40" LCD Rank Arena (rebadge?) has standby, V+ seem OK, but wont turn on.

[wa11y]

Hello everyone. My names Wade im from Australia and my mother in law's tv stopped working so I am here trying to help her out.. Ive learnt from the badcaps forums in the past but never actually needed to post before, this time I do so hello..

My problem is with a

RANK ARENA : SV-4042AFHD

Apparently it just "wouldn't turn on one day" (but was working perfectly fine the last time she was using it probably a day or so before).. It does have the RED standby light which strangely seems to flash [very briefly] EVERY ~33 seconds.

Ive checked the voltages on the [CON2] which I have listed and all seems fine to me although im not sure if the ON/OFF should have the constant voltage.

1. [ON/OFF] = 4.6V .............. (CONSTANT 4.6V, weather i press power or not)
2. [5V_STB] = 5.23V
3. [+5V] = 5.23V
4. [+5V] = 5.23V
5. [P_PWR] = 11.8V
6. [P_PWR] = 11.8V(n/a - not connected)
7. [GND]
8. [GND]
9. [GND]
10.[12+V] = 11.8V
11.[12+V] = 11.8V

I also have 24v present on
[CON1]

1. [24V_IN] = 24.34V
2 [ 24V_IN] = 24.34V
3. [GND]
4. [GND]


This is the exact mainboard
[MODEL NUMBER] - CV119MA
http://www.cultraview.com/en/Products/view_82.html
(and I found a "SERVICE MANUAL" for the "CV119MA" MANIBOARD which might be somewhat helpful)


From my research it has the same mainboard as a few other TV's so although there are no specific RANK ARENA models mentioned on these forums doesnt mean my problem hasnt occured to someone before.. TV's that share the same mainboard that I know of so far are strangely all 32".......
Kogan KGN1080P32VAA 32"
Vivo VSLH32E7A 32"
NEC LTV81 NLT-32FHDL1 32"

The power supply model is
E211940


There is absolutely no change when I press the power button. I have also tried to power the tv up with the T-CON board DIS-connected and I get absolutely NO change, the exact same standby light blinking every 33 secs and nothing else.



Is there anything else I can check here.?? I just dont know where else would I start looking for problems and at very least how could I tell if its the mainboard or something else doing this?? I dont even think the mainboard is something I can buy so its really either FIX it or BIN it (and I hate throwing good stuff like this away if I can help it)

I can upload photos if needed not sure if they will help or not.

Thank you anyone for your time I really look forward to hear back =)
Wade

[wa11y]

Re: 40" LCD Rank Arena (rebadge?) has standby, V+ seem OK, but wont turn on.

I did check ESR and capacitance on ALL power supply caps which all seemed fine, and also checked the 'bigger' caps on the mainboard, the smaller ones I only checked the ESR while in circuit because I couldn't bother pulling the tiny ones out just to check them when I dont even think there the problem....

Thats the main reason im looking at what I can test on the mainboard, and mainly looking in that direction, although I guess it could be something else as I certainly dont hear a relay click or anything from the power supply, I can only hear a VERY quiet 'HUM' sound that seems to occur about every 1/2 second and is a in out type sound..

Like if I break a second into the humms it would be like this..

...........,~25ms quiet,......~5ms HUM noise.........~25ms quiet.........~5msHum............

So its like an -on-off-on hum noise where it just hums but extremely quietly (almost have to put my head close enough to get shocked by the active heatsinks its really not very noticable hum at all....


Well thats all I know.

[selldoor]

Re: 40" LCD Rank Arena (rebadge?) has standby, V+ seem OK, but wont turn on.

Well you seem to have most of the voltages in the right places.

Have you checked the on/off switch and tried with remote?
Make sure no buttons are stuck

Pictures might help as even the one in the manual is not great.
please post good clear pictures of the whole chassis, and then pictures of each board, front and back (in the same orientation) and close up of connectors, (max resolution 2000x2000 and 2MB) using the manage attachments button, which is found by clicking "go advanced" under quick reply.

Please do not post inline and offsite as they slow down the loading of pages.

