Why is the inverter in a Toshiba 40LV685D being shut down so the CCFL backlights never even flash, and what should be checked to stop the cyclic reset?
The inverter is most likely being shut down by its protection circuit because of a fault in the inverter/power section, not because the lamps need to be “forced” to start. For this model, a service kit was mentioned for no-backlight faults that replaces F101/F102, U101, and the switching transistors Q301-312, Q321, and Q322 [#15640332] The key checks suggested were the SEM2107 supply and protection pins: the IC should have the correct Vcc and UVLO-related voltages, and one measured case showed about 17 V on SEM2107, which was considered suspicious [#15644142][#15644317] Bypassing the Protect pin on SEM2107 did not change the symptom, so the reset/lockout was not cleared that way [#15644142] The replies also pointed to comparing all inverter voltages against a known-good board and checking the protection line and related transformer/transistor stages, because the inverter can remain latched in protect even when the lamps themselves test OK [#15644207][#15644317]
TV as in the subject, initial symptom - does not turn on. Replaced STR-A6069 chip. There is no backlight after switching on the power supply. After replacing the SEM2107 chip and AO4614 transistors. Inverter SSI-400-14A01 TV turns on for a moment, 24 V voltage is applied to the Inverter but the fluorescent lamps do not light up even for a moment and the TV resets cyclically every few seconds. The TV reset effect is also present when the Inverter is unplugged. My question is what causes the Inverter to be blocked to the point where the fluorescent lamps will not even flash.
After all, I wrote that I replaced SEM2107 and all transistors. After replacing the Inverter, it does not block the motherboard because the Main board has not leaked before. But the TV keeps resetting.
OK, I'm at home now, I can catch TV on Mon I think the topic is interesting. Mirex has already checked everything And what and how I will write on Monday, because to d ... I write with phone !! Thanks "Lisek"
Inverter voltage 24V OK. The power supply on SEM2107 equals 17V and it is still at this level even though the TV resets. Bypassing the Protect on the SEM does nothing. So what ....?
The method of removing the Protect lock in these ICs must be adapted to the given system, pay attention> they have different numbers of pins ... I showed for SEM2106
For SEM2107 it is SSOP-28 pin housing.! View and take measurements on pin "ah, give it up." It is important, for example, on a pin. (Vref)
There is also an output system. on the 4th trafo. with 14 ohm field transistors * described on the "Chinese website" Link
For example, they say that Below is the job center for SEM2106 SSOP24
I don't know what Main is, but the series Toshiba 40LV655xx LCD TV Main Board - PE0772 (V28A001020A1) ** CPU_scaler - MST 6B885GL-LF-3 T-Con SYNC60C4LV0.3 PSU DPS - 276AP A behind Link_ the minimum voltage values were given on T-con
Quote:
In the service menu> point: Model (for my model TV ie 40LV655P) set the value 02H and after that make initilization memory. Click the return button (i +) and holding it press the PROGRAM button +. After the initialization of the TV, turned on the auto channel search. .... (as if the brightness and contrast low). These after the initialization data is not preserved the LCD panel. Put a new ?24?64. Made again as mentioned above and TV ork fine.
??? "Lisek" I know what it looks like since I replaced it and as you can see it has 24 pins. It would be more important if the 17V is OK. I do not have a service center or a diagram and that would be helpful. In addition, in this model, Inerter cooperates with T-CON which gives INV_On and nothing changes there. There is no TPS65167 converter on T-CON, maybe there is a problem here, the only question is why the fluorescent lamps will not collapse even for a second despite the protect photo. How do I force an entire Inverter to start?
Added after 2 [minutes]:
Do you think this is an EEPROM problem? Where did the charge come from (I'm not registered on this page)
1. voltage on pin you have approx 2. role of pin.15 UVLO, what voltage value and compare with datasheet 3.Vcc usually is 12V, (Tip # 14: VCC: 12.36V) / * (your value + 17V maybe too much) see what will happen when you connect the R-150k between pin.14-pin.15 what then with the voltage on pin.15 (increases)
___________________ Voltage on PFC 390V CN801 Pin # Label: measured voltage 1 High (FET): 3 Low (FET): 8 GND: 9 OVP: (? V) (Seems to be a backlight-confirm Signal.) 10 CNT_PRT: (? V) 11 VCC: 12.38V (13V) 12 LD: (? 12V)
I replaced DAP015D with L6599 and ... nothing - the same, the same voltages (i.e. no described). I have enough of it for today - let it "bloom" until Wednesday.
From the link I provided earlier, you have the tension from a good TV PJ91 1Power_Protect + 3.5V 2Power_Sig + 3.1vV 3AC_Detect + 3.3V 4Power_LCD + 3.1V 5.6SGND 0V 7.8 LCD + 12.08V
NCP1607B + 2sk3569 * SSC9512 STR-A6069H There during work POW PROT - 2.92V POW SIG - 2.2V AC DET - 2.7V POW LCD - 3.1V
Measurement of voltages during operation L6599D, NCP1606B Link
and see v Link From the Electrode forum, e.g. Link
_______________ DPS145PP-131 A for TOSHIBA 37XV743 (V71A00014900) and matrix LC370WUD_G * 32AZ510 with matrix T315HW041 STRA6069H MP-130I (AV-DP9060) NCP1607B SSC9502S
The Delta company in its dogs is "monothematic", the same IC has almost identical work layouts. NCP1607B / NCP1606B
✨ The discussion revolves around a Toshiba 40LV685D TV that fails to turn on, exhibiting no backlight after replacing the STR-A6069 chip, SEM2107 chip, AO4614 transistors, and the inverter SSI-400-14A01. Despite applying 24V to the inverter, the fluorescent lamps do not illuminate, and the TV resets cyclically. Participants explore potential causes, including issues with the inverter, T-CON board interactions, and the possibility of an EEPROM problem. Various voltage measurements are shared, and suggestions for bypassing protection circuits are discussed. Ultimately, the TV remains unrepaired as the client opts not to pursue further repairs. Generated by the language model.
