Component identification

[halfloaf]

Hi all,

I have a component I need to replace on a PCB of a very old custom graphics card for an SGI machine. I've managed to take a picture of an intact one, does anybody know what this is and how I can spec a replacement?

The part looks like a very small fuse but with a metal half loop cage around it. The cage is soldered to the PCB as well as the ends of the insulated section. On the broken part I can see a copper wire connecting the two ends. The metal cage is just that, metal. L511 on the board

Thank you.

[petehall347]

Re: Component identification

L is designation for a coil

[R_J]

Re: Component identification

I suspect it is used as a small filter, basically a wire coil with a ground shield around it, made by MuRata maybe?
https://www.murata.com/~/media/webre...ifil/c31e.ashx

[halfloaf]

Re: Component identification

I suspect it is used as a small filter, basically a wire coil with a ground shield around it, made by MuRata maybe?
https://www.murata.com/~/media/webre...ifil/c31e.ashx

Thanks! From googling it seems to be the MuRata feed through capacitor used as an EMI filter as you've suggested. Question is, how do I go about measuring the capacitance of the one on the board? They seem to come in a few pF ratings.

[R_J]

Re: Component identification

I don't really know, I doubt they are that critical, try measure the capacity from one end to the center.

[petehall347]

Re: Component identification

why do you suspect as faulty ?

[halfloaf]

Re: Component identification

why do you suspect as faulty ?

Hi, the other one on the board is smashed to bits. Seems like it was knocked, the one end has come off the board, the ceramic and coil winding have been broken as well.

[R_J]

Re: Component identification

The parts from digikey are only $1.00 each, get a couple different values and try them.

[halfloaf]

Re: Component identification

The parts from digikey are only $1.00 each, get a couple different values and try them.

Thank you for your help.

I've managed to source a replica PCB in non-working state, I'll pull one from the donor board as there are about 5 on each board. These aren't usually the culprits when these boards fail, it's most likely the old style IBM compression connectors that get damaged.

Failing all this I'll just buy a few new ones.

Thanks again.

Picture of broken filter below...

[Shane711]

Re: Component identification

I have a part I can not identify. It says XTL on the circuit board. Here are some pictures. Does anyone know what this is? I am guessing it is a crystal or oscillator. But if so I need to know it's value so I can order some. It has 3 legs.

[eccerr0r]

Re: Component identification

what's the bottom of the board look like, what's this being used in?

Three pin crystals are usually crystal filters, which are normally only found in radio equipment. There are some crystal resonators that are used in lieu of crystals for oscillators. This one appears to be 8MHz which is strange for radio use. What makes you think it's broken?

[R_J]

Re: Component identification

It's an 8Mhz 3 terminal ceramic resonator with built-in load capacitors
PDF for Murata brand https://www.murata.com/~/media/webre...lock/p17e.ashx

[Shane711]

Re: Component identification

Awesome, so glad I got some answers. Well it is on a main board for a GE microwave. The reason I suspect it to be bad is because it is located next to 3 resistors that get very hot. All the capacitors near the resistors are fried from the heat and after replacing all the capacitors on the board the display still flickers but before replacing the capacitors the microwave was completely dead. So I suspect this part is bad because I can confirm all the other parts are good. And I test all my capacitors before installing them for correct value and ESR. from what I can see online, this part is responsible for creating the microwaves but could also be the cause of the flickering display.

[Shane711]

Re: Component identification

I now need to know the value of the internal capacitor. Would help to know the manufacture as well. I guess the brand is Murata.

[R_J]

Re: Component identification

That part is the oscillator for the microprocessor ic It has NOTHING to do with creating microwaves. If you are getting any display at all the part is ok. The microwaves are created from the magnatron NOT from that ceramic resonator/crystal.
post pictures of the board and the model number

You really need to be carefull when working on microwave ovens, there is over 2 KILLovolts on the capacitor for the high voltage to the magnatron

[Shane711]

Re: Component identification

I know it does not create the microwaves but it might have something to do with the frequency that makes the magnatron work, anyway that is what I believe I read in the datasheet. As far as if the part is bad or not I will know in the next few weeks as I have a bunch of these microwaves to test on. You might be right about it not being the problem but I will figure it out no matter what part is bad.

[R_J]

Re: Component identification

It has NOTHING to do with the frequency of the microwaves either. The frequency is determined by the magnatron at approx. 2.45 Ghz.
If you do something wrong you could expose the people using this mwo to harmfull radiation.
These ovens need to be tested for proper operation (shutdown when door is opened) and have a leakage test done after working on them.