What maybe causing this Chopper to short ?

[Agent24]

Re: What maybe causing this Chopper to short ?

This might help you: http://www.repairfaq.org/samnew/tvfaq/tvhorkboeh.htm

Also check through the whole document for general CRT TV information http://www.repairfaq.org/samnew/tvfaq.htm

[stj]

Re: What maybe causing this Chopper to short ?

did you check the flyback transformer?

[ben7]

Re: What maybe causing this Chopper to short ?

Great page on fake transistors!
http://sound.westhost.com/fake/counterfeit-p2.htm

Usually the silicon die is too small, and can't handle the power that the bigger ones can. Sometimes the labeling looks strange.

[Agent24]

Re: What maybe causing this Chopper to short ?

Yeah, that would do it. Power transistors are very often fake from China (Usually they use a lower-rated part and relabel it)

[SM-Piyes90]

Re: What maybe causing this Chopper to short ?

Hi again am back on topic again .

I just want to point out the solution for my original problem with the welder

I have used original IGBTs from fairchild and they have worked without getting shorted , i guess i was using counterfeit components ( big mistake ) .

[Agent24]

Re: What maybe causing this Chopper to short ?

Btw, is there any way to recognise fake parts or items?

If it comes from China and they cost half the price of a genuine part, or you can buy ten of them for the price of one genuine one, you're probably looking at a fake\knockoff\other dodgy part.

They don't usually sell outright fake chips (eg: lumps of metal coated in plastic) - too many people would complain and eBay is biased towards the buyer - but they may be clones with lower power ratings, worse specifications, or genuine 2nds that were supposed to be dumped, or used chips cleaned up to look like new, or some other dodgy version.

As always, you get what you pay for.

I do buy some cheap crap from there, like LM1117 regulators, got 20 for $1.50 or something - they seem to work OK but I'm only using them for prototyping etc and not running them at full capacity.

[senz_90]

Re: What maybe causing this Chopper to short ?

Nearly none, aside from carefully comparing known originals and the supposed replacements -- but that can be wrong, as manufacturers can change parts over years, and fakes can also look very good!
Just have to buy from honest suppliers who buy direct from manufacturers.

So it looks like we hope from luckiness, my experience is less on ebay. hahaha

[SM-Piyes90]

Re: What maybe causing this Chopper to short ?

They don't show ESR in those sheets because it's not a 'Low ESR' capacitor. However, I did measure a couple of 200v 470uF caps the other day and they were 0.06 and 0.08 ohms ESR, and as far as I know, not faulty. So if you measure some and they are significantly higher than that, they may be bad.


I don't know how much difference it will make. The datasheets almost always specify ESR at 100kHz, and 60kHz is almost half that. It may mean your readings would end up about half (or twice) what they should be, which would be rather useless.

oH , that makes a difference then .
So better build a 100 KHz one , i hope i can find one using ICl71xx

[tom66]

Re: What maybe causing this Chopper to short ?

Nearly none, aside from carefully comparing known originals and the supposed replacements -- but that can be wrong, as manufacturers can change parts over years, and fakes can also look very good!
Just have to buy from honest suppliers who buy direct from manufacturers.

[senz_90]

Re: What maybe causing this Chopper to short ?

You could try eBay - but beware the Chinese sellers, there are many fake parts.

Btw, is there any way to recognise fake parts or items?

[Agent24]

Re: What maybe causing this Chopper to short ?

What is normal ESR for a 400V 470 uf , i don't see esr values for high voltage ratings on online charts .

They don't show ESR in those sheets because it's not a 'Low ESR' capacitor. However, I did measure a couple of 200v 470uF caps the other day and they were 0.06 and 0.08 ohms ESR, and as far as I know, not faulty. So if you measure some and they are significantly higher than that, they may be bad.

If results accuracy is a negligeable then its not a big deal for me .

I don't know how much difference it will make. The datasheets almost always specify ESR at 100kHz, and 60kHz is almost half that. It may mean your readings would end up about half (or twice) what they should be, which would be rather useless.

[SM-Piyes90]

Re: What maybe causing this Chopper to short ?

