Sony KDL-46D3500 - no image, just bars

[tn245]

Hi

What does this look like to you? t-con? Panel? Main?

I'm interested in replies, maybe I'll fill in the back-story later.

[multimeter]

Re: Sony KDL-46D3500 - no image, just bars

is that with a signal?bring up menu,the same?,im thinking t-con on this one

tab bonds as far as ive seen so far resemble thin lines rather than big block lines,but dont quote me on it.

things to try...

re-seat lvds cable after cleaning both ends with iso-alc

also the tab bonds if they removable and not intergrated in the screen

check voltage at t-con,and for anything getting hot on there,gamma chips processor etc.freeze spray can be your friend here,(blast it around the bezel joint of the panel boarder),may shortly bring picture back.
flex the screen,does anything change,(will also confirm bad tab bonds)

test mainboard by scart socket out to another tv,if pic good ,mainboard should be ok.

what panel is in this tv ?,auo,samsung?,chimei?.

ive never had a problem with sony kdl's with panel failiure ,always a 1st though.these suffer a lot with firmware issues,a usb update works.it wont on this fault though.

[tn245]

Re: Sony KDL-46D3500 - no image, just bars

Thanks multimeter! Very helpful.

It's with and without signal. Changes in signal and bringing up menu only change the brightness of the pattern. After leaving it on for a while some coloured thin lines do sometimes appear and also a slightly darker grey rounded inner box visible in the light bars as can be seen a bit on the left bar on the above attached image.

Interestingly with the t-con metal shielding removed for testing voltages, the display shows only all white.

Connecting to another TV by SCART I can display TV channels, but not menu or HDMI inputs. Is that normal behaviour? Thanks for this tip. Didn't know I could do that believe it or not.

t-con voltages:
12VIN: 12V
VCC: 3.34V
VGL: -6V
VGHC: 0V !! This should be ~25V right?

Couldn't find VGH to test. Gamma voltages look ok. Nothing on t-con is getting particularly hot.

Panel is AUO T460HW02 V4

So would 0V VGHC cause this symptom? Does this confirm bad t-con or could something else cause VGHC to be 0V?

[tn245]

Re: Sony KDL-46D3500 - no image, just bars

btw, VGHC is 0V with panel ribbons disconnected too and is not shorted to ground.

[multimeter]

Re: Sony KDL-46D3500 - no image, just bars

if you have scarted out to another tv,you should see the channel program being viewed,the menu may not come up as it will be another section on that mainboard that deals with all that,the scart out option will normally be video and audio.

25v on vghc,seems a little too high,can you give the part number of this t-con

im thinking t-con,or panel

have you tried flexing the screen around its bezel? ,if its tab bonds it will alter the picture,i like to grab top 2 corners and twist lightly

[multimeter]

Re: Sony KDL-46D3500 - no image, just bars

ok can see part number..on pic

[tn245]

Re: Sony KDL-46D3500 - no image, just bars

No.. I think you misread. Vghc is 0v. With and without panel ribbons connected.

[multimeter]

Re: Sony KDL-46D3500 - no image, just bars

No.. I think you misread. Vghc is 0v. With and without panel ribbons connected.

vghc will be generated from the t_con,there should be voltage on that pin,i cant find a spec on that panel to find out what it should be

[multimeter]

Re: Sony KDL-46D3500 - no image, just bars

can you check input output voltage from u802,looks like an adjustable regulator,check for input voltage ,(vcc),check for output voltage,(normally the large fat tab)if you get stuck put up the part# for that regulator

hopefully there should be input voltage,a reduced or missing output would be a failed reg.

[tn245]

Re: Sony KDL-46D3500 - no image, just bars

Here you go. Also tested U804 While I was at it.

So, looks like U802 is bad?

[multimeter]

Re: Sony KDL-46D3500 - no image, just bars

(double post)

[multimeter]

Re: Sony KDL-46D3500 - no image, just bars

Here you go. Also tested U804 While I was at it.

So, looks like U802 is bad?

whats the part number of u802 reg?

