Sony KDL40V4100-Dark Picture

[budwich]

Re: Sony KDL40V4100-Dark Picture

I kind of doubt the "not getting 12v" "observation"... :-( It is unlikely that you would be getting any sort of picture if there was no power to the tcon.

further, checking voltage at a fuse isn't really how to check a fuse UNLESS you know exactly how the circuit is designed since some tv designs (and others) put fuses in places next to grounds which means a voltage measurement is going to yield "0".

You need to confirm 12v at areas where there are printings on circuit boards..... hence the OFTEN REPEAT quote here on this forum, provide good pictures of how the set boards are connected / laid out on the back off the set with clear ones showing printing of voltage / pin designations then people are able to readily move through appropriate questions / comments.

further, what is the history of the set? The "no sound on hdmi" could be as simple as a wrong setting although it is also possible the hdmi ports are toast since this is a common problem across sets.

[Davi.p]

Re: Sony KDL40V4100-Dark Picture

On the mainboard near the lvds connector there is always a transistor or a couple that enables power to tcon, check it.

[budm]

Re: Sony KDL40V4100-Dark Picture

Put all the boards back in place, turn the TV on, black probe on the chassis, red probe on point 'A' to see what you have then move red probe to point 'B' to see what you have.
BTW, there are lots of fuses on the bottom side of the main board also.

[DoubleDD]

Re: Sony KDL40V4100-Dark Picture

Zomi thanks for the follow up. I checked the fuses you marked on the main board and two others here are the results:

F7005 1.6A 24V - I have 3.3V on both sides of fuse
F7006 1.6V 36V- I have 12V on one side and 11.98V on other side of fuse

F2000 1.6A 36V - I have 3.3V on both sides of fuse
F2001 5A 24V - I have 15.26V on both sides of fuse

I also checked another fuse looking item marked
PS5000 .5A 50V- I have 2.8 V on one side and 2.9V on other side

When TCON is connected I have 0 V on both sides of the TCON Fuse, so it appears that voltage is not getting to the TCON board. Are there points to check the incoming voltage on the TCON and the power exiting the main board.

[DoubleDD]

Re: Sony KDL40V4100-Dark Picture

BudM, I took readings at the two points ( A & B) you suggested, please see photos to insure I had the correct spot for the test probe. I have 0 volts at both A and B

Budwich, Sorry for the confusion I no longer have a picture or a menu (at the start I did, but now is just a backlight glow, not sure what failed). I have attached a photo of the installed TCON board. I took readings at C303 and both sides of the white fuse with the K on it.

[budm]

Re: Sony KDL40V4100-Dark Picture

https://www.badcaps.net/forum/attach...3&d=1520521395
So you have 0V on both end of that Fuse F7005?
You also have fuses on the bottom side of the board that you need to check their resistances.

[Davi.p]

Re: Sony KDL40V4100-Dark Picture

"So you have 0V on both end of that Fuse F7005?"
Budm he said 3,3v in & out.
For my advice he can start tv then jump 12v from psu directly to the ton to ensure what i've said before (beware, tcon supply must be applied after mainboard start.)

[DoubleDD]

Re: Sony KDL40V4100-Dark Picture

I have 3.3V on both sides of fuse marked F7005 1.6A 24V.

I can try jumping from the main board PSB to the TCON board, can you provide the points from where I should jump from on the main board and the point where I should jump to on the TCON. I get the part that I need to power the TV on first. Should the connection cable from the power board to the TCON be connected or disconnected during the jumping process?

[Davi.p]

Re: Sony KDL40V4100-Dark Picture

"main board PSB" No, i've said PSU=power supply unit. You can locate the 12v output from the printed legend near connector (if any exists), to the tcon on the main fuse.

[budm]

Re: Sony KDL40V4100-Dark Picture

"So you have 0V on both end of that Fuse F7005?"
Budm he said 3,3v in & out.
For my advice he can start tv then jump 12v from psu directly to the ton to ensure what i've said before (beware, tcon supply must be applied after mainboard start.)

https://www.badcaps.net/forum/attach...3&d=1520521395

But OP indicates 0 Volt in post 25.
https://www.badcaps.net/forum/attach...4&d=1520444306
It looks to me that the main board has printing errors, it shows two F7005: one is near the white connector, one is near the LVDS connector that I shown.
How about all those fuses on the bottom side of the main board, did you test them?

Sony A-1641-933-A (1-876-561-13) BU Board for KDL-40V4100
Pictures provided by shojimmy.

[Davi.p]

Re: Sony KDL40V4100-Dark Picture

Check especially F1422 and the 8 pin mosfet near it on the under side.

[DoubleDD]

Re: Sony KDL40V4100-Dark Picture

Looks like we may be close. On the back side of the power board I am getting 12V on the outer side of F1422 5A 24V fuse and 0V on the side closer to the center of the board. I think I will try replacing the old fuse with a PICO II fuse rated at 5A 125V, I believe this was recommended by BUDM in a different post several years back for another Sony with similar issues. I couldn't find an exact replacement for the 5A 24V fuse (Sony 1-576-933-21 FUSE MICRO (1608) FUSE (5A 24V) ) so any recommendation on replacement fuse is welcomed.
I have 12V on both sides of what I think was F1421 (see attachment for where I tested). I have 12V on both sides of F7003 on bottom left. I can't figure out where F2002 5A 24V fuse is or where the test points are, the fuse marking is on the top right of attachment.

[Davi.p]

Re: Sony KDL40V4100-Dark Picture

Electrically is ok the fuse, phisically it's up to you to adapt it well.