Tonepad Boss Ds1 Problem

[stringsthings]

I'd measure the voltages on the IC and the transistor.

[tvjoda]

sure no problem

Battery 8.73

IC
4.35     8.73
4.35     4.35
3.78     4.35
0          4.35

Q1
E
3.22     2.73      8.73

Q2
E
0.02        0.66       0.96

Q3
E
2.83      1.95        8.73

[robthequiet]

The readings on 2 look a bit odd. I would check the resistors around Q2, for the right values.

[tvjoda]

code values

C1 : 474
C2 : 223
C3 : 683
C4 : 471
C5 : 473
R1 : blue , gray, red
R2 : red , red, red
R3 : blue , gray, red
R4 : brown, black, orange
R5 : brown, black, yellow
R6 : brown, black, yellow
R7 : brown, black, green
R8 : red, red, black
R9 : yellow, purple, yellow
R10 : brown, black, orange


Is this information useful?

[ElectricDruid]

The readings on 2 look a bit odd. I would check the resistors around Q2, for the right values.

The readings around Q2 do look odd. Checking the values form your image, that looks ok, so I'd check the soldering and for shorts. It looks to me like something is shorting and pulling the voltage down.

HTH,
Tom

[tvjoda]

If I measure the voltage at resistance 4 at the input it gives me 8.73 and at the output I have 0.96

[robthequiet]

Yes. What I would do would be to consider each resistor that is attached to Q2, measure the voltage at each end, and see if it tells us that there is an open or short. Something is making that transistor not transist.

Come to think of it, Q1's and Q3's emitter are higher than their bases. Is this right?

[tvjoda]

Ok thanks i am going to do that, but the r4 the voltage at the end is wrong right?

[robthequiet]

R4, as you have labeled it, connects from +v to the collector of Q2. Both voltages line up with your voltage readings, but the collector voltage should read much higher, perhaps between 5V to 6V. This would indicate that the transistor is not transisting, and the culprit may be a wrong resistor value or a short somewhere. I would look for the short, even if you have scraped between the traces, maybe take another pass. But you should still look at voltages at each end of each resistor attached to Q2. Q1 might be suspect as well, but if there is one voltage out of spec, it might affect all of the other readings as well.

[robthequiet]

Now for a brief intermission:

Read this thread and see if you don't see something familiar. Hint: Different manufacturers of transistors may have different pinouts. Before removing anything, check the face of each transistor and note the numbers and manufacturer, then check against their datasheet. You have built the pedal according to instructions as far as I can see, but this is an issue that pops up from time to time. We'll be glad to answer any questions that you may have along the way.

[tvjoda]

At the end off The post that you mention he sayd

The Qs still gave the same readings, so I thought lets just flip em round (i'm finding different pinouts for the same transistor!!)

I don't know if i should do the same
It looks like he was having The same values and problem than me

[robthequiet]

Similar. Sometimes we move something that fixes it but we thought we were doing something else. Having a 22R instead of a 2M2 will definitely make trouble. Nonetheless, if all of your resistors and traces seem OK, I would see about getting the datasheet for your transistors just to verify the pinout. 2N5088s are pretty consistent. Do you want to take a photo of one of your transistors face and upload it for the committee?

[ElectricDruid]

Ugh..same transistors, different pinout drives me crazy. I've seen the same thing with voltage regulators too, but only negative ones, so far.

Definitely worth a check. If you bought the transistors online somewhere, they should have a link to the datasheet (if they don't..well, they should!!).

Tom

[griff10672]

I'm currently doing a lot of messing around with the DS1 circuit ......... I'm pretty much a noob at building ..... but ... one thing I noticed about the DS-1  .... it does what you describe even as a stock circuit .... I've always noticed that .... totally seems like a a overdrive till you have it on 10 ...  which I always assumed was because it isn't a " hi gain " pedal .

I just got done mocking up a " very " modded DS-1 .... and am sort of having the same trouble with the level ... all the way off it's silent .. turn it up just a little and it's cranked ... and stays just as loud as I turn it up .... wondering if I have the dam pot hooked up backwards or something .

[tvjoda]

I can't make a good photo off The transistor, but it says
F 408
2n
5088
[IMG_20170604_122532906.jpg](https://postimg.org/image/hzsh5y45v/)
https://postimg.org/image/hzsh5y45v/

[robthequiet]

So the search engines seem to think that it's a Fairchild 5088 from a few years back, in a TO-92. The pinout looks correct as you have it:

Datasheet: https://www.onsemi.com/pub/Collateral/2N5088-D.PDF

As our colleague griff10672 posted, this does not seem to be a unique problem. So having gone through the troubleshooting so far, I'm pretty confident that you built the thing correctly and perhaps a stray solder bridge or open connection exists, although it looks like your cleanup on the board is not bad.

If you feel like doing some surgery, you could simply move the transistors around without flipping them, so Q1 <-> Q2, for instance, carefully not to overheat them. This might auto-correct any microscopic issues with the boards or components. Also, if the voltage issue moves with the transistor, you know which one is bad.

[tvjoda]

Thanks robthequiet i already did that, I changed order q1 to Q2 and the values were The same ,then i use an alternative for q2 the bc549 o something like that , and nothing, values and sound are The same , in the other thread, the guy was having the same values as my, but them when he rotated the q's the values change completly, i think that is my last bullet in this pedal

[robthequiet]

Well, go for it.

You might be interested in this,

http://www.diystompboxes.com/DIYFiles/up/Build_Your_Own_DS-1_Distortion.pdf

Has a lot of good information.

Let us know what happens.

[robthequiet]

P.P.S.

So I was looking at the schematic assuming Tonepad knows a lot about circuits and definitely more than I. Nevertheless, comparing their schematic to a couple of others it struck me that a 1M biasing resistor to ground might be a bit heavy.

If you have a resistor between 100K and 470K maybe just clip it across R4 to see if you get better performance. My theory is that Q2 is possibly mis-biased.

I would also try the same with Q1, try swapping a 100K resistor for the 470K. Do one at a time so that we see the effect at every move.

These are experimental probes I would try myself, it might be wise to get a second opinion.

[tvjoda]

Ok i tryed changing the orientation and it sound with Even less distortion jaja

So yes i can try change some parts