Author Topic: Weird SMD resistor marking  (Read 1462 times)

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Offline FuzzlesTopic starter

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Weird SMD resistor marking
« on: September 16, 2018, 07:15:38 pm »
Hi everyone !

I am currently repairing an inspection machine (Rothenberger Modul Pipe 25/16 https://www.rothenberger-russia.ru/f/iblock/f18/roscope_2000_modul_pipe_25_16_komp_schema.pdf)

A crack in the plastic case let some water get inside so the PCB was completely oxydated.

I cleaned up everything but it seems that one resistor was damaged : a big 2512 SMD package between the power input terminal and the main voltage regulator.
I removed it and replaced it by a short-circuit just to test and the device is working fine.

This is a temporary fix, I would like to replace the resistor but it is weirdly marked "751C" on both sides. Never seen that before...

I thought it could be a "7510" but 751 Ohm is not really a common value ... and I don't even know what is the purpose of this resistor right after the input power connector. It does not seems to be a current sense. The Ohmmeter give me 10 Ohm in both direction.

Anybody have an idea about the purpose or the right value of this resistor (or maybe it's not a resistor) ?
(I have attached a picture of the component)

Thanks guys.
 

Offline JustMeHere

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Re: Weird SMD resistor marking
« Reply #1 on: September 16, 2018, 07:18:50 pm »
Pretty sure its a fuse.
 
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Offline perieanuo

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Re: Weird SMD resistor marking
« Reply #2 on: September 16, 2018, 08:03:40 pm »
yep, fuse. see littelfuse examples. it's an rearmable ptc fuse, easy to find specs.

Envoyé de mon HUAWEI NXT-L29 en utilisant Tapatalk

 
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Offline alsetalokin4017

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Re: Weird SMD resistor marking
« Reply #3 on: September 16, 2018, 08:11:48 pm »
Quote
I removed it and replaced it by a short-circuit just to test

 :palm:

The easiest person to fool is yourself. -- Richard Feynman
 

Offline FuzzlesTopic starter

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Re: Weird SMD resistor marking
« Reply #4 on: September 16, 2018, 08:23:59 pm »
yep, fuse. see littelfuse examples. it's an rearmable ptc fuse, easy to find specs.

Envoyé de mon HUAWEI NXT-L29 en utilisant Tapatalk

That was finally so simple  ;) ! Just after my message was posted, I thought "This really sound like a fuse !" but I never saw ones with this package.

Anyway thank you guys !

Great to see that the forum is always very reactive and helpfull.
 

Offline mikeselectricstuff

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Re: Weird SMD resistor marking
« Reply #5 on: September 16, 2018, 08:54:55 pm »
751 on a resistor (with no suffix) would be 750R  75x10W1- quite common to have codes like this, basically the same as the colour codes on TH resistors
Youtube channel:Taking wierd stuff apart. Very apart.
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