ESR meter for a novice

[sam67]

Hi guys been looking at this and wondered what your thoughts were

http://www.peakelec.co.uk/acatalog/jz_esr70.html

I am only just getting started as said in an earlier post .

I want to get involved in diagnosing problems with computers and have read about bad capacitors ,so i thought i would try and get a few handy tools to start me off ..

Would the above meter be reliable when testing for a bad capacitor out of the board as well as on the board ?

Also do all capacitors have the right rating on them so that when you hook it up you can tell whether it is in spec or not..Also i have read that you have to sometimes discharge a capacitor before testing ..This meter says it does it for you ,is that correct ? and would this meter be all that i would need to start fault finding bad caps on motherboards and psu's..

I am also looking at other meters that will aid me finding other faults on mother boards and psu's .. Are there any meters on that same site that i could also use..I want to learn as much as i can but like i say i am a novice but love stuff like this (only wish i'd learned years ago..better late than never lol).

Would love as many recommendations as possible for trouble shooting mother boards ..

Best

sam

p.s please take it easy with me guys I really would love to do this and have time on my hands to get stuck in.

[hardwareguy]

Re: ESR meter for a novice

Looks like a nice meter. It seems to do more than the Bob Parker meters.... it not only discharges but it tells you the capacitance.

[Krankshaft]

Re: ESR meter for a novice

You have to hit the test button each time you test a cap. If the cap is in circuit you're gonna need an extra hand . Alligator clips are useless in circuit you need probes.

You'd have to buy the third hand kit also to make it workable when testing caps in circuit which you will be doing a majority of the time.

[sam67]

Re: ESR meter for a novice

Hi Guys, so will this atlas discharge any caps in a computer and psu?

Cheers

sam

[hardwareguy]

Re: ESR meter for a novice

See if you can download the manual....it might have a limitation on how much voltage can be on the cap.

It will almost certainly discharge caps in the low voltage side but as for the input caps, I'm uncertain.

[sam67]

Re: ESR meter for a novice

Hi There,

I have had a look on there site at the bottom of that page in the link ,and it just tells you it discharges the caps ..not sure what v though there is 2 links there that open up telling you the specs..Not really sure what all the specs are as i am a novice but would like to get hold of a good ESR meter to learn..Just don't want to shell all that cash for some one on here to say it is not up to scratch..

Any advice appreciated guys..

sam

[sam67]

Re: ESR meter for a novice

Just looked again and it says if the voltage across the capacitor is greater than 50v then it will not discharge the capacitor ,you have to manually discharge a capacitor yourself...What the highest caps in a pc and psu in volts..

cheers

sam

[hardwareguy]

Re: ESR meter for a novice

400V or so....with a mains voltage of 240V that's about 340V DC on the cap. (or caps if its two 200V units in series...each cap in that case will have 170V on it)

Most of the time these discharge on their own.

[Krankshaft]

Re: ESR meter for a novice

I'm also sure unlike Bob's meter where replacement parts are available and are through hole.

Replacement SMD ICs for the Atlas should you pop one connecting onto a HV cap will be nonexistent.

[sam67]

Re: ESR meter for a novice

So guys would most recommend getting Bobs Esr meter ,if so i would prefer it to be already assembled...What the best way to discharge a larger capacitor..I did read some where that you can do it with a resistor ..How would you do that correctly when it's already on the pcb ..Is there a how to guide anywhere showing you...Like i say i am a novice but am willing to learn as this interests me ..

Unfortunately there is no where near me where i can go and learn ..It's either look up on the net or try to find videos of how to's.

sam

[i4004]

Re: ESR meter for a novice

>Replacement SMD ICs for the Atlas should you pop one connecting onto a HV cap will be nonexistent.

what do you mean?
did peak went out of business so they can't fix it?

-----------------
you have a guide on discharging in repairfaq....
http://www.repairfaq.org/sam/captest.htm#ctsdc

>It's either look up on the net or try to find videos of how to's.

correct, but inputting "discharging capacitor" in google has good results right there on the top, so why not search first, and if you can't find it, ask here.
learning to find data is most important for learning.

don't expect others to do all your work for you.

[Krankshaft]

Re: ESR meter for a novice

They do offer it assembled but assembly isn't that difficult.

It's good soldering practice and helps you grasp the mechanics of installing components during servicing. Which is why you want it right?

Peak is just like Vizio I don't stand behind a company who refuses to divulge servicing information and sell parts.

If they won't sell parts they should at least protect it up to 400 volts.

[sam67]

Re: ESR meter for a novice

>Replacement SMD ICs for the Atlas should you pop one connecting onto a HV cap will be nonexistent.

what do you mean?
did peak went out of business so they can't fix it?

-----------------
you have a guide on discharging in repairfaq....
http://www.repairfaq.org/sam/captest.htm#ctsdc

>It's either look up on the net or try to find videos of how to's.

correct, but inputting "discharging capacitor" in google has good results right there on the top, so why not search first, and if you can't find it, ask here.
learning to find data is most important for learning.

don't expect others to do all your work for you.

sorry did not expect anyone to do the work for me ? i have looked on the net ,you tube etc but i don't fancy putting a screwdriver on top of a capacitor like some say and show on the net to discharge a larger cap..i am trying to find the correct way..Knowledge is good when you know how to ! Every one has to learn some where but i guess some people don't like being helpful!

