how to eliminate high voltage leakage from flyback ?


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how to eliminate high voltage leakage from flyback ?

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gilwe
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Jun 30, 2007, 12:17 AM

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how to eliminate high voltage leakage from flyback ?	Can't Post

Hi all !

I've just been given away a huge Sony 34" TV which uses to make hiss noises when powered on, then it goes "tick-tick" after a few minutes working. I opened it up and I can hear the hiss noise coming from the flyback system. On this model, the flyback transformer has a plastic wire going from it to another block which is attached to the chasis on the upper side, just near the CRT, and another plastic wire of the same type going from that block to the CRT. That wire seems to be broken just at the place where it connects to the block mentioned. If you shut the room light down, you can notice a blue arc going out at that spot.
I've been reading that this can be fixed by applying some silicon at the spot where the leakage occurs, if that correct ? which type of material should I use ? Is it ok to glue this crack with Lock-Tight (super glue) or UHU glue, or should I only use silicon ?
Thanks all for your help !!

Paulpablo
Enthusiast

Jun 30, 2007, 12:26 AM

Post #2 of 29 (16074 views)
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Re: [gilwe] how to eliminate high voltage leakage from flyback ? [In reply to]	Can't Post

Use silicon and let it completely dry and if that does'nt work, you have to replace.

gilwe
New User

Jun 30, 2007, 2:24 AM

Post #3 of 29 (16069 views)
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Re: [Paulpablo] how to eliminate high voltage leakage from flyback ? [In reply to]	Can't Post

Hi, Thanks !
Well, I tried to temporarily insulate it with electrical tape, and about 90% of the arc and noise disappeared, but now I hear noises which sound like "tick tick tick" from the flyback transformer itslef and when I watch the transformer closely at its bottom end, I can see a spark with every "tick" noise heard... do you think the flyback itslef is bad, generating too much voltage and causing the initial arc I spoke about ?

Is there any way to confirm that the transformer does work ok and that the problem is caused by a different conponents which is related with the HV circuit, before looking for a new flyback ?
(this is an old Sony and I'm not sure where I can get a replacement flyback anyway...)
Thanks !!

Hect7369
User

Jun 30, 2007, 4:38 AM

Post #4 of 29 (16063 views)
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Re: [gilwe] how to eliminate high voltage leakage from flyback ? [In reply to]	Can't Post

Just replace the fly..
look it here:
http://www.tritronicsinc.com/

gilwe
New User

Jun 30, 2007, 10:23 AM

Post #5 of 29 (16059 views)
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Re: [Hect7369] how to eliminate high voltage leakage from flyback ? [In reply to]	Can't Post

Thanks,
Well, how can I verify that this IS the flyback which has gone bad ?
Is there any known procedure to test a flyback ?

shadetree
Veteran

Jun 30, 2007, 2:24 PM

Post #6 of 29 (16052 views)
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Re: [gilwe] how to eliminate high voltage leakage from flyback ? [In reply to]	Can't Post

take a hair dryer and dry all the hi voltage wires well ,may have moisture in set

gilwe
New User

Jul 1, 2007, 12:26 PM

Post #7 of 29 (16037 views)
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Re: [shadetree] how to eliminate high voltage leakage from flyback ? [In reply to]	Can't Post

In Reply To

take a hair dryer and dry all the hi voltage wires well ,may have moisture in set
Thanks,
are you refering to the arcing problem when suggesting there's moisture somewhere ? or do you think that the moisture causes the flyback to make that noise (tick tick) and flash ?

shadetree
Veteran

Jul 1, 2007, 2:49 PM

Post #8 of 29 (16034 views)
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Re: [gilwe] how to eliminate high voltage leakage from flyback ? [In reply to]	Can't Post

moisture will make everything arc and can crack picture tubes this so simple to do why ask just do it

techchris
Veteran

Jul 1, 2007, 7:51 PM

Post #9 of 29 (16032 views)
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Re: [gilwe] how to eliminate high voltage leakage from flyback ? [In reply to]	Can't Post

all this messing around, just change the transformer, you wont stop 30Kv arcing with bits of insulating tape or silicone.you will end up with more damage to the rest of the tv with all that arcing and sparking

gilwe
New User

Jul 1, 2007, 9:38 PM

Post #10 of 29 (16025 views)
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Re: [techchris] how to eliminate high voltage leakage from flyback ? [In reply to]	Can't Post

Sure... I don't care at all about replacing the FB,
I just wanted to make sure the the FB wrong behaviour is indeed because the FB is bad,
and not because some other bad part driving it bad... So what do you say ? any procedure to verify that the FB is indeed bad, before oredering a replacement ?
Also, btw, would you recommend ACME replacement FB for Sony ? or do I go wrong here, and should get an original Sony FB ?

