Repairing my cable tester. Bad resister?

[roveer]

I've got a cable tester that has a thing called a super injector. You put it at the other end of the cable you are testing and it communicates with the test set.

It's been giving an error saying that pin 3 is not connected. The test set works just fine (I got another injector to verify). I opened it up and found what looks like a cooked resister (or is it a diode?). It's a board mounted device marked 2430



I googled around and couldn't seem to find this component. Can someone give me some advice on where I could find it or what I could substitute. This pcb fits in a fairly large box so there's lots of room above those pads.

Thanks so much. Looking forward to doing my first board level repair.

Roveer

[R_J]

Re: Repairing my cable tester. Bad resister?

It's a resistor, check it with an ohm meter, 243Ω
It is likely ok and something else is bad
Lots of them at digikey https://www.digikey.com/products/en/...=1&pageSize=25 measure the physical size to get the correct one

[roveer]

Re: Repairing my cable tester. Bad resister?

It's a resistor, check it with an ohm meter, 243Ω
It is likely ok and something else is bad
Lots of them at digikey https://www.digikey.com/products/en/...=1&pageSize=25 measure the physical size to get the correct one

All the other similar resistors are measuring .325-330 but that one is open. Thanks for the digikey info. I'm going to try and get a replacement and see what happens.

Roveer

[R_J]

Re: Repairing my cable tester. Bad resister?

Something caused it open so check if there is something shorted that is connected to that resistor. Without seeing both sides of the board its hard to say what caused it.
Or was there external voltage on the cable being tested?

[roveer]

Re: Repairing my cable tester. Bad resister?

Something caused it open so check if there is something shorted that is connected to that resistor. Without seeing both sides of the board its hard to say what caused it.
Or was there external voltage on the cable being tested?

I think there are 8 of these resisters around the RJ45 so it's possible the stray voltage came in from the external connection. I will look to see if I can follow the traces and check components on either side. This device isn't critical, I long ago replaced it. I'm using it more as a project to teach myself a little about diagnosis/testing and component level soldering. Fortunatly this particular component is just big enough to not require microscope or heat gun.

How can I determine the wattage of that resister? Looking through the digikey listings there are many different values.

Roveer

[R_J]

Re: Repairing my cable tester. Bad resister?

I doubt the wattage is that critical, I would make sure the length is correct to fit the pads. The wattage won't be that high, likely 1/4 watt

I will take a guess based on the transistor (sot23-3) that the resistor length is 3mm

[roveer]

Re: Repairing my cable tester. Bad resister?

I received my resistors today from digikey. Tonight I soldered in the replacement and the unit now works. My first board level repair.

I learned that I need something to hold a magnifying glass and a better soldering iron. Eventually I'll probably get a Weller or a Hakko. I want to be just like Louis!

Thanks for the help.

Roveer