Examples of what is needed

https://www.badcaps.net/forum/attach...7&d=1280167246

https://www.badcaps.net/forum/attach...6&d=1280167246

https://www.badcaps.net/forum/attach...4&d=1280167246

[wa11y]

Re: 40" LCD Rank Arena (rebadge?) has standby, V+ seem OK, but wont turn on.

Thanks for the reply =)

Yes I tried the remote and also power button, same thing [nothing] happens both times. I checked the SMD switch itself with my multimeter (quick continuity test) and checked the remote with my camera. I also tried to hold ON for 10 seconds (over 10 actually) with no response.


Well here are the pictures I wasn't really sure what you meant by the orientation or about posting 'inline' ?? I just uploaded these as 'attachments' so I hope this works fine?? I downsized them all to save on bandwidth theres like 5MB of pics all up now.

I also did my best to make it easy to look at, for reference I put a red circle around the "same pin" on both sides of the board, and I named all the pictures for easier sorting (hope it doesnt rename them)..

I do hope I did the right thing here and havent taken to many pics.... :S

[wa11y]

Re: 40" LCD Rank Arena (rebadge?) has standby, V+ seem OK, but wont turn on.

Also last night I meant...

I can only hear a VERY quiet 'HUM' sound that seems to occur about every 1/2 second and is a in out type sound..

Like if I break a second into the humms it would be like this..

...........,~45ms quiet,......~5ms HUM noise.........~45ms quiet.........~5msHum............

For some reason a few beers + working on the TV at 2am my brain was thinking seconds were only made of 60ms..lol

[retiredcaps]

Re: 40" LCD Rank Arena (rebadge?) has standby, V+ seem OK, but wont turn on.

There is absolutely no change when I press the power button. I have also tried to power the tv up with the T-CON board DIS-connected and I get absolutely NO change, the exact same standby light blinking every 33 secs and nothing else.

You can try disconnecting the main board. With the main board disconnected, the ON/OFF should be 0V DC.

If it is, then you can jumper 5V SB to pin 1 using a 1K resistor. That should at least light up the backlights on the TV.

PS. On the main board, there are a number of voltage regulators. You can test them by following the "guides" link below. Report your findings in the format exactly as shown in the how to document.

[wa11y]

Re: 40" LCD Rank Arena (rebadge?) has standby, V+ seem OK, but wont turn on.

Thanks so much for the very helpful replies so far =]..


U3
BM1117-ADJ
9332T
PIN 1 = 1.377V
PIN 2 = 2.627V
PIN 3 = 5.224V

U8
BM1117-ADJ
9332T
PIN 1 = 2.036V
PIN 2 = 3.289V
PIN 3 = 5.232V

U10
BM1117-ADJ
9332T
PIN 1 = 2.05V
PIN 2 = 3.295V
PIN 3 = 5.23V

U15
BM1117-ADJ
9332T
PIN 1 = 2.027V
PIN 2 = 3.277V
PIN 3 = 5.221V

U16
BM1117-ADJ
9332T
PIN 1 = 554mV
PIN 2 = 1.804V
PIN 3 = 3.28V

U19
BM1117-ADJ
9332T
PIN 1 = 2.030V
PIN 2 = 3.283V
PIN 3 = 5.235V

U13
AS7805D
-E1
BM09351Q
PIN 1 = 10.09V
PIN 2 = 0V
PIN 3 = 4.98V



With mainboard disconnected ON/OFF is indeed 0v, but when I jumper a 1k resistor to 5V_STB I dont get the backlight at all, the only difference is the buzzing sound I mentioned earlier occurs much more frequently, like 4 or so times a second and after like 10 seconds it starts to alternate between a moment of silence and then buzz-buzz-buzz-buzz in very short intervals and then the short pause again it just seems weird the 'pulsing' buzzing noise is it something trying to turn on but cant?.. Once again this noise is so slight I can barely hear it but it seems to be coming from the power supply maybe around the area of the main bridge rectifier but I have no idea whats making the noise and dont want to stick my head to close. I can probably pinpoint it better if need be I do have a stethoscope somewhere.

All the regulators look OK to me? Should I remove the transformers and test them individually under a load or test the 24v with 2x car lights or something??

