On 16 Sep 07 at group /sci/electronics/repair in article
(Bjarne) wrote:

I have a BOSS HC-2 hand clapper that is broken

The problem is that it makes crackling noise when I touch the pcb.
Since the audio connecters are wired to the pcb it crackles whenever
the cord is touched.

I have almost zero experience in repairing stuff but I want to learn,
and since it's not a very expensive item, I think it makes sense to
practice on it. Taking it appart it looked to me as at least of the
capacitors had leaked? Could that generate crackling noise?

I took this pictu

http://www.bgst.dk/pcb.jpg

What do I do?

I think, that's some glue (sometimes waxe) to fix parts and not caused
by leaked capacitors. It's not a perfect but cheap/common method to
prevent failures from vibrating parts or changing values/adjustments in
some high-frequency application.

I don't think, that that's your problem. Look for could solder points,
bad (corroded) contacts, broken copper, cracks on the pcb...


Saludos Wolfgang


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Hi!

I have a BOSS HC-2 hand clapper that is broken

The problem is that it makes crackling noise when I touch the pcb.
Since the audio connecters are wired to the pcb it crackles whenever
the cord is touched.

I have almost zero experience in repairing stuff but I want to learn,
and since it's not a very expensive item, I think it makes sense to
practice on it. Taking it appart it looked to me as at least of the
capacitors had leaked? Could that generate crackling noise?

I took this pictu

http://www.bgst.dk/pcb.jpg

What do I do?

The solder joints on the wires look suspect. You might want to remove the
solder and re-solder them.

thanks for the replies. Unfortunately I couldn't find any other
problems. All the solder joints seems fine, and I couldn't find any
cracks in the pcb. I'm suspecting that the output jack connector
socket is the problem, so tomorrow I will try to solder the cord
directly to the pcb, to see if I'm right.

On Sep 15, 7:37 pm, Bjarne wrote:
thanks for the replies. Unfortunately I couldn't find any other
problems. All the solder joints seems fine, and I couldn't find any
cracks in the pcb. I'm suspecting that the output jack connector
socket is the problem, so tomorrow I will try to solder the cord
directly to the pcb, to see if I'm right.

If you carefully touch each component with an insulated stick,
something like a chopstick, and each wire, you should be able to find
out the area of the circuit board that is most sensitive. The
material in the photo looks like cheap hot glue which the manufacturer
used to hold down wires that might flop loose during the final
assembly.

H. R. (Bob) Hofmann

If you carefully touch each component with an insulated stick,
something like a chopstick, and each wire, you should be able to find
out the area of the circuit board that is most sensitive.

I did that, and maybe it seemed like the most sensitive part was a
Roland IC named BA662310A. But I could be wrong, since it was very
easy to bring out the crackle everywhere on the pcb. I should hardly
touch it with the chopstick. It wouldn't be the first time roland
made bad chips though.

Anyways, I probably have to buy another hand clapper. Thanks for the
all the good advises. I will remember those next time something
breaks.

and here is a pic of said chip:
http://www.bgst.dk/pcb2.jpg

"Bjarne" wrote in message
...

If you carefully touch each component with an insulated stick,
something like a chopstick, and each wire, you should be able to find
out the area of the circuit board that is most sensitive.

I did that, and maybe it seemed like the most sensitive part was a
Roland IC named BA662310A. But I could be wrong, since it was very
easy to bring out the crackle everywhere on the pcb. I should hardly
touch it with the chopstick. It wouldn't be the first time roland
made bad chips though.

Anyways, I probably have to buy another hand clapper. Thanks for the
all the good advises. I will remember those next time something
breaks.

As you will probably be buying a new unit, it can't hurt to experiment with
the one you have.

Just because solder joints "look good", that doesn't mean they are. And the
solder joints on that board don't look very good. I would unsolder and
resolder all the wires connected to the board.

Bjarne wrote:
and here is a pic of said chip:
http://www.bgst.dk/pcb2.jpg

can you show us a pic of the other side of the board in that area?

Ron(UK)

can you show us a pic of the other side of the board in that area?

That was almost impossible because the board was reflecting light and
so my cam couldn't focus. Maybe I can take a better one in daylight
tomorrow.

Here's the best one
http://www.bgst.dk/pcb3.jpg

Bjarne wrote:
can you show us a pic of the other side of the board in that area?

That was almost impossible because the board was reflecting light and
so my cam couldn't focus. Maybe I can take a better one in daylight
tomorrow.

Here's the best one
http://www.bgst.dk/pcb3.jpg

Well firstly try resoldering the pins on that chip. use a good magnifier
to inspect every joint on the board and resolder any that seem even
slightly suspect.

Ron(UK)

Well firstly try resoldering the pins on that chip.

The solder joints on the pins looked perfect to me. But they weren't.
I reheated the solder and now it works as it should I think.

Thanks for the help. It felt really good when I plugged it in and
realized that i worked again.