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Doward said:Would a decent multimeter be able to check caps, without removing them from the PCB? As in, is there a certain ohm value or something that a cap should have? I've seen the 470mf and 1000mf caps, but am unsure exactly what a 'mf' is
Sirje31337 said:Yes, but only to tell if it's bad or good not to tell the uF rating. Just test the resistance of it. If it reads infinite it's good, if it shows low resistance it's bad. Hold the probes on there for a little bit though because it will have to discharge. And a mf is a Micro Farad.
joecool234 said:Ok, this is one of the few areas high school physics apply:
Add 'em said:I was under the impression that physics and its governing laws applied to the entire universe. Maybe I was mistaken...
joecool234 said:The reason I said "high school" was that NY state's regents high school course is just flat out wrong. Anyone that took physics in NY can attest to that...I was taught that current flows from - to +.....left hand rule instead of right hand rule....should I go on?
joecool234 said:The reason I said "high school" was that NY state's regents high school course is just flat out wrong. Anyone that took physics in NY can attest to that...I was taught that current flows from - to +.....left hand rule instead of right hand rule....should I go on?
Doward said:The screen itself is rather shaky - like the vertical lines are having trouble staying 'vertical' LOL
It gets worse, the more 'data' on the screen.
It's a 53" Sony KP53V45 projection screen, and has been unplugged for about 3 days now. I know they can hold a heck of a bolt, so I'm being careful with it.
I'm picking up a service manual in the next couple of days - I have a feeling a couple of caps on the board around the frame IC are bad, though - just never tested caps before
Duh... current DOES flow from negative to positive. Please, go on.joecool234 said:The reason I said "high school" was that NY state's regents high school course is just flat out wrong. Anyone that took physics in NY can attest to that...I was taught that current flows from - to +.....left hand rule instead of right hand rule....should I go on?
joecool234 said:The reason I said "high school" was that NY state's regents high school course is just flat out wrong. Anyone that took physics in NY can attest to that...I was taught that current flows from - to +.....left hand rule instead of right hand rule....should I go on?
joecool234 said:The reason I said "high school" was that NY state's regents high school course is just flat out wrong. Anyone that took physics in NY can attest to that...I was taught that current flows from - to +.....left hand rule instead of right hand rule....should I go on?
plot said:current DOES actually flow from - to +... most technitions are taught this way too, and you'll see it on alot of schematics at certain websites... it's known as "Electron Flow"
Sirje31337 said:Yes, but only to tell if it's bad or good not to tell the uF rating. Just test the resistance of it. If it reads infinite it's good, if it shows low resistance it's bad. Hold the probes on there for a little bit though because it will have to discharge. And a mf is a Micro Farad.
gee said:Electrons do flow from negative to positive. But as long as you're not working with electrons themselves (designing transistors or whatnot...) it doesn't matter at all.
Anyway, to the thread starter... to check if a capacitor is bad, here's my way of checking:
1) remove it from the circuit first!
2) verify if it's shorted using a DMM
3) measure capacitance using a DMM, LCR meter, or whatever you have.
4) bring it up to its rated voltage and measure the leakage current.
5) reinstall if it's good.
Anyhow, what's wrong with the TV? the "sci.electronics faq" on repairfaq.org has an excellent guide on how to fix them.
If you're working in a factory when you've got boxes and boxes of these parts and you're getting paid for your time, then replacing it makes a lot of sense.aL Mac said:this is ridiculous I think.. if you are going to remove it just replace it..They are cheap. it's not even worth the time of testing it, especially if you may make a mistake and not replace it if it's bad.
ya know... you guys have made a mess of this thread. start a new thread for the - to + debate!
and do you know how many times i have posted a question on a forum, and someone replies saying, "hey- wouldn't it be easier just to blah blah blah?". yeah of course it would be. but i wouldn't be here asking this question if i wanted to do it the easy way.
and i know you guys know how it feels to fix somethng. especially something so complicated...
and how do you learn how to do things unless you do them?? he should test the cap! then he'll know how to from now on. it's not a waste of time if he's learning something!
can't someone just provide him with some help?
aL Mac said:this is ridiculous I think.. if you are going to remove it just replace it..They are cheap. it's not even worth the time of testing it, especially if you may make a mistake and not replace it if it's bad.
Kerri Ann said:and do you know how many times i have posted a question on a forum, and someone replies saying, "hey- wouldn't it be easier just to blah blah blah?". yeah of course it would be. but i wouldn't be here asking this question if i wanted to do it the easy way.
if you want to quote me, leave it in it's context. i wasn't aiming my comment at you. i was simply saying that many times when I ask questions about things, i receive advice on how to do it a different, easier way. but many times i asked the question because I want to know how to do whatever it is i'm trying to do, and why it works the way it works.joecool234 said:I love how a simple anecdote results into a completely off-topic rant.
chances are, the caps you find inside a television set aren't available at radio shack... you'll probably end up placing a digikey order.aL Mac said:It's not that expensive.. probably not even at radio shack.. It will only cost a few cents and probably less time to go to radio shack and buy a capacitor. now if you had 50 to test that might be different but if it is just one in question just go replace it. It is the sure way to do it.
gee said:chances are, the caps you find inside a television set aren't available at radio shack... you'll probably end up placing a digikey order.
But before fingering bad capacitors, an understanding of the circuit that the cap is in is needed. The http://www.repairfaq.org site offers an excellent guide on repairing TV sets, and using this the thread starter should be able to track down a certain section of the TV that's causing grief.
aL Mac said:It's not that expensive.. probably not even at radio shack.. It will only cost a few cents and probably less time to go to radio shack and buy a capacitor. now if you had 50 to test that might be different but if it is just one in question just go replace it. It is the sure way to do it.
Whatsisname said:Ok, So you think a cap is bad. You remove it. It's fine. You have two options:
1) Put it back in.
2) Go to radioshack, buy a new one, put the new one in, throw away the perfectly good old one.
2 is a better option to you?
aL Mac said:I'm sorry you said "it's fine" I'm glad you are omniscient.
I would think you'd need to make your own circuit and have an oscilloscope to really test a capacitor.. no? So go blow several hundred dollars, get yourself some equipment and then buy yourself several more parts to build a circuit and you can test all the capacitors you want. Or.. you could of taken a 5 minute trip to the store bought some assorted parts that every electronics hobbyist should have laying around and just replace the capacitor in question.
Whatsisname said:but the charge carriers are negative so it goes plus to minus at the same time depending on how you're looking at it
things like this are why ME > EE