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Old Dec 04, 2006, 03:44 PM
Joined Oct 2004
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Ah, the good old days

[QUOTE=Gary Warner]Ah, the good old days...

When beer was tuppence a pint, and a gallon of petrol was 2 shillings and sixpence!! (12.5 pence in new metric money...petrol now hovering around 3-85 or $7-53!!!! a gallon)

TV's never had those multilegged fuse's (chips) they had valves that burnt the flesh off your fingers. 1964 and BBC2 opened their colour TV service....2 hours a day no less, with a few colour trade tests during the day. Cigarettes were lit from the arc drawn from the top cap of the line output valve/tube.

Having seen an all digital chassis this week, I'm really glad I hung up my boots! It's still interesting.....but no longer viable to make a proper living from servicing "brown goods" alone. Anyway receivers are much more fun and so is modelling. 45 years in the trade, and still finding a PC to be challenging. Tissue and a can of dope is better! !967 I got married, proportional RC was 169 for a 3 channel set.........just look what we get now for less than this.

John.
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Old Dec 05, 2006, 04:33 PM
dieselburner
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Wyke, Bradford, west yorks
Joined Mar 2005
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Quote:
Originally Posted by Chippie
If you use a TV or any other device to receive or record TV programmes (for example, a VCR, set-top box, DVD recorder or PC with a broadcast card) - you need a TV Licence. You are required by law to have one.


http://www.tvlicensing.co.uk/informa...ndex.jsp#link1.....

Very kind of them to give a 50% discount on the yearly TV tax if you are blind
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Old Dec 11, 2006, 04:07 AM
just look at it smokin'
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Joined Dec 2005
1,233 Posts
Quote:
Originally Posted by thanhTran
Thanks Mr.RC-CAM. It's sad when the thoudsand-dollar TV is not usable because of some couple-dollar parts.

I found lcdrepair.net while searching around. They said they can fix the board for $66 flat rate if there is no fried transformer. So I will give it a try.

One option I'm thinking of if I cannot fix this back light issue is that I may play with bunch of LED's shining on the back. Not sure if LED can provide enough brightness or how much spacing I need between LED . Maybe it will look funny hehe . Currently, there are 8 lamps sitting evenly and horizontally across the back of the LCD.

Hopefully there is enough space on the back (I couldn't look at it yet because the current back light is shield.

Wow, it's sure expensive to live in UK. I wonder if I own a sling box, a DVD recorder, but I'm using for my own personal and not broadcast anything, would I have to pay liscense?


Thanh
get 1W high efficiency Cree Xlamp white leds
experiment how many leds are neccessery for your application, evenly space them, these are very bright from current: 120-350mA, so don't stare into them.
there are warm white or cold white as you prefer.
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Old Dec 11, 2006, 04:19 AM
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Joined Dec 2005
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Quote:
Originally Posted by thanhTran
Hi Gary,

Thank you very much for your help. I called Syntax yesterday but noone picked up the phone. I'll call the number you gave me here. To see if there is any luck this time.

The TV seems having pictures just fine when the backlight flash up briefly. So I think it's just the backlight controller is bad.

Here are some pictures of the board.

Thanks Gary

Thanh
hi Gary,
i see that is an interesting, but cheap design, note the skipped capacitors, pads

that chip is probably a micro controller that has a custom typenumber and made for your tv set, i suppose it does the neccesary brightness adjustment, and the pwm control of the 8 ccfl driver smd mosfets.
the lm 324s are simple quad linear operational amplifiers, the lm393s are moderate speed cheap dual comparators.
when servicing the whole panel goes to trash...

btw, i have a design that uses lm393s too driving ccfl, still needs core control of output power level at different voltages.
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Old Dec 12, 2006, 03:02 AM
That tree again!!!!
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Germantown, MD, US
Joined Sep 2004
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Thanks for the info Z-Matrix.

