[Ludicrous Speed OD] First attempt at a DIY pedal, not even turning on

[adinapoli]

Good morning fine folks,

this is my first post ever and I hope to not be violating some rules or not posting in the correct section.

I have purchased a Ludicrous Speed OD kit from Musikding.de for which you can see the schematics here. Being my first attempt, and being relatively inexperienced with soldering, it sort of went decently (and learned how to do acceptable soldering along the way) but alas a few things went wrong, including me stupidly mounting the 3PDT board that they included upside down (i.e. flipped a-la pancake).

As it was too late to desolder (I have a desoldering pump, but it's very basic) what I have done was to treat the board as upside down so I have done all the wiring mirrored. However, once I have completed soldering, I have tried to stomp on the footswitch and .. nothing happened

I'll try to bring this to my in-law this weekend as basically he used to do this stuff before retirement, but a couple of questions are:

1. The obvious first step would be to use a multimeter (which I have) to check for continuity, but I'm a newbie using it. My intuition is that I should start from the power input jack and walk my way "upwards" (whatever that means) but I have no clue what to check first. Can somebody suggest a good initial step to check the obvious?
2. One of the first suspect I had was that I mounted the LED diode flipped (I have checked multiple times the anode and cathode but .. I'm human). Is there a way using the multimeter to check orientation? I have used the multimeter in the "diode/continuity" mode (I guess?) and placed the black end on the input power supply ground and if I touch one of the three leg (only a particular one) it "beeps", which I guess that means that is ground? What do I make out of this information?

Thanks in advance

Alfredo

 

[adinapoli]

Ok, so, some updates : I have desoldered the R10 and installed a 4k7 CLR resistor and we now have a led light (see pics).

However , I still get no bypass signal, and it's puzzling me. I have attached the pics of the two jacks, the input stereo blu lead goes into the BI and the I now goes into the IN of the PCB, ditto for the output jack but with BO / O.

Confusingly enough now with the multimeter I get no continuity between IN and OUT on the PCB, yesterday I was. Maybe in my clumsy attempt to desolder and fix existing, poor-looking solder joint I have fried everything?

 

[adinapoli]

Further update: I have discovered that if I make the two tips of the input and output touch (see photo), I get a bypass signal. What does that mean?

 

[Mcknib]

It means you're bypassing the 3PDT switch and jacks ie joining the two cables making one cable from guitar to amp if you take the cables out of the jacks and touch the tips together you'll get the same thing

*EDIT* just re read your post jacks go to I and O pcb to BI and BO ( board in and board out)

You don't say if you now get audio when switched to effects mode

Continuity check your switch in bypass mode try to place your probes on the top of the switch lugs and not the solder joints

Place one probe on the in jack tip and check from in jack tip to 3PDT I pad along the red lines to out jack tip




Check the switch in both positions in bypass mode middle common row should connect to bottom row only

In effects mode middle to top row only

The middle row should only connect to the top or bottom row and not both at the same time

You could simply have a cold solder joint somewhere on the jacks or 3PDT or in and out connections

 

[adinapoli]

It means you're bypassing the 3PDT switch and jacks ie joining the two cables making one cable from guitar to amp if you take the cables out of the jacks and touch the tips together you'll get the same thing

Ah, good to know, today I have learned yet another thing

You don't say if you now get audio when switched to effects mode

I do get audio but it was a bit messy trying to engage the effect while manoeuvring everything with one hand. However I can't remember if I was getting sound only when the switch was pressed. I vaguely remember the sound wasn't present on both foot switch states, but I will have to double check , don't quote me on that

Continuity check your switch in bypass mode try to place your probes on the top of the switch lugs and not the solder joints

Place one probe on the in jack tip and check from in jack tip to 3PDT I pad along the red lines to out jack tip


View attachment 68718

Check the switch in both positions in bypass mode middle common row should connect to bottom row only

In effects mode middle to top row only

The middle row should only connect to the top or bottom row and not both at the same time

You could simply have a cold solder joint somewhere on the jacks or 3PDT or in and out connections

Thanks, I will try later tonight. One dumb question, as you are very kind in assisting: those red lines are just the paths I need to check for connectivity right , not anything I should have soldered together , correct ? (I.e. the purpose of the daughterboard is exactly the one to not have me do any manual wiring apart from the obvious soldering , but you never know).

