DYNEX DX55L-150A11 Randomly turns off

[102mm]

Helllo Again,
I Picked up this 55" Dynex that works great with the exception that it will randomly shut off. when i first got it it played with no issues for days, then one day i finally turned it on and i got a quick flash of the backlight then nothing. i unplug it and try again and the thing works fine for an hour then turns off.
This seems to be a common problem with this TV but i have not seen a remedy. If i had a guess i would suspect the inverter boards, but i am not for sure.. any ideas?

[Caleb]

Re: DYNEX DX55L-150A11 Randomly turns off

You can try to isolate the specific trouble with a hairdryer and freeze spray on each board and see if you can get it to go on and off at will with heat and cold.

[bossksm]

Re: DYNEX DX55L-150A11 Randomly turns off

Hello,
l am having essentially the same issue with my Insignia NS-55L260A13 the Dynex and Insignia are closely related devices.

The TV often will not turn on. I have to remove it from Power completely and plug it back in for it to turn on. (And this only helps sometimes)

I found many people having the same issue on the Insignia Forum (http://community.insigniaproducts.co...own/td-p/72958) However there was no Technical Help given.

So I took the TV apart and started to read the Voltage values and two of them (12V and 5V pins) were Low.
There are no Bulging or leaking Capacitors.
My Question now is, how to procede with the Troubleshooting, I do not know how to move on to the next step in resolving the issue.
My next step would most likely be to take out all the capacitors and check their values, but I was wondering if you could guide me to a more efficient way in solving this.

Unfortunately the replacement board is sold out. (http://www.shopjimmy.com/dynex-15188...upply-unit.htm)

Attached is my board.

[bossksm]

Re: DYNEX DX55L-150A11 Randomly turns off

After doing more research, I found that some people advise to replace the Inverter board? I still believe something is wrong with the Power supply board though.

Any help would be greatly appreciated.

These are the pins that showed low readings:

[Caleb]

Re: DYNEX DX55L-150A11 Randomly turns off

best way to tell is if you test all the voltage points on the power supply when it is working then wait till it shuts off then test again. If you post it in a
pin1 (16v) 15v
pin2 (16v) 15v
format so we can see what the voltages are supposed to be vs what they really are it would be helpful.
If both the 12v and 5v are low ( how low are they? ) they may be derived from the same transformer and you could have trouble in the feedback circuit, or you may have a mild short beyond that is overtaxing the power supply. Also the labels on these boards are sometimes not very accurate. I had a phillips that was labeled 9v on the board and 7.2 in the service manual, was a wild goose chase until I looked at the manual.

It could also be a cold solder joint, I had a dell display that would work fine for hours then randomly shut off, ended up with a cracked joint on a tiny 0406 10k resistor that was causing it. It was so tiny you had to look under a magnifying glass to see it. The feedback circuit is on the underside of the board near the optoisolators.

[budm]

Re: DYNEX DX55L-150A11 Randomly turns off

We need ALL the Voltage readings of all the pins when the TV works and when the TV does not work, we need to know if the command signals from the main board is missing or not when the TV does not work.

[bossksm]

Re: DYNEX DX55L-150A11 Randomly turns off

Thank you for getting back to me. First I want to clarify my issue better:
My TV does not AUTO Shut Off, at least not yet. However, it fails to Turn ON properly. The TV will briefly flash and then remain off. Here is a video of what it looks like (https://youtu.be/Eb8nGLC4xHE)
The Outlet my TV is hooked up to, can be turned OFF/ON with a Switch on the wall, to remedy the failed start up, I flip the switch OFF and leave it for 5-20 minutes and flip it back ON and the TV either starts up successfully or reacts like in the video. (NOTE: When flipping switch ON, the TV initates start up without me having to even press any button on the remote)

I took measurements both when the TV is fully ON and working as well as when it fails to fully start (after the flash seen in the video)



When fully ON // *When failed to start up
(A)
pin1 (24) 24.3V
pin2 (24) 24.3V
pin3 (24) 24.3V
pin4 (24) 24.3V
pin5 (24) 24.3V
pin6 (GND) 0V
pin7 (GND) 0V
pin8 (GND) 0V
pin9 (GND) 0V
pin10(GND) 0V
pin11(BRI 1) 0V
pin12 (SW 1) 4.4V // 0V

