Need help debugging RAT clone (from AionElectronics)

[danilov]

Hello. This is my first build, and I don't know really how to debug the pedal (even if I've a multimeter...).
I think that I f*cked up with the wiring and not with the PCB, because:
- I made this pedal following directly the documentation, and using LEDs for the other clipping section,
- the pedal turns on but there is no sound (neither in bypass mode) but when I play the guitar switching the LEDs clipping section, the LEDs blink as I play softly or harder, that's why i think that the problem is the wiring (maybe the output?).

Please help me to debug this pedal.
The schematic: https://aionelectronics.com/wp-content/uploads/2013/11/aion-helios-rat-documentation-v2.pdf
Some pictures: https://imgur.com/a/wP5RP

[Kipper4]

Some ideas
Are the correct jack lugs connected to the switch right. Ie Are you sure you didnt connect the ground to the place where the tip should go on the little switch pcb.
I ask because normally even if the effect circuit doesnt work and the switch was wired right normally you would get a signal in bypass mode.
assuming its a true bypass switching arrangement.


The next thing to do is use said multimeter to take some chip voltages and transistor voltages.

heres a guide to doing that. If its not making sense to you. Google using a multi meter.

http://en-us.fluke.com/training/training-library/test-tools/digital-multimeters/how-to-measure-dc-voltage-with-a-digital-multimeter.html

Rich

[Kipper4]

Also if you google audio probe and make one then it will help you for the future in debugging.

croc clip (ground)-----------------\(sleeve)------------
                                                                            1/4 mono jack (male)
wire--100nf ceramic capacitor-----/(tip)---------------

Edit. Forgot the kind welcome.

[Elijah-Baley]

Hi, and welcome.
You can verify if the circuit works. Disconnect the footswitch and connect the input and the output wires directly with the jack input and output. And connect the ground, the two sleeves and the negative of the dc jack all together. Make a research about it in case I am not clear enough.

Search how the 3PDT works, and use your multimeter to test the contacts of the wires starting from the board.
It is all enough easy. Make some little researches to see how to do these operation.

[danilov]

wow guys thank you really much I appreciate this (and omg I didn't believe i'd get answers so fast!). Now I'm not at home, tomorrow I will follow every advice.

Note that I followed this documentation for the wiring https://aionelectronics.com/wp-content/uploads/2014/09/aion-3pdt-bypass-documentation.pdf and also I'm new to these things (never soldered jacks so maybe there is a mistake there).

EDIT: I'm so dumb, watching the pictures I made a mistake with the input jack tips/sleeves ...

Btw, thanks for the welcome

[duck_arse]

in this photo, I can see .......



.... the left-side jack has the tip connection to ground, and the sleeve connected to the F/S. reverse those connections and see what is. also, look VERY closely at your two clipping leds, because I think they are both facing the same direction, and the yellow is backwards (to the overlay) - the kathode body-flat is not clearly visible on the red led.

also, welcome +1.

[danilov]

in this photo, I can see .......



.... the left-side jack has the tip connection to ground, and the sleeve connected to the F/S. reverse those connections and see what is. also, look VERY closely at your two clipping leds, because I think they are both facing the same direction, and the yellow is backwards (to the overlay) - the kathode body-flat is not clearly visible on the red led.

also, welcome +1.

Yes! I saw that big mistake. However, I thing that for the leds I made it right, cause I soldered the positive legs of both LEDs in the "square joint". ( I'm not sure where i saw that, but I soldered a little "bridge" on the other joints that were free)

[rutabaga bob]

Welcome to the forum...always room for one more!

[duck_arse]

D3, the yellow led, has the body flat, indicating the cathode connection, facing the overlay's anode marking. the cathode goes to "more ground" than the anode, which goes to "more positive" if you want the led to conduct, produce light, or clip signal. BUT - if your other led is also 'backwards', then the two will be anti-parallel as the circuit requires and you can leave them. I just can't see a polarity indicator on the red led to say good or bad.

[jez79]

Looks to me like the 3pdt is in the wrong orientation.
Those solder lug tabs should be horizontal, not vertical...

[danilov]

Looks to me like the 3pdt is in the wrong orientation.
Those solder lug tabs should be horizontal, not vertical...

Nope, the orentation is good... You can see it better here //[url="http://i.imgur.com/Knf8Wwq.jpg"]http://i.imgur.com/Knf8Wwq.jpg[URL]

Inviato dal mio Nexus 5 utilizzando Tapatalk

[danilov]

UPDATE: I've reversed the connections on the input jack -> input jack goes to the tip, ground to the sleeve. You can see some pics here: https://imgur.com/a/VFLid
I do not hear sounds in bypass mode nor when the pedal is on.
This time, when I switch to the LEDs clipping section, the yellow and red leds don't blink... 