[tn245]

Re: Sony KDL-46D3500 - no image, just bars

After scraping off the thermal crap it looks to me like the markings say APR 748. I didn't find any datasheet for it.

[tom66]

Re: Sony KDL-46D3500 - no image, just bars

VGH should be around 25V, this could be causing your fault

[tn245]

Re: Sony KDL-46D3500 - no image, just bars

Ok, time for the back-story I think.

This TV originally had a functioning t-con with bad gamma voltages. Panel and main working fine but washed out image and inverted colours. I replaced the AS15-F chip which improved things but image wasn't perfect and gamma voltages still a little suspect. Figured maybe my soldering job wasn't quite perfect so removed the chip and had another go. This time fuse F1 blew. Resoldered AS15 again, bridged F1 with another fuse (this time with panel ribbons disconnected), it blew again and a transistor on the t-con went up in smoke. Oops!

So I gave up on that t-con and ordered another 'tested working' from ebay. Replacement t-con arrived but gives this bar issue.

So seems the t-con I was sent was faulty. But then I thought there was a small chance the old t-con had caused a new fault on the panel or main so wanted to make sure the new t-con was actually faulty before sending it back.

[multimeter]

Re: Sony KDL-46D3500 - no image, just bars

Ok, time for the back-story I think.

This TV originally had a functioning t-con with bad gamma voltages. Panel and main working fine but washed out image and inverted colours. I replaced the AS15-F chip which improved things but image wasn't perfect and gamma voltages still a little suspect. Figured maybe my soldering job wasn't quite perfect so removed the chip and had another go. This time fuse F1 blew. Resoldered AS15 again, bridged F1 with another fuse (this time with panel ribbons disconnected), it blew again and a transistor on the t-con went up in smoke. Oops!

So I gave up on that t-con and ordered another 'tested working' from ebay. Replacement t-con arrived but gives this bar issue.

So seems the t-con I was sent was faulty. But then I thought there was a small chance the old t-con had caused a new fault on the panel or main so wanted to make sure the new t-con was actually faulty before sending it back.

ahh,that explains a lot,i didnt know all that...always try and buy from sellers with a return policy!

im 80% sure its t-con,try and get another ,and it would be better with one that isnt from a smashed screen,as shorts could occur and knacker the panel drivers,thus knacker the t-con

im not getting any luck with that part number by the way...

[tn245]

Re: Sony KDL-46D3500 - no image, just bars

There don't seem to be a lot of these t-cons about. This one cost me £40 inc delivery.

Do you think this one might be repairable by me with your help? That regulator part number might be a problem but maybe the one from the old board still works?

I thought about offering the seller a lower price for the faulty board rather than sending it back (given I'm going to have to pay postage anyway), but if it's going to be too hard or costly to repair I'd prob rather wait for another board to appear for sale.

What do you think?

[multimeter]

Re: Sony KDL-46D3500 - no image, just bars

trouble is,there is now 2 faults on the board as you blew a transistor earlier?,so going by the size of the parts ,intricate soldering ,is it worth it?

id be inclined to just get another from a trusted seller with returns,at least if it dosent work you can return it

[tn245]

Re: Sony KDL-46D3500 - no image, just bars

No the blown transistor was on the old board. The new one just has the missing vghc as far as we know. If it's only that regulator I don't think the soldering will be a problem, but if it's going to be a lot more complicated than that maybe better to wait for another board.

So yeah, to clarify I'm talking about repairing the new replacement board that has vghc 0v.

[multimeter]

Re: Sony KDL-46D3500 - no image, just bars

No the blown transistor was on the old board. The new one just has the missing vghc as far as we know. If it's only that regulator I don't think the soldering will be a problem, but if it's going to be a lot more complicated than that maybe better to wait for another board.

So yeah, to clarify I'm talking about repairing the new replacement board that has vghc 0v.

ok,well would need to check the datasheet for that part,to make sure its tested right,it looks to me like a fixed reg,,im not sure on this ,still studying how it works.but i cant see any resistors for an adjustable reg,only zero ohm resistors,that are in series with the reg pins,check those too,they should read dead short or nearly

but i cant find anything on that part..