(B)
pin1 (24) 24.3V
pin2 (24) 24.3V
pin3 (24) 24.3V
pin4 (24) 24.3V
pin5 (24) 24.3V
pin6 (GND) 0V
pin7 (GND) 0V
pin8 (GND) 0V
pin9 (GND) 0V
pin10(GND) 0V
pin11(BRI 1) 0V
pin12 (SW 1) 4.4V // 0V
pin13(BRI 2) 1.2V // 0V
pin14(SW 2) 0V

(C)
pin1 (5V_M) 5.2 V
pin2 (5V_M) 5.2V
pin3 (GND) 0V
pin4 (GND) 0V
pin5 (SW) 4.4V // 0V
pin6 (PWM) 1.2V //0V
pin7 (GND) 0V
pin8 (12) 11.7V
pin9 (12) 11.7V
pin10(5V_S) 4.9V
pin11(5V_S) 4.9V
pin12 (ON/OFF) 3.6V

(D)
pin1 (16) 17.2 // 16.4
pin2 (16) 17.2 // 16.4
pin3 (GND) 0
pin4 (GND) 0
pin5 (12) 11.7
pin6 (GND) 0
pin7 (5V_M) 5.2
pin8 (GND) 0
pin9 (GND) 0
pin10(5V_M) 5.2
pin11(5V_M) 5.2
pin12 (GND) 0
pin13 (GND) 0

[budm]

Re: DYNEX DX55L-150A11 Randomly turns off

OK, I can see that when the TV is not working properly, the main board is still sending out the PS-ON (Connector 'C' pin 12: ON/OFF) but it stopped sending out
Connector 'C'
pin5 (SW) 4.4V // 0V: BL-ON (Backlights ON)
pin6 (PWM) 1.2V //0V: PWM DIMMING

These two signals are from the main board and fed into connector 'C' and routed out to the connector 'A', and 'B' pin 12 which is then feed the inverter board.
What caused those two signals to disappear I do not know exactly which parts are bad on the main board.

[bossksm]

Re: DYNEX DX55L-150A11 Randomly turns off

Thank you very much for your analysis!! So it is safe to assume that the Power Supply board is working fine, and the issue lies with the Main Board?? If that's the case I'm glad I didn't invest in a new Power supply board.

[budm]

Re: DYNEX DX55L-150A11 Randomly turns off

You can force on the backlights AFTER THE TV's power switch is activated by disconnect the two wires from the B FEMALE connector first so now you will have two wires sitting in the air, the other ends of this two wires go to the inverter board.
So then you will need to put 500~1K resistor between the SW (BL-ON) wire and the 5V_M pin on the connector 'D', the do the same thing for the PWM wire using another same value resistor (you may be able to leave the resistor off this wire first to see if the backlights will come on, if it does then you do not need to connect anything to this PWM wire). You must be careful not to let the wires short to anything else and make sure to label the wires.

[bossksm]

Re: DYNEX DX55L-150A11 Randomly turns off

Okay thanks budm. Forcing the backlights on, the way you described seems like a quite involved and tedious undertaking.. Would replacing the Main Board be an alternative? Or are there other components that could be failing?

[RJARRRPCGP]

Re: DYNEX DX55L-150A11 Randomly turns off

Hello,
l am having essentially the same issue with my Insignia NS-55L260A13 the Dynex and Insignia are closely related devices.

The Dynex and Insignia brands are probably TMs of Best Buy.

IOW, probably store brands.

[102mm]

Re: DYNEX DX55L-150A11 Randomly turns off

I just realized that i started this thread.. It's definitely the power supply.. I picked up another TV with a broken screen and swapped them out, problem solved.. Didn't get a chance to troubleshoot the old one... my wife broke the danm thing throwing it at me.. Joke gone wrong....SMH
Kept the other boards just in case i was wrong tho, but it's been the main TV for the last year no issues..

[budm]

Re: DYNEX DX55L-150A11 Randomly turns off

Well that does not make sense to me since those two missing signals are not generated by the power supply board.

