Author Topic: EEVblog #631 - Soniq LCD TV Repair Part 2  (Read 11570 times)

0 Members and 1 Guest are viewing this topic.

Offline Stonent

  • Super Contributor
  • ***
  • Posts: 3824
  • Country: us
EEVblog #631 - Soniq LCD TV Repair Part 2
« on: June 17, 2014, 12:40:11 am »


I found the datasheet for the suspect part:



 :-+
« Last Edit: June 17, 2014, 12:41:57 am by Stonent »
The larger the government, the smaller the citizen.
 

Offline fluxcapacitor

  • Frequent Contributor
  • **
  • Posts: 345
  • Country: gb
Re: EEVblog #631 - Soniq LCD TV Repair Part 2
« Reply #1 on: June 17, 2014, 01:54:44 am »
the fuse is made by Little Fuse ,LF catalog  number 0468 01.5   .Slow blow ! marked TK  .

http://www.farnell.com/datasheets/94905.pdf
 

Offline nowlan

  • Frequent Contributor
  • **
  • Posts: 639
  • Country: au
Re: EEVblog #631 - Soniq LCD TV Repair Part 2
« Reply #2 on: June 17, 2014, 03:26:46 am »
I thought had other issues originally, like no tv signal, only pi on hdmi, and issues turning it off. Wouldnt have thought the flex cable would cause that.
 

Offline pickle9000

  • Super Contributor
  • ***
  • Posts: 2132
  • Country: ca
Re: EEVblog #631 - Soniq LCD TV Repair Part 2
« Reply #3 on: June 17, 2014, 04:47:34 am »
I wonder how many people on this forum end up fixing their mom's TV? I do believe it's mandatory.

How come everyone thinks anyone involved with electronics in any way shape or form is a TV repairman?

Quotes:

"You own a soldering iron? Can you fix my TV?"
"Oh your an Electrical Engineer? Can you fix my TV?"


 

Offline komet

  • Supporter
  • ****
  • Posts: 155
  • Country: ch
  • Shenzhen Retroencabulator Mfg. Co.
Re: EEVblog #631 - Soniq LCD TV Repair Part 2
« Reply #4 on: June 17, 2014, 08:54:41 am »
"You own a soldering iron? Can you fix my TV?"
"Oh your an Electrical Engineer? Can you fix my TV?"
It applies to anyone, even people who can't wire a plug.

"I brought you into this world and wiped your bottom. Can you fix my TV?"
 

Online tom66

  • Super Contributor
  • ***
  • Posts: 3472
  • Country: gb
  • Electronic Engineer & Hobbyist
Re: EEVblog #631 - Soniq LCD TV Repair Part 2
« Reply #5 on: June 17, 2014, 09:01:56 am »
I "fixed" my Mum's TV because I found it at a dump and replaced the bad capacitors on the PSU, does that count?
 

Offline digital

  • Contributor
  • Posts: 47
  • Country: au
Re: EEVblog #631 - Soniq LCD TV Repair Part 2
« Reply #6 on: June 17, 2014, 09:48:12 am »
Dave as you would know fuses have a mind of their own especially slow blow fuses, that cheap and nasty connector   would probably would have resulted in a large repair bill or the set would have been landfill Mum will be happy.
 

Offline nowlan

  • Frequent Contributor
  • **
  • Posts: 639
  • Country: au
Re: EEVblog #631 - Soniq LCD TV Repair Part 2
« Reply #7 on: June 17, 2014, 09:51:06 am »
I replaced some caps in psu for a friends lcd monitor. Only to break the flex cable socket on the motherboard. After which it just palette cycled. Called it quits and went to hard rubbish.
 

Offline swabaxter

  • Newbie
  • Posts: 4
Re: EEVblog #631 - Soniq LCD TV Repair Part 2
« Reply #8 on: June 17, 2014, 10:18:36 am »
This was the first time I had seen inside a modern LCD TV. It's surprising how little electronics there is inside. A great piece of trouble shooting by Dave to find the blown fuse and identify the flat flex as a possible cause.
 

Offline RupertGo

  • Regular Contributor
  • *
  • Posts: 77
Re: EEVblog #631 - Soniq LCD TV Repair Part 2
« Reply #9 on: June 17, 2014, 10:27:13 am »
It's barely worth fixing your mother's TV these days, even if it's just a fried cap or mis-seated cable. As everyone else on the planet has, I fixed one up for my mother when the parental CRT dinosaur finally faded to grey - a pa had a (then very expensive) Samsung 40" LCD which had, in his words, "belched funny smelling smoke from the back and the picture went funny". He gave it to me rather than getting it fixed, and one new cap later it went to the wrinklies.

