Rangemaster not working

HeavyFog · January 22, 2017, 12:47:44 AM

Just got around to wiring up 2 rangemasters according to this layout

No surprise, it doesn't work. I get a loud drone at all times and the pot does seem to quiet it down but i get no guitar signal coming through at all times. Tried this exact same circuit as well with a separate circuit instead made with a small bear sino rangemaster transistor and it still didn't work and i had the same problem.
I used a small bear 0c44 in my first one and a small bear sino in the second and i double and triple checked before i soldered them that they were in the right way around and the emitter and collector were where they should be. Also this is my first time making a PNP pedal.
Right now i have 2 theories as to why this isn't working:

1: Im powering it from the same regular one spot i use to power my regular effects (not daisy chaining for the test) and this is somehow causing the problem. I tried reversing the 9v and the ground and i just got a ticking like noise. I tried as well with a 9v battery and it still didn't work. Iv'e got the positive and negative wires going straight to the power jack (plastic not metal) and neither is connected to the ground of the jacks. When i tried connecting wither to ground all noise stopped. even weirder when i disconnect the power i can play clean as i normally would but the pot does nothing. Not sure if thats supposed to happen but its odd to me.

2: There could be something up with the layout that i'm not getting and i'm suspicious of this because along with this layout the guy who did this layout included a picture of a drawn schematic that doesn't entirely match up with the layout, plus he calls it a "negative ground" rangemaster despite him saying to use a oc44 or an ac128.

I'm horrible with figuring out stipboard layouts and i can't seem to solve the problem so any help is appreciated.

HeavyFog · January 22, 2017, 04:11:56 AM

Just took a good look at the layout and i'm at least 90% sure there's nothing wrong with it and i was just overthinking it. So now i'm almost certain its my power supply is the problem or i'm doing something with the offboard wiring wrong. I'm guessing hooking p a regular one spot adn wiring the 9v as i normaly would isn't what i should be doing. Like i said this is the first time iv'e done a PNP pedal. Here's my off board wiring as iv'e been trying it so far. The diode is busted from me trying to fully remove it and it didn't work before or after i removed it.

Cozybuilder · January 22, 2017, 05:23:32 AM

If you are using a PNP, and you have the leads identified correctly, the strip board ls correct for a rangemaster.

Pot VR is connected between the collector and 0V with lugs 1 and 3, the circuit out is lug 2 of the pot through cap C2. R1 and R3 are setting the bias voltage at the base of Q1, input is through cap C3. R2 connects the emitter to 9V with C4 in parallel providing AC Bypass- like a fuzzface with the gain maxed. The values given for the components look about right. VR is not specified, but I would expect this be 10K for a PNP transistor, an audio taper pot is preferred but a linear will work fine.

If you wired the strip board correctly, it should work. You DID make the cuts under C3 and C2, right?

Edit: this was my tracing

whoisalhedges · January 22, 2017, 05:31:23 AM

Yeah, you can't power a (unmodified) PNP circuit from a 1-Spot....

Make sure the - lead from your battery is going to the "9v" strip on your board, and th + is ground. Also make sure you didn't fry yer transistor - the diode is supposed to protect against that (and if working correctly, could be precisely the reason it's not working).

Just a few reminders for an OC44 RM:
1) - is the 9v in
2) + is GND
3) the cathode (stripe side) of the diode goes to GROUND (reverse biased, opposite of what it would be in a NPN circuit)
4) Hey, whaddya know - looking at this layout, the caps and diode are all backward: the NEGATIVE leads of C1, C4, and D1 need to be at 9v. I hope nobody tries building this layout with tantalum caps.... This layout is for an NPN transistor, not an OC44; despite what the BOM says. It's no big (as long as nobody blows nothin' up), it's just D1, C1, and C4 that need turned around.
5) You remembered to make cuts under C2 and C3, right?
6) make sure your transistor is oriented correctly - old black glass trannies aren't pinned the same as modern TO-92 packages. MOST LIKELY the base is in the middle, and the emitter is slightly closer to it than the collector is.

After you verify all that good stuff, take voltage readings at 9v (should read -9v, give or take) and ground (needs to read 0), and at all 3 leads of your transistor, and post your findings. Someone here should be able to fix it based on these.

whoisalhedges · January 22, 2017, 05:33:51 AM

Quote from: Cozybuilder on January 22, 2017, 05:23:32 AM
If you are using a PNP, and you have the leads identified correctly, the strip board ls correct for a rangemaster.

I'm not used to reading layouts (more of a schem guy), but the diode and polarized caps look wrong... doesn't the bar represent -?

Cozybuilder · January 22, 2017, 05:55:42 AM

This strip layout is correct, using a 1 spot will not cause a problem for polarity. Just make sure you isolate the board- wrap it in an insulated material, wire the box as normal. The circuit card couldn't care less how you label ground, its relative positive and negative that are important.

Edit:
Note on the schematic above that C3 and C2 isolate the signal from the DC levels on the board, so that if the circuit card is insulated from the enclosure, you have 6 wires to it: signal in, signal out, +9V, 0V, and pot lugs 1 and 2. Pot lug 3 is connected to 0V, which you can wire to the 0V (Gnd) on any of the 3 jacks. This is an example of a standard (or negative) ground PNP circuit layout.

Edit 2:
You need to ground the input and output jacks- I just noticed they aren't. Using the 1-spot 0V to either one will do the trick, the enclosure will connect the other.

whoisalhedges · January 22, 2017, 11:16:42 AM

Aaah, gotcha Cozybuilder... now I see.

Yup, the jacks need to be grounded for sure.

HeavyFog · January 22, 2017, 12:29:55 PM

That makes a bit more sense. Il try it with a battery before i try it powering it with a dedicated power supply. Didn't miss the trace cut underneath the caps either.
So to be clear in order to get this working all i need to do is ground the jacks from the negative lug on the on the power supply?
Do i need to reverse the caps and diode?

Cozybuilder · January 22, 2017, 01:01:51 PM

Yes, just ground the jacks. The power supply leads, diode, and caps are drawn correctly on the circuit layout.

HeavyFog · January 22, 2017, 02:30:22 PM

Just grounded the jacks and now its working great! I'm guessing i can't daisy chain it with negative ground pedals. It sounds really great going into my deluxe reverb. Thanks for the help guys! Il post pictures in a bit in the pictures thread of both of them when i get them done.

Cozybuilder · January 22, 2017, 04:27:02 PM

Quote from: HeavyFog on January 22, 2017, 02:30:22 PM
Just grounded the jacks and now its working great! I'm guessing i can't daisy chain it with negative ground pedals.

Why not daisy chain it? This is a negative ground pedal.

HeavyFog · January 23, 2017, 07:12:06 AM

Quote from: Cozybuilder on January 22, 2017, 04:27:02 PM
Quote from: HeavyFog on January 22, 2017, 02:30:22 PM
Just grounded the jacks and now its working great! I'm guessing i can't daisy chain it with negative ground pedals.

Why not daisy chain it? This is a negative ground pedal.

So it is. Trying to wrap my head around the idea of positive ground just has me lost at this point.

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Rangemaster not working