Also, as I said the arcing is not at the flyback itself, but at the tube that is on the box (high voltage block?) which is attached to the chasis, to which the FB cable is connected , and from which the anode goes to CRT. So, is the FB defected or is that block defected ? Is that box an integral part of the FB and I should expect to get the FB with the box and all wires, in case I order a replacement FB?

Thanks all for your help !

(This post was edited by gilwe on Jul 1, 2007, 10:35 PM)

shadetree
Veteran

Jul 1, 2007, 11:05 PM

Post #11 of 29 (16019 views)
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Re: [gilwe] how to eliminate high voltage leakage from flyback ? [In reply to]	Can't Post

you don't need the flyback just the block

rrobor
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Jul 2, 2007, 8:06 AM

Post #12 of 29 (16013 views)
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Re: [gilwe] how to eliminate high voltage leakage from flyback ? [In reply to]	Can't Post

The one thing you must do if you are attempting a repair is clean everything. Its no use wrapping tape around a lead if there is a burnt track mark as that is carbon and will continue like a river from a lake, to deepen and widen. So If need be scrape the surface and clean till spotless with a solvent. Then apply a waterproof silicon, (window and gutter clear silicone) if its an easy surface, put a flat sheet of plastic on top then another layer of silicon. The portable in our kitchen is 20 years old, last 18 years the flyback has worked with a bit of a pop bottle and silicone to block a hole. NEVER EVER use super glue. Most plastics are slowly destroyed by superglue.

HiTech
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Jul 2, 2007, 1:35 PM

Post #13 of 29 (16012 views)
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Re: [gilwe] how to eliminate high voltage leakage from flyback ? [In reply to]	Can't Post

Have you tried to look for any signs of arcing with the rooms lights off? Cover the tv screen with something to further reduce ambient light. Like it was mentioned earler, 30kv of arcing voltage is difficult to contain with band-aid fixes. My experience has been to simply troubleshoot, verify, and replace the defective part. Then again, I had to please paying customers and keep return repairs to an absolute minimum.

gilwe
New User

Jul 2, 2007, 2:23 PM

Post #14 of 29 (16009 views)
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Re: [HiTech] how to eliminate high voltage leakage from flyback ? [In reply to]	Can't Post

The problem is that I don't understand a few things :
1. What does the arcing indicate ? Is the tube like part on the high voltage block, to which the flyback connects, and from which the arc is coming , broken ?
2. Should I replace the FB or the block in that case ? Does the flyback makes that "tick-tick" noise and sparks at its bottom because it is bad or as a result of the block failure ? or has the FB gone bad as well because of this problem ?
3. As long as I still see a healthy picture, does it meant that all other parts are OK ?

Thanks all once again!

HiTech
User

Jul 2, 2007, 5:39 PM

Post #15 of 29 (16000 views)
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Re: [gilwe] how to eliminate high voltage leakage from flyback ? [In reply to]	Can't Post

Arcing is never a good thing unless perhaps you are welding something! In electronic circuits such as those in a television, arcing can burn through a circuit board and create carbon paths which destroy circuitry further. Arcing will further breakdown insulation and eventually destroy the circuitry that develops the high voltage. In most repair cases, silicone putty/dope, and thick tape are not long term fixes. Replacement of the defective part(s) as well as a thorough examination of the surround area of arcing is mandated. Anytime high voltage arcing occurs in a television, take it as a clear indicator that the insulative properties are not performing to design/spec.
I think it's time for you to be honest with yourself and seek the services of a professional serviceman( or woman!). High voltage circuits are nothing to gamble with between your safety, money and time. You could risk further damaging the set if you perform the wrong repair action. In no way am I slamming you for trying to learn and save some money, but this could be the writing on the wall for you to heed. Just my 2� worth!
Regards,
HiTech

(This post was edited by HiTech on Jul 2, 2007, 5:44 PM)

gilwe
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Jul 2, 2007, 7:20 PM

Post #16 of 29 (15991 views)
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Re: [HiTech] how to eliminate high voltage leakage from flyback ? [In reply to]	Can't Post

Well, I am a technician, although not much experienced with those high voltage circuits. I think that I am going to ditch it and just throw it away. I'm not sure spending almost a 100$ in *trying* to repair it can be a wise step. After all no one knows what I can find once I replace the parts, and these TV sets are going used for the price of repairing that specific one...
Thanks ;)

gilwe
New User

Jul 21, 2007, 7:15 PM

Post #17 of 29 (15947 views)
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Re: [gilwe] how to eliminate high voltage leakage from flyback ? [In reply to]	Can't Post

Hi all !
Some news....

