Hey all
True to form I've just finished another pedal and it doesn't work. It's my second attempt at a Doombutter. Sound in bypass but nothing when the pedal is engaged. The internal LED doesn't light and the transistor/regulator is getting really hot.
I've been through it multiple times and can't find the problem/s. Without wanting to sound like I'm having a tantrum, I'm seriously thinking about hanging up my soldering iron for good this time. I don't think I've got the skills for this.
Is there anyone out there with greater debugging skills than me that would be kind enough to have a look at it for me? I'll post it out to you and obviously cover the return postage and buy you a pint. I'd be extremely grateful and you might just stop me throwing my parts box out of the window!
Pictures:
(http://img.tapatalk.com/d/13/06/17/rebypezy.jpg)
(http://img.tapatalk.com/d/13/06/17/7apy2eze.jpg)
Thanks
Martin.
Martin,
Right off the bat I see a few items of interest.
1) Right where your power wire (red one i assume) is soldered onto the PCB. Looks like the solder joint is suspect. Same goes for the larger cap in the upper right hand side of the component-side pic. Looks like a bad joint.
2) Right next to the "Ver 1", there appears to be a solder bridge. Could be wrong though as it looks like it is a power filter cap connected to the power rail.
Have you gone through the circuit and looked for solder bridges annd verified component values?
Voltages might help as well ;)
Don't give up! Like most things worth doing, it takes some practice. You'll get better at it, and you'll feel awesome.
Absolutely don't quit. I've been thinking about this post the better part of the day.you didn't learn to play guitar over night,it just takes patience and practice. You've chosen an etched board for number 2, and those are no easy task. Be patient and well talk you down.
In addition to advice above look and see if there is a possible bridge where your input wire is soldered (green wire) and at C2 as well. This is not an easy project if you are just beginning so don't be discouraged. Etched boards are not easy at all. My first attempt was a phase 90. FAIL. Then I tried a TS-808. FAIL!!! I was pretty discouraged myself, but I shifted gears and started working with fabbed PCB's and basically honed my soldering skills. I eventually tried etching again and started with a simple fuzz. It worked! I'm still no pro, but I have done a few complicated etched boards with no problem. Some people have no problem jumping in the deep end but if we can't help you get this one running I would consider an easier etch (i.e. boost/fuzz/low parts count overdrive) or a fabbed board. Don't give up! You deserve to have the feeling of firing up your own build...
These etched boards that have such tight ground planes are a challenge to begin with. You might want to try a layout from www.generalguitargadgets.com. His designs usually have more room between traces. You can build up you're soldering skills and get a few successful builds.
If you like compressors his Orange Squeezer is a nice easy one pot build and is a great sounding pedal.
http://www.generalguitargadgets.com/pdf/ggg_osq_lo_pot.pdf?phpMyAdmin=4a28f86a515b7883e7bc35a68d4e7b6d&phpMyAdmin=78482479fd7e7fc3768044a841b3e85a
Like the others have said, don't give up you have a whole community here that will help you. It is a fantastic feeling to look down and see pedals you have built yourself.
Hi guys
Thank you for all the advice and encouragement. I'm sure you've all had moments where you feel like packing it in! Ha.
I've checked all the joints and there doesn't seem to be any bridges. A pad has lifted slightly C12 but I've checked with my dmm and there's continuity between the leg of the cap and the connecting leg of the IC socket so I don't think that's the issue.
I checked all the component values and they all seem spot on. The Wima box cap at C4 is marked 0.01. That is 10nf isn't it?
I plugged it in again this morning (I'm in the uk) and the transistor/regulator instantly started smoking. This happened with my last attempt too. Could I have a dodgy batch or is this more likely to be a sign of a problem elsewhere in the circuit?
Thanks again for the help. It's really appreciated.
Martin.
Hi, as you are saying that the regulator immediately started smoking- can you remove it and use your DMM to find out if there is a shortcut between Pin 1 and 3 or 4 of the PT 2399? (Remove ic and meassure resistance at the socket)
If the reading is 0 Ohm then you can make the next step and check the IC socket pins for bridges or remove C8
To check again.
EDIT: i just digged the build doc and the only way you can have that trouble is right where the regulator is soldered (you might want to reheat the three pins and see it they flow apart or stick togeteher) and with C8.
It only goes step by step Im afraid.
So in brief I need to remove the regulator, re-solder the socket and C8? I'll give it a shot after work.
Thanks again!
yes, just go step by step.
remove regulator
meassure resistance (to see if there is a shortcut)
if shortcut then reheat regulator socket pins or desolder socket.
if there s still a shortcut remove C8, meassure again.
depending on the outcome next steps vary.
Check the pinout and orientation on your voltage regulator. I think it may be in backwards.
Edit:
If it is in backwards, it's likely dead now. So, you should try another. The pinouts for very similar regulators can be different, so you need to check the spec sheet for your particular model.
Quote from: RobA on June 17, 2013, 12:22:27 PM
Check the pinout and orientation on your voltage regulator. I think it may be in backwards.
Edit:
If it is in backwards, it's likely dead now. So, you should try another. The pinouts for very similar regulators can be different, so you need to check the spec sheet for your particular model.
What he said, Voltage Regulator is backwards.
I REALLY hope that this is the problem. I bought them off eBay and tey doidn't come with a spec sheet so I can't check. I'll just have to stick one in back to front and see if it works.
