Changhong color TV repair Changhong Tong disease fault summary - Home Appliances

High frequency probe high frequency line can be customized other specifications

Crystal resonator 2.5*2.0mm 2520 16MHZ (16.000MH

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1, Changhong series for LA7688N decoding block shutdown highlights improvement: remove the Y board (viewing board) VD611, VD612 back welding a 4148 diode, positive VD613 positive and negative connection VD617-B pole.
2, Changhong 29A18 line size is not full, the main power supply is only 75---85V, after checking the power supply part VD520 performance is poor, replace RU2.
3, Changhong CK56B2----22", the field vibration TA7698 integrated block 33 feet VCC + 8.6V, if only about 4V, for the line to open the way [including the push tube, transformer, etc.].
4, Changhong 2939FD, the upper retrace line [has some stations], enter the "S" bus, and return to ABK--ENABLE [normal]. [Brightness becomes bright when fault occurs]
5, Changhong N2918 machine only blue background no picture AV into, AV output has no picture with accompanying sound, adjust the fine adjustment of the AV can have sound, the TV sometimes has sound, the picture difference, and the Y signal seems to be lost. After repeated investigations, the comb is faulty, and the internal re-welding is repeated once and everything is normal [estimated capacitance has leakage]. Note: If you remove the button socket of this unit, the channel will automatically flip.
6, Changhong C2589 work in the upper part of the venue there are numerous black lines, poor linearity, repeated heating to check the C329--471K polyester capacitor is bad, normal after replacement.
7, Changhong C2191 appeared "吱" sound does not work, unplug the deflection coil, the line C voltage is normal, after investigation: C428--1UF/250V capacitor short circuit, replacement is normal.
8, Changhong C2992 appears in the upper part of the image is jagged, after checking C825 [field supply capacitor] 35V/1000UF normal.
9, Changhong G2125 machine, the upper half of the length of the investigation R402 [120K] resistance open circuit, after the change is normal.
10, Changhong 2118FA (A6 movement), VD514 (4148) open circuit, the main power supply is completely normal when the dummy load. Burn the tube for 2 seconds when the load is generated.
11, Changhong C2919PK color TV, there is power indication, standby 50V normal, but the second boot, immediate protection, is the line output load (7) foot VD408 (RU4Z) short circuit, after replacement everything is normal.
12, Changhong G2132 (K) boot with power indication, but not secondary boot: the line is not heated when the second time is not hot, with the main load 130V with a dummy load is normal, after repeated investigations for the line deflection coil short circuit. (This machine is prone to this failure)
13, Changhong R2916N (R2518N same) line center shift to the right 3 cm, no characters, AV also no picture: line pulse high voltage package (9) feet D403, D404 short circuit, replace D404 (5.1V) normal. The negative end of D403 is normally 0.7V.
14, Changhong 25K18 (using LA7841 field block), the upper part of the work will appear compression, the lower side of the thin: check for C301 (1000P) capacitor is bad, replace the normal.
15, Changhong G29K36 machine level a bright line: check for N30 (LA7841) is bad. At the same time, you must check the VD302 (1Z75) voltage regulator tube, such as the short circuit before burning LA7841.
16, Changhong 25N16 map compression 10 cm, and roll up, C302, 10N capacitors are bad.
17, Changhong C2919PK (1) upper retrace line (no dark), for C318--35V/220UF. (2) The upper retrace line, no under the field, it is good to change C305---50V/1UF.
18, Changhong C2919PS machine, there are stripes (like the line is not synchronized), while the "black" sound (blue background off), the comb circuit is bad.
19. Changhong C2588A machine, there is a rare compression failure, replace the C317--2.2UF capacitor. 20. Changhong C2169 has “M” red character fault handling: this fault indicates entering the debug mode. If the remote control cannot be turned off, press an unused button between “SYS1/SRC” and “AN-SEL” under the K1L remote control to make it The character red turns green and can be eliminated when the remote control is turned off. If the fault cannot be eliminated, the remote control must be replaced, and the remote control should be turned off.
21, Changhong C2169 and other models start the "AV" state: This fault indicates that the working program has changed, usually the memory and the external circuit have failed, and the replacement is normal.
22, Changhong R2518AE (D) machine has instructions, but can not be turned on twice (has "support" ... sound), has burned the tube: after checking the line frequency 15625 has gone to the tube, sometimes can be turned on but there is a line to the left of the raster Compression, accompanied by drawing, repeated investigations to push the part of the VD431 (1N4148) diode defective.
23, Changhong C2588PS machine, there is a small amount of retrace line in the upper part: repeated check is not C320, the field is blanking bad (go to the visual release), the resistor R321--2.2K and the same resistance troubleshooting. Sunday, December 22, 2002
24, Changhong C3419PS 5 cm at the upper part of the retrace line (normal amplitude): check the C318 capacitor is bad, replace the normal.
25, Changhong R2518AE is always burning tube: check the capacity of C436, C435RO, if it is blue CBB81 type, it must be exchanged. After changing the capacitor and the tube, everything is normal.
26, Changhong 2938FD without sound: no 16V, check 872 (0.27/0.5W) resistance open circuit, with 1W/0.33 replacement after normal.
27, Changhong R2519N automatic shutdown automatically, sometimes not boot: R820 (0.15 ohm) deterioration to 0.5 ohms or more, replacement is normal.
28, Changhong 2518FN series movement: the upper length, the lower side compression, the bottom side has 3--4 cm no light, are caused by C306 (4700/25V).
29, Changhong R2519N (using TDA6103Q for viewing) brightness is a little brighter, because the ABL circuit R421 (100K) becomes larger; if the boot is bright, it becomes a bright line, open for RX19 (220K). 30, Changhong D2962A three no, the line has been worn, capacitor C461 (7200P/1500V) deterioration (including 5100P). Replacement is normal.
31, Changhong G2536 search does not save the table, close the blue background, fine-tuning can be saved, and the AV map flip: after checking the CPU---36 feet on C022--(101N). Normally, 36 feet are 3.5---4.5V.
32, Changhong T2981, T2982 machine map difference: Check the antenna input amplifier box has a problem, you can cross-line tuner and antenna input box.
33, Changhong SF2915 has power indication, but can not boot: check CPU (N100) 3.3V voltage is only 2V, after replacing the power supply part V871 (C2688L) everything is normal. Thursday 2003 01 23
34, Changhong 2588K machine burning line, the new line of the line-changing tube is small (high pressure is high), check the C472--7200P/1600V capacitor on the pillow board is bad, normal after replacement. Thursday, January 23, 2003. 35, Changhong C2919PK put a few minutes later, some channels run, automatic search may not be completed: check the main box in the middle of the week 1160 bad.
36, Changhong C2919PS irregular running (normal picture-in-picture): crack welding at the main high-frequency head pin.
37, Changhong 2118FA burning tube V432 (D1651), check the power supply and capacitance are normal, and then check the VD441 (RM11C diode) short circuit on the deflection circuit. February 10, 2003.
38, Changhong G2125 has instructions, do not boot: check for 18V power supply has a short circuit, because V832 (D400-E) is bad, burn D834, D835, R824. It is normal after the change.
39, Changhong SF2551 three no: after changing N801 (STR-F6454), VD830, VD808, V801 (C2655) is normal.
40, Changhong C3419PD lack of Y signal: check for the clarity enhancement box is bad, short-circuit 1--3 feet can be emergency troubleshooting.
41, Changhong H29D80 sound bad, only "black" sound: Z608{L6.5C} bad. Replacement is normal.
42, Changhong G2985 (B), line width distortion, left and right difference 1CM: R931 (0.5W 15 ohms). Increase to 150 ohms, replace normal..
43. Changhong C2152 (KV): LA7680 for small signal, with instructions, automatically turn on after a few minutes: normal after changing C563 (35V/330UF) capacitor. Such as wood grain interference for C562.
44, Changhong T2982 has power indication, but does not boot: diode VD408 (RU4Z) is bad, replacement is normal.
45, Changhong C3419PD standby normal, start burning C4706 adjustment tube: 400V/560UF capacitor is bad. (The boot is accompanied by a "click" sound.)
46, Changhong C3419PK: The main power supply 115V is only 100V, and it is R868 270K/1W open circuit with the sound size.
47, Changhong HP series rear projection power supply improvement: R888/270K/1W changed to 470K/1W; between VC801 (2) (3) feet and 0.22UF/250V capacitor (power "吱" sound, and interference (1) channel ).

