, mainly check the components on the LA7688 (1) off-circuit circuit and the baseband delay processing block LC89950. The determination method is: measuring the voltage of the LA7688 (1) pin. When the TV receives the TV-PAL/NTSC system, the working voltage of the foot should be set between 1.7 and 2.6V. When the TV is operating AV-PAL/NTSC, this pin should be 2.9-3.8V. When the (1) pin voltage is normal, the fault is on the LC89950 and surrounding circuits.

4. The 21" color TV produced by the A6 movement has the phenomenon of frequency drift after the program under the program number “1” is turned off, but there is no such phenomenon under other program numbers. The solution is to replace the original CPU with CHT0408-5L21. CHT0408-5L21 can replace CHT0405-5J77 and CH0403-5H61.

5. LA7688A can be replaced by LA7688B. To avoid multiple damage to the LA7688A, back a solder capacitor between the left end of R362 and the positive end of VD622 on the Y board with board number JU7.820.1534/1360. On the Y board with the board number: JU7.820.1535/1462, back a soldering capacitor between the V617 "C" pole and the grounding pin of the display tube base. The size of the capacitor is: CT-500V-100P.

Changhong 2

6. CN-5 movement appears to have a map, then there is a horizontal bright line fault, please check the AN5095 (20) foot external automatic brightness control circuit components, the foot voltage is lower than 0.7V, (20) foot connected The maintenance switch circuit is activated.

7. The components used in the CN-5 switching power supply must use the model specified by the machine. For example, the switch must use THD215.

8. The CN-5 movement enters the maintenance method by short-circuiting the CPU (36) to the ground or the CPU (9) to the ground. After entering the maintenance state, press the background button on the remote control to set the function status of the whole machine. After pressing the background button, FF-FF will be displayed on the screen. Press this button repeatedly to select two parameters and press the volume button to change the parameter size. The following table lists the two parameter values for some models:

Item N2918 2916FN 2518FN 25N1, 29N16, 25N18, 29N18, 25N19 21" R2518N 2919FN
Mode 1 27 07 07 04 C1 07 24
Mode 2 47 47 03 03 04 03 47

Changhong 3

1. When the NC-5 movement power supply block TEA2261 is replaced by BL8701, it will be in the circuit:
The R810 was changed from the original 1.5K to 6.8K; the R818 was changed from the original 680 Euro to 1.5k.

2. For the products produced in the later stage of the CN-5 movement, the power supply components were changed as follows: C821 was changed from the original 0.68U to CD11-50V-1UF; the C825 was changed from the original 50V/1UF to 50V/2.2UF.

3, CN-5 movement power inductor L801 without 1uH inductance, can be replaced with 2.2uH.

4. The individual color TVs produced by the CN-5 movement have a "å—¡å—¡" field: the C675 is changed from CD11-16V-470uf to CD288H-16V-2200uF.

5. In order to improve the stability of the CN-5 movement and the adaptability of the area, the following improvements are proposed:
R819 was changed to RT13-0.166W-330 ohm;
R822 is changed to: RT13-0.166W-1.3K;
C821 is changed to: CD11-50V-1UF;
C825 is changed to: CD11-50V-2.2UF;
C824 was changed to: CL21X-50V-1000PF.

1. CPU: When CHT0807 is replaced with CHT0819, please disconnect D301.

2. In order to improve the G2510B, G2529, G2532, G2536, G2538, G2539 and other color TVs, when the TV and AV signals are received, the following circuits must be processed to solve the problem. (1) Change the flying wire (AWM1007-11/0.16 black 120MM, back welding between W028 hole and W410) to AWM1007-11/0.16 black 70MM. Back welding to the ground hole between the original hole and W412 and R048. (2) Increase the jumper W412 10mm. Note: Keep the short wiring away from the high frequency tuner and secure it with tape.

Changhong 4

1. CH-10 movement power supply part C-MOS tube V840 can be replaced by STW10NB60, BUZZ334, IRFIB5N65A. The installation position only needs to shift the VD840 and R821.

2. There are currently four CPUs for the CH-10 movement. They are CHT0808, CHT0818, CHT1201, and CHT1202. CH0808 and CH0818, these two CPUs can only use 8MHZ crystals; the latter two use 6MHZ crystals. The two crystals must not be mixed, otherwise there will be a phenomenon that "the remote control does not receive, the local buttons and other functions are normal".

3. Inspection and repair methods for individual faults of CH-10 movement:
(1) After booting for a period of time, there is a gap black screen (flashing) on the screen, accompanied by noise; sometimes after the flashing multiple times, it will automatically shut down (the B/B background will not appear), and the above fault will be repeated after booting again.
(2) Solution: Change R061 from 470 ohms to 100 ohms; W076 is changed from 2CK75D to hang needles.
(3) For some individual color TVs, the TDA6108 is damaged several times, and when the full screen return line appears:
A. Add resistor RY04A (0.5W/470 ohms), disconnect the trace between CY01 and CY02, and RY04A between CY01 positive terminal and CY02 positive terminal.
B. Cut the cable plug of the (1) pin of XPY03.
C. VDY01A, VDY02A, VDY03A assembly method: the positive ends of the three diodes are unchanged, and the negative ends of the three diodes are removed and connected to the positive terminal of CY01.
D. Increase the hanging line at CY88.

4. Some color TVs have character jitter. When the character is shaken up and down for a period of time, (1) change the BE pole of V438A to 5MM hanging needle; (2) change R120 to CL21X-50V-6800PF.

5. When receiving local station programs in individual areas, an instant black screen appears, sometimes a blue background appears. You can try the following two methods. The method is to change CHT0808 to CHT0818 or coordinate the local TV station to adjust the signal, so that the signal modulation degree reaches 87.5% of the national standard, and the video signal synchronization head amplitude reaches 30% of the signal amplitude. If the above method does not work, you can also reduce the resistance of R206.