I know a bit about cars and help others on car related issues on auto forums ,like i say knowledge is good when you know how but some people don't like to share that knowledge .

I prefer to try and ask people who do this the right way rather than the wrong way ..After all electronic parts can cause a nasty zap or kill.

Thanks any way.

sam

[Krankshaft]

Re: ESR meter for a novice

A high ohm high wattage wire wound resistor is the way to discharge a HV filter cap without the fireworks show. It's gentler on the cap too.

The screwdriver discharge which shorts the cap out instantly can sometimes damage the cap.

Most designs have a bleeder resistor that drains the cap shortly after the PSU is unplugged anyway. But occasionally the bleeder can open leaving the cap charged.

[sam67]

Re: ESR meter for a novice

Hi Krankshaft,

Thanks for the response..i think i might end up going with bob's meter but will have to wait till after the holidays now ,also it allows me to learn a bit more before i go out and buy all sorts of gadgets and not know how to use them correctly.

I stumbled across this forum and it has intrigued me and got me wanting to learn things mainly for computer repair..As stated above i am mechanically minded when it comes to working on cars but electronics is a whole new ball game..

Best

sam p.s just seen your reply to the cap discharge ,thank you for the response..

Also i4004 thanks for the bad caps link on my other thread...Don't think i was referring to anyone on here who has replied when i say they don't want to share the knowledge ( this was what happened when i searched previously before finding this site ).

[i4004]

Re: ESR meter for a novice

the thing is that usually you won't be discharging hi voltage caps, mainly because you probably won't be repairing primary side of psu, and then even if you do, those caps are usually ok, and then if not, you can measure the voltage there first and then if you see any you can discharge it etc.

so you don't have to worry about it too much, just be carefull.
discharging is more important when working on tv-sets, for mobos chances are it's all discharged allready...and voltages are up to 12v on mobo...

[sam67]

Re: ESR meter for a novice

Thank you i4004 it is much appreciated...

I am currently watching a similar pc to the one i already have on ebay that is currently not working and is going really cheap..Was thinking of getting it so i can have a play around so to speak.Was also thinking of buying one that does work just a cheap one..Then recap it just to see if it fires back up again which would at least tell me whether or not i capped it right ..I think it's better than just buying a motherboard on it's own to check..At least i get to see it work before and after with a cheap pc..

Will need a new soldering kit also..I do have one but the iron is only 30w and the gun is 100w so i guess i need to look for a 60w like mentioned on the caps lab link that you so kindly directed me to ..

Thanks

sam

[i4004]

Re: ESR meter for a novice

yes, that makes sense, if you can't find some old pcs at your local recycler or so....

[sam67]

Re: ESR meter for a novice

Hi guys i have been looking around for typical ESR values ..I found this chart apparently by Bob parker.. http://www.your-book.co.uk/design/esrchart.htm

Is this guide useful for comparing a cap i.e say i have a 1,000uf at 25v does this mean i would be looking at no more than 0.08 ohms for a cap that's just in spec like on the chart using an ESR meter ? How do you guys know the maximum ESR that it should be when the cap specs are not on that chart ?

Been reading loads and looking at various meters and got a motherboard on it's way for testing and practice soldering caps

No point in me buying a ESR meter if i don't understand it properly (hehe)..

I know you could check a new cap of the same spec and compare but the new cap could also be out ( will happen i guess) or i need to check before i buy a new one .

The ESR70 i was looking at in my first post at the beginning of this thread says you can test in circuit, but if its in parallel then i would have to at least desolder one leg of the cap that i am testing to get the right ESR am i correct? Also if i did go with the ESR70 (as i am from the uk so would be easier to deal with them) would i be able to add a couple of pins to the croc clips so that i could try in circuit testing or would they mess with the ESR value..

You see i can visually tell when a cap don't look right but that does not mean a cap that shows no sign of leakage or bulging is in spec..

Now this is why i would like a ESR meter but also be able to use it correctly to distinguish a good cap from a bad cap...the ESR70 also shows a rough value guide in there user manual but that seems different to the one bob has..So how do i successfully get the right ESR value without having to come on here and ask one of you guys

Sorry guys if i seem to be repeating myself but i am eager to learn and get the right tools so i can check caps on PCS and PSUS.

Thanks in advance.

[Bob Parker]

Re: ESR meter for a novice

Please read this page from the notes which were supplied with the Dick Smith Mk2 ESR meter kits:

"If you're getting the idea that it's tricky to identify defective electrolytics, relax! Experience has shown that in almost every case, a capacitor's ESR needs to rise to at least 10 times its normal value to cause a circuit malfunction. Often, you'll find that it's risen to >30 times its normal value, or is so high that the meter just displays '- ' (ie, >99 ohms).

So, with few exceptions, the electrolytic capacitor(s) causing a fault will be very obvious. It's for this reason that the front panel figures don't need to be extremely accurate or complete. When you encounter an electrolytic whose value or voltage isn't on the chart, it's sufficient to assume that its ESR should be similar to that of a capacitor adjacent to it on the chart.

If you have any doubts, it's best to compare the meter's reading on a suspect capacitor with that of a new capacitor of the same value and voltage rating."


For your info, the ESR figures chart you're referring to is out of date. A later one which is closer to typical figures for current generation electrolytic capacitors is at:

http://members.ozemail.com.au/~bobpar/2003esrchart.txt


Merry Christmas to most of the people here.