How do I find out the rating of an SMD fuse?

[Dang]

Hi, I have an inverter for a 22" LCD tv with a blown SMD fuse with the letter "S" displayed on it, I have no idea on it's rating so is there any way of working it out or what's best I can do to replace it?

I have tested the board for shorts and even had it powered up by bridging the fuse with a pair of tweezers for about 15 seconds, everything seemed fine.

The inverter has two 12v power feeds and a 5v control feed with three ground wires.

[Kiriakos GR]

Re: How do I find out the rating of an SMD fuse?

If you are interested to find similar answers you need to buy one AC/DC low current clamp meter.

One temporally bridge wire in the position of the fuse, it will be enough so to measure the current by the clamp and in the end, even to use a regular glass fuse with fuse box if there is free space for them.



.

[budm]

Re: How do I find out the rating of an SMD fuse?

It may be 2A, see PDF. I do not know if you have 402, 603, or 1206. Notes: Not all manufacturers use the same code. Is this fuse in the DC path? then just set your DMM DCA 10A range and take the reading, then you can double up the reading. You can also do peak-hold to see the inrush current.

[tw2005]

Re: How do I find out the rating of an SMD fuse?

I've got no experience with these but the S would be the rating code, no idea if there's a standing labelling system.

Found this for cooper bussman http://pdf1.alldatasheet.net/datashe...PER/CC12H.html

S = 4A, ?

[tom66]

Re: How do I find out the rating of an SMD fuse?

You don't need a clamp meter, the 10 amp range on a multimeter will work fine for most checks.

[Kiriakos GR]

Re: How do I find out the rating of an SMD fuse?

You don't need a clamp meter, the 10 amp range on a multimeter will work fine for most checks.

When you will grow enough so to own a profesional multimeter which its fuse cost 12$, then you will buy a good quality clamp meter (150 - 200$) too.

[tom66]

Re: How do I find out the rating of an SMD fuse?

Not everyone owns a Fluke. The fuses for my BK 2709B cost about $3 each and it's unlikely a 22" LCD PSU will let you draw 11 amps to blow the fuse anyway. If he's using an average cheap meter, they don't usually fuse the 10A range, which is OK if you're testing a current limited PSU. (240VA on most PSUs will minimise hazards.)

[Kiriakos GR]

Re: How do I find out the rating of an SMD fuse?

Not everyone owns a Fluke.

Since the beginning of 2013 the European union set as active specific rules regarding the manufacturing standards of multimeter, especially regarding fuses and test leads.

Glass fuses and unsafe multimeter are banned from Europe.

Therefore Fluke does not hold any more the privilege to use expensive fast-blow fuses, every officially imported multimeter comes today with HRC fuses, with exception old cheap Chinese stock which is available, but not for long.

[Dang]

Re: How do I find out the rating of an SMD fuse?

It may be 2A, see PDF. I do not know if you have 402, 603, or 1206. Notes: Not all manufacturers use the same code. Is this fuse in the DC path? then just set your DMM DCA 10A range and take the reading, then you can double up the reading. You can also do peak-hold to see the inrush current.

Hi and thanks for the response. I'd say it were a 2 amp slow blow fuse too looking at the PDF, "S" looks like it represents 2 amps, I'll check using the above method just to be sure, thanks.

[Dang]

Re: How do I find out the rating of an SMD fuse?

Not everyone owns a Fluke. The fuses for my BK 2709B cost about $3 each and it's unlikely a 22" LCD PSU will let you draw 11 amps to blow the fuse anyway. If he's using an average cheap meter, they don't usually fuse the 10A range, which is OK if you're testing a current limited PSU. (240VA on most PSUs will minimise hazards.)

Yep, it's cheap and un-fused, cost £2.59, an Ebay throw away if you like, and I'm happy with it. It does do the job as you know so no complaints and yes, this 22" has a PSU as big as your palm, as always, thanks.

[multimeter]

Re: How do I find out the rating of an SMD fuse?

You don't need a clamp meter, the 10 amp range on a multimeter will work fine for most checks.

absolutley,you dont need one,as long as the circuit is fine and isnt blowing fuses,then its safe to use a cheapy multimeter on amp setting and measure across the fuse,and then rate it slightly higher for the fuse,

@ Kiriakos,not everyone can afford the gear your on about mate,ive got by for years on a round a £100 worth of test gear that isnt top range.and it has served perfectly .

top range gear on a chaps workbench,will reflect in his bank balance

the hare and the tortoise!

[Kiriakos GR]

Re: How do I find out the rating of an SMD fuse?

@ Kiriakos,not everyone can afford the gear your on about mate

In this case keep your hands away of a 400$ TV set, that some one else kicked his ass on working hard, so to buy it.

Every one who avoids the reasonable way about working with tools because they are expensive according to his pocket money, he is dangerous.

You may even own, even ten low cost meters, if you are wise not using them in critical applications, then everything is good.
But what happens if this damn critical application arrives? The wise repair man we will feel naked, the unwise one he will have in-door fireworks.

TV power supplies are actually inverters = advanced high-frequencies application.
There is no room any more for poor multimeter in such repairs.
Price have nothing to do any more as selection factor for buying a DMM.

[tom66]

Re: How do I find out the rating of an SMD fuse?

Uh, well, you'd be overpaying if you paid $400 for a 22" LCD nowdays but anyway, it's really not necessary in MOST cases to have a high end Fluke for basic repairs.

If you want to test the primary side of SMPS, it's highly recommended to get a safe meter, to limit the hazard and harm from mis use or failure. You can buy those without "Fluke" or "Agilent" name, too. High frequency has little to do with it; in general, you're looking for DC voltages, shorted and open components, and resistance check, all of which a meter costing £20 can do quite well. A scope, even an analog one, can assist in these diagnoses.

