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PostPosted: Sat Jan 20, 2018 7:03 pm 
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Hello, all!

I just finished building the Echo Royal last night. It was my 12th build for the week and the only one that's not working. I spent the last couple hours double checking everything and I can't find any errors. Resistor and cap values are all accurate, touched up a couple weak solder joints, repositioned an IC just to be safe. But when I plug it in, the delay time led just stays on, but no other one comes on at all. The signal goes through clean when it's off. The only things I did different are that I'm not using enclosed jacks, and I mounted the 470 ohm resistor adjacent to the trimpot on the backside of the board since I'm using 1/4w. I'll be able to post pictures in the morning, but any ideas or suggestions in the meantime would be much appreciated.

Thanks.


Last edited by BadAnderson on Sat Jan 20, 2018 9:15 pm, edited 1 time in total.

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PostPosted: Sat Jan 20, 2018 9:07 pm 
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Here are the pictures.

https://flic.kr/p/JGNtwe

https://flic.kr/p/23DCbCF


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PostPosted: Sun Jan 21, 2018 12:56 am 
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I also touched up the JFET solder joints and replaced the wires to the pots. Wasn't my best work the first time around. :lol: Anyway, I've checked everything like 10 times now. I just tried it through the amp again, and all i'm getting is a slight clean signal when I turn the amp all the way up. Maybe monday I'll drive back out to Mouser to get some IC replacements just in case that's it.


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PostPosted: Sun Jan 21, 2018 4:56 am 
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Looks like your soldering still needs some work. I can see several solder pads when they should normally be completely covered with solder. Several solder joints are dome shaped which is a sign of a cold solder joint. Several joints have a thorn like look to them. This is another sign of a cold solder joint. A few of the pot solder joints look suspect as well.

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PostPosted: Sun Jan 21, 2018 10:25 am 
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I went back and replaced the pot wires and touched up ALL my joints last night, so that can't be the reason it's not working. I'll post another picture when I get some coffee in me.


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PostPosted: Sun Jan 21, 2018 3:32 pm 
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A couple questions:

I understand that you get clean signal in bypass, but what does the pedal do is effect mode? And do you get clean signal from the dry output?

Also, it looks like you’re using panel mount pots and jacks. How are you mounting the PCB?

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PostPosted: Sun Jan 21, 2018 8:12 pm 
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Hi, Morgan. The board fits in the enclosure I'm using with plenty of room to spare, so it just floats off the wires for now. I'll secure it in place when I get it working. But the back of the board isn't touching the pots if that's what you're thinking.

It doesn't do anything in effects mode, simply because I can't toggle effects mode. Hitting that switch just dampens the signal while it's compressed. I'm really quite baffled by the whole thing, as I've never had a problem building pedals, but this particular one is giving me problems I've never seen.

I'll be getting a new multimeter tomorrow, as I loaned mine to an electrician friend who lives an hour away, but I'll also be running back out to Mouser to pick up an order, so I'll be adding transistors, ICs, and diodes to my order in the morning. I can't see a logical problem, so my best guess for now is that maybe it's a problem I can't see, i.e. a bad IC or transistor.


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PostPosted: Mon Jan 22, 2018 6:39 pm 
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Update: Replaced the 1N4001 and four of the ICs. The 1N4148s look fine. No changes. I'll try transistors in a little bit after I finish some other work.


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PostPosted: Tue Jan 23, 2018 12:01 pm 
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This sounds a lot like a switching problem. The bypass switching on this pedal uses the microcontroller (IC6) to kill the wet signal path using the 4 jFETs in the lower, right-hand corner of the PCB. When you press the bypass switch, the MCU changes the voltage on the jFETs, which changes their state and blocks signal flow.

This isn't super easy to hash out when something goes wrong. One thing I see in your photos is that one of the Q8 leads appears devoid of solder on the top side. I would go through and touch up all the component solder joints associated with the bypass switching - Q5-Q8; D1-D4; R13, 21, 25 & 26; C8, 21, 23 & 24. I know you already resoldered, but trust us when we say that sometimes it takes a few swipes at it before correcting that one cold joint that is screwing things up. Also make sure IC6 is seated properly in its socket.

You can also make sure that DC voltage is changing when you hit the switch at IC6 pins 3, 5 & 7; and at D1-D4.

Image

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PostPosted: Tue Jan 23, 2018 1:37 pm 
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Thanks for the reply, Morgan. Q8 I noticed right after I posted those photos. That was one of the first things I fixed. I reseated and even replaced IC6 yesterday to no avail. I got some replacement JFETs and diodes yesterday, but haven't had a chance to try those yet. Last night, I was wondering if it might be a bad voltage regulator because it seems that power isn't getting past the initial power circuit. I had to go to Mouser today to pick up parts for a prototype I'm working on and I added another 78L05. I'll let you know how it goes today. And I'll be checking those JFETs and diodes as well.

Thanks again for the help!


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PostPosted: Wed Jan 31, 2018 10:05 pm 
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Hey, y'all. Sorry for the DELAY.

I've been waiting days for that joke. I've been swamped with work and haven't had much chance to work on this.

I just checked voltages. I checked the pins on IC6. I'm getting about 2.5 on pin 3, and nothing on 5 and 7. No change when I press or hold the switch. I'm getting nothing on the diodes either. I should have some more time tomorrow, so I'm just going to go through and check everything. Though any other leads on where to start are greatly appreciated.

Thanks again, y'all.


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PostPosted: Thu Feb 01, 2018 12:56 pm 
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Okay - it's definitely a switching problem. But we need to figure out if your MCU is bad or if something else is wrong. Your voltage readings are strange, which could mean a bad chip, bad bias voltage, or a bad joint somewhere.

Quick note - make sure you are reading voltage from the correct pins. The MCU is sort of installed upside down with pin 1 located at the lower right side of the chip, pin 3 is 3rd up from the bottom, 5 is 5th up from the bottom, 7 is upper right corner. Look at the orientation of the chip on the PCB map to make sure you are reading the correct pins.

Make sure your MCU is getting the voltage it needs. It should have a solid 5 volts on pin 1. If you have less than 5 volts on pin 1, also check IC3 pin 1, IC 4 pin 1, and IC5 pin 14. Let us know what you have there.

Check the voltage at the striped side of the 1N4001 - I get about 8.5 volts with a 9.3 volt supply.

Check continuity of your bypass switch - You should have no continuity in the 'unpressed' state; you should have continuity (0 ohms resistance or a beep from your meter) when you press and hold the switch.

Here is how the switching logic on my build looks:
IC 6 (MCU) DC Voltage - Bypass on / bypass off (bypass/trails LED is lit)
Pin 3 - 0 / 5 (cuts wet signal output in bypass, trails off)
Pin 5 - 0 / 5 (cuts wet signal input in bypass)
Pin 6 - 0 / 5 (turns bypass/trails LED on)
Pin 7 - 5 / 0 (cuts dry signal bypass loop in effect mode)

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PostPosted: Sat Feb 24, 2018 2:54 pm 
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Hi, y'all (Morgan)!

I finally got a chance to work on it a little more today. Still no luck. IC6 is performing just fine. I'm getting no voltage (actually, fluctuating between zero and negative decimals) at 1N4001. I replaced it and got the same on the new one. I'm barely getting anything at D1-4. I'll be able to work on it a little more tomorrow, but if you know where to look next, that'll save me a time-consuming hunt.

Hope all is well!


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PostPosted: Tue Feb 27, 2018 3:55 pm 
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BadAnderson wrote:
I just checked voltages. I checked the pins on IC6. I'm getting about 2.5 on pin 3, and nothing on 5 and 7. No change when I press or hold the switch.

BadAnderson wrote:
...IC6 is performing just fine.

I'm curious as to why the different readings. First you were getting half voltage, then IC6 is performing fine. Why did that change? Were you measuring the wrong pins before, or something?

BadAnderson wrote:
I'm getting no voltage (actually, fluctuating between zero and negative decimals) at 1N4001. I replaced it and got the same on the new one. I'm barely getting anything at D1-4.

This must be a false reading. The 1N4001 feeds voltage to the entire pedal. You wouldn't get any signal in bypass or any voltage on IC6 if it were not working.

Using a SIGNAL TESTER or AUDIO PROBE would be a great help in finding out where the wet signal is dying. Are you up for building and using one of those tools?

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