Help identifying a SMD component.

[Spork Schivago]

Hello. I am working on an effect pedal for a guitar. I wasn't sure if I should of posted this in the audio troubleshooting / installation forum or here. I figured since I don't need any help in troubleshooting what's wrong with the pedal, I would post it here. I apologize if this is in the wrong place.

The owner used a transformer that was rated for a higher voltage than the pedal needed. He fried a component on the PCB. The fried component kind of exploded a bit and burned off all the markings. After spending some time, I've come to the conclusion that there are three other components of the same type on the board. I am having trouble identifying them.

They are blackish in colour and have a white and yellow band on them. I believe that the white band might be the cathode side and not a band per say. If I test the working components as diodes and have the black probe on my DMM on the side with the white mark, it shows a reading of some wheres around 5.6 Mohm's. If I switch the probes, I get O.L.

Can some one help me identify these and perhaps find a place that sells them? I cannot find anything on the net. I am attaching a picture of the components. Thanks.

Spork Schivago

[Wrog]

Re: Help identifying a SMD component.

Can you include a picture of the surrounding area? Maybe there are reference designators that might give an indication of what they are...

[Spork Schivago]

Re: Help identifying a SMD component.

I will include a picture of the surrounding area. I did not see any reference designators though on the PCB. I hope this is enough area. If not, let me know, I will take another picture zoomed out a bit. Thanks.

[Spork Schivago]

Re: Help identifying a SMD component.

It's been a few days and I haven't gotten an answer. Should I try posting in the audio equipment forum? Or maybe try another website? Any suggestions on a different website where they might be able to answer my question? Just in case it might help, the effects processor is an EBS UniChorus Analog Signal Processing unit. Thanks.

[selldoor]

Re: Help identifying a SMD component.

You could try that - id agree that they are diodes and as you say the white ring is probably the cathode. The markings on these are not standardised so unless you could find someone with the same unit its almost impossible.
What you could do is post pictures of the whole board and we could try and trouble shoot the problem as a whole, looking at other components that might have been destroyed. Shot yourself in the foot a bit as 90 odd people have looked at it but could not identify the component so moved on. Can you change the heading as original poster?

[Evil Lurker]

Re: Help identifying a SMD component.

I want to say its some sort of heavy duty zener diode or a 1N400X series in an SMD package.

I have seen the 1N's in that package, perhaps the yellow band is a voltage rating?

Yank em off and do a reverse voltage test on them.

[Spork Schivago]

Re: Help identifying a SMD component.

You could try that - id agree that they are diodes and as you say the white ring is probably the cathode. The markings on these are not standardised so unless you could find someone with the same unit its almost impossible.
What you could do is post pictures of the whole board and we could try and trouble shoot the problem as a whole, looking at other components that might have been destroyed. Shot yourself in the foot a bit as 90 odd people have looked at it but could not identify the component so moved on. Can you change the heading as original poster?

I can post pictures of the whole board. I'm not too certain if I can change the heading. If I can, what should I change it to? I will post the pictures after Star Trek Next Gen is over with (in about an hour). Thanks

[Spork Schivago]

Re: Help identifying a SMD component.

I want to say its some sort of heavy duty zener diode or a 1N400X series in an SMD package.

I have seen the 1N's in that package, perhaps the yellow band is a voltage rating?

Yank em off and do a reverse voltage test on them.

Okay. How do I do a reverse voltage test on them? Thanks.

[budm]

Re: Help identifying a SMD component.

You indicated that you use the DMM to test the Diode, did you use the Ohm function or the Diode test function to test this unknown device? Just want the verification.
Also, is the non-banded side connected to the circuit ground? waht is the make and model of this Effect pedal?

[Spork Schivago]

Re: Help identifying a SMD component.

Here are some pictures of the board. I've included a semi-close up of the area where the burned part was. I have unsoldered the bad part from the board.

[Spork Schivago]

Re: Help identifying a SMD component.

You indicated that you use the DMM to test the Diode, did you use the Ohm function or the Diode test function to test this unknown device? Just want the verification.
Also, is the non-banded side connected to the circuit ground? waht is the make and model of this Effect pedal?

I used the Ohm function on the DMM because I do not have a Diode test function.

As for the non-banded side being connected to the circuit ground, I do believe it is. I'm still learning about this stuff so I'm not certain if I tested it right. What I did was put the DMM on the Ohm function and touched one probe to the negative part on the DC jack (where the transformer end plugs into) and touched the other probe on the non-banded side of the unknown component. The meter read 0.000 ohms. If I put the probe on the positive side of the jack, I would get an O.L. reading. Was this the correct way of testing?

The only thing the pedal says is UniChorus Analog Signal Processing EBS. Under that, it says TRUE BYPASS and there's a switch for the mode. Flanger, P.M. or Chorus. There are two nobs, one for DEPTH and the other for RATE. Here is a link to a website that sells it: http://www.musiciansfriend.com/ampli...ocessing-pedal

Hope this helps and thanks for the help {: -)

[budm]

Re: Help identifying a SMD component.

Is the band side of the same type of diode by the DC JACK connected to the center pin of the DC jack? So it has 3 same type of diodes on this board. The pictures are not clear enough for me to see the burnt section.

[Spork Schivago]

Re: Help identifying a SMD component.

I do not believe the band side of the same type of diode by the DC JACK is connected to the center pin of the DC jack. I used the Ohm function on the DMM and it shows O.L.

There are three of the same type of diodes now. Four if you include the broken one. I can only assume the burnt one was the same component as the other three. It's burned too bad for me to be certain.

[Duncanbest]

Re: Help identifying a SMD component.

Maybe
white-yellow
BYM 10-400

http://www.vishay.com/
search GL41G

[b700029]

Re: Help identifying a SMD component.

http://www.ebay.com/itm/50-SMD-Diode...-/280723441133

I think we have a match.

[selldoor]

Re: Help identifying a SMD component.

Wow Duncanbest - pretty impressive - did you know the Vishey Diode colour band codes - how did you find it. I tried a few searches on colour bands diodes etc etc etc but came up with nothing. Well done.

[budm]

Re: Help identifying a SMD component.

Great detective works Duncanbest! He can use 1n4xxxx series.

[Spork Schivago]

Re: Help identifying a SMD component.

Thank you guys so much! I guess the owner of the pedal decided to purchase a new one and said I could keep the old. I don't play guitar, I've only fiddled with one back in the day. I have friends though that play. Maybe I can fix it and sell it to them. Would any 1n4xxxx series diode work? Or should I find one with a 400v / 1A rating? Thanks again! I searched for a long time on the net and couldn't find anything!

[b700029]

Re: Help identifying a SMD component.

Yes, you'll need to find a replacement with at least 400V and 1A rating. 1N4004 seems to be OK although it has slightly higher thermal resistance.

You might want to think about why they decided to use that Vishay part over a 1N4004...

[smason]

Re: Help identifying a SMD component.

What kind of pedal is it? Some are worth it, some are a dime a dozen.