Problem with Dallas Rangemaster and introduction

[mth5044]

Post a link to the one you used. Post voltage measurements if you have a multimeter.

[Trolorol]

Post a link to the one you used. Post voltage measurements if you have a multimeter.

The link is a previous post, the measurements do you want them all ?
The user karbomusic referred to the circuit as a positive ground, and thinking about it it seems right, especially becose of the capacitors that have the positive lead on the supposed ground. Then I asked the following question, if the circuit is positive ground, I just have to switch the outputs of the powersource (positive to ground and negative to positive) ?

[Trolorol]

Post a link to the one you used. Post voltage measurements if you have a multimeter.

As for the measurements, I found that the voltage on the colector is 1,50v and I think that is pretty low, considering that is coming from the pot booster and its linked with the 9v supply. ( pot was fully turned ti max in the measurement).

[Ben Lyman]

I don't think turning the pot will affect the voltage to collector but the *VALUE* of the pot definitely will. Are you using a 10k pot?

[Philippe]

there appears to be an inherent gain issue/problem involved with your build.

having used a germanium transistor, did you heat sink the leads prior to soldering?  Ge transistors can fry easily when exposed to excessive/continuous heat. I use a small pair of hemostats to dissipate the heat when soldering them.

test your transistor & replace it if necessary. the RM is a relatively simple circuit with minimal components.

as others have stated, the RM is essentially a booster & depending upon your volume settings, it should easily overdrive the upper frequencies of a tube amplifier. on an SS amplifier the RM will have a less prominent effect as the clipping characteristics are different.

[Trolorol]

I don't think turning the pot will affect the voltage to collector but the *VALUE* of the pot definitely will. Are you using a 10k pot?

Yeah I am using a 10k pot, the transistor is fine, it isn't soldered I have put a socket to be able to try another trans if I want to...

[Ben Lyman]

Looking at the schem, I see no reason the collector shouldn't be getting more volts. The -9v goes straight to the 10k pot (passing by a 47uF cap) and to the collector. Did you by any chance put a protection diode alongside the 47uF filter cap? And if so, is that diode maybe backwards?

[PRR]

> measurements do you want them all ?

There are only five points in a properly wired RM. Measure ALL of them, please.

Battery
Collector
Base
Emitter
Ground

(Yes, we could assume 9V and 0V, BUT many-many times a builder with a problem comes back and reports maybe 2V where there should be 9V. Weak battery, bad solder joint..... we can not see your build, you can not see the electrons, measure!)

[Trolorol]

> measurements do you want them all ?

There are only five points in a properly wired RM. Measure ALL of them, please.

Battery
Collector
Base
Emitter
Ground

(Yes, we could assume 9V and 0V, BUT many-many times a builder with a problem comes back and reports maybe 2V where there should be 9V. Weak battery, bad solder joint..... we can not see your build, you can not see the electrons, measure!)

Ok so,

Battery = 9,18V
Collector = 1,60V
Base = 1,50V
Emitter = 277mV

And I found an error in the board, I followed up the layout schematic (see end of this page: http://fuzzcentral.ssguitar.com/rangemaster.php) instead of the schematic itself and I just realized that the layout as 2 1M resistor added that don't show in schematics, I desolder them and now is exactly as the schematic for pnp one with the oc44, but....... It has the same problem, volume too low comparing with bypassed one (end of the tunel low without the reverb).

I have the positive on the -9 and the ground on ground, I was asking before what is the diference between +9v or 9v to -9v, I see that the capacitors are with the positive lead on the ground, that means that I have it backwards ?

What will you do with the voltages that I gave you, if its not asking too much can you please elaborate your thinking so I can begin to understand this?

[Trolorol]

Looking at the schem, I see no reason the collector shouldn't be getting more volts. The -9v goes straight to the 10k pot (passing by a 47uF cap) and to the collector. Did you by any chance put a protection diode alongside the 47uF filter cap? And if so, is that diode maybe backwards?

No Diode Ben, I am doing the pnp one with an oc44.

[Ben Lyman]

This is all good info, you are getting close to solving it so hang in there! 
My first PNP pedal was SO confusing but these guys got me through it, when it clicked in my brain, it all made sense.
Make sure your battery neg (I like to call it "the black wire") is ONLY touching 3 components, 47uF, 470k, and 10k pot. Then make sure your pos ("red wire") is touching ALL the things marked with the ground symbol and nothing more.
These other guys here are going to get you through it, good luck!

[Keppy]

Battery
Battery = 9,18V
Collector = 1,60V
Base = 1,50V
Emitter = 277mV

First of all, all those voltages are negative with respect to ground, right? They should be for a PNP transistor circuit. For the layout on the page you posted, 1 is for the Red wire from the battery snap, and 3 is for the black one.

Second, that 1.2v base-emitter drop is way too big. That looks more like a number for a silicon Darlington transistor than any germanium. Your transistor is not happy.