6. The line change BSC68H2 and BSC70E2 used in G2985 are interchangeable.

7. When the individual signal color TVs damage V840 (W10NB60), VD840 (WOSZ15B), VD873 (RG2), F801 (4A/250v), replace VD873 (RG2) with BYM26D to eliminate this phenomenon.

Changhong 5

1. When some of the 25K18, 29K19, and G2911 of the various types of color TVs produced by the CN-12 movement play a karaoke signal, when the sound is abnormal, the grounding end of the C523A "+" end and the R501 can be used, and two sets of diodes are connected. Each set of diodes is made up of three 2CK75D diodes in series. One set of diodes is connected at the positive end of C523A, the negative end is connected to the ground of R501, the other set is negatively connected to the positive end of C523A, and the negative end is connected to R501. Where. See picture (2).

2. The G2502 and G2911B color TVs produced by CN-12 movements have karaoke sounds, which are processed according to the method of (3).

Changhong 6

1. When the NC-6 movement has an individual channel, the R123 in the main assembly is changed to 1K and the C125 is changed to 0.1UF.

2. When the G2966B color TV data is disordered and the VGA function disappears, the OPT0 is adjusted to 81 at this time, and the OPT1 is adjusted to 87 to be set in this state.

3. When repairing the NC-6 movement power supply, the charge stored on the C810 must be discharged with a 10K resistor for maintenance. When it is determined that the STR-S6709 is damaged, please replace the D809 and D815 (Note: Replace even if the measurement is normal).

4. When the G2967A has three faults due to the damage of the sound amplifier block, in addition to replacing the sound amplifier block and the Z889, it is also necessary to check whether the clamp diode of the output block of the power amplifier block and the speaker weld line of the sound tube are too close.

5. There is sawtooth interference in the lower part of NC-6 movement screen: the reason is due to poor performance of L442, please replace L442 (TLN3063) to solve.

Other information:

Changhong 1

1. When overhauling the 21" color TV fault produced by the A6 movement, or repairing the TDA7496 without the sound failure, connect the CRT, the left and right speakers of the main channel and the main board to the screen.

2. For individual models of color TVs, there are more snowflake points in the signal receiving areas, and there are noise problems. You can take one of the two ends of the front intermediate frequency amplifier circuit V101 "E" pole resistor R115. Capacitance resolution, the reference value is 0.01UF.

3, A6 movement of various types of color TV production when the black and white image display is normal, after the color saturation is opened, the full screen green screen failure, mainly check the components on the LA7688 (1) off-circuit circuit and the baseband delay processing block LC89950. The determination method is: measuring the voltage of the LA7688 (1) pin. When the TV receives the TV-PAL/NTSC system, the working voltage of the foot should be set between 1.7 and 2.6V. When the TV is operating AV-PAL/NTSC, this pin should be 2.9-3.8V. When the (1) pin voltage is normal, the fault is on the LC89950 and surrounding circuits.

4. The 21" color TV produced by the A6 movement has the phenomenon of frequency drift after the program under the program number “1” is turned off, but there is no such phenomenon under other program numbers. The solution is to replace the original CPU with CHT0408-5L21. CHT0408-5L21 can replace CHT0405-5J77 and CH0403-5H61.

5, LA7688A can be replaced by LA7688B. To avoid multiple damage to the LA7688A, back a solder capacitor between the left end of R362 and the positive end of VD622 on the Y board with board number JU7.820.1534/1360. On the Y board with the board number: JU7.820.1535/1462, back a soldering capacitor between the V617 "C" pole and the grounding pin of the display tube base. The size of the capacitor is: CT-500V-100P.

Changhong 2

6, CN-5 movement appears to have a map, then there is a horizontal bright line fault, please check the AN5095 (20) foot external automatic brightness control circuit components, the foot voltage is lower than 0.7V, (20) foot connected The maintenance switch circuit is activated.

7. The components used in the CN-5 switching power supply must use the model specified by the machine. For example, the switch must use THD215.

8. The CN-5 movement enters the maintenance method by short-circuiting the CPU (36) to the ground or the CPU (9) to the ground. After entering the maintenance state, press the background button on the remote control to set the function status of the whole machine. After pressing the background button, FF-FF will be displayed on the screen. Press this button repeatedly to select two parameters and press the volume button to change the parameter size. The following table lists the two parameter values for some models:

Item N2918 2916FN 2518FN 25N1, 29N16, 25N18, 29N18, 25N19 21" R2518N 2919FN
Mode 1 27 07 07 04 C1 07 24
Mode 2 47 47 03 03 04 03 47

Changhong 3

1. When the NC-5 movement power supply block TEA2261 is replaced by BL8701, it will be in the circuit:
The R810 was changed from the original 1.5K to 6.8K; the R818 was changed from the original 680 Euro to 1.5k.

2. For the products produced in the later stage of the CN-5 movement, the power supply components were changed as follows: C821 was changed from the original 0.68U to CD11-50V-1UF; the C825 was changed from the original 50V/1UF to 50V/2.2UF.

3, CN-5 movement power inductor L801 without 1uH inductance, can be replaced with 2.2uH.

4. The individual color TVs produced by the CN-5 movement have a "å—¡å—¡" field: the C675 is changed from CD11-16V-470uf to CD288H-16V-2200uF.

5. In order to improve the stability of the CN-5 movement and the adaptability of the area, the following improvements are proposed:
R819 was changed to RT13-0.166W-330 ohm;
R822 is changed to: RT13-0.166W-1.3K;
C821 is changed to: CD11-50V-1UF;
C825 is changed to: CD11-50V-2.2UF;
C824 was changed to: CL21X-50V-1000PF

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