I looked into the CREE LED. Their LED's do look sharp. I'll send them an email seeing if they do offer some small quantity. Going the LED route is sure a last resource as that would require me to open the protective cover of the LCD pannel. I'm afraid I would break some of the ultra delicate connectors that LCD pannel has. Currently the LCD pannel is still sandwitched betwen a few layers of metal frames.

I'm still waiting for LcdRepair.net to see if they can fix it. I just received it today eventhough I sent it the Monday last week.

I read around on the net about circuit that controls the CCFL lights, they seem to take lots of precaution and consideration into those circuits. I also found a chip that controls CCFL tube: FAN7310 LCD backlight inverter driver IC. The circuit is somewhat similar to a portion of a single back light of my tv. Maybe we can build 8 of them? But how do we know that the current supplied matches with the CCFL tube specification? Are they always using 5 or 6mA? I dont have any equipment to measure the current it consumes.

I cross my fingers that the board can be fixed.

Thanh
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Old Dec 12, 2006, 09:12 AM
just look at it smokin'
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Joined Dec 2005
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Quote:
Originally Posted by thanhTran
Thanks for the info Z-Matrix.

I looked into the CREE LED. Their LED's do look sharp. I'll send them an email seeing if they do offer some small quantity. Going the LED route is sure a last resource as that would require me to open the protective cover of the LCD pannel. I'm afraid I would break some of the ultra delicate connectors that LCD pannel has. Currently the LCD pannel is still sandwitched betwen a few layers of metal frames.

I'm still waiting for LcdRepair.net to see if they can fix it. I just received it today eventhough I sent it the Monday last week.

I read around on the net about circuit that controls the CCFL lights, they seem to take lots of precaution and consideration into those circuits. I also found a chip that controls CCFL tube: FAN7310 LCD backlight inverter driver IC. The circuit is somewhat similar to a portion of a single back light of my tv. Maybe we can build 8 of them? But how do we know that the current supplied matches with the CCFL tube specification? Are they always using 5 or 6mA? I dont have any equipment to measure the current it consumes.

I cross my fingers that the board can be fixed.

Thanh
well, a ccfl is a gas filled tube simlar to an ordinary neon tube, it has a negative resistance in the operating area, the current has to be limited, after it has been ignited (and heated up a bit), to a SOA (safe operating area), a 4W ccfl should have 4W supplied to it, no more, or will significantly shorten life - this is the interesting part, there are several methods to accomplish this.

You could simply use 8 ccfl drivers too, but if you can, you can use leds, this is cool, because life of the leds offered by Cree >50000 working hours maintaining >70% optical output power (light).

btw.:
instead of buying Leds straight from factory, you can try searching local distributors first...
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Old Dec 12, 2006, 09:39 AM
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Joined Dec 2006
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Quote:
Originally Posted by Gary Warner
The Olevia brand is a china import.

Give me the model number and I'll do a search on a subscription site I use. Most tv techs can't stand the china import models and won't work on them, so the database might not have much for us.

Gary Warner
York TV
--

Edit: I did a search w/o the model number. If this is the Syntax Olevia LT30HV then you might have luck talking to the factory at #1-888-796-8298. On the 28th of this month there has been some discusion about this model with the exact same problem, but no solution just yet. I did note that the backlight inverter board is about $40. The consensis is that it's the inverter PCB or the display panel. If it's the display panel, the factory is not selling it to us techs and it must be shipped to the factory to be replaced. They are getting $500 for an out-of-warranty replacment of the display pannel and someone noted that it's been taking about 5-6 months to get the sets back. Good luck and hope this helps.

Gary,
I'm in the same boat as Thanh. I've got the same TV with the same problem. The cost of the inverter board you mentioned - is that direct from Syntax or is it available through the aftermarket? If Thanhs repair proves sucessful I'd like to get my hands on one of those boards.
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Old Dec 12, 2006, 12:15 PM
York Electronics
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Dallas Tx USA
Joined Apr 1999
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The price is what another technician said it cost him. Usually list prices are 10-40% higher than our costs.

BTW, I checked back in on the thread where I found this information. He said he got the picture to come back on by resoldering the power supply circuits. Unfortunatly, he said he now has vertical lines in the picture. He's still trying to resolve that issue.

