Could someone please help me identify this component on a PCBA

  • Thread starter carlos468
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Could someone please help me identify this and how to test it
Capture.PNG

it is inside a soundbar that someone brought to me to look at as sound was only coming out of one side everything else looks ok apart for these or at least one doesnt look good and has some heat marks.
any help would be appreciated.
 

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  • #2
phinds
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4148 is a diode. Look it up.
 
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  • #3
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cool thankyou :)
 
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...has some heat marks.
Those marks are soldering marks: the component was replaced at least once. It does not means that it is broken or cooked.
 
  • #5
jim hardy
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BUT - hand soldering that close to the component is risky. If you replace them leave about a half inch of the lead wires . Hold each wire as you solder it with needle nose plier or a hemostat to keep heat out of the glass package.

upload_2018-1-24_10-2-17.png
 

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Thankyou for all your replys sort of just got stuck on what i was looking at so after testing them they were fine but it turned out to be a cold solder joint only ever see one in a tv that i fixed but now seeing this can occur in anything thats i would say on the cheeper side.
But again thankyou sure i will be back to pick your brains :)
and jim hardy i will keep that in mind thankyou.

 
  • #7
rbelli1
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leave about a half inch of the lead wires
Those are MELF1 surface mount diodes. The do not come with leads.

BoB

1Mostly Ends up Lying on Floor
 
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  • #8
jim hardy
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Those are MELF surface mount diodes.
Aha ! Good name for them....
I haven't mastered surface mount yet so still use through-hole components. You can tell when i've fixed something , the parts i put in stick up like asparagus sprouts.

A couple months ago i had to fix my microwave oven. The intermittent loss of power got too frequent and Fair Anne lacks the strength to apply the requisite "Whack" .
To my astonishment the power supply board had a 'temporary tattletale' power on indicator i'd soldered in ten years earlier and forgotten - a through hole resistor and LED tacked in amid all those factory MELF parts. Deserving of an Ugly Award. But touching the transformer made the tattletale flicker , which led straight to a broken connection.

old jim
 
  • #9
CWatters
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I once knew a technician that could remove and replace a 160 pin quad flat pack SMD device using hand tools. On one occasion we asked him if he thought he could save the device being removed and clean it up so it could be tested in another rig! That was a big ask but he managed it.
 
  • #10
Averagesupernova
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160 pin device is quite a lot but I am not surprised. I did a lot of those with a pair of tweezers and a heat gun 25 years ago but probably half that number of pins. Have just enough solder on the pads, lay the part on and reapply the heat. When the solder flows, tap the PC board and the mechanical shock along with the molten solders surface tension will pull the part into place.
 
  • #11
jim hardy
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I once knew a technician that could remove and replace a 160 pin quad flat pack SMD device using hand tools.
That is impressive.

I hark from the days of the Zenith "Hand Wired Chassis" .
courtesy http://www.boxcarcabin.com/vintagetvs.htm
ZenithHandwired.jpg


“In times of change, learners inherit the earth, while the learned find themselves beautifully equipped to deal with a world that no longer exists.”
eric hoffer
Synchronicity ?
Just today, out of pure curiosity i took apart a junked 46 inch Sony flatscreen TV . Well actually i'd heard they have a replaceable lamp inside. This one lit up so i thought it might have a spare lamp for my 40 inch.
Wow! I'm obsolete.
The "Lamp" is an array of twenty-four 39 inch long cold cathode fluorescent tubes.
Oh well the power supply boards might interchange.

old jim
 

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  • #12
rbelli1
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factory MELF parts
Actually my expansion for the acronym MELF was a joke. It means Metal Electrode Leadless Face. It's those ones that look like through hole with the leads cut off.

The problem with them is that once the get rolling the tend to obey Newton's first law better than most objects. Either that or they're afraid of the soldering iron.

BoB
 
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  • #13
jim hardy
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Actually my expansion for the acronym MELF was a joke.
I figured it was. But i couldn't top it.....
 
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