[bossksm]

Re: DYNEX DX55L-150A11 Randomly turns off

Could this be the cultprit? http://www.shopjimmy.com/insignia-ns...eprom-only.htm

The description seems promising:
Symptoms EEPROM replacement MAY fix:
- On screen display is stuck on logo screen
- TV won't power on with remote or buttons (LED indicator remains same color)
- TV won't turn on after being off for 30+ minutes
- TV shuts off by itself during channel scan or when switching inputs
- TV turns on and is stuck in color test pattern mode forever
- TV turns on but there is no backlight (LED indicator shows TV is on but there is no image)

[LloydJane]

Re: DYNEX DX55L-150A11 Randomly turns off

Probably not a lot of interest anymore as this is now an older TV, but I picked up one of the Insignia models because it was being discarded for this very reason. I found that there is a current-limiting thermistor on the power supply that runs extremely hot. The part # is MF72 5D20L, and an infrared scanner shows it at approx 170 degrees (F) when the TV is running. I suspected that this was overheating and shutting down the power until it cooled down, so I installed a 5v PC fan to keep it cool. Tapped into the 5v DC coming off of the white ribbon cable and - problem solved! Have had the TV running for 5 days straight now and has not shut down.

[fcisolutions]

Re: DYNEX DX55L-150A11 Randomly turns off

I have the same TV as Bossksm. It's an Insignia NS-55L260A13. Did we ever figure out if this is the power supply or main? I'm guessing main but can't find the this board. I do on Ebay that a ton of E7 eproms sold. Not sure which chip this is. Any help is appreciated!!

Ok here are my voltage readings ...

When fully ON // *When failed to start up
(A)
pin1 (24) 24.3V
pin2 (24) 24.3V
pin3 (24) 24.3V
pin4 (24) 24.3V
pin5 (24) 24.3V
pin6 (GND) 0V
pin7 (GND) 0V
pin8 (GND) 0V
pin9 (GND) 0V
pin10(GND) 0V
pin11(BRI 1) 0V
pin12 (SW 1) 4.4V // 0.027V

(B)
pin1 (24) 24.3V
pin2 (24) 24.3V
pin3 (24) 24.3V
pin4 (24) 24.3V
pin5 (24) 24.3V
pin6 (GND) 0V
pin7 (GND) 0V
pin8 (GND) 0V
pin9 (GND) 0V
pin10(GND) 0V
pin11(BRI 1) 0V
pin12 (SW 1) 4.4V // 0.026V
pin13(BRI 2) 2.5V // 0V
pin14(SW 2) 0V

(C)
pin1 (5V_M) 5.2 V
pin2 (5V_M) 5.2V
pin3 (GND) 0V
pin4 (GND) 0V
pin5 (SW) 4.4V // 0.027V
pin6 (PWM) 2.4V //0V
pin7 (GND) 0V
pin8 (12) 11.6V
pin9 (12) 11.6V
pin10(5V_S) 4.9V
pin11(5V_S) 4.9V
pin12 (ON/OFF) 3.7V

(D)
pin1 (16) 16.7 // 16.43
pin2 (16) 16.7 // 16.43
pin3 (GND) 0
pin4 (GND) 0
pin5 (12) 11.6
pin6 (GND) 0
pin7 (5V_M) 5.2
pin8 (GND) 0
pin9 (GND) 0
pin10(5V_M) 5.2
pin11(5V_M) 5.2
pin12 (GND) 0
pin13 (GND) 0

[dskall]

Re: DYNEX DX55L-150A11 Randomly turns off

I just realized that i started this thread.. It's definitely the power supply.. I picked up another TV with a broken screen and swapped them out, problem solved.. Didn't get a chance to troubleshoot the old one... my wife broke the danm thing throwing it at me.. Joke gone wrong....SMH
Kept the other boards just in case i was wrong tho, but it's been the main TV for the last year no issues..

Bad power supply. I have same problem. I replaced mainboard before seeing this post. Main did not fix problem. I am now trying to find powerboard problem. Going to replace N802. While poking around on pins it would turn off. I will update if I have any success

[fcisolutions]

Re: DYNEX DX55L-150A11 Randomly turns off

Well I see the power supply fixed the problem for 102mm the OP but Bossksm's problem is identical to mine and I tend to think like Budm that the signals for the backlight come from the main.

[dskall]

Re: DYNEX DX55L-150A11 Randomly turns off

Well my problem is same as op, randomly shutting off. Not the same as hijacker of the post which had different problem.