SONY KDL-46EX710 no error code failure

[notsogentle]

I've searched the forums and found others with this model that have a 7 times blinking red error.

This set does not do that.

Power on cold, set works great for a time then it power cycles off then on (green light off then on). Works for a minute or two then power cycles again, however green led stays lit and no picture or sound comes back.

No error codes, power button still cycles relay on/off but no backlight or sony boot screen etc.

when checking -out1 -out2 and +out1 and +out2 (to ground) i get

before failure (power led on, normal operation):

-OUT1 69.6
-OUT2 69.6

+OUT1 148.8
+OUT2 148.8

after failure (power led on but no operation):

-OUT1 0.3V
-OUT2 0.3V

+OUT1 99.6V
+OUT2 99.6V

I have downloaded the service manual and training manual.

Does anyone have any ideas where I should begin on this?

(photo is from shopjimmy but is exacted same model and revision# from my set)

[budm]

Re: SONY KDL-46EX710 no error code failure

Need to check the DCV of the connector of the power supply board that goes the main board to see what is/are missing when the TV does not work.
We also need the pictures of the whole backside of the TV so we can see all the boards.

[notsogentle]

Re: SONY KDL-46EX710 no error code failure

here you go

cn6150 plug to mainboard (when no picture)

tcon_on 3.3
tcon vcc12 12.6
dimmer-dc 3.3
dimmer 1.17
bl_on 0
bl_err 3.3
reg 12v 12.6
reg 12v 12.6
reg 12v gnd 0
reg 12v gnd 0
audio 12v gnd 0
audio 12v 12.6
power on 3.28
ac-off-det 3.3
stby 3.3

if you need any other values I can get them

[budm]

Re: SONY KDL-46EX710 no error code failure

'bl_on 0': Main board is not sending the backlights on command to turn on the backlights, it must have been present for seconds before dropping down to 0VDC because you did see +OUT1 148.8
+OUT2 148.8.

[notsogentle]

Re: SONY KDL-46EX710 no error code failure

yes, those values are readings taken after the tv has done the power cycle twice and is stuck with no picture but green power light.

if you want readings when its running normal I'll do them next once the tv has been off awhile it will stay on for ten minutes before failure

[budm]

Re: SONY KDL-46EX710 no error code failure

At least now you know what is missing when it is not working, typical vale will be >2VDC for Backlights ON, <1VDC = Backlights OFF.
BTW, the 'bl_err 3.3' this one may be the clue as to he BL-ON signal is shutdown for protection, I am not sure sure if >2VDC = BAD or Good, you may want to look at this one also, I will need to look at the service manual.

[notsogentle]

Re: SONY KDL-46EX710 no error code failure

just read this in the training manual, this may just be it.

No Backlight, No Shutdown
It is possible for a symptom of no backlighting to occur that does not
cause the television to go into protective shutdown. Dynamic dimming
control of the backlights is performed by monitoring information from the
TCON board. This is in the form of data and determines the brightness
level of the backlights based on video content.
If the TCON fails to process the RGB video data, or if the dimmer data line
fails, the backlights will not turn on. Audio will be present if the selected
input has it available. The television will remain on indefinitely with the
green Power LED lit. If the TCON is available, it can be replaced to resolve
the issue. If not, the LCD panel must be replaced.

[budm]

Re: SONY KDL-46EX710 no error code failure

Do you have name of this SONY Training manual? It will usually be SONY XXX CHXX.

[notsogentle]

Re: SONY KDL-46EX710 no error code failure

sony_kdl_32ex700_kdl_46ex700_chassis_az1l_training_manual.pdf

I found a link to it in another thread about this same model

[vinceroger69]

Re: SONY KDL-46EX710 no error code failure

[notsogentle]

Re: SONY KDL-46EX710 no error code failure

just read this in the training manual, this may just be it.

No Backlight, No Shutdown
It is possible for a symptom of no backlighting to occur that does not
cause the television to go into protective shutdown. Dynamic dimming
control of the backlights is performed by monitoring information from the
TCON board. This is in the form of data and determines the brightness
level of the backlights based on video content.
If the TCON fails to process the RGB video data, or if the dimmer data line
fails, the backlights will not turn on. Audio will be present if the selected
input has it available. The television will remain on indefinitely with the
green Power LED lit. If the TCON is available, it can be replaced to resolve
the issue. If not, the LCD panel must be replaced.

Contrary to the above paragraphs, I lose sound as well as I have since tested with an hdmi source playing.