I'm assuming I'm going to learn how to use the multimeter today :-)

[duck_arse]

don't use the clipping leds to indicate correct operation, they may be working 100% and you mightn't see anything happening. or they might light up like a xmas tree.

so now you need to do some meter checks. FIRST OFF - power off, set yr meter to low ohms/continuity and insert a lead into each jack. probe from one free plug tip to the other - work the footswitch. does the meter drop to 0.00 or some similar low-low reading? do the same with the free plugs and their sleeves, you should have 0.00 both times when you work the switch. then probe from the input plug tip to the circuit board input pad, work the switch - what reading do you get? do the same for the output plug jack, and report back.

the next step is voltages.

[danilov]

don't use the clipping leds to indicate correct operation, they may be working 100% and you mightn't see anything happening. or they might light up like a xmas tree.

so now you need to do some meter checks. FIRST OFF - power off, set yr meter to low ohms/continuity and insert a lead into each jack. probe from one free plug tip to the other - work the footswitch. does the meter drop to 0.00 or some similar low-low reading? do the same with the free plugs and their sleeves, you should have 0.00 both times when you work the switch. then probe from the input plug tip to the circuit board input pad, work the switch - what reading do you get? do the same for the output plug jack, and report back.

the next step is voltages.

Man this is really helpful!

EDIT: btw the LEDs blink when I strum the guitar... even if it is not a good point, I didn't check well before haha

assuming my jacks are made with the sleeve and two tips (the longest tip is the plug?), here are the checks

w/ switch OFF

input plug - output plug = near 0

input plug - input tip= near 0
input plug - input sleeve = near 0
input tip - input sleeve = near 0

output plug -  output tip = near 0
output plug - output sleeve = near 0
output tip - output sleeve = near 0

input plug - truebypass mini circuit board input pad = near 0
input plug - circuit board input pad = near 0

output plug - truebypass mini circuit board output pad = near 0
output plug - circuit board outpud pad = It oscillates between big numbers and 1

w/ switch ON

input plug - output plug = 1

input plug - input tip= near 0
input plug - input sleeve = 1 (I guess it's ok here because of ground)
input tip - input sleeve = 1 (I guess it's ok here because of ground)

output plug -  output tip = it oscillates a bit but more or less near 0
output plug - output sleeve = near 0
output tip - output sleeve = near 0

input plug - truebypass mini circuit board input pad = near 0
input plug - circuit board input pad = near 0

output plug - truebypass mini circuit board output pad = near 0 but oscillates
output plug - circuit board outpud pad = sometimes 1, sometimes a big number, sometimes near 0... < maybe the problem is here.

I think that the wire that starts from the output jack tip isn't well connected to the mini pcb of the true bypass, because when the pedal is on if I probe ( output jack tip - output jack pad on mini pcb ) I get values near 0 but oscillates a lot.

[duck_arse]

hrm, I'm confused. 0.00 indicates a good connection, a working switch closed, a short circuit, conduction between two points. 1- indicates open circuit, an open switch, no connection between. so what you want to see is a connection from the input lead plugg tip thru the pedal and switch to the output lead plug tip. this would be "bypass wired good" .

when you work the switch, you want the meter reading to change - it will almost certainly have capacitors somewhere between the in and out of the circuit, so you will get infinity or counting reading. that will indicate that the switch is at least opening.

next you want to prove that the signal is reaching the circuit board, at the input, where the work starts. so from the tip of the plug of the lead plugged into the input socket, to the input pad on the pcb - you should get 0.00 and then 1-, showing connected, then open.

then the same with the output pad to the tip of the plug on the end of the lead plugged into the output socket. open and closed. connection and disconnection.

and at all times, all switch states, you want to be able to read 0.00 from ANY sleeve to ANY other sleeve and ANY point on the pcb marked as 0V/ground/earth. it sounds like a load of things, but it only takes a few seconds with a pair of leads and the meter, and you can prove the working signal path right thru.

so, now, have a look thru your numbers, see if you still think the problem is there. if yes - well, what is that problem?

[danilov]

hrm, I'm confused. 0.00 indicates a good connection, a working switch closed, a short circuit, conduction between two points. 1- indicates open circuit, an open switch, no connection between. so what you want to see is a connection from the input lead plugg tip thru the pedal and switch to the output lead plug tip. this would be "bypass wired good" .

when you work the switch, you want the meter reading to change - it will almost certainly have capacitors somewhere between the in and out of the circuit, so you will get infinity or counting reading. that will indicate that the switch is at least opening.

next you want to prove that the signal is reaching the circuit board, at the input, where the work starts. so from the tip of the plug of the lead plugged into the input socket, to the input pad on the pcb - you should get 0.00 and then 1-, showing connected, then open.

then the same with the output pad to the tip of the plug on the end of the lead plugged into the output socket. open and closed. connection and disconnection.

and at all times, all switch states, you want to be able to read 0.00 from ANY sleeve to ANY other sleeve and ANY point on the pcb marked as 0V/ground/earth. it sounds like a load of things, but it only takes a few seconds with a pair of leads and the meter, and you can prove the working signal path right thru.

so, now, have a look thru your numbers, see if you still think the problem is there. if yes - well, what is that problem?