It was fun to fix and the parents were delighted to get a modern telly. But adding up time and transport costs, and the sad fact that few people of my parents generation care much about picture quality (or aspect ratio. Drives me batty when I visit) it would have been simpler and cheaper just to send them a Chinese cheapy via Amazon.

But it's good to keep one's hand in - another reason I like EEVBlog so much; Dave spends his time profitably doing the stuff I'd like to do if I could afford to, because that's the way I'm wired. Beats the footie by a very, very long chalk.
 

Offline station240

  • Supporter
  • ****
  • Posts: 852
  • Country: au
Re: EEVblog #631 - Soniq LCD TV Repair Part 2
« Reply #10 on: June 17, 2014, 05:39:21 pm »
My assumption is the socket o the LVDS board is really critical as to the entry angle of the matching plug. By passing the cable under the PSU, they applied enough sideways force to make the contact between the pair of metal fingers intermittent.

Jamming something thin between the back of the screen and the cable plug could also have fixed it.
 

Offline SeanB

  • Super Contributor
  • ***
  • Posts: 15091
  • Country: za
Re: EEVblog #631 - Soniq LCD TV Repair Part 2
« Reply #11 on: June 17, 2014, 05:47:52 pm »
You get the toaster and iron repair requests here, along with the TV and cellphone requests.
 

Offline Towger

  • Super Contributor
  • ***
  • Posts: 1551
  • Country: ie
Re: EEVblog #631 - Soniq LCD TV Repair Part 2
« Reply #12 on: June 17, 2014, 06:19:57 pm »
Re Dave missing the fuse values on the silkscreen.

I was presented with a rice cooker to fix on Sunday, sigh.
Anyway, upon diagnosing a blown thermal fuse I was left with the problem of reading its near non existent value.
Well I am Dave's age and thought I still had good eyesight, when wearing glasses...
I could make out the last number and a guess at the others.  It was not the font size, but the lack ink.  The cookers owner was worse, but showed it to his young lad, he read them straight off.  I was left thinking how the #@$@ could he read it, but he was right, it was a standard value even Maplin stocked them!

Oh well they say life begins at 40, but I think it is all down hill from there :-)

 

Offline SeanB

  • Super Contributor
  • ***
  • Posts: 15091
  • Country: za
Re: EEVblog #631 - Soniq LCD TV Repair Part 2
« Reply #13 on: June 17, 2014, 06:25:25 pm »
195C right?
 

Offline Stonent

  • Super Contributor
  • ***
  • Posts: 3824
  • Country: us
Re: EEVblog #631 - Soniq LCD TV Repair Part 2
« Reply #14 on: June 17, 2014, 07:18:39 pm »
Yeah, I know.  I was just giving him a bit of a hard time.  We get to see his videos in 1080P and bigger than real life in many cases where he gets to see regular 1x zoom :)
The larger the government, the smaller the citizen.
 

Offline deth502

  • Frequent Contributor
  • **
  • Posts: 420
  • Country: us
Re: EEVblog #631 - Soniq LCD TV Repair Part 2
« Reply #15 on: June 17, 2014, 09:09:10 pm »
loved seeing that half-assed rigging job with that fuse done by a "pro", makes me feel better about some of the amateur shit i do!  :-+
 

Offline HyLite

  • Newbie
  • Posts: 2
Re: EEVblog #631 - Soniq LCD TV Repair Part 2
« Reply #16 on: June 17, 2014, 10:05:36 pm »
That was a spot-on lesson in trouble-shooting technique. Mucho take-away there. Dave's knowledge of what's on the PC board and what it does shows a lot of engineering experience. This guy is one sharp cookie!
 

Offline lowimpedance

  • Super Contributor
  • ***
  • Posts: 1060
  • Country: au
  • Watts in an ohm?
Re: EEVblog #631 - Soniq LCD TV Repair Part 2
« Reply #17 on: June 18, 2014, 03:48:12 am »
You get the toaster and iron repair requests here, along with the TV and cellphone requests.
Certainly get many requests, but the Aunties toaster was considered an immediate write off not just for the pile of cooked cockroaches in the bottom but also the electrocuted mouse 'stuck' to the mechanical thermostat control  :o
The odd multimeter or 2 or 3 or 4...or........can't remember !.
 

