Need help with Rangemaster

[FloorIt]

I've got a Madbean Rangemaster all soldered and wired up but it isn't working.  Off position passes signal but nothing in the on position.  Before I start looking into assembly issues (already did a visual check of solder joints) I would like it if someone could review my wiring schematic, in particular the switch pcb and the Range pot.  My third suspect is the correct placement of the transistors.  I'll post photos later.  In the meantime, I would appreciate a reveiw of my schematic.

[dont-tase-me-bro]

Not sure if it will kill the cicuit, but the treble switch is listed as a spdt switch, not a pot

[FloorIt]

Not sure if it will kill the cicuit, but the treble switch is listed as a spdt switch, not a pot

Correct, but some put a pot in as a mod and I had another member recommend this wiring scheme to me.

[RobA]

I can't say how responsive the pot will be in place of a switch in the middle ranges of the pot or how it will interact with the pickup loading that's important to this circuit, but at least at the extreme CCW and CW positions it should be no different than a toggle.

Get voltages from the inputs to the PCB and the outputs from the charge pump. If you aren't getting the right voltage levels off the charge pump, nothing is going to get through the PCB.

I don't know that 3PDT switch board at all, but there are a couple of things I would check. Trace the schematic and make sure that the SW output from the main PCB aligns with the LED input usage on the 3PDT board. I think that in bypass it should make the connection float and when the effect is in, the connection should take SW to ground.

The other thing I would check is all of the ground connections. First is the 7 spot on the 3PDT. I'd guess that this is connected on the 3PDT board, but I'd make sure. The next is that it looks like there is all sorts of potential for ground loops to ground potential mismatches with the grounds chained that way plus the connections through the enclosure. I'd say that it isn't likely the cause for passing no signal at all, but it can introduce noise and cause some other issues. I personally use a star ground configuration to avoid these possible issues.

[midwayfair]

I can't say how responsive the pot will be in place of a switch in the middle ranges of the pot or how it will interact with the pickup loading that's important to this circuit, but at least at the extreme CCW and CW positions it should be no different than a toggle.

It works just fine. The first one I ever built was like that.

Op: What transistor are you using? What are you powering the pedal with? Have you boxed the circuit yet? Pics of both sides of your board?

[FloorIt]

Op: What transistor are you using? What are you powering the pedal with? Have you boxed the circuit yet? Pics of both sides of your board?

I'm using an OC44.  Powering the effect with a Fuel Tank power supply.  I have not boxed it yet.









Regarding the SW input on the Rangemaster pcb, I connected it to the LED output on the 3DPT pcb.

Thanks guys, for offering to help.

[FloorIt]

Still looking for help, please.

I took some voltage readings:
TC1044 IC:
1.  9.0
2.  5.25
3.  0
4.  -3.7
5.  -9.0
6.  4.1
7.  5.7
8.  9.0

OC44 Transistor:
E  -.5
B  -.6
C  -7.3

Is it possible that my OC44 is connected incorrectly?  How can I check for that?

[midwayfair]

Your voltages are fine and the circuit would actually pass signal (just not very pleasantly) even if your transistor was backwards. Of course, you can try flipping it around to see if that helps.

I suggest removing the switch and its PCB from the equation. Just solder the input and output wires directly to the jacks.

[FloorIt]

Your voltages are fine and the circuit would actually pass signal (just not very pleasantly) even if your transistor was backwards. Of course, you can try flipping it around to see if that helps.

I suggest removing the switch and its PCB from the equation. Just solder the input and output wires directly to the jacks.

I did some checking out of the switch and its connections to the board (using a voltmeter/continuity) and I am reasonably confident that everyting is okay there.  I'd like to pursue some other options before I rip that wiring apart.

I also check for grounding at various points in the circuit and everything was ok.

Are there any other voltages that I could measure?  Can I damage the transistors by placing them incorrectly?  Other suggestions?

[RobA]

The good thing about looking at it without the switch and jacks in place is that you can eliminate any of that as a source of the issue -- thus the rock it before you box it motto.

Your next step should be audio probing. You can do this with the switches and jacks in place, it'll just mean you have to start the probe through the circuit at the input jack and go through the switch circuit and onto the main PCB. It's a small enough circuit anyway that you could be able to work through it pretty quickly even with the external components in place.

[FloorIt]

The good thing about looking at it without the switch and jacks in place is that you can eliminate any of that as a source of the issue -- thus the rock it before you box it motto.

Your next step should be audio probing. You can do this with the switches and jacks in place, it'll just mean you have to start the probe through the circuit at the input jack and go through the switch circuit and onto the main PCB. It's a small enough circuit anyway that you could be able to work through it pretty quickly even with the external components in place.

Well I guess I need to build an audio probe then.  That will be my project for the weekend.  I'll report back after I do that.

[TGP39]

Hey. I just thought of something. Make sure your guitar is hooked up to the input jack. This happens more than you would think because the circuit is flipped upside down when you are working with it. If the guitar is in the output jack and the input jack is going to your amp...you will get clean signal when it's off and no signal when it's on, just as you described. This happened to me on my first build so take a look at that.

Steve.

[RobA]

Hey. I just thought of something. Make sure your guitar is hooked up to the input jack. This happens more than you would think because the circuit is flipped upside down when you are working with it. If the guitar is in the output jack and the input jack is going to your amp...you will get clean signal when it's off and no signal when it's on, just as you described. This happened to me on my first build so take a look at that.

Steve.

Yep, I've done this one too, multiple times.

[FloorIt]

Hey. I just thought of something. Make sure your guitar is hooked up to the input jack. This happens more than you would think because the circuit is flipped upside down when you are working with it. If the guitar is in the output jack and the input jack is going to your amp...you will get clean signal when it's off and no signal when it's on, just as you described. This happened to me on my first build so take a look at that.

Steve.

Ha ha, I can see doing this too.  I marked the jacks with a Sharpee to help me with this, but it would be a good idea to check again.