Since you socketed the transistor, I recommend that you pull it out and measure the resistances in the circuit. You can also try another PNP transistor (2N3906, 2N5087, etc.) or try flipping around the one you have in there now just to check the pinout. A quick search shows some variety in the look of OC44 transistors, so even if you attempted to check the pinout it might not be right.

And I found an error in the board, I followed up the layout schematic (see end of this page: http://fuzzcentral.ssguitar.com/rangemaster.php) instead of the schematic itself and I just realized that the layout as 2 1M resistor added that don't show in schematics, I desolder them and now is exactly as the schematic for pnp one with the oc44, but....... It has the same problem, volume too low comparing with bypassed one (end of the tunel low without the reverb).

Those are just there to prevent popping noises when building the circuit as a true bypass pedal. You should put them back before boxing the circuit up, but they won't affect your debugging.

I have the positive on the -9 and the ground on ground, I was asking before what is the diference between +9v or 9v to -9v, I see that the capacitors are with the positive lead on the ground, that means that I have it backwards ?

It's customary to ground the negative (black) probe and poke around with the positive (red) one. Doing that in this circuit, all of your voltage readings should be negative numbers.

What will you do with the voltages that I gave you, if its not asking too much can you please elaborate your thinking so I can begin to understand this?

Bipolar transistors (PNP or NPN) are made of diodes. If a transistor is functioning properly in a circuit, it will have a diode drop from base to emitter. This diode drop is about .6v for silicon or .3v for germanium. For NPN, the base is more positive than emitter, for PNP it is more negative. The collector can have a wide range of voltages, but for high output in a circuit like this should probably be around the middle of the voltage supply, close to -4.5v. Your base-emitter voltage looks wrong, making me suspect your transistor is bad or has the pins mixed up. -1.5v base should lead to about -1.2v emitter, give or take a tenth. The collector won't be right until that happens.

[Trolorol]

First of all, all those voltages are negative with respect to ground, right? They should be for a PNP transistor circuit. For the layout on the page you posted, 1 is for the Red wire from the battery snap, and 3 is for the black one.

Second, that 1.2v base-emitter drop is way too big. That looks more like a number for a silicon Darlington transistor than any germanium. Your transistor is not happy.

Since you socketed the transistor, I recommend that you pull it out and measure the resistances in the circuit. You can also try another PNP transistor (2N3906, 2N5087, etc.) or try flipping around the one you have in there now just to check the pinout. A quick search shows some variety in the look of OC44 transistors, so even if you attempted to check the pinout it might not be right.

And I found an error in the board, I followed up the layout schematic (see end of this page: http://fuzzcentral.ssguitar.com/rangemaster.php) instead of the schematic itself and I just realized that the layout as 2 1M resistor added that don't show in schematics, I desolder them and now is exactly as the schematic for pnp one with the oc44, but....... It has the same problem, volume too low comparing with bypassed one (end of the tunel low without the reverb).

Those are just there to prevent popping noises when building the circuit as a true bypass pedal. You should put them back before boxing the circuit up, but they won't affect your debugging.

I have the positive on the -9 and the ground on ground, I was asking before what is the diference between +9v or 9v to -9v, I see that the capacitors are with the positive lead on the ground, that means that I have it backwards ?

It's customary to ground the negative (black) probe and poke around with the positive (red) one. Doing that in this circuit, all of your voltage readings should be negative numbers.

What will you do with the voltages that I gave you, if its not asking too much can you please elaborate your thinking so I can begin to understand this?

Bipolar transistors (PNP or NPN) are made of diodes. If a transistor is functioning properly in a circuit, it will have a diode drop from base to emitter. This diode drop is about .6v for silicon or .3v for germanium. For NPN, the base is more positive than emitter, for PNP it is more negative. The collector can have a wide range of voltages, but for high output in a circuit like this should probably be around the middle of the voltage supply, close to -4.5v. Your base-emitter voltage looks wrong, making me suspect your transistor is bad or has the pins mixed up. -1.5v base should lead to about -1.2v emitter, give or take a tenth. The collector won't be right until that happens.

Ok so I bought a cheap trans tester, the oc44 seams to be ok, but I have read in other posts that the "normal" hfe of this trans is 200??? and mine is 148...

I also have a question regarding the tester itself, I have an OC45 and the results re quite different, can someone tell me why ? I will now measure the resistances in the circuit and come back here later with the results.

[Trolorol]

This is all good info, you are getting close to solving it so hang in there! 
My first PNP pedal was SO confusing but these guys got me through it, when it clicked in my brain, it all made sense.
Make sure your battery neg (I like to call it "the black wire") is ONLY touching 3 components, 47uF, 470k, and 10k pot. Then make sure your pos ("red wire") is touching ALL the things marked with the ground symbol and nothing more.
These other guys here are going to get you through it, good luck!

I did that and the pedal didn't work, not even a clean sound.... Is driving me nuts.. But thank you for the optimism and support

======#####=======

First of all, all those voltages are negative with respect to ground, right? They should be for a PNP transistor circuit. For the layout on the page you posted, 1 is for the Red wire from the battery snap, and 3 is for the black one.

