Octave Distortion Build.

[anotherjim]

You can't go wrong with a DPDT switch, it's 6 pins are in a rectangular matrix. A 3PDT usually has 9 pins in a square matrix, and they can be fitted sideways - which won't work.
The Octopus schematic has the wrong opto device schematic. The intended TLP222 part is a MOS opto-relay. It couldn't work with the BJT opto drawn!

[GuyCorbin2001]

Hi all, recently finished wiring up everything but good news and bad news.
The switch works and the Jack's get my signal from one side to another however when the pedal is engaged the sound is cut out and the LED doesn't light up, no sure where to start with the troubleshooting and testing, I've just acquired a multimeter in order to test it.

[Marcos - Munky]

Actually it'll be really strange if you got sound out of it as it is. Where's the volume pot?

[GuyCorbin2001]

There's a vol 1 and vol 2, vol 2 is optional boost as far as I'm aware.

[GuyCorbin2001]

Correction Vol 2 is just there if you want a different knob layout.

[iainpunk]

i suggest you lookt at this link:debugging guide

it might be wise to add 1 volume control, since the signal doesn't pass, on most circuits, if the volume control is left out.

The intended TLP222 part is a MOS opto-relay. It couldn't work with the BJT opto drawn!

it can work if you don't mind a bit of crossover distortion and loss in amplitude on one side of the zero-crossing...

cheers

[ElectricDruid]

Reheat the joints on your pots. Some of them look a bit undercooked to me. You need the solder to flow into the hole and around the pin, not make little blob. You're heating a great big bit of metal (a pot leg) so it needs a few seconds more than a resistor.

[Marcos - Munky]

Ok. Could you post a link of the build guide for this board? I googled for sunn t fuzzdog, but found different boards.

[GuyCorbin2001]

http://pedalparts.co.uk/docs/SunnTAMZ.pdf

[duck_arse]

how come you've linked across R3?

[Marcos - Munky]

R3 is the current limiting resistor for the led. Since you're not using the led pad, you could just leave it empty. Anyway.

One thing you didn't noticed is you soldered all your pots in the correct place but in reverse. They all should be rotated 180º. Compare your picture with the first one on the build doc. That won't keep the circuit from working, will just make all pots working in reverse rotation. That means they'll be at max setting when you fully rotate them counter-clockwise instead of clockwise. Well, you won't get any sound out of it if your volume pot is set to minimum when you're thinking it is at maximum but I'm sure you tried to rotate it when testing the circuit.

Btw, I was wrong on the missing volume. The doc says it's a extra place for a centered volume pot, so that's ok the way you did it.

The connection between both boards seems to be correct. The reason for no sound could be swapping in and out jacks, but that doesn't explain the led not liting.

So, before we start to take voltage measurements, let me asking another thing. Are you using a battery or a dc adaptor to power the circuit? If it's a dc adaptor, could you post a picture on how you wired the dc jack?

Also, a (not so) random question, but do you happen to have a spare cap of any value between let's say 10nF and 470nF, and also a spare 1/4" plug or jack (the same as used for guitar cables)? You can make a very useful debugging tool with just those things.

[GuyCorbin2001]

I'm using a 9v battery but I only did the lick test to check it was dead or not, I linked r3 out of pure desperation to see if it made a difference or no.
I have some jacks but am waiting for more capacitors to arrive as I'm out.

[Marcos - Munky]

First thing, check the battery voltage. Set your multimeter to dc voltage, red probe on + pin of the battery, black probe on the - pin of the battery. If your multimeter have different voltage ranges, set to the one just above 9V (it's usually 20V). You should expect more than 8V from a healthy battery. That said, the 386 draws a good amount of current and you have two of them in the circuit, so I woudn't go for a battery. But anyway.

After you test the battery, plug it on your circuit. Since you used mono jacks (more on that later, let's first do some measures), you don't need to worry on plugging anything else, just the battery. Don't even worry on the switch. And btw, because of the mono jacks, the battery is drained as soon as you put it in the circuit, even you don't plug anything else.

With the multimeter still on dc voltage setting and the same voltage range as before, put the black probe on the ground connection. Any of them will do it. For example, the part of the jack that's connected to ground. Then, with the red probe, check both sides of D1. The side without the line should have the same voltage as the battery, the side with the line should have a bit less voltage. Then check pin 6 of both ICs, they should have the same voltage as the line side of D1. Also check pins 2 and 4 of each IC, they all should be zero. If you don't know how to tell the pin number, look at the ICs with that notch on the "upper side". On the left side you have pins 1, 2, 3 and 4 from top to bottom, and on the right side you have pins 5, 6, 7 and 8 from bottom to top.

Those voltages should give us some info to start the troubleshooting. If the doc had the expected voltages for each IC pin, we could measure them, but I really can't get the reason for not including the voltages on the doc.

And since you have a spare jack but not spare caps, not a problem (if you know what you're doing and we'll help you with that). You can build a tool called audio probe, which is one of the best tools to troubleshoot pedals. Get two pieces of wire, two different colors if possible (and black for one of them, if you have it). Solder one wire to each lug (black wire on the ground lug), and that's it for now. You'll improve it a bit after you get a spare cap. After you post the voltages, if those are correct, I'll guide you on how to use an audio probe.

[GuyCorbin2001]

I'll get some new batteries on the way back from work, also have Cioks power supply so could use that if that is optimal

[GuyCorbin2001]

Just found out my wife had taken liberty to order spare kits for all of them just in case they are FUBAR'd

[Marcos - Munky]

also have Cioks power supply

Imo, it's a better idea to use a good power supply when you're testing the stuff you built. If you're gonna use a battery to power it after you box it, it's totally up to you. But when testing, it's good to remove all possible external sources of errors/problems. It's very common to people to spend some time debugging a circuit that's actually good but it wasn't working because of a bad cable or dead battery. And by using a dc adaptor, you'll be sure your power supply is good and the possible issues on the circuit aren't caused by a bad power supply.

[GuyCorbin2001]

Hi guys just put it in to test it and it's kinda of working, led still doesn't working and circuit is very very noisy and wants to feedback, if I touch the parts or footswitch (any substantial piece of metal) the noise goes down significantly, a grounding issue?

[GuyCorbin2001]

Update - in the attempt to reorient the pots I messed up the board, luckily have spare board though.

[Marcos - Munky]

Noisy can means lots of things. Grounding issue, wires too long (could be an issue  on higher gain circuits), interference from other electromagnectic fields that cames from things like a computer, and the list keeps going on.

It was nice you could get it to make it kinda work, but too bad you messed up the board. So it's time to remove everything form one board and put in the new board.

Btw, what made it to go from no sound to kinda working?

[GuyCorbin2001]

I didn't do anything it seems like a bad solder joint must have been the culprit.