Dynex DX-22LD150A11 - No life besides Power LED

[MLBZ521]

So I was given one of these Dynex DX-22LD150A11 TVs that has been posted about in a few other threads here. I reviewed the five threads I believe I have checked all items that were mentioned in those threads. Results are below.

Issue: No Life (No Video/possibly no audio) -- but kinda shows power. I assume no audio, haven't been able to blindly switch to a connected HDMI source.

Symptoms:

• No click
• No back light (not even a flash -- confirmed in a pitch black room)
• No response from buttons
• Nothing from the DVD player
• No other life what so ever, even when pushing buttons

It does do:

• Red light is ON with power cable plugged in.
• Red light changes to blue when power button is pressed.

Measurements:
Off
Power Board to Control Board lines (PSU side)
DIM = -.055v
BL_ON = 0.0
12v Lines = 13.44v
5v Line = 4.86v
AC_OFF_DET = .199

T302 Transformer (Secondary)
S1 -> S2 = 959 kohms
S3 -> S4 = 955 kohms

IC101 Chip
P1 -> P2 = 1.599v
P1 -> P3 = 0v
P1 -> P4 = 164v
P1 -> P5 = 3.81v
P1 -> P6 = 0v
P1 -> P7 = 13.23v
P1 -> P8 = .054v
P1 -> P4 = 0 ohms
P1 -> P7 = 0 ohms

On
Power Board to Control Board lines (PSU side)
DIM = -.032v
BL_ON = 0.0
12v Lines = 12.16v
5v Line = 4.96v
AC_OFF_DET = .199

T302 Transformer (Secondary)
S1 -> S2 = 959 kohms
S3 -> S4 = 955 kohms

IC101 Chip
P1 -> P2 = 1.667v
P1 -> P3 = 0v
P1 -> P4 = 163.1v
P1 -> P5 = 3.87v
P1 -> P6 = .003v
P1 -> P7 = 13.46v
P1 -> P8 = .299v
P1 -> P4 = 0 ohms
P1 -> P7 = 0 ohms


I don't see anything visibly on the board that looks suspect. Any thoughts?

Pictures attached of the Power Board and Control Board. Two of each side (front and back). One with and one without camera flash. I did find this little guy in the last picture.

Thanks!

[dick_barton]

Re: Dynex DX-22LD150A11 - No life besides Power LED

Initially it looks like the ac detect does not change voltage between On, Off so I would be thinking you may well have a problem there.

Check R104, R105, R106.

[MLBZ521]

Re: Dynex DX-22LD150A11 - No life besides Power LED

Checked those and they seem correct, if I understand and am doing this correctly..?
R104 = 99.9 kohms
R105 = 50.9 kohms
R106 = 50.9 kohms

Thank you for your time!

[budm]

Re: Dynex DX-22LD150A11 - No life besides Power LED

"Red light changes to blue when power button is pressed." To that means the AC-DET is OK Otherwise you will not able to turn on the TV and see the LED indicator changes state. Right now the main board is not sending out the BL-ON, DIM to turn on the backlights, so I would check the main board.
You can also dis connect the AC-DET wire and then check the Voltage on the AC-DET pin of the main board to see if it stays low or high, if it goes high then try turning the TV on and off with the power switch to see if the power LED will change state or not and if the TV will start working or not.

[MLBZ521]

Re: Dynex DX-22LD150A11 - No life besides Power LED

I should probably clarify my measurement definitions:
"Off" = TV Standby (Off, with power -- Red indicator light is ON)
"On" = TV On (Blue indicator light is ON)

Also, the measurements originally posted and included below are with the DVD Player and LCD Panel disconnected -- though I have tested with the LCD Panel connected and did not observe a noticeable difference. So if anything will determinately require the LCD Panel connected for testing, please let me know.


Measurements with AC_OFF_DET Connected:
Power Board to Control Board lines (Checked at PSU side)
Off
AC_OFF_DET = .200v (<-- Original post had .199, but it does change between OFF and ON states)

On
AC_OFF_DET = .199v


Measurements with AC_OFF_DET Disconnected:
Power Board to Control Board lines (Checked at PSU side)
Off
AC_OFF_DET = 0v

On
AC_OFF_DET = 0v


Measurements with AC_OFF_DET Disconnected:
Power Board to Control Board lines (Checked at Control Board side)
Off
AC_OFF_DET = 3.095v

On
AC_OFF_DET = 3.094v

With the AC_OFF_DET disconnected, the Status LED does still change from Red to Blue, but there are no other noticeable changes (no clicks, no backlight on the LCD, or anything else), except for:
With AC_OFF_DET disconnected, the first attempt to power on the TV (press power button), the Status LED changes from Red -> Blue, and then quickly changes back to Red. After that, it will change from Red -> Blue and stay there.


So.... Make any sense to anyone?

[Andrew F. Ali]

Re: Dynex DX-22LD150A11 - No life besides Power LED

You seem to have a bad Main Bd. The PSU is OK AC_DET is working. You are not getting a BL-ON signal from the Main Bd.

[MLBZ521]

Re: Dynex DX-22LD150A11 - No life besides Power LED

Sorry, for the delayed response, been quite busy with work this week.

Would you, or anyone have any recommendations for troubleshooting steps on the Main Board?

Thanks for everyone's time and input!

[MLBZ521]

Re: Dynex DX-22LD150A11 - No life besides Power LED

In case anyone else comes across this thread.

I ordered a main board and that resolved the issue. Not sure what is wrong with the original main board, but all aspects of the TV are working with the new board.

To be honest, I didn't think the new board was working (completely) either. When I first installed it and turned it on, I only got a white picture. After looking more closing I realized the ribbon cable to the LCD was not seated completely -- thanks to the awkward layout of this TV (the LCD Panel is just 'free floating' inside the case with connections on the top and right side; so it's hard to bench test it).

Anyways, thanks again to everyone would took the time to respond. On to the next item to fix!