Second, that 1.2v base-emitter drop is way too big. That looks more like a number for a silicon Darlington transistor than any germanium. Your transistor is not happy.

Since you socketed the transistor, I recommend that you pull it out and measure the resistances in the circuit. You can also try another PNP transistor (2N3906, 2N5087, etc.) or try flipping around the one you have in there now just to check the pinout. A quick search shows some variety in the look of OC44 transistors, so even if you attempted to check the pinout it might not be right.

Ok so I am kinda newbie at this and this was the resistance results I got, some of them were decreasing when I mesure them so I write up the mas value that appeared, any help in this matter is kindly appreciated.

The measurements were made without battery and the transistor and also without the resistances marked with an red X in the picture below.



http://s18.postimg.org/xa6fk6iq1/Screen_Shot_2016_01_11_at_16_12_47.png

[Electric Warrior]

Ok so I bought a cheap trans tester, the oc44 seams to be ok, but I have read in other posts that the "normal" hfe of this trans is 200??? and mine is 148...

I also have a question regarding the tester itself, I have an OC45 and the results re quite different, can someone tell me why ? I will now measure the resistances in the circuit and come back here later with the results.

The hfe range for OC44s is 40 to 225 according to some datasheets. The Rangemaster circuit is not all that picky about hfe. Leakage is more important to get it biased right with stock resistor values.

Very low gain is not uncommon for OC45s. I've got a zip lock bag full of them, but none measure over 40 iirc.

The output cap in your layout is 0.001µF instead of 0.01µF, btw. That doesn't explain your odd voltage readings and your problems, though.

Double check all your resistor values and pot wiring. Something is definitely wrong..

[davent]

Double check your resistor values, they're easy to mix up, misread the code, unless you religiously measure each just before you install it on the board.
dave

[Trolorol]

Double check your resistor values, they're easy to mix up, misread the code, unless you religiously measure each just before you install it on the board.
dave

I've put them in the board directly from the mouser bag, so the problem is not there, plus I already check them up :p

Ok so I bought a cheap trans tester, the oc44 seams to be ok, but I have read in other posts that the "normal" hfe of this trans is 200??? and mine is 148...

I also have a question regarding the tester itself, I have an OC45 and the results re quite different, can someone tell me why ? I will now measure the resistances in the circuit and come back here later with the results.

The hfe range for OC44s is 40 to 225 according to some datasheets. The Rangemaster circuit is not all that picky about hfe. Leakage is more important to get it biased right with stock resistor values.

Very low gain is not uncommon for OC45s. I've got a zip lock bag full of them, but none measure over 40 iirc.

The output cap in your layout is 0.001µF instead of 0.01µF, btw. That doesn't explain your odd voltage readings and your problems, though.

Double check all your resistor values and pot wiring. Something is definitely wrong..

My mistake on writing the layout :p

The mouser part numbers on 2 items were outdated and this isn't working with the "green caps" instead I put these ones that were polyester types:

Mouser PTN:
598-WMF1D5K-F
667-ECQ-E12103KF

Is it possible that the problem is coming from here ?

[PRR]

> 1M resistor added that don't show in schematics

Not important to getting it to "work".

Helpful to reduce POP when switching.

> Battery = 9,18V
> Collector = 1,60V
> Base = 1,50V
> Emitter = 277mV



Your "10K" Boost pot *might* really be 100K. Collector current should be "same" as emitter current; instead they appear to be 10:1 different. One possible reason is that a resistor is 10X different than it is supposed to be.

However as Keppy said, the Base-Emitter voltage is a big red flag for a bad transistor. Single Silicon should be 0.6V; Germanium more like 0.2V. Higher voltages are "impossible"; if found, it means the transistor is blown-up (or the leads are mis-identified).

[Trolorol]

> 1M resistor added that don't show in schematics

Not important to getting it to "work".

Helpful to reduce POP when switching.

> Battery = 9,18V
> Collector = 1,60V
> Base = 1,50V
> Emitter = 277mV



Your "10K" Boost pot *might* really be 100K. Collector current should be "same" as emitter current; instead they appear to be 10:1 different. One possible reason is that a resistor is 10X different than it is supposed to be.

However as Keppy said, the Base-Emitter voltage is a big red flag for a bad transistor. Single Silicon should be 0.6V; Germanium more like 0.2V. Higher voltages are "impossible"; if found, it means the transistor is blown-up (or the leads are mis-identified).

Ok as I said I choose this circuit because it seams easy to built for a first timer, lets go more basica with the following question.

I think I am connecting this all wrong.. the board is ok but my inputs and outputs are all messed up, does someone have a schematic for connecting the jacks and the battery to this circuit ?

I am asking for this because as before mentioned, this is a positive ground circuit and the layout is not very specific, at first I thought that it was a simple, tip -> input on the board and sleeve to gnd, and in the other side output to tip etc etc, but now I am confused.

Regarding the transistor being bad, the transistor tester should warn me, no ?