| Electronics > Beginners |
| help replacing a resistor |
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| tteknulp:
--- Quote from: schmitt trigger on April 24, 2019, 07:16:35 pm ---Brown, black, red, gold: 1000 uH, 5% inductor. Similar to this: https://www.digikey.com/product-detail/en/epcos-tdk/B82144A2105J000/495-5614-1-ND/4245953 The rated DCR, for the component I've shown are 3.8 ohm max. So you could assume that if YOUR inductor will have a similar resistance value. --- End quote --- It looks an exact match thanks for the link --- Quote from: tteknulp on April 24, 2019, 09:31:52 pm --- --- Quote from: ArthurDent on April 24, 2019, 06:17:27 pm ---There are a couple of ways to check the inductor to see if that is your problem. First, with the unit unplugged, check the resistance between the two leads of the inductor as others have suggested. The reading of a good inductor of that size should be essentially zero ohms, or the same readings on your meter set to ohms with the leads shorted together. If the reading is higher, the inductor is probably bad and any higher resistance readings you see are from the other parts of the circuit. Second, with the unit powered up, carefully measure the voltage on either side of the inductor to ground or the common reference. The voltage on both sides of the inductor should be almost exactly the same. If the inductor is in the power line going to the display and you have say +5 or some value on one side and 0 volts on the other side, the inductor is open and has to be replaced. If it is open (bad) and in a supply line, the value probably isn't that critical and if you can find another small inductor of any value close to it, that should work to clip into the circuit to see if it works. There is also a chance that if the inductor is open that something else like a shorted capacitor across the supply line caused it to fail. The inductor may be the reason the display is out but it may not be the ultimate cause of the problem. As with any testing, be careful not to accidentally short anything out and make the problem worse and more expensive to have someone else repair. If there is any chance of getting near mains voltage, or you are uncertain what to do, definitely have someone else with adequate knowledge do the checking. --- End quote --- Will do as stated thanks very much for information. --- End quote --- |
| digsys:
ok back. Some good advice, especially from ArthurD. There should be NO reason for the Inductor to fail, if it does read as such, in which case - there WILL be a fault down the line - eg a cap etc is the most common. IF it has failed, then replacing it and just "switching on" is a bad idea. I'd solder a couple leads and put a ~1A fuse, Inductor and say 0.1R resistor in series, off the board and easy to get to, then power on and check currents or a POP :-) if the fuse blows. IF that looks ok, and everything "seems" to work ok, I'd possibly put it down to a random failure. They do sometimes happen. See how you go |
| tteknulp:
Very good advice, will do definitely Thanks |
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