Oh sh*t. I checked with the multimeter without plugging in some jacks...
I'm going to EDIT this post with the correct measurements in 15mins. < It took me 1 hour lol

Ok, let's see if I've understood.
I take 2 patch cables and insert them in the input and output of the pedal.
With the free input plug tip I mean the input jacks which is not stucked into the pedal.
WIth the socket input tip or sleeve I mean the sockets tip or sleeve (not the jack plugged into the pedal).
With the input plug tip I mean the tip of the jack plugged into the pedal.


w/ switch OFF (bypass mode)

free input plug tip - free output plug tip = drops near 0

free input plug tip - socket input sleeve (star ground) = drops near 0
free input plug tip - socket input tip = drops near 0
free output plug tip - socket output sleeve = drops near 0
free output plug tip - socket output tip = drops near 0

input plug tip - circuit board input pad = drops near 0 // I guess it should be 1
output plug tip - circuit board output pad = 1


w/ switch ON (effect mode)

free input plug tip - free output plug tip = 1   

free input plug tip - socket input sleeve (star ground) = 1
free input plug tip - socket input tip = drops near 0
free output plug tip - socket output sleeve = drops near 0
free output plug tip - socket output tip = drops near 0

input plug tip - circuit board input pad = drops near 0
output plug tip - circuit board output pad = drops near 0

Due to these datas, I got confused. THat's not how It should be, there isn't continuity between input and output. Maybe it's the True Bypass...

[danilov]

Update

w/ SWITCH ON

input plug tip - true bypass circuit board input jack pad = near 0
t.b. circuit board input jack pad - t.b. circuit board pcb input pad = near 0
t.b. circuit board pcb input pad - (master) circuit board input pad = near 0
circuit board input pad - circuit board output pad = 1
circuit board output pad - t.b. circuit board pcb output pad = near 0
t.b. circuit board pcb output pad - t.b. circuit board output jack pad = near 0
t.b. circuit bord output jack pad - output plug tip = near 0

where
free input plug tip - free output plug tip = 1

W/ SWITCH OFF
with the same procedure I got all drops near 0 in except of

circuit board input pad - circuit board output pad = not 1 but 1138
t.b. circuit board pcb output pad - t.b. circuit board pcb output jack pad = not 1 but 1138
t.b. circuit board pcb output jack pad - output plug tip = some reading but near 0

where
free input plug tip - free output plug tip = some reading but near 0

I guess - if the procedure is good - there is a broken connection on the master pcb between the input pad and the output pad, or am I wrong?

[danilov]

UPDATE!

I was going crazy, so I decided to remove the switch from the pedal to verify if the circuit worked.

I connected the negative of the dc jack and the ground of the circuit board to the input jack sleeve, then I connected the tip of the input jack to the input pad of the circuit board and the tip of the output jack to the output pad of the circuit board. I did not connected the output jack sleeve to ground. The SW wire is free (it's useful only for the LED). You can see the wiring in this pic: https://imgur.com/a/RvSxU

So I plug the guitar into the pedal to the amp and the pedal sounds great!

Ok, It seems that the problem was in the switch itself or the wiring, but before I try to re-install the 3PDT I have some questions.
Now that the circuit works without the switch, I tried to check continuity with the multimeter and...

free input plug tip - free output plug tip = 1
circuit board input pad - circuit board output pad = 1

Am I missing something? This should drops to 0! How could it possibly work?

BTW here there are some pics of the switch: https://imgur.com/a/BNsBU
I checked under the little board and I didn't see multiple pads covered up with the same solder. I don't know which could be the cause of the problem.

[duck_arse]

patch cords - exactly that, I can never remember their name. yes, plug a patch cord each .... oh, you've done all that.

I was just going to post that you should disconnect the wires from the switch to the pcb, so you could test across the switch, but It seems you've worked that out for yourself. (one test I forgot to mention was input (and output) plug tip to sleeve, to rule that out.)

now that you know the board is ok, meter from the input pad to the output pad - it should be a nonsense or infinite because of all the caps inbetween. and so you are left with the switch - it is possible too much heat when soldering will allow things internal, and under spring tension, to shift just far enough that a part of the switch won't swing properly. I'm not familiar with that/those switch pcbs, so I don't know quite what readings too expect from it, but it should short input to output, then break/open input and output; it might short the input to ground in bypass, which makes a little trikky for the remote debuggers.

best option - dump the board and switch, get a replacement - TEST THE SWITCH before solder, test the board before solder, solder, test, hope for the best and connect the wires.

with switch problems, I always say "draw the circuit". learn the right way to draw a 3pdt switch, then you just need a few ins and outs, and how it works and what to expect will become very much clearer.

[danilov]

Yeah I'll get a replacement for that switch. I should get also another multimeter (this is from the early 90s.... it doesn't even beep on continuity mode) because I don't really understand why it shows '1' when I test input pad to output pad and input plug tip to output plug tip if the pedal works ahah. Maybe it doesn't support 'infinite' or 'nonsense', I really don't get it.

However, you and the other guys were really helpful. I appreciate it a lot. Surely I'm gonna go DIY for pedals again ;-)