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SMD component identification !

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aljamri

Member
Hi again,

Attached is a photo for a similar component to a blown one in a faulty card I'm trying to repair. As an prehistoric technician, I'm not much familiar with SMD so, I do not know what are these two components.

I do contact EBCOS company and amazingly, the swift reply me, the yellow one is " tant chip capacitor" when I asked about its value and the identity of the black component, they gently excused that they can not help me.

Any body can help for the value of the yellow capacitor and the identity of the black one.

Thanks
 

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aljamri

Member
Thanks for your help, for the black one, similar idea came to my minde, but the 2N diverted the whole things.

Is there any problem -except for the space- to replace them with the ordinary snap capacitors.

Thanks again.
 

justDIY

Active Member
colin nailed the values, both are tant caps, and the line indicates positive, unlike the line on a diode or aluminum electrolytic cap which indicates negative!

without seeing more of the board, can't tell you what an appropriate replacement, other than the exact same thing, would be. sometimes tant are used because of low esr, high frequency, etc. sometimes they're just used because they offer high capacitance in a small size.
 

Pommie

Well-Known Member
Most Helpful Member
colin nailed the values, both are tant caps, and the line indicates positive, unlike the line on a diode or aluminum electrolytic cap which indicates negative!

Isn't it weird though that the negative end connects to the positive rail in a bridge rectifier.
9018-brect.gif


Just kidding.:D

Mike.
 

noptical

New Member
Hi again,

Attached is a photo for a similar component to a blown one in a faulty card I'm trying to repair. As an prehistoric technician, I'm not much familiar with SMD so, I do not know what are these two components.

I do contact EBCOS company and amazingly, the swift reply me, the yellow one is " tant chip capacitor" when I asked about its value and the identity of the black component, they gently excused that they can not help me.

Any body can help for the value of the yellow capacitor and the identity of the black one.

Thanks

Hi
You can find tantalum caps in 10packs on ebay and they're very cheap.
 

colin55

Well-Known Member
the line on a diode indicates negative

The line on a diode indicate cathode (k) (kathode) NOT NEGATIVE - the cathode end of the diode may be connected to the negative rail or the postive rail of a circuit (or anywhere in-between), but the black or silver or red stripe or indent or dot or chamfer or symbol on a diode ONLY INDICATES THE CATHODE. Nothing else.
 

Sceadwian

Banned
However in order for a diode to pass current the cathode has to be negative in relation to the anode. Thinking the diode cathode itself actually represents a negative voltage is a bad habit to get into like I think Colin was trying to say.
 

rob001

New Member
About Tantalum Caps

colin nailed the values, both are tant caps, and the line indicates positive, unlike the line on a diode or aluminum electrolytic cap which indicates negative!

without seeing more of the board, can't tell you what an appropriate replacement, other than the exact same thing, would be. sometimes tant are used because of low esr, high frequency, etc. sometimes they're just used because they offer high capacitance in a small size.

How do you know when a tantalum cap goes bad? What's a good testing method?
When ever I put my meter on continuity and go touch a tantalum, it beeps. I thought that meant there was a short, until I noticed it'll do that on working boards too, which left me confused.
Ceramic caps are easy - they usually fail shorted. Just lift a row of them one at a time and test them until you find the bad one. But tantalums? I'd like to know more about this mysterious device. Do they fail often?
 

Sceadwian

Banned
Tantalums are generally intollerant of votlages over their rating, moreso than other cap types. I think they fail short circuit as well, not sure why you would get a continuity reading.
 

colin55

Well-Known Member
You have to put your meter on a 10u electrolytic and see if it beeps on continuity. Then put the probes on a 10u tantalum and see if it beeps.
This way you are working out the characteristics of the CONTINUITY section of your multimeter.
I have had enormous problems with tantalum capacitors in TV sets. They go short-circuit. It may be due to over-voltage or merely a fault in a batch from a particular manufacturer.
 

rob001

New Member
You have to put your meter on a 10u electrolytic and see if it beeps on continuity. Then put the probes on a 10u tantalum and see if it beeps.
This way you are working out the characteristics of the CONTINUITY section of your multimeter.
I have had enormous problems with tantalum capacitors in TV sets. They go short-circuit. It may be due to over-voltage or merely a fault in a batch from a particular manufacturer.
Here is an example of a nightmare I had that ended up in having to buy another motherboard. I had a Sony laptop, no power. Spotted a cracked ceramic cap in about 30 seconds. Removed it, tested it to confirm it was shorted. Replaced it with a good one. Still no power. Started probing around and noticed meter would beep when I probed tantalums too. First time I ever did that, so I thought that one of them may have been bad. About 10 tantalums later, that "short" remained. Of course, none of those tantalums would beep when tested out of circuit. Subsequent tests in working boards have showed the same "short". I know I need a better meter, but still - this was starting to frustrate me.
So, to really test a tantalum, should I just remove it from the circuit and check continuity? If it beeps replace? I have a dark infrared rework station, so I could easily remove several components in a short time. It just seems like a lot of work to have to do. I'm wondering if I could use a digital capacitance meter to test tantalums. I'm thinking about getting the capanalyzer.
What problems would a laptop motherboard typically exhibit when a tantalum cap goes bad? I guess one way to simulate a bad tantalum would be to short one by soldering leads to each end, then observing it's effect on the circuit. I plan to try that with some salvage boards some time this week.
I have had many unresolved cases in which a board power on, then shuts right off. In most of those cases I have confirmed that the GPU, maxim/isl chips and fets were not at fault.
I just ordered a kill a watt meter. I'm hoping to use it to observe the current draw of a working board and establish profiles to use with non working boards. Then, isolate (by temporarily disabling) various sections of the power rail.
 
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Sceadwian

Banned
If the cap went partially bad you might have trouble spotting it, it may appear to work perfectly normal at lower power or low frequencies and then short out at higher power/frequencies, you may not have punched all the way through the dielectric, just nicked it in one spot.
 
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