RangeMaster- First Build Problems

[achavel]

Hi Everybody

first time builder and poster, excited to learn...

i just built a MadBean Rangemaster as my first project...

first plugged it in using a Boss 9V wall supply, got horrible screeching as soon as i engaged the pedal.

after reading the forums I saw that it was most likely the a power issue.

I plugged it into a power brick and no screeching...Good news...

BUUUT...i now get a clear signal in bypass mode, but NOTHING as soon as i click on the pedal...

the BOOST pot does seem to affect the little bit of white noise in the amp, but NO guitar signal whatsoever...

really new to this, followed the MadBean wiring very closely, not sure where to start...

Thanks!

[m-Kresol]

Hi and welcome to the forum!

There are a few things you can and should do to ensure that your build will work correctly. Please refer to: http://www.madbeanpedals.com/forum/index.php?topic=902.0

So generally start by double and triple checking all your component values and orientation of electrolytic caps, diodes, transistors (and ICs which doesn't apply for the rangemaster, afaik). then make sure to check your soldering with a magnifying glas. Check if there are any solder jumpers between pads (you can take a blade and GENTLY scrap between solder pads to make sure) and that you have no cold joints (maybe reflow all of them to make sure).

If you can't spot anything there, then please post pics of your both sides of your board and build, if you already boxed it. If you have a multimeter, please measure voltages on the transistor legs too.

good luck 

[kgull]

Also, where did you source the transistors? Germaniums are a bit finicky and if the leakage is too high you'll get bad results. For example, a supplier like smallbear will verify the devices they sell are low leakage but a lot of sellers don't care. If you have a bad transistor, that may be the issue.

[achavel]

Hey!
I should have read the guide liens for tech help before starting, my apologies!
Transistors are from smallbear...

I'll read the guidelines and post back with all required info!

[achavel]

Finally getting back into troubleshooting this first build of mine, range master...
Life got in the way of this project....

I'm getting a clean guitar signal with pedal off, NO signal whatsoever with effect engaged, just a very slight hiss that changes when I turn the pot.

Rechecked and reflowed all solder, components are All correct, EXCEPT:

I bought my OC44 from small bear, they supplied/recommended a 47k resistor for r3 instead of the 470k madbean schematic calls for.

When I test with my DMM I'm getting -8.7v on one side of the 47k, and only -2.9v on other side of resistor.

I'm also getting -2.9v at each pin of my OC44.

This is my first build, so I apologize in advance for the total confusion over here!

[darrenw6000]

I bet most of the signal is going to ground. Try it outside your enclosure.

[achavel]

You mean just take it all out of the enclosure and test it?
If that's the case what did I do wrong?

[darrenw6000]

Grounding can just part of the circuit making contact with the enclosure. Easily done. In fact I did it myself on this project and it was my pot that was touching the circuit. I love madbeans project but I have to say, the layout of this 1 ain't the best especially for the pot. I would have liked an angled mount pot like other project......so yea take out, just lift the pcb and pot out, no need to take the switch and jacks out. Just make sure the pcb and pot are not touching the enclosure.

[achavel]

Took the pcb and pot out, still only getting bypass signal, when I switch on effect everything cuts out...still hearing a little noise when I turn the pot, and placing the pot back in makes some popping noises, but still not getting any effect, just signal cuts out...

[darrenw6000]

post some close up pics if you can

[m-Kresol]

a friend just looked at the post and was like: "did he swap in- and output?" Could actually happen quite easily, so check that too

[midwayfair]

(a) Link to the version of the PCB you used. There are multiple boards.
(b) All pins of your transistor have the same voltage. This is impossible for a working transistor. This means that either they are shorted together, you have some wrong components, you have measured wrong, or the transistor has been damaged. Read here: http://www.diystompboxes.com/wiki/index.php?title=Debugging
(c) You need to reexamine the schematic to figure out where that 47K goes, because you've put it in the wrong place. 470K is a huge (10x) difference from 47K. Smallbear isn't referring to the Madbean schematic. Not every version of a circuit uses the same numbering.

[achavel]

Thanks for all the info guys, really appreciated...
Input and output are correct, though I wouldn't put it past someone with as little experience as I have!

Midwayfair, I'm going to bet the two points you brought up are part of my problem...

Boneheaded move, but when I opened my Oc44 from small bear it didn't even occur to me that the Resistor positions didn't necessarily apply to the madbean pedal schematic!
It should have clicked that going from 470k to 47k didn't make a lot of sense...

As for the transistor voltages, I hope I didn't damage it while troubleshooting, it's socketed so I'll pull it out to test it again while I try to determine my resistor positions.