sony lcd tv advice please?


	FORUM HOME	SEARCH POSTS	WHO'S ONLINE	LOG IN	RULES F.A.Q.

TV Forums: TV Equipment: TV Repair Forum:
sony lcd tv advice please?

Print Thread

stu76
New User

Jan 15, 2012, 12:02 PM

Post #1 of 25 (2926 views)
Shortcut

sony lcd tv advice please?	Can't Post

hi all.

new to the forum today.
i am in the tv repair trade privately.

i am after some advice on a sony lcd set if anyone can help me out here please.
model sony KDL-37V5810

SOON AS YOU TURN IT ON AT MAINS YOU HEAR THE RELAY CLICK THEN THE GREEN POWER LIGHT ILLUMINATES, NO DISPLAY ,BUT SO HAVE SOUND!
NOT ABLE TO TURN THE TV INTO STANDBY FOR SOME REASON EITHER? BY BUTTON ON SET OR REMOTE, BUT OTHER REMOTE BUTTONS SEND SIGNAL AS STANDBY GREEN LIGHT WILL FLASH WHEN PRESSING REMOTE.
ANYONE HAVE ANY IDEAS, I AM SUSPECTING THE INVERTER BOARD AS FAULTY??? Blush

mr. shr
New User

Aug 6, 2015, 5:27 PM

Post #2 of 25 (2676 views)
Shortcut

Re: [stu76] sony lcd tv advice please? [In reply to]	Can't Post

I have exactly the same problem with exactly the same model.

Could do with seeing a service manual or schematic of the boards as I can't figure out where the BL_ON signal is supposed to come from and can't tell what voltages should be on the power supply for testing.

jts1957
Veteran

Aug 6, 2015, 7:27 PM

Post #3 of 25 (2671 views)
Shortcut

Re: [mr. shr] sony lcd tv advice please? [In reply to]	Can't Post

Board part numbers may help. Does Inverter have VCC and Enable voltages & is there a dim voltage. Also notice discrepancy (between here and BC) - One says HAS sound - other doesn't.

-------------------------
Location: Far, Far Away

(This post was edited by jts1957 on Aug 6, 2015, 7:29 PM)

mr. shr
New User

Aug 6, 2015, 8:11 PM

Post #4 of 25 (2666 views)
Shortcut

Re: [jts1957] sony lcd tv advice please? [In reply to]	Can't Post

Thanks for the reply.

I can't get any image on the screen so can't select an input to test if sound works.

With regards to voltage, I'm getting 24 volts to the inverter board (via the psu board).
There are 3 wires that run from the MAIN board to the inverter board. I think one of those is the BL_on signal. It sits at 1.9V. Back Lights do NOT fire up.
If I disconnect this 3 wire connector (from MAIN board to inverter board) the back lights come on. But still not image on screen.

For testing the psu, if I disconnect all boards and just have the psu powered up, what voltages should I see on the psu board?

jts1957
Veteran

Aug 6, 2015, 8:29 PM

Post #5 of 25 (2662 views)
Shortcut

Re: [mr. shr] sony lcd tv advice please? [In reply to]	Can't Post

Board part numbers (Usually the number that gets the most Google 'hits' is the 'correct' number.)? Inverter / Main & Power. I need clearer pictures and can possibly do my own research.

Original poster on this thread says he HAS sound ... Original poster on Badcaps forum thread said he does Not have sound. May or may not be of any importance.

'BL_ON' would imply that backlight is active low, so unplugging wires would make go low ('Float' actually). IF it goes to 1.9V when first plugged into Mains and stays like that, with a relay click and green power LED that also illuminates (and STAYS illuminated with no flash codes) I'd suspect the Main board.