Thanks again ;]


p.s here are the manuals for both the voltage regulators (if it matters at all)


datasheet.eeworld.com.cn/pdf/172446_BCDSEMI_AS7805D-E1.pdf

[tom66]

Re: 40" LCD Rank Arena (rebadge?) has standby, V+ seem OK, but wont turn on.

All regulators are OK. Buzzing from the PSU or inverter?

[wa11y]

Re: 40" LCD Rank Arena (rebadge?) has standby, V+ seem OK, but wont turn on.

Definitely from power supply.

It sounds like it comes from the area with the red circle. (top left)

[tom66]

Re: 40" LCD Rank Arena (rebadge?) has standby, V+ seem OK, but wont turn on.

When it buzzes, what do you measure across the large cap EC1 -- take care high voltage.

[wa11y]

Re: 40" LCD Rank Arena (rebadge?) has standby, V+ seem OK, but wont turn on.

The voltage appears to rise with every 'zap' sound to around ~410V and when it goes quiet it drops off to ~390V before rising/zapping again.

I just had a listen and the sound actually seems to be coming from the transformer thats right there if it matters?.. Im pretty sure its not coming from the big filter cap..

(i used a toilet roll to 'pinpoint' the sound which I read to do on another thread

[tom66]

Re: 40" LCD Rank Arena (rebadge?) has standby, V+ seem OK, but wont turn on.

Could be C5 capacitor, it's the startup capacitor for PFC (voltage boost.) Try heating up C5 to see if the voltage stabilises. If that doesn't work try replacing C5 anyway.

[wa11y]

Re: 40" LCD Rank Arena (rebadge?) has standby, V+ seem OK, but wont turn on.

How hot should I aim for? like 50c ?

You do mean the nippon KY 1000uF cap at EC5 dont you?? Dont know if it matters to you but I did have those 3 caps out already and tested them for ESR before putting them back (most likely into different spots) so would it be likely that even after swapping it with one of its 'sisters' it would still do this?

Im actually waiting for some new 1000uF caps so if no luck with my heat gun I will have to report back when I actually know something new..

Thanks so much for the help.

[tom66]

Re: 40" LCD Rank Arena (rebadge?) has standby, V+ seem OK, but wont turn on.

No, I mean C5, right near the big cap. Not EC5.

Hairdryer-like temperatures. You can use a hairdryer to achieve hairdryer-like temperatures.

[wa11y]

Re: 40" LCD Rank Arena (rebadge?) has standby, V+ seem OK, but wont turn on.

Oh im obviously blind.

Its only 10uF ill grab one this arvo from the store should be cheap enough....

.....& I dont own a hairdryer... Dont own enough hair these days to justify owning one I dont think. (although so many times I wish I did have one never once for my hair though)
Ill just hit it with hot air and see what happens..

[selldoor]

Re: 40" LCD Rank Arena (rebadge?) has standby, V+ seem OK, but wont turn on.

I have read somewhere on here in the last few days that someone had a set where the standby light was supposed to flash when it was working ok? Perhaps ask the MIL if it used to do that.

Can you take some close up shots of C9 the red cap it doesnt just look uniform along its length - havent seen one fail for some time but may be worth a look.

[wa11y]

Re: 40" LCD Rank Arena (rebadge?) has standby, V+ seem OK, but wont turn on.

I just replaced it with a nichicon cap I harvested from a old board I had here.. Exact same results as before

(The board was 'good' & not exactly from a dead TV it came to me from a set who's owned decided to throw it on the floor to break the screen during a fight with their spouse, screen was all trashed and I harvested the boards, so I could use now I suppose..lol[well thats what ill tell the mrs later].)

[wa11y]

Re: 40" LCD Rank Arena (rebadge?) has standby, V+ seem OK, but wont turn on.

It's not uniform.. Here are some more pics for you good sir.

EDIT: It looks like its supposed to have that 'dimple' in the middle from what I can tell..??

[tom66]

Re: 40" LCD Rank Arena (rebadge?) has standby, V+ seem OK, but wont turn on.

It's good. You can't measure the ESR of such a cap though on a conventional ESR meter, due to the low capacitance.

[wa11y]

Re: 40" LCD Rank Arena (rebadge?) has standby, V+ seem OK, but wont turn on.

fair enough, I wasnt sure if it mattered so did anyways since wouldnt hurt,lol, but now I know thanks tom