What is normal ESR for a 400V 470 uf , i don't see esr values for high voltage ratings on online charts .

That one with ICL7106 looks nice but test frequency is only 60kHz. Datasheets almost always spec their ESR at 100kHz. If you use this meter you will get an inaccurate result.

Either change the design so it's 100kHz or use a different design.

If results accuracy is a negligeable then its not a big deal for me .

[Agent24]

Re: What maybe causing this Chopper to short ?

But I couldn't found anyone sell this ICL7106 or ICL7107 on my town

You could try eBay - but beware the Chinese sellers, there are many fake parts.

[senz_90]

Re: What maybe causing this Chopper to short ?

You know i actually got 10 of those ICL7106 but i guess they may work instead of 7107

You see the problem is only on the availability of parts , building is easier after testing the circuitry on breadboard


Thanks for this bro , i will add this to my other ANATEK ringer replica.

Yes, indeed ICL7106 would work. But I couldn't found anyone sell this ICL7106 or ICL7107 on my town. thank you, please inform if you build it successful. By the way, I am too build ringer replica from anatek . It looks like not a problem since I don't sell it, I am using it for myself to servicing CRT TV and Monitor.

[Agent24]

Re: What maybe causing this Chopper to short ?

I don't recognize the configuration they are using that 555 in, but at a guess if you change C5 value to a little over half, it will probably run at 100kHz. Good idea to test it on a breadboard first, probably.

I don't know if the rest of the circuit will still operate properly, though.

[SM-Piyes90]

Re: What maybe causing this Chopper to short ?

That one with ICL7106 looks nice but test frequency is only 60kHz. Datasheets almost always spec their ESR at 100kHz. If you use this meter you will get an inaccurate result.

Either change the design so it's 100kHz or use a different design.

This design is using a 555 timer as frequency generator , is there a way i can make it give 100 kH by variying some parameter , and would the tester work as expected ?

[Agent24]

Re: What maybe causing this Chopper to short ?

That one with ICL7106 looks nice but test frequency is only 60kHz. Datasheets almost always spec their ESR at 100kHz. If you use this meter you will get an inaccurate result.

Either change the design so it's 100kHz or use a different design.

[SM-Piyes90]

Re: What maybe causing this Chopper to short ?

If you don't mind you could try this
http://electronics-diy.com/esr-meter...ance-meter.php
I want really to build this but I couldn't found any supplier on my town has ICL7106/7 IC. If you found this really useful I will try to buy it via Ebay or my brother when he is going abroad. Im really curious for this one . thank you

You know i actually got 10 of those ICL7106 but i guess they may work instead of 7107

You see the problem is only on the availability of parts , building is easier after testing the circuitry on breadboard


Thanks for this bro , i will add this to my other ANATEK ringer replica.

[Agent24]

Re: What maybe causing this Chopper to short ?

There's quite a few digital ones too, if you can't get an analog meter. There's also this one: http://circuit-zone.com/?electronic_project=484 which uses the multimeter for a display.

Myself, I built Bob Parker's BlueESR meter, it's really nice, but it is rather expensive.

[senz_90]

Re: What maybe causing this Chopper to short ?

there are many esr meter design on googling. just try type esr meter on it and many of them are analog one. If you have budget, you could get a decent ESR meter likes Blue ESR Meter, ESR Micro, etc. Since I do this electronics thing just for hobby I don't buy commercial one If you are expert in microcontroller, also there some site share design with LCD panel display if you find hard to read on analog display.

like this
members.shaw.ca/swstuff/esrmeter.html
ludens.cl/Electron/esr/esr.html

Mine is just a copy of them since I'm not expert on electronic and couldn't make a good design, so I just make a little change to suit it with my VOM mA range. btw there are other design on this forum made by budm or tom66. you can try it too.

If you don't mind you could try this
http://electronics-diy.com/esr-meter...ance-meter.php
I want really to build this but I couldn't found any supplier on my town has ICL7106/7 IC. If you found this really useful I will try to buy it via Ebay or my brother when he is going abroad. Im really curious for this one . thank you