-------------------------
Location: Far, Far Away

(This post was edited by jts1957 on Aug 6, 2015, 8:30 PM)

mr. shr
New User

Aug 6, 2015, 9:15 PM

Post #6 of 25 (2655 views)
Shortcut

Re: [jts1957] sony lcd tv advice please? [In reply to]	Can't Post

I've taken some pics now trying to work out how to upload them to here. Blush

On the power board with everything else disconnected I get this;

Power On pin: 0v
AC Off Det pin: 3.33v
3.3v pin: 3.3v
15v pin: 0v
15v pin : 0v
SGND1 pin: 0v
SGND1 pin: 0v
SGND pin: 0v
SGND pin: 0v
SGND pin: 0v
12v pin: 0v
12v pin: 0v
12v pin: 0v

Now I expected most pins to be at zero but wasn't sure about the two pins showing 3.3v
Is one of these the ps_on signal. Thought there should be at least 1 pin with 5 volts on it?

jts1957
Veteran

Aug 6, 2015, 9:38 PM

Post #7 of 25 (2654 views)
Shortcut

Re: [mr. shr] sony lcd tv advice please? [In reply to]	Can't Post

Board numbers !!!! I can probably find HIGH resolution photos. The ones posted on badcaps forum were of very little use.

"Power on pin" should start at zero with the TV unplugged. When TV is plugged in this voltage may or may not change to another value (2V to 5V). Ideally, this voltage then should change state each time the power key is pressed. 12V and 15V & BL_ON should follow the same pattern.

3.3V "is the new ~~black~~ 5 volt."

-------------------------
Location: Far, Far Away

(This post was edited by jts1957 on Aug 6, 2015, 9:50 PM)

mr. shr
New User

Aug 6, 2015, 9:50 PM

Post #8 of 25 (2649 views)
Shortcut

Re: [jts1957] sony lcd tv advice please? [In reply to]	Can't Post

Power supply board number is psc10270f m
Main board number is 1 878 942 31

Do you think those two voltages at 3.3v are correct then?
If I connect the psu to the main board then the other pins do go to 12v and 15v accordingly.

jts1957
Veteran

Aug 6, 2015, 10:26 PM

Post #9 of 25 (2643 views)
Shortcut

Re: [mr. shr] sony lcd tv advice please? [In reply to]	Can't Post

In Reply To

Power supply board number is psc10270f m 147416213?
Main board number is 1 878 942 31

Do you think those two voltages at 3.3v are correct then? 3.3v (stand-by/all time) should be present whenever the TV is plugged into the AC Mains AC OFF DET is NOT a supply voltage.
If I connect the psu to the main board then the other pins do go to 12v and 15v accordingly. Are you saying that when all is connected correctly that 12v and 15v are working well. If so do they turn on/off as you turn the TV on/off?

-------------------------
Location: Far, Far Away

mr. shr
New User

Aug 6, 2015, 10:54 PM

Post #10 of 25 (2636 views)
Shortcut

Re: [jts1957] sony lcd tv advice please? [In reply to]	Can't Post

Thing is, I'm not convinced the tv is switching on and off.

When I plug in at the wall there is a relay click and then either red standby light or green power light (depending on previous state prior to pulling plug out). Pressing the power button on remote or side panel SOMETIMES toggles light ( from red to green or green to red ) but there are no relay clicks between these light toggles.

To me, it's just staying in standby mode.
Are there any checks or tests you could recommended?

jts1957
Veteran

Aug 7, 2015, 1:04 AM

Post #11 of 25 (2631 views)
Shortcut

Re: [mr. shr] sony lcd tv advice please? [In reply to]	Can't Post

Monitor each source one at a time. What happens to each when: 1) the set is plugged in?; 2) then, when power button is pressed ONCE?; and 3) finally, when Power button is pressed a second time?

3.3v is Standby: It should be there as long as alternating voltage (AC) is supplied to set, Set can be turned on or off and it shouldn't be affected.
15V is Unregulated 15 volts for audio; 12V is Regulated 12 volts. Both 12 & 15 will only be present when set is on. They shouldn't be present with set Off.
All three voltages should be fairly steady - not full voltage and then slowly drops off.

Relay should click once to energize. If it then turns off the click may be less audible.

-------------------------
Location: Far, Far Away

mr. shr
New User

Aug 7, 2015, 7:30 PM

Post #12 of 25 (2613 views)
Shortcut

Re: [jts1957] sony lcd tv advice please? [In reply to]	Can't Post

OK did the tests you suggested. First readings are when tv just plugged in at the mains / second readings when standby button pressed once:

Power On pin: 0v / 3.18v
AC Off Det pin: 3.33v / 3.33v
3.3v pin: 3.33v / 3.33v
15v pin: 0v / 17.49v
15v pin : 0v / 17.49v
SGND1 pin: 0v / 0v
SGND1 pin: 0v / 0v
SGND pin: 0v /0v
SGND pin: 0v /0v
SGND pin: 0v /0v
12v pin: 0v / 12.13v
12v pin: 0v / 12.13v
12v pin: 0v / 12.13v

Pressing the standby button on the side of the set again doesn't change any of the above voltages. Each press sometimes changes light from green to red. Sometimes green goes out but no red. But either way, the voltages don't change.

