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Projects => General Questions => Topic started by: yanko_mr on March 02, 2012, 05:32:20 PM

Title: Low volume mud bunny
Post by: yanko_mr on March 02, 2012, 05:32:20 PM
Hi, after a long break I am triying to fix my mudbunny, and I really dont know whats wring with it, in the off postition the bypass is working, on the on position is givinig me a really low signal.

I triple chack all the conections and values, and they look fine.

(https://lh5.googleusercontent.com/-5qK95CzstpA/T1EDHnoxLHI/AAAAAAAAAFM/xRoM0EiP_r0/s800/DSC_0034.JPG)

(https://lh4.googleusercontent.com/-6YdaGrcU0PQ/T1EDIaR9tBI/AAAAAAAAAFg/e72ZWr5PKp0/s800/DSC_0036.JPG)

(https://lh4.googleusercontent.com/-4UBhttxx-sk/T1EDH6z_ZiI/AAAAAAAAAFU/BSyl0T3Qn5s/s800/DSC_0035.JPG)

here some pics

Title: Re: Low volume mud bunny
Post by: mgwhit on March 02, 2012, 06:02:49 PM
I don't know if the photos are working for anyone else, but I'm not getting anything other than the thumbnail size.  If you can get some larger versions up there I'd be happy to go over them.  (And apologies if this is just a me-and-my-browser issue.)

Please let us know what version of the Mudbunny you built.  What parts/values did you substitute?  Which transistors did you use?

Can you measure and post the voltages on each pin of Q1, Q2, Q3 and Q4?

Did this board ever work and is now acting up, or has it been malfunctioning all along?

Title: Re: Low volume mud bunny
Post by: DutchMF on March 02, 2012, 06:07:39 PM
Thumbnails here as well, nice carpet though!  ;)

Paul
Title: Re: Low volume mud bunny
Post by: yanko_mr on March 02, 2012, 06:32:49 PM
I am sorry, jajaja

heres a link to the album,

https://picasaweb.google.com/102836483918153422220/Pedal#
Title: Re: Low volume mud bunny
Post by: marmaliser on March 02, 2012, 06:39:12 PM
What transistors ?  Mine was low on volume until I turned around all the bc550's to the opposite of the silkscreen.  Now it screams
Title: Re: Low volume mud bunny
Post by: jkokura on March 02, 2012, 06:44:25 PM
Yanko, I can't see anything from the shots you've given. I would suspect either a wrong value part or a backwards transistor(s) simply by your description. We would need some high definition macro shots of the top and bottom of the PCB if you want us to look at that.

Jacob
Title: Re: Low volume mud bunny
Post by: yanko_mr on March 02, 2012, 06:46:48 PM
2n5088 b29
Title: Re: Low volume mud bunny
Post by: yanko_mr on March 02, 2012, 06:56:41 PM
Ok this pics are better, sorry there wasnt enought light in the morning,

(https://lh6.googleusercontent.com/-o7OL4PkR388/T1EXTk_aQUI/AAAAAAAAAF4/HFx8ZQjLD2E/s800/DSC_0047.JPG)

(https://lh5.googleusercontent.com/-XuYeuGjr4vY/T1EXZHljVxI/AAAAAAAAAGA/aCCJfAzmfW0/s800/DSC_0045.JPG)

(https://lh6.googleusercontent.com/-_U3GsPHo9eQ/T1EXokJaFII/AAAAAAAAAGI/pPU6lyAOp9c/s800/DSC_0044.JPG)

you can also check the album i post before


thank you
Title: Re: Low volume mud bunny
Post by: mgwhit on March 02, 2012, 07:29:25 PM
I haven't seen any bad values so far, but the back of the board has some dodgy soldering.  I'd recommend touch up any of the ugly joints, and doing some basic continuity testing with a multimeter.  Good luck!
Title: Re: Low volume mud bunny
Post by: jkokura on March 02, 2012, 07:33:03 PM
Yes, I agree. You may have cold solder joints. It doesn't look awful, but it doesn't look really good either.

A key to a good solder joint is to use a well heated iron, and to not use too much solder. It looks like you have in some cases used not enough heat and too much solder.

Pinout would be correct if you're using the 5088.

Jacob
Title: Re: Low volume mud bunny
Post by: yanko_mr on March 02, 2012, 07:55:52 PM
I know it look ungly, jaja it was my first, but i check all the point with my multimeter and they are fine,
Title: Re: Low volume mud bunny
Post by: mgwhit on March 02, 2012, 08:22:42 PM
The proof's in the pudding.  ;)  Let's see those transistor pin voltages!
Title: Re: Low volume mud bunny
Post by: jkokura on March 02, 2012, 08:24:34 PM
I'm not sure how you checked it with your Multimeter, but you may have been checking wrong.

I will say however, that despite being ugly, the ugliness has nothing to do with the quality of a solder joint. It may look fine, and it could still be cold. However, ugly joints usually point to there being not enough heat or too much solder, which may be giving you your result. I still recommend removing the excess solder and redoing some of the solder joints you've done that look suspect.

I encourage you not to assume anything at this point. You've said that your parts and wiring check out, but I know plenty of examples of people who've said the same thing only to find a resistor with the wrong value on their PCB, or faulty wires, or...

Transistor voltages would also be helpful for us at this point too.

Jacob
Title: Re: Low volume mud bunny
Post by: yanko_mr on March 02, 2012, 09:27:37 PM
You were rigth, now it is rocking, thank you all,
Title: Re: Low volume mud bunny
Post by: mgwhit on March 02, 2012, 10:17:55 PM
Congratulations -- enjoy!
Title: Re: Low volume mud bunny
Post by: jkokura on March 02, 2012, 11:40:48 PM
Awesome.

Jacob
Title: Re: Low volume mud bunny
Post by: pietro_moog on March 03, 2012, 08:58:09 PM
oh my god Yanko_mr , i'm sorry to say this but the soldering job look s VERY bad.
very. (don't get offended, i didn't mean to be harsh, you just have have to make a little bit of practicing with the soldering iron, that's it. my first job i threw it in the trash)

soldering is the first thing you have to take care of.
if you made something wrong somewhere it will pop out when the soldering is good.

good luck!
Title: Re: Low volume mud bunny
Post by: yanko_mr on March 06, 2012, 06:00:05 PM
Yeah, i know, but now is working, and the second and third ones turn way better,  :)
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