Another silly question: how can one make a cold solder joint , and how do I avoid it? Better technique?

Thanks a lot for your time

Alfredo

 

[Mcknib]

Yes red lines just show signal route in bypass mode

Just to clarify you said this:

I have attached the pics of the two jacks, the input stereo blu lead goes into the BI and the I now goes into the IN of the PCB, ditto for the output jack but with BO / O.

Are you saying you've soldered the jack tip wires to BI and BO on the 3PDT pcb and IN and OUT from the main pcb to I and O on the 3PDT pcb? Or have you just written it wrong

The in and out jack tips go to I and O
The main pcb IN and OUT go to BI and BO

 

[adinapoli]

Yes red lines just show signal route in bypass mode

Just to clarify you said this:

I have attached the pics of the two jacks, the input stereo blu lead goes into the BI and the I now goes into the IN of the PCB, ditto for the output jack but with BO / O.

Are you saying you've soldered the jack tip wires to BI and BO on the 3PDT pcb and IN and OUT from the main pcb to I and O on the 3PDT pcb? Or have you just written it wrong

Sorry, it's just a typing mistake (I hope): I can confirm that (for example for the stereo input jack) the blue lead goes from the Jack to the I, and then the green lead goes from the BI of the daughterboard to the IN of the main PCB.

For the mono output , the blue lead goes from the Jack to the O, and the green lead from the BO to the Out of the main PCB board.

The in and out jack tips go to I and O
The main pcb IN and OUT go to BI and BO

 

[adinapoli]

It means you're bypassing the 3PDT switch and jacks ie joining the two cables making one cable from guitar to amp if you take the cables out of the jacks and touch the tips together you'll get the same thing

*EDIT* just re read your post jacks go to I and O pcb to BI and BO ( board in and board out)

You don't say if you now get audio when switched to effects mode

Ok, I have done another test tonight, and it's weird. First of all, I get the signal (via touching the two tips) only in effect mode, but when in effect mode, only the volume seems to work, drive and tone do nothing

If I go into bypass mode (red light ) then I get no signal whatsoever even when the two tips touch. How am I sure that I am in the right mode and that I haven't swapped the diode orientation? Because when the led is RED I can successfully execute the test that Mcknib suggested, and I get connectivity from the input tip to O via the bottom row as per picture.

However, when in effect mode, I get connectivity up until the top right pin, then nothing, and I have no connectivity between I and O.

Time to abandon ship and throw everything in the trash? I am starting to fear that I have fried either the PCB or some of its components

Continuity check your switch in bypass mode try to place your probes on the top of the switch lugs and not the solder joints

Place one probe on the in jack tip and check from in jack tip to 3PDT I pad along the red lines to out jack tip


View attachment 68718

Check the switch in both positions in bypass mode middle common row should connect to bottom row only

In effects mode middle to top row only

The middle row should only connect to the top or bottom row and not both at the same time

You could simply have a cold solder joint somewhere on the jacks or 3PDT or in and out connections

 

[Mcknib]

Try reflowing the 3PDT lug solder joints first just hold your iron on each joint for around 6 seconds until you see the solder flow take a few seconds between each lug to allow it to cool once done check if you get bypass signal

The top row you won't get continuity between input and output because it goes through the circuit so they're not directly connected, how it works below


When the middle common row connects to the top row (purple lines) it sends your guitar signal in from the input jack to lug 2 which connects to lug 1 and to the input pad of the circuit it goes through the circuit to the out pad which connects to lug 7 then lug 7 connects to lug 8 output jack to your amp

At the same time lug 5 ground connects to lug 4 switching your LED on in effects colour

When switched to bypass mode (red lines) you can see 2 connects to 3 goes along the jumper to 9 and connects to 8 sending your signal from the input jack straight to the output jack completely bypassing the circuit and again lug 5 ground connects to lug 6 switching your LED on in bypass colour

You should continuity check your switch as advised before, making sure that in effects mode the middle row connects to the top row only and not the bottom row at the same time in bypass mode middle connects to bottom row only and not the top row this will let you know if your switch has any internal damage caused by too much heat from soldering

I wouldn't give up on it yet it can't be much causing your fault