The back lights do not come on at all.

jts1957
Veteran

Aug 7, 2015, 7:54 PM

Post #13 of 25 (2612 views)
Shortcut

Re: [mr. shr] sony lcd tv advice please? [In reply to]	Can't Post

Power IS turning on and staying on irregardless of how many more times the standby button is pressed ... Pretty well eliminates that board.

Don't see Inverter board part number. Please provide.

-------------------------
Location: Far, Far Away

mr. shr
New User

Aug 7, 2015, 8:31 PM

Post #14 of 25 (2607 views)
Shortcut

Re: [jts1957] sony lcd tv advice please? [In reply to]	Can't Post

Struggling to work out what the part number is.

Printed on the board is:
VIT71865.50
VIT71861.50
LOGAH REV:3

On a barcode sticker is the following:
LS-1937T04020-958-8980089-54748-07

jts1957
Veteran

Aug 7, 2015, 9:20 PM

Post #15 of 25 (2605 views)
Shortcut

Re: [mr. shr] sony lcd tv advice please? [In reply to]	Can't Post

I think we have enough info to state it is quite likely the Main board that's defective.

-------------------------
Location: Far, Far Away

mr. shr
New User

Aug 7, 2015, 9:24 PM

Post #16 of 25 (2600 views)
Shortcut

Re: [jts1957] sony lcd tv advice please? [In reply to]	Can't Post

OK I'll search for a replacement board.
There are a few kicking about on the web as expected but some with slightly different part numbers. Is there a way to know if these other boards are compatible or must it be exactly the same part number for it to work?

jts1957
Veteran

Aug 7, 2015, 9:39 PM

Post #17 of 25 (2595 views)
Shortcut

Re: [mr. shr] sony lcd tv advice please? [In reply to]	Can't Post

Best to replace like with like. Wouldn't want to get one that ONLY displays Minionese OSDs.

-------------------------
Location: Far, Far Away

mr. shr
New User

Aug 7, 2015, 9:42 PM

Post #18 of 25 (2593 views)
Shortcut

Re: [jts1957] sony lcd tv advice please? [In reply to]	Can't Post

Fair point.
OK thanks for all the help and support.
Much appreciated.
Will keep my eye out for a cheap replacement board and go from there.

mr. shr
New User

Aug 14, 2015, 1:07 PM

Post #19 of 25 (2566 views)
Shortcut

Re: [jts1957] sony lcd tv advice please? [In reply to]	Can't Post

Hi again,
I've installed a replacement board and now the TV is switching on with sound.
However, the image is all weird!!!! I think it's called solarisation.

I've done a firmware update but no change.

I noticed that in the "product information" screen under the setup menu, it says TV is 40" but this is only a 37" Could it be that this replacement board came from a 40" set and now needs to be told it's in a 37" inch TV?

If so, how would I do that?

I got in to the service menu but have no idea what I should change as don't know what any of the options mean. How can I get a list of what all the service menu things mean? As expected, they do not have meaningful names as they are not supposed to be played around with by the consumer, but the Sony technicians must have a list of what they all mean when they do house calls? Do you have access to them?

Any help much appreciated.

(This post was edited by mr. shr on Aug 14, 2015, 2:26 PM)

jts1957
Veteran

Aug 14, 2015, 5:26 PM

Post #20 of 25 (2558 views)
Shortcut

Re: [mr. shr] sony lcd tv advice please? [In reply to]	Can't Post

Solarisation can also be caused by a defective tcon.

Entering or making changes in service mode by untrained persons can cause significant and permanent damage to your television. If you are not qualified to service your television, please DO NOT ENTER these service menu codes.

Quote

the Sony technicians must have a list of what they all mean when they do house calls?

They probably do, but I haven't been able to find them.

Service literature is very quiet for your chassis variant (and the chassis before and after).
"There are no adjustments necessary for these models. All data has been set for optimal viewing for our customers. The following sections are for informational purposes only."

-------------------------
Location: Far, Far Away

mr. shr
New User

Aug 14, 2015, 5:30 PM

Post #21 of 25 (2555 views)
Shortcut

Re: [jts1957] sony lcd tv advice please? [In reply to]	Can't Post

Are there any checks or tests I can do to confirm it's the TCON?

jts1957
Veteran

Aug 14, 2015, 6:59 PM

Post #22 of 25 (2551 views)
Shortcut

Re: [mr. shr] sony lcd tv advice please? [In reply to]	Can't Post

Quote

Are there any checks or tests I can do to confirm it's the TCON?

Unless you're good at swapping surface mount quad ICs ... Better to swap tcon. You are quite right, it could also easily be a option or other setting in the service menus.
IF replacement Main board matched your original ones numbers in all regards (Prefix /Suffix / Revision, etc), which I doubt, then that could be eliminated.

IF YOU DECIDE TO TRY A FACTORY RESET ... I'd recommend writing down EACH & EVERY parameter and it's value BEFORE factory reset is implemented, and even then there is NO guaranty that you'll be able to put them back. Also these settings are usually stored on an EEPROM on the Main board, IF number matches you might try swapping that. But bear in mind that that being corrupted MIGHT be why your original Main board died.

Side story (also some speculation): The set I'm using to type this on had been through a fire and received minor smoke damage. Prior owner did a good job on outside cleaning it up, but didn't wait until smoke condensation on inside had dried completely before he started using the set again. He didn't say how long after he started using again that the set died. He then brought it in to me and I found the main electrolytic and the TNY277 IC both blown apart. I gave estimates for board replacement versus parts replacement with the usual caveats about which way is more likely to cure (if either), which might last longer, which is better, etc. He never called, which I interpret as he went TV shopping. So I replaced the two parts and viola, TV works.
Played fine for almost two days then solarized. A friend who runs a TV repair business happened to have same tcon w/FFCs. Installed and has been working for last two years.

-------------------------
Location: Far, Far Away

mr. shr
New User

Aug 14, 2015, 7:38 PM

Post #23 of 25 (2548 views)
Shortcut

Re: [jts1957] sony lcd tv advice please? [In reply to]	Can't Post

I've done a factory reset via the menus available to the end user but that doesn't make any difference.

I can't see any reference to RESET in the service menu. I can't really tell what any of the items in the service menu mean. I believe there are 8 different categories but don't know what they are.
Each category has a bunch of items, and then each item has an associated data value. But none of the mnemonics are meaningful so I can't know what I might be changing.

Interesting story about the smoke damaged set. Good you were able to get a replacement tcon easily.
Thing is, now that I've forked out for a replacement main board, if I now buy a replacement tcon board too, then I'll have spent more then the TV's actually worth!!!!

jts1957
Veteran

Aug 14, 2015, 8:02 PM

Post #24 of 25 (2546 views)
Shortcut

Re: [mr. shr] sony lcd tv advice please? [In reply to]	Can't Post

I'll say it again ... For the Factory Reset accessed via the Service Menu ... It may not even be thru either menu, it may be a combination of buttons.

... I'd recommend writing down, (Or at least capture clearly Each & Every screen with a camera), EACH & EVERY parameter and it's value BEFORE factory reset accessed through the Service Menu is implemented, and even then there is NO guaranty that you'll be able to put them back.

This is all the service manual for the model closest to yours that I've found (so far) has to say: http://imgur.com/g5EkArI

Edit: Do the screens in link look like your sets SM screens?

-------------------------
Location: Far, Far Away

(This post was edited by jts1957 on Aug 14, 2015, 9:04 PM)

mr. shr
New User

Aug 14, 2015, 10:12 PM

Post #25 of 25 (2536 views)
Shortcut

Re: [jts1957] sony lcd tv advice please? [In reply to]	Can't Post

Yes my service menu is as per your link.

I've been through all of the options and don't know what to change. The first category is model. I wondered (hoped) if there would be 5 choices in this setting, one for each screen size they made for this range. But there are only four choices (model 0 to 3). I tried playing around with them but nothing changed. (I thought changing model would be relevant as product info screen in setup menu says TV is 40 inch. But I only have 37 inch model.)

Think I'll have to scrap this set as just can't see what else to do?

Print Thread

Search for (options)

- Page loaded in: 0.24 s on (CGI/1.1)