Other information: Changhong 1
1. When overhauling the 21" color TV failure produced by the A6 movement, or when the maintenance is damaged due to TDA7496 failure, connect the CRT, the left and right speakers of the main channel and the main board to the screen.
2. For some models of color TVs, there are more snowflake points in the signal receiving areas, and there are noise problems. It can be connected at both ends of the front intermediate frequency amplifier circuit V101\"E\" pole resistor R115. A capacitor is solved with a reference value of 0.01 UF.
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-inch color TV produced by the A6 movement has the frequency drift phenomenon after the program under the program number \"1\", 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 TEA2261 of the NC-5 movement power supply block is replaced by the BL8701, the circuit will be changed from the original 1.5K to 6.8K; the R818 will be changed from the original 680 ohm 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 subwoofer that emits a "å—¡å—¡" field: the C675 can be 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 improvement methods are proposed: R819 is changed to RT13-0.166W-330 ohm; R822 is changed to: RT13-0.166W-1.3K; C821 is changed to: CD11-50V-1UF; C825 was 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 of "the remote control does not receive, the local buttons and other functions are normal".
3, CH-10 movement individual fault repair methods: (1) boot for a period of time, the screen appears a gap black screen (flashing), accompanied by noise; sometimes after a number of flashes, automatically shut down (will not appear B/B background), repeat the above fault again after booting. (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. When the full screen return line appears: A. Increase the resistance RY04A (0.5W/470 ohms), disconnect the printing line between CY01 and CY02, and RY04A is installed in CY01. Between the end and the positive end of CY02. 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 karaoke signals are played in some types of color TVs produced by CN-12 movement, when the sound is abnormal, the grounding at C523A\"\" and R501 can be used, and the two groups can be connected. diode. 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 welding wire of the sound tube are too close.
5. There is sawtooth interference in the lower part of the NC-6 movement screen: the reason is due to poor performance of L442, please replace L442 (TLN3063) to solve.