Offline rob77

  • Super Contributor
  • ***
  • Posts: 1848
  • Country: sk
Re: EEVblog #631 - Soniq LCD TV Repair Part 2
« Reply #18 on: June 18, 2014, 03:57:40 am »
You get the toaster and iron repair requests here, along with the TV and cellphone requests.
Certainly get many requests, but the Aunties toaster was considered an immediate write off not just for the pile of cooked cockroaches in the bottom but also the electrocuted mouse 'stuck' to the mechanical thermostat control  :o

was the electrocuted mouse the root cause of the malfunction ? :D
 

Offline SeanB

  • Super Contributor
  • ***
  • Posts: 15091
  • Country: za
Re: EEVblog #631 - Soniq LCD TV Repair Part 2
« Reply #19 on: June 18, 2014, 04:50:03 am »
Probably not, likely the plastic bits it had nibbled on as snacks inside as well.
 

Offline Towger

  • Super Contributor
  • ***
  • Posts: 1551
  • Country: ie
Re: EEVblog #631 - Soniq LCD TV Repair Part 2
« Reply #20 on: June 18, 2014, 08:21:01 am »
195C right?

It was higher, low 200s. I left it with the owner to source the replacement.
 

Offline VK3DRB

  • Super Contributor
  • ***
  • Posts: 1487
  • Country: au
Re: EEVblog #631 - Soniq LCD TV Repair Part 2
« Reply #21 on: June 18, 2014, 01:25:44 pm »
No mention of an mains safety isolation transformer. All TV techs have them. An ELCB is a poor substitute. Most of these so-called safety switches are trip at way above the lethal current. 10mA CAN KILL YOU. You cannot beat a mains isolation transformer for safety. Use both.

A side story: Many ago I bought several hundred 1kW 1:1 mains isolation transformers as new in their box complete with mains plugs for 50 cents each at an auction. An absolute bargain. No-one else at the auction knew what they were. I resold them at at an obscene profit to a distributor who resold them to TV techs around Australia at a price below retail. Everyone was a winner! They would be in numerous repair shops today as essential equipment :-+

As for auctions and people not knowing what things are, about 3 years ago I missed an auction by 2 weeks... a brand new high end Mantis microscope sold for $230. |O
 

Offline VK3DRB

  • Super Contributor
  • ***
  • Posts: 1487
  • Country: au
Re: EEVblog #631 - Soniq LCD TV Repair Part 2
« Reply #22 on: June 18, 2014, 01:34:33 pm »
Try a fine pencil rubbed lightly on the flat ribbon tabs then clean with isopropyl alcohol. Then resolder the connector socket pins with higher than normal heat so the longer/higher heat heat flows right into the connector itself. Clean off the flux, even if it is no-clean flux. Then soak the entire connector or board end in isopropyl alcohol for an hour, then blow dry. Your problem might well be solved.
 

Offline grumpydoc

  • Super Contributor
  • ***
  • Posts: 2681
  • Country: gb
Re: EEVblog #631 - Soniq LCD TV Repair Part 2
« Reply #23 on: June 18, 2014, 02:15:13 pm »
Quote
You cannot beat a mains isolation transformer for safety. Use both.


Doing so does not necessarily increase your protection - not that using an isolation transformer isn't good advice but it is not a panacea.

If you have equipment connected via a transformer and come into contact one point in the equipment you will not recieve a shock because no current can flow to earth - all well and good.

If you come into contact with two points at significant potential difference then you will still recieve a shock. Worse the current flow that the GFI/RCD sees will be totally balanced and it will not trip whereas without a transformer enough current might flow to earth to trip the breaker.

Also if you connect some point which is normally at a significant potential to ground within the now floating DUT to ground via a 'scope probe lead then areas which are normally safe might wind up at a significant potential relative to ground.

By all means power your equipment from a transformer but even then "one hand in pocket" is a good rule to follow. Even better hook up probes with the equipment powered down and keep both hands off while you power the equipment and take measurements.
 

Offline David Aurora

  • Regular Contributor
  • *
  • Posts: 153
  • Country: au
Re: EEVblog #631 - Soniq LCD TV Repair Part 2
« Reply #24 on: August 07, 2014, 01:37:51 pm »
Picked up the same model today from Cash Converters. They had their clearance pile with a few "broken" TV's, and my sister needed a TV, so I offered them $50 for the two without cracked screens. One seems completely fine unless it has an intermittent issue I haven't seen yet, the other was the Soniq.

The cable going up to that small board is an issue in this one too, though this one has WAY messier wiring. Seems to be an interference issue, when I got the cable further away from the power supply it sprang back to life so I just ripped off the tape and zip tied it in place as far away as possible and it was working fairly well but had some glitches still. I guarantee with some shielding I could get it 100%.

BUT... Turns out I don't need to. I was just stuffing around with it and as soon as I turned the power saving mode to off, the flickering and glitches COMPLETELY stopped instantly. If I turn on any of the power saving modes the issues come back.

So there you go. Get the cable isolated, turn off power saving and all is well.
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf