sony kdl46s4100

[nomoresonys]

Re: sony kdl46s4100

or test mode solid green red n blue then striped screen loop.

[budm]

Re: sony kdl46s4100

OK, I see what you mean, at least it is putting out something. So right now the T-CON and the main board are the original one or the replacement one.

[nomoresonys]

Re: sony kdl46s4100

OK, I see what you mean, at least it is putting out something. So right now the T-CON and the main board are the original one or the replacement one.

yes, original main and tcon are in now.

[budm]

Re: sony kdl46s4100

Notes; the color looping mode may be due to the input is in PC input mode (I have seen this mode in Dell monitor when it does not see the video signal from PC, then it will go into standby mode a couple minutes later). So try using the remote to change the input source. I myself never seen this color looping in TV before, may be someone else in this fourum may have seen them.

[nomoresonys]

Re: sony kdl46s4100

get normal reading on bl on from 2 pin on power supply with cn303 unplugged, with cn303 plugged in get 0.6 and 1.7 power on and off never goes to 5 v, get same 0.6 and 1.7 with both main boards, is it correct to think that both boards are not putting out enough volts to bl on and are both bad, even tho they both measure exactly the same?

[budm]

Re: sony kdl46s4100

As I explained earlier, the BL-ON pin has the built-in pull up resistor to provide >3v, the main board will have switched transistor to take that voltage at BL_ON PIN to GROUND to keep the BL_ON LOW which will cause the backlights to be off, no need to worry about the backlights at this point sicne we can have backlights by not having BL_ON connected to the main board, the problem right now is the main board is not functioning.
If both board keep the BL_on pin low when turn on, then yes, your main board is bad. Now the problem is that this TV may use error signal from the T-CON to keep the backlights off, not all SONY use that signal. Too bad that this model does not use blinking LED to show the error codes. I will have to dig further into the service manual. In the mean time, can you get me the LCD panel model number as printed on the sticker so I can see the spec of the T-CON to find out if it uses the ERROR pin or not?
Looping color screen would indicate to me that the main board is not functiong for sure.

[nomoresonys]

Re: sony kdl46s4100

As I explained earlier, the BL-ON pin has the built-in pull up resistor to provide >3v, the main board will have switched transistor to take that voltage at BL_ON PIN to GROUND to keep the BL_ON LOW which will cause the backlights to be off, no need to worry about the backlights at this point sicne we can have backlights by not having BL_ON connected to the main board, the problem right now is the main board is not functioning.
If both board keep the BL_on pin low when turn on, then yes, your main board is bad. Now the problem is that this TV may use error signal from the T-CON to keep the backlights off, not all SONY use that signal. Too bad that this model does not use blinking LED to show the error codes. I will have to dig further into the service manual. In the mean time, can you get me the LCD panel model number as printed on the sticker so I can see the spec of the T-CON to find out if it uses the ERROR pin or not?
Looping color screen would indicate to me that the main board is not functiong for sure.

for sure, why they left out codes is strange, the panel model is LTZ460HB10.

[budm]

Re: sony kdl46s4100

This is the low end model, so no error code function. Let me look up the spec of the panel next.
From servie manual:

IMPORTANT:
The units in this manual DO NOT contain a self-diagnostic function. If an error occurs, the TV will not stay on. It is our recommendation that if a repair
is required for this set, the technician should bring both the A Board and the G Board to the customer location.
Description of LED Indictors
The units in this manual DOES NOT contain a self-diagnostic function.

Follow-up; I look at the service manual, they do not use any error signal from the T-CON.

[nomoresonys]

Re: sony kdl46s4100

This is the low end model, so no error code function. Let me look up the spec of the panel next.
From servie manual:

IMPORTANT:
The units in this manual DO NOT contain a self-diagnostic function. If an error occurs, the TV will not stay on. It is our recommendation that if a repair
is required for this set, the technician should bring both the A Board and the G Board to the customer location.
Description of LED Indictors
The units in this manual DOES NOT contain a self-diagnostic function.

Follow-up; I look at the service manual, they do not use any error signal from the T-CON.

I get 0.6 and 1.7 power on and off never goes to 5 v, so I think even tho both main boards measured exactly the same, they must both be bad, Im thinking I should try a mainboard from someone other than shop jimmy.

[budm]

Re: sony kdl46s4100

The number (PCBA -Printed Circuit Board Assembly) as printed on the barcode sticker matches your original board?

[nomoresonys]

Re: sony kdl46s4100

pretty close, original is 5571H01411G841082E1J03G, the other is 5571H01411G819263E3J03C, and shop jimmy swore up and down that 1 857 092 11 would work, but tried 2 of those, thanks.

[nomoresonys]

Re: sony kdl46s4100

theres a guy on another forum that had the same exact symptoms, he ordered bad mainboard, but the next one he got solved the issue.

[budm]

Re: sony kdl46s4100

That is good to know then.

[nomoresonys]

Re: sony kdl46s4100

was trying to save this from the landfill, but not sure its worth it, heard nothing but bad things about sony and specially the kdl line.

[nomoresonys]

Re: sony kdl46s4100

thanks a lot for the help, I think I'll try 1 more main.

[nomoresonys]

Re: sony kdl46s4100

does anyone know what voltage I should get from just the main board bl_on switch with cn303 unplugged, so I know for sure this main board is bad, if it was explained before, I got lost in the technical terms, thanks for any help.

[budm]

Re: sony kdl46s4100

Well, if you read my explanation, we already forced the backlights to come on and you still do not see pictures on the screen, so you have bad main board or bad T-CON regardless what the BL_ON signal is.

[IK74]

Re: sony kdl46s4100

Sorry for jumping on one year old thread. I have same Sony KDL-46S4100 and same symptoms as "Nomoresonys". also ordered second replacement A board which did not work... I researched several threads online and this one has the most helpful information. But I have additiona question:

I noticed there is a DC voltage about 57V between grounds of primary and secondary circuits on the Power board (there is 57V DCV on the big left&middle heatsinks (they are connected) and small heatsink on the right (which is connected with general ground of the entire chassis or primary AC input.
It looks like leveled half wave from the 120V AC input from the bridge rectifier.
Is this a normal design or sign of failure ?

Btw, did you resovle your problem Nomoresonys? Thanks

[budm]

Re: sony kdl46s4100

"I noticed there is a DC voltage about 57V between grounds of primary and secondary circuits on the Power board (there is 57V DCV on the big left&middle heatsinks (they are connected) and small heatsink on the right (which is connected with general ground of the entire chassis or primary AC input.
It looks like leveled half wave from the 120V AC input from the bridge rectifier.
Is this a normal design or sign of failure ?" That is because you are using the wrong ground ref point when you work in the Primary side of the circuit, you have to use the negative leg of the main filter cap as the Ground ref point for the primary side of the circuit.

[Peter Chiu]

Re: sony kdl46s4100

Same problems after change main Board and TV fixed ..........Sony 1-857-092-21 Main A Board for KDL-46S4100 Panel Sticker Number: LTY460HB08

PS: This TV no needs to update sofeware.