Can you dignose from the photo ? . Toshiba 65S2650EV

[Ancient1]

Re: Can you dignose from the photo ? . Toshiba 65S2650EV

Hi Davi.P

I know you use Smartphone here and don't know English well. "la pratica rende perfetti"
Thank you !
p.s From my experience, people from the Franconian belt : Romania, Italy, France, Spain, Portugal, have the English language syndrom : they always add "excuse my bad english". Its isn't as bad as you imagine

Here are the results :
To make it clearer I did not type 0.L
Method : Diode Mode . Black probe fixed , test 1 , 2 , discharge with finger, test 2,1 .
No conflicting results
And all that, was done twice

P.S The white print is the White Silicon Thermal Paste treatment. touch the paste , touch the IC, wipe gently with another finger

[Davi.p]

Re: Can you dignose from the photo ? . Toshiba 65S2650EV

Sad to see my bets go to the water closet, i can't believe it.. let me check better the ic2 datasheet..

[Davi.p]

Re: Can you dignose from the photo ? . Toshiba 65S2650EV

My suspicion is that the sense wire resistor burned a bit and reduced its value, it must be precise i think, since the current on CS pin of ic2 is measured in uA, and/or the new R37 is not precise.. this would bring to a OCP protection that shuts down the pfc..

[Ancient1]

Re: Can you dignose from the photo ? . Toshiba 65S2650EV

Hi

R37 measures fine. The Wire Resistor - I don't know how to replace ( to buy).

Looking at the IC2 Pins description - I don't know what I can do , is it possible to trick the IC or .. no clue. If VCC is present , where else does it go ..
What can we do .. could it be the other, IC3 ? Cold side not related at all ?

I marked the Mosfets TF20N60 .
I measured the resistors around them. They have same ones of course. One anomaly : R is 103 . but measures - in both - 5K Ohm. Not 1000 Ohm.

I will check all other SMDs

[lotas]

Re: Can you dignose from the photo ? . Toshiba 65S2650EV

Check also R33-R35.

[Davi.p]

Re: Can you dignose from the photo ? . Toshiba 65S2650EV

So you don't want to follow my clue? You can simply try to enlarge the wire resistor, by using a thick copper wire from old electric home wiring or from an inductance with exposed wire..

[Ancient1]

Re: Can you dignose from the photo ? . Toshiba 65S2650EV

Davi.P - What Clue ? of course I want to follow !
Also, would it be helpful if I take exact mV measurements for IC2 ?

lotas - I will check all I can, I need to find the time. I, like Davi.P , find this repair unbelievable. Its not like I didn't check before. I will verify Coils too. I mean.. unbelievable

[Davi.p]

Re: Can you dignose from the photo ? . Toshiba 65S2650EV

i don't know how to measure the current on pin CS other than putting amperometer in series, it seems that at 100uA it measures 10mV, but since the measuring is to be done in a short window before protection, them try my previous suggestion, make wire res. longer of some mm, start with 1cm

[Ancient1]

Re: Can you dignose from the photo ? . Toshiba 65S2650EV

I understand. it would be quite a job to measure A on CS , even if one can freeze the reading somehow.

I will look for a copper wire fitting in diameter and length. Do you know what metal is used for Jumper Wire Resistor ( if this is the correct name) ? If we know that, we can perhaps, using its electric parameter vs copper , actually create few, with good approximation, variable R and test .

I just found this https://www.quora.com/What-is-the-ty...in-breadboards

[Davi.p]

Re: Can you dignose from the photo ? . Toshiba 65S2650EV

indeed i don't know these resistors, you can only try to measure lenght / thicknes / resistance of it and try to add the correct resistance for the supposed missing burnt part.., i would not calculate too much, i would just take a 2cm long wire, solder on to it and start tests, shortening it eventually.

[Ancient1]

Re: Can you dignose from the photo ? . Toshiba 65S2650EV

Hi

Soldered copper wire , than regular wire , both rather long 10-15cm. 310V on Min Caps, 5VSB present - No luck .
Am currently taking a pause to think about what I did, and what to do : What if I put 1 Ohm resistor ? which really means, should I increase R or lower it ( remember that extra thin, watch's coil wire I used on the Fuse ?
But overall, It seems these are the last steps in the effort to repair the PSU, I tend to look favorably on buying a new PSU, I owe it to you .

What do you think ?

[Davi.p]

Re: Can you dignose from the photo ? . Toshiba 65S2650EV

how much measures the wire resistor without prolonges? To lower the current you must increase the resistance, so let's say it now measure 1ohm, you increase by 20%, then 30% etc...on each test.. use a carbon resistor or metal resistor, power at least 2w, i don't know if it would last but it's only for test..

[lotas]

Re: Can you dignose from the photo ? . Toshiba 65S2650EV

K-250N1 R44 = 0.075Om 2W
From the Chinese forum: https://zhidao.baidu.com/question/13...9%B0%E3%80%82&

[Davi.p]

Re: Can you dignose from the photo ? . Toshiba 65S2650EV

So since that value is hard to find, get a couple of 1,5ohm/1w.. 1% tolerance, put in parallel..

[lotas]

Re: Can you dignose from the photo ? . Toshiba 65S2650EV

Then it is necessary not 1.5 Om, but 0.15 Om two resistors connected in parallel.

[Davi.p]

Re: Can you dignose from the photo ? . Toshiba 65S2650EV

ehm... yes, of course, but seems low too, the best would be 3x0,23ohm/1w in parallel

[Ancient1]

Re: Can you dignose from the photo ? . Toshiba 65S2650EV

Thanks guys
Where in my junk would I probably be lucky and find such low R resistors ? I mean what sub circuits , what are those used for. I got thru-hole and SMD boards

I was thinking about creating a variable resistance device in that low range, I have few of those ( forgot the name), some from a dial ( circular ctrl ) and some , cubes, with screwdriver ctrl. If successful I could move through a range with better success of finding the right spot. With fixed R, you will always think "maybe".
I think have 1k Var , certainly 100k . I'll check later. The issue is to design how to reach such low R

[Davi.p]

Re: Can you dignose from the photo ? . Toshiba 65S2650EV

don't be so "short arm", think positive and buy one, or if you have plenty power boards, on the primary you can find some in 2w format..

[Ancient1]

Re: Can you dignose from the photo ? . Toshiba 65S2650EV

3 x 0.23 Ohm ?
I never bought something like that , I wonder If such are sold in a local store

[Davi.p]

Re: Can you dignose from the photo ? . Toshiba 65S2650EV

get them on eBay..