Gary
--
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Old Dec 12, 2006, 12:19 PM
aka: A.Roger Wilfong
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Novi, Michigan, United States
Joined Jan 2001
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Quote:
Originally Posted by andrew b
Very kind of them to give a 50% discount on the yearly TV tax if you are blind
They must be basing that on number of senses you are using, if they were going on the fraction of the TV signal's bandwidth you were using when "just listening", it'd be a lot lower than that.

- Roger
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Old Dec 12, 2006, 03:19 PM
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holy crap, why in the world would uk require a license to watch tv?!$#&^%$&^$#% What possibily could be so dangerous that a license is needed besides the government is just being greedy? I've recently heard about needing to pay gas taxes for people in the UK who run on biodiesel! Biodiesel! Even when you use the oil from a restaurant and make it yourself. That surely is going to give everyone the incentive to switch. What's next? license to breath?

Thanh, instead of LED, why not just some good 'ol floursecent tubes from homedepot? Cheap, uniform white light, easy to install. Line them up the same way as the original ccfl tubes.
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Last edited by rcboosted; Dec 12, 2006 at 03:27 PM.
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Old Dec 12, 2006, 04:15 PM
That tree again!!!!
thanhTran's Avatar
Germantown, MD, US
Joined Sep 2004
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Quote:
Originally Posted by rcboosted
...
Thanh, instead of LED, why not just some good 'ol floursecent tubes from homedepot? Cheap, uniform white light, easy to install. Line them up the same way as the original ccfl tubes.
Interesting idea. My TV would glow on the back ... brightly . The original ccfl tube is only 3 or 4mm in diametter. I think the tube from homedepot is about hundred times bigger than that . Problem is with the mechanical chassis. I don't think it has enough clearance. Here is how it goes: the LCD pannel, and then the ccfl tubes, and a layer of metal, then the inverter board, and then a big metal frame, and then electronics & power supply, and then the mounting hardware, then the cover, then the leg of the TV.
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Old Dec 12, 2006, 05:06 PM
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How about the ccfl tubes for pc case modders?
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Old Dec 12, 2006, 10:15 PM
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Joined Dec 2005
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Quote:
Originally Posted by rcboosted
How about the ccfl tubes for pc case modders?
rcboosted:
that whould work too
from 12V,

donno how reliable, it has 2 transistors, and tiny EI ferrite transformer inside,this drives the ccfl tubes, well, at least they are cheap, you might try to put 8 of these in your tvs for a dirty hack-
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Old Dec 12, 2006, 10:18 PM
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Quote:
Originally Posted by rcboosted
holy crap, why in the world would uk require a license to watch tv?!$#&^%$&^$#% What possibily could be so dangerous that a license is needed besides the government is just being greedy? I've recently heard about needing to pay gas taxes for people in the UK who run on biodiesel! Biodiesel! Even when you use the oil from a restaurant and make it yourself. That surely is going to give everyone the incentive to switch. What's next? license to breath?

Thanh, instead of LED, why not just some good 'ol floursecent tubes from homedepot? Cheap, uniform white light, easy to install. Line them up the same way as the original ccfl tubes.
i think original ccfls have some adventages, dis adventage is: needs a driver inverter to be cool.
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Old Dec 12, 2006, 11:31 PM
That tree again!!!!
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Germantown, MD, US
Joined Sep 2004
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Quote:
Originally Posted by z-matrix
rcboosted:
that whould work too
from 12V,

donno how reliable, it has 2 transistors, and tiny EI ferrite transformer inside,this drives the ccfl tubes, well, at least they are cheap, you might try to put 8 of these in your tvs for a dirty hack-
Would putting different ccfl driver to my ccfl tubes damage them or shoten its life? I wonder if it's bright enough or even have uniform brightness.

I think it may be easiser to find laptop inverter boards . There are also very inexpensive HV driver for cold light string:



http://grandrc.com/inc/sdetail/31126
I wonder if it works
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