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What is this component?

What is this component?

What is this component?


This is a Roland Amps Board Assembly 5100009354 in a Roland Amps KC-110.

The one of the jacks does not take input signal anymore and it makes a lot of static noise.

What I am trying to do is replace all the components on the board but I can't recognize one of the components.

Attached are the pictures and the component in question is circled in red.


RE: What is this component?

They could be ferrite cores.

RE: What is this component?

There are markings on the board by each of the components. What do the markings say?

It's not that old - Roland has a video from 2010 introducing it. It is from the period of time when poor quality electrolytic capacitors were being put into a lot of products, so if there are no other diagnostics available, I would start with those. The other components should still be OK. Also, be on the lookout for any on-board fuses. There are some that look like small capacitors; the board labeling will indicate them if they are there.

I agree with Compositepro that the large black parts are ferrites; the board should have an "L" prefix on a number next to them if the are. I don't know if ferrites can fail; only the wire passing through might have a failed solder joint or otherwise fractured, so there's no need to buy new ferrites.

RE: What is this component?

Thanks for the reply.

There is absolutely no marking on the component. It has a marking on the board next to the component (L252.) I don't think that helps much.

There is a similar marking (L252) on the board for a different component. It is for a jump wire.

I just ordered the capacitors.

RE: What is this component?

L is the code for an inductor, as 3DDave already pointed out. You have a wire passing through a ferrite, which is an inductor, not simply a jumper (which would use a J code letter).

RE: What is this component?

It's a ferrite bead. Here's an image of that component loaded onto an insertion machine strip.

The other one is likely a ferrite bead too, there are lots of different styles, some look like jumpers.

" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

RE: What is this component?

Thanks, I don't think they can fail.

RE: What is this component?

If something else in the circuit has failed you could be getting too much current through the beads/ferrites and saturating them so they aren't having the desired effect. This is hard to test or quantify on unmarked parts unless you pull them off the board for isolated testing. You might be able to remove them from the design and see if you notice a difference (but this also might let the blue smoke out too of the circuit...).


RE: What is this component?

Have you checked the integrity of the jack itself and possibly the cable that plugs into the jack? That is where I would start investigating at.


"It's the questions that drive us"

RE: What is this component?

There are a bunch of Roland schematics and service manuals at the below link. Maybe there is something in there similar to yours that you can use for troubleshooting.


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