I found a fusable resistor that shows no reading in circut. Should show a reading?
Thanks Charles
Thanks Charles
Fusable resistor
- Thread starter tonyclark
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K9WG
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What do you mean no reading? It it measuring infinite or zero ohms? Most fusible resistors are very low in resistance.
It is a 1k ohm fusible it is still in circut and reads 0. Just like if you were to check a fuse that is blown, nothing. Should I unsolder one side and take a reading? There is another fusible resistor in circut that reads resistance.
It is a Fluke meter and it comes on but won't read anything. The schimatic shows the resistor right after the test lead jack to protect the rest of the circut. I think it might be blown.
Sounds like the fuse used in the current measuring mode. Measuring voltage in the current mode gets the fuse every time. Replace only with same type for continued protection. Usually a fast blow type. If the interior of the meter or the markings on the fuse are not present or readable the manual can be found online.
Mike
Mike
I have a service manual for it.
The resistor is blown.
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if a 1k resistor read 0 ohms, then it NOT the same as reading a blown fuse which would be infinity. the resistor, or most likely something else in the circuit, is shorted. sounds like you had it in the wrong position when tyring to take a reading and ran current thru the wrong portion of the meter. honestly if you can't troubleshoot it with the service manual, you would come out cheaper just buying another one off Ebay or somewhere. at times you will catch NIB Flukes for pennies on the dollar that someone purchased a case of them from government surplus. We got 10 Fluke 85 meters for less than 40.00 that way, still seal in US Army boxes!
WA1ATA
Member
1k ohm is a strange value for a fusible resistor. Are you sure that it is not a PTC (positive temperature coefficient) resistor? In many DMMs PTCs are used to protect the resistance measuring circuit from overloads when connected to live circuits.
When overloaded, the PTC heats up, and the resistance goes more than 100 times higher, thus limiting the current.
Charlie
Service manual says:: R1) Res., MF, 1K Fusible 2% Did a temp fix with another reg. 1K ohm resistor and it was working normal. Did not do any voltage test until I get the proper part.
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WA1ATA
Member
That's definitely a normal 1K resistor. MF probably stands for "metal film", which is commonly used in flameproof fusible resistors.
Ordered the resistors from Digikey should be here Monday.
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Let me guess, shipping was three times what the order was?
No $2.05 postage
Got the meter back together and working. Meter cost me the price of shipping $5.20 + $4.46 for the parts $9.66 total. Got an extra resistor just in case. My other meter is a Radio Shack 22-178.
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