APEX model LE 1910 (LED TV)

[mnpdreed]

I have an Apex LED TV. Will not turn on...no power light or back light. It does have 12V at F1 and 12V at the Black and Red wire on the blue color board. Any ideas? Thanls

[mnpdreed]

Re: APEX model LE 1910 (LED TV)

Any suggestions on what to look for

[fzabkar]

Re: APEX model LE 1910 (LED TV)

What are the voltages at CN7? Is there a 5VSB? 5V?

What are the voltages at the regulators - UL1 (+3.3V?), UL51, LD41 coil or nearby capacitor, coil or capacitor ED2 near inverter connector?

[mnpdreed]

Re: APEX model LE 1910 (LED TV)

Is CN7 the white plug if so 3.3 volts
UL1 3.3v/1.8
UL51 0v
ED2 5.1v
FE1 12v
EL54 0v
EM11 5.15v
EA12 and EA5 12 V
EA2,3,4,and 6 0v

[fzabkar]

Re: APEX model LE 1910 (LED TV)

There appear to be two more LDOs at UT1 and UL41. What are the voltages there?

Can you tell us the markings on UT1, UL41, UD41, UL51, and the 8-pin IC near ED2?

My first approach is to verify the presence of the onboard supply voltages. So far it appears that you have found the Vcore (1.8V) and Vio (3.3V) supplies for the MSD3391DS SoC. The 5V supply is also present.

Where does connector CN7 go? I suspect one group of 4 wires goes to the switch PCB.

[mnpdreed]

Re: APEX model LE 1910 (LED TV)

UT1 1084B. 33A92V
UL41 1117B ADB72V
UD41 gg2j
UL51 117B AD B72V
8 pin AIC2857F GR8 07728
CN7 4 wires to switches 4 wires to power light

[mnpdreed]

Re: APEX model LE 1910 (LED TV)

UL41. 0v

[mnpdreed]

Re: APEX model LE 1910 (LED TV)

Ut1 0v

[fzabkar]

Re: APEX model LE 1910 (LED TV)

UT1 is not an LT1084. Look for it near the HDMI section.

ISTM that UL1 should have 0V, 3.3V and 5V on its pins, not 1.8V.

AISI, the main board should have a 3.3V Standby voltage. This appears to be present at CN7, presumably for the switches and IR sensor.

AFAICT. the 1.8V supply is present, but not where you stated that it was. Otherwise there is some weird fault.

I believe there should also be a VDDC voltage for the HDMI section, and 2.5V for the SoC.

Can you check your measurements and the part markings?

FYI, the Sanyo DP32642 TV uses the same SoC. Although it is a different TV, its service manual has troubleshooting information and circuit diagrams that are pertinent to your Apex.

Sanyo TV with MSD3391DS SoC and circuit diagrams:
ftp://helpedia.com/pub/temp/datashee...32642-04_Z6TJ_[SM].pdf

[mnpdreed]

Re: APEX model LE 1910 (LED TV)

UT 1 has 0V

[fzabkar]

Re: APEX model LE 1910 (LED TV)

ICs have more than 1 pin. Therefore they have more than 1 voltage.

You still haven't told us what UD41 is doing, eg what is the voltage at the pin going to the LD41 coil?

You still haven't confirmed where you measured 1.8V.

[mnpdreed]

Re: APEX model LE 1910 (LED TV)

I could not find 1.8v so I guess I read it wrong. I will attach a pic with all the readings I have. I couldn't get the Sanyo li k to open. Thanks

[mnpdreed]

Re: APEX model LE 1910 (LED TV)

Did those readings help

[fzabkar]

Re: APEX model LE 1910 (LED TV)

Thanks. The 1.8V reading was confusing, but you've cleared it up now.

AISI, the +5V and +3.3V standby supplies are present, so the TV is in standby mode. When the TV is powered on, the other supplies should come up, namely 1.8V, 2.5V, 1.26V (VDDC), and a second 3.3V supply, if the Sanyo circuit is any guide. The reason that there are no input voltages on many of the regulators is that this input voltage is switched by the POWER_ON logic. ISTM that you need to find where the input voltages to UD41 and UL51 come from, probably from a MOSFET switch. Then you need to confirm whether this switch is being activated by the MSD3391DS SoC.

BTW, the URL for the Sanyo service manual was truncated by the forum software. Just drag your mouse over the entire URL, including the "[SM].pdf" that was cut off.

Edit: You should measure the voltages again after pressing Power_On.

[mnpdreed]

Re: APEX model LE 1910 (LED TV)

Thank you for helping. I will measure the voltage with power on tomorrow and post. Thank you again!!!!

[fzabkar]

Re: APEX model LE 1910 (LED TV)

I've cropped the "Standby Micro Block" from the Sanyo manual. ISTM that the SoC may be brain-dead. I say this because it should be driving the standby LED. If this turns out to be the case (ie no response to POWER_ON at the regulators), then I would check the crystal (Y1) and the voltage on the HWReset pin (216).

[mnpdreed]

Re: APEX model LE 1910 (LED TV)

Had no response to power on..no lights...all reading where still the same.

[mnpdreed]

Re: APEX model LE 1910 (LED TV)

I will check the crystal (Y1) and the voltage on the HWReset pin (216) and post results tomorrow. Thanks again

[fzabkar]

Re: APEX model LE 1910 (LED TV)

The voltage at the HWReset pin (#216) should be high. However, I suggest you avoid testing the pin itself since this area is very "busy". A slip of your probe might do serious damage. Instead I would find an appropriate test point at one of the nearby components.

Testing the Y1 crystal would require an oscilloscope with a high impedance probe, so I don't know how you would go with that. AFAICT, it's a 24MHz type so it should be cheap and easy to find.

[mnpdreed]

Re: APEX model LE 1910 (LED TV)

I tested before I read the post. Y1 read 1.4 V. Pin 216 was 0 V