Accuracy is rarely an issue, most regulators and power supplies have tolerances in the range of 5 to 10% so any decent 1% meter will do fine. Rare to find 1% resistors but if you do then you can see if they are obviously failed, though that's an uncommon fault.

I'm not sure what you're getting from being here, you simply disagree with anyone who seems to think spending less than £5,000 on a lab for £20 TV fixes is crazy?! Why bother?

My £60 multimeter hasn't saved me any more money than a £400 Fluke would. A Fluke is a nice bit of kit, and I'd like to have one, but for me, there's little point, given that it wouldn't add anything more to my repairs and diagnosis. An extra digit or 0.05% DC volt accuracy really doesn't matter to me or anyone else here.

[multimeter]

Re: How do I find out the rating of an SMD fuse?

in all fairness,yes i do have a fluke 87-v,but then again i work a lot on motor circuits which would warrent the use of such a meter.

then again for my tv repairs ,my success rate using both high end equipment and "el-cheapo" gear ,is the same.

using low end gear keeps you on your toes more ,because of the lack of in built fail-
safes in low end gear,your more aware of the situation you are in and take more care.

its more easy to get complacent with top end gear.

and most of the time,i rarely have no need to be working on PFC front end circuits,most is always on DC .

as tom said above there is quite a bit of tolerance on PSu's +- 10%,which most cheap meters will happily cope with.

yes years down the line get something pricey and sexy when you have learnt the basics on the cheap stuff,still the same principle on top end gear,am i wrong?no.


its like giving a newly qualified driver a nissan skyline gtr,rather than a fiesta!

as for clamp meters,i actually dont like them,i prefer point to point measurements,im not a great fan of something that dosent contact the copper cable,.take non-contact voltage testers,sometimes they work sometimes they dont !which in its self would be a safety issue.

we all like the big toys,but unfortunatly we dont like the affordibuility .

[multimeter]

Re: How do I find out the rating of an SMD fuse?

going back to OP,budm pointed out how to do it it.but when you take the measurement,ensure you have the brightness set high on the tv,to get the highest amp reading as it will draw more on the inverter.

you can solder new fuse by piggyback right on top of the old one if you want.

looking at my paperwork "s" is related to 4a,sounds about right to me.

these do fail quite often,they get designed to close to the actuall amp draw and fail with no other problems.

[Kiriakos GR]

Re: How do I find out the rating of an SMD fuse?

complacent

Wrong selection of word due your own mindset.
I use as source of bragging rights the satisfaction that my customer feel after finishing my work, because this feeling will make him to trust me again in the future.

yes years down the line get something pricey and sexy when you have learnt the basics on the cheap stuff,still the same principle on top end gear,am i wrong?no.

One low end multimeter was enough before the pulses start jumping around in every tiny PCB.

Your denial to update your mindset about this reality it will just hold you back in comparison with others which are open minded and ready to adjust faster in those new changes.

its like giving a newly qualified driver a nissan skyline gtr,rather than a fiesta!

You lost the game here, even about making a blade sharp the Japanese were practicing for hundreds of years, every sector of the industry contains hundreds of small secrets, the test & measurement manufacturing have their own.
The comparison with cars is a huge fail here.
The true question here is if you are ready to discover what a better multimeter can do for you?

we all like the big toys,but unfortunately we dont like the affordability .

If you describe the reliable tools as big toys, you need to replace all your background of friends with better ones, which will contribute back to you one more positive influence regarding the realism that one successful repair man should have.

[multimeter]

Re: How do I find out the rating of an SMD fuse?

Wrong selection of word due your own mindset.
I use as source of bragging rights the satisfaction that my customer feel after finishing my work, because this feeling will make him to trust me again in the future.



One low end multimeter was enough before the pulses start jumping around in every tiny PCB.

Your denial to update your mindset about this reality it will just hold you back in comparison with others which are open minded and ready to adjust faster in those new changes.




You lost the game here, even about making a blade sharp the Japanese were practicing for hundreds of years, every sector of the industry contains hundreds of small secrets, the test & measurement manufacturing have their own.
The comparison with cars is a huge fail here.
The true question here is if you are ready to discover what a better multimeter can do for you?




If you describe the reliable tools as big toys, you need to replace all your background of friends with better ones, which will contribute back to you one more positive influence regarding the realism that one successful repair man should have.

then after all that,maybee you should set up your own website for people with a substantial bank balance,rather than running down the guys on here for showing an interest,and willing to spend what THEY can afford,on test gear,so THEY can learn?.

if spending your money on high grade test gear that isnt neccersary on tv repairs (most coming into a repair cost of normally less than 20-30bucks? for component level repair is your thing,then feel free,id like to see the website!

im a hobbiest tech on "here",and will remain so,and im happy to pass on usefull repair techniques to anyone who is willing to learn

if that is a crime then shoot me!,im sure most on here will agree with me.

i enjoy reading your posts,and they have been interesting and informative.

unfortunatly i dont have a gold credit card,along with most on here i expect.

people make do with what they got until a time they can buy different.

its not that people dont want the nice things,they just cant afford it


what did you start out with when you 1st started?......

01. a massive electronics lab with 3 of everything?

02. or a shed in the garden with an enthusiastic approach?

most will tick 02......

[Dang]

Re: How do I find out the rating of an SMD fuse?

I just want to know how to test my fuse . Thanks for the help guys, really much appreciated, Andy.

[Ltank]

Re: How do I find out the rating of an SMD fuse?

Hop this helps. SMD Fuse Code

[Dang]

Re: How do I find out the rating of an SMD fuse?

Hop this helps. SMD Fuse Code

Thank you.