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Hello,

I don't have access to a camera to post picks right now per the tech forum post thread, but I have a compressor I built and rarely used but now I'm getting back to trying to use it. I built it about 3 years ago. It's a 5kc.

Anyhow.

1. Level works
2. LED works
3. Bypass works
4. Ratio does not seem to work
5. Perhaps my ears aren't good, but I can't hear the bass cut with the tone knob.
6. The level definitely boosts/cuts the signal but all the other knobs seem to do nothing. This would make sense if my ratio knob is jacked and just sending dry signal through I imagine.

When I turn Ratio fully CW, there is no output signal.

The trimpot is set to noon.

Anyone have issues like this before? I'll post pics as soon as I can, just thought it might be a common issue.

Thanks,

- Mike

Yep, that pot's the first place I'd look, anyway. Alpha pots are cheap, but not always so durable.

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Ratio fully cw is the compressor side of the circuit. So the ratio knob is working but the compressor side is not. Reflow, check components and it may help expediate things if you can eventually post pics.

Ah right that makes sense. Can you give me an idea of where to begin troubleshooting? Do I just trace everything after the ratio knob looking for voltage drop? I can't remember, but originally I remember the back of the pots shorting oout against the leads on the pcb. I put a blob of hot glue on the pots, let it dry then put the pots back as insulation. Anyhow, here are the pics.

Thanks for any assistance.

- Mike

Sorry clicked submit a bit early.




Thanks again.

Compression, my friend, is like heroin. A little is fun but too much will kill you. It can sometimes be a very subtle effect.

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That which you fear, you draw near.

The only thing the mlkew's pedal has in common with heroin is - it needs a fix, so lets focus some comments on that.

Shorts from the back of the pots might very well have permanently fried something like the BA6110 or some of the transistors. The easiest action is to try a new BA6110.

You could check a few voltages with a DMM. The emitter of Q2 should be somewhere around 2.5V and the collector at around 6.5V. The collectors of Q4 and Q3 are connected together and with no signal in should sit somewhere near +9.

Thanks Tark,

So I remember now after 3 years and actually finding the old post I made back in Sept 2009 - the day after I built the pedal. When using DC jack, no workie, when using battery - things seem to work just fine. I remember having issues wiring the DC jack but everything looks good now. I'll double-check the build specs and make sure all is well but obviously something is wrong there...

Thanks again, appreciate any help.

Old post I found:

viewtopic.php?f=19&t=20421

Thanks,

- Mike

I checked the build docs, I still can't figure out what is wrong, maybe my dc jack is just flubbed?
It's wired correctly as far as I can tell...

So i'm kind of a electronic newbie, but I'm guessing the two + on the dc jack is that one is active when plugged adapter plugged in, the other is active when no ac plugged in (battery powered)

So tracing the PCB, i see the DC jack + prong on the outside, is connected to the inside + on the pcb. This trace runs to the only diode on see in the schematics next to the battery +/- then entering the capacitor in the series of 3 on the edge of the board. These are the three same capacitors that get hot when using the ac adapter.

The inside DC prong + is connected to the outside + on the pcb. This trace runs to the + battery terminal.

I'm guessing these are reversed and the outside dc + jack is the one that should be running to the battery + terminal on the pcb

I'm not sure which + is active vs. not active when the dc jack is plugged in.

I guess I can check continuity between battery terminal + and dc jack - on the pcb with out anything plugged in? It should read not infinite ohms yes?

Thanks for any pointers.

- Mike

The external power sockets should be wired with the centre pin as - / minus / negative input and that goes to circuit ground. The two + terminals are parts of a switch that is used to disconnect the battery + / plus / positive from the circuit when the external power is plugged in. One of these terminals goes to the battery positive and the other goes to the circuit positive. If you get those two swapped around when you plug in external power you end up with no power to the pedal at all and the external supply connected across the battery, which is not a good thing.

Of course, you must use a centre negative ground, DC, 9V supply with the right size of power connector (there are two sizes that might fit) with these pedals.

The two bottom posts on this thread would be helpful for troubleshooting this since the compression side isn't working on your pedal.

You will need a signal tester for the first test and a DMM for the second. The emitter leg is the far left looking at the flat side of the transistor. The collector is the far right leg.

http://www.buildyourownclone.com/board/viewtopic.php?p=121346#p121346

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Math illiteracy affects seven out of every five people.

I can't get enough minimalism.