Well, after taking the High Voltage Block out yesterday, diconnecting the lead from the Flyback to the block, cleaning the dirt and moisture and reassembling the unit, I got very minor arcing compared to what it was at the first place. Realigning the lead can make the arc almost disappear.
The TV works in general without any problem, but every few minutes or so, I can still hear ticking noise from the Flyback and see a small flashing light coming from its bottom with every "tick" noise.

I'll be careful and say that I think that the ticking/flashing happens more when the arcing from the High Voltage Block is bigger, and almost doesn't happen when the arcing is minimal.

So my question is -

Do you think that the Flyback itself is bad, or the ticking/flashing is the result of the small arcing which still happens at the High Voltage Block, just where the lead from the Flyback connects to it ??

I tend to suspect that the only cause is the arcing and while this is entirely solved I won't get the ticking/flashing anymore... does this makes sense ?
Thanks !!

(This post was edited by gilwe on Jul 21, 2007, 7:17 PM)

Hect7369
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Jul 22, 2007, 2:27 AM

Post #18 of 29 (15935 views)
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Re: [gilwe] how to eliminate high voltage leakage from flyback ? [In reply to]	Can't Post

Do you think that the Flyback itself is bad??

Yes,the Fly is bad,change it!!

rrobor
Veteran

Jul 22, 2007, 9:11 AM

Post #19 of 29 (15927 views)
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Re: [gilwe] how to eliminate high voltage leakage from flyback ? [In reply to]	Can't Post

Short the top cap to the metal sprayed on the back of the tube, then with some sort of solvent clean everything. When everything is clean and dry switch on. If you hear some tick, breathe on it, sort of haa haa close to where it seems bad. if it gets worse its that, try silicone sealant

gilwe
New User

Aug 19, 2007, 11:05 PM

Post #20 of 29 (15870 views)
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Re: [rrobor] how to eliminate high voltage leakage from flyback ? [In reply to]	Can't Post

A little update -

Well, I finally fixed the problem by disconnecting the lead going from the FBT to the High Voltage Block, cleaned everything and reconnected in the correct angle. The arcing has almost disappeared and so far the TV set is working fine,
Thanks all !

rrobor
Veteran

Aug 20, 2007, 8:51 AM

Post #21 of 29 (15862 views)
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Re: [gilwe] how to eliminate high voltage leakage from flyback ? [In reply to]	Can't Post

You have stopped 1 point short and your repair will not last. If you know where the leak was get silicone sealant and block the chance of dirt and moisture getting back there. After puting on a thickish layer of silicon you may have to hold it in place with some form of plastic. Do not switch the TV on for several hours till the silicon has got a good skin. If you switch on you will see the silicon migrate off the problem area and you may see strings of it fly through the air to earth points.

terminator
User

Sep 5, 2007, 10:16 PM

Post #22 of 29 (15825 views)
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Re: [gilwe] how to eliminate high voltage leakage from flyback ? [In reply to]	Can't Post

you dope just buy a new tv its a whole lot cheaper. the thing will have more problems in the future. trust me you dont want to pay thosands to keep the thing running like i did and that was a waste of money

rrobor
Veteran

Sep 6, 2007, 9:35 AM

Post #23 of 29 (15817 views)
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Please refrain from calling people dopes, after all you are only 15 years old and have not been renouned for your wisdom. You said you would stop this, obviously your mouth overtakes your brain and you spew out this crap.

terminator
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Sep 6, 2007, 10:11 PM

Post #24 of 29 (15805 views)
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Re: [rrobor] how to eliminate high voltage leakage from flyback ? [In reply to]	Can't Post

i just want to give advice and i appoligize for the dope name. i was trying to tell him to buy a new tv since consoles dont last very long

rrobor
Veteran

Sep 7, 2007, 11:15 PM

Post #25 of 29 (15787 views)
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Re: [terminator] how to eliminate high voltage leakage from flyback ? [In reply to]	Can't Post

I have a console TV in my workshop still working fine which I modified for fixing videos. That is exactly twice your age, given that you must be nearing 16. That TV works most days. Yes I have fixed it, last time about 5 years back. So why do you state stuff thats nonsence?

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