Thanks
EDIT: These are the regulators I bought http://www.ebay.co.uk/itm/REG-LM78L05ACZ-5-0V-100mA-TO-92-3-IC-VOLTAGE-REGULATOR-NATIONAL-/190816232397?ssPageName=ADME:X:AAQ:GB:1123
It looks to me like you have the regulator in correctly according to your pic (based on the datasheet).
Quote from: Effectsiation on June 17, 2013, 01:48:13 PM
Quote from: RobA on June 17, 2013, 12:22:27 PM
Check the pinout and orientation on your voltage regulator. I think it may be in backwards.
Edit:
If it is in backwards, it's likely dead now. So, you should try another. The pinouts for very similar regulators can be different, so you need to check the spec sheet for your particular model.
What he said, Voltage Regulator is backwards.
+2 if you are using LM78L05 in IC3, it's backward...
Looks like there's some different opinions on this. I'll just have to give it a try I guess.
Thanks everyone.
The easy way to get spec sheets is to just go to Mouser and search for the part. Their info almost always has links to the spec sheet. If they don't have it, you can find them on the manufacturers website. These are from National Semi, who was bought out by TI. So, TI's website search will get you this link,
http://www.ti.com/lit/ds/symlink/lm78l05.pdf (http://www.ti.com/lit/ds/symlink/lm78l05.pdf)
When you look at that doc, it's import to note that the diagram is from a bottom view. I hate it when they do that.
Quote from: TreeSlayer on June 17, 2013, 02:42:20 PM
+2 if you are using LM78L05 in IC3, it's backward...
If he is using the LM78L05A, when looking at the TO-92 with the flat side facing you and the legs down, the INPUT should be the RIGHT leg.
Judging by his circuit, and the orientation of the TO-92 in the pic above, it looks like it is correct to me ???
(https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcS9P3aIXO4Devu74fqKcqjNmncPVbGim0QWr_-dNOIn_kozw7Xpyw)
I think the input on the board is off of the diode and not the side to the power wire.
Edit:
By input on the board, I mean the input to the regulator. The diode is inline in the schematic. It's not a crowbar.
Quote from: Govmnt_Lacky on June 17, 2013, 03:01:49 PM
Quote from: TreeSlayer on June 17, 2013, 02:42:20 PM
+2 if you are using LM78L05 in IC3, it's backward...
If he is using the LM78L05A, when looking at the TO-92 with the flat side facing you and the legs down, the INPUT should be the RIGHT leg.
Judging by his circuit, and the orientation of the TO-92 in the pic above, it looks like it is correct to me ???
(https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcS9P3aIXO4Devu74fqKcqjNmncPVbGim0QWr_-dNOIn_kozw7Xpyw)
EDIT: CORRECTION... after looking more closely. IT IS IN REVERSED!! :-\
Quote from: RobA on June 17, 2013, 03:05:44 PM
I think the input on the board is off of the diode and not the side to the power wire.
Edit:
By input on the board, I mean the input to the regulator. The diode is inline in the schematic. It's not a crowbar.
yup... 9v to diode, diode to leg 3i, leg 1o to PT2239+...
Quote from: TreeSlayer on June 17, 2013, 04:15:45 PM
Quote from: RobA on June 17, 2013, 03:05:44 PM
I think the input on the board is off of the diode and not the side to the power wire.
Edit:
By input on the board, I mean the input to the regulator. The diode is inline in the schematic. It's not a crowbar.
yup... 9v to diode, diode to leg 3i, leg 1o to PT2239+...
Sorry you have lost me a bit here. Are you still saying just switch the regulator around or is there another issue? Sorry if I'm being a bit dumb.
Yeah, you do need to change the regulator around. I was just explaining why it looks confusing. in the picture.
yes you do. I was just explaining that part of the power path. you'll get it...
Well I put a new regulator in the opposite direction but there's still no sound.
I'm stumped.
Thanks for all the help guys. It's really appreciated.
Have you tested any of these regulators on a breadboard just to be sure that they are working?
After that, you need to measure the voltages on your circuit. Check to see that you are getting the right voltages on each of the pins for the regulator and the IC's. Start by tracing the power path with the voltages and be sure they are what they should be.
There's a possibility that a part could have been blown when the regulator was smoking.
Also, do you have a link to the build doc/layout you built this one from?
+1! another part could be damaged. do you have an audio probe tester? you need to follow the audio path and see where the signal ends. then you know where to start...
I do have an audio probe into my test rig but I'm embarrassed to say that I don't know how to use it. My knowledge of schematics is non existent so any very basic pointers on how to use the probe would be appreciated.
Here's a photo of my test rig if anyone has the time to tell me how to use the audio probe.
(http://img.tapatalk.com/d/13/06/18/esepyquj.jpg)
Yellow=In, Red=9vt, Black=Grnd, Green=Out. Do I just attach everything as if I were testing the circuit or do I need to disconnect anything? Sorry, it's my first attempt to use it.
I think I may have bitten off more than one can chew here. It's my 4th pedal so thought I'd try something a bit more difficult but I'm starting to regret it!
Here's the build doc for the version I'm building http://tinyurl.com/kmqdx5a
Thanks for the build doc. I see why you put the regulator in that way. On the newer layout, it shows the regulator the other way around. But, the input power circuitry is basically the same. You do have to be careful with the regulators. The pinouts differ for different models of essentially the same regulator.
I can't see the whole resistor on your photo, but if R3 is a 5-band resistor, it looks like it could be a 1MΩ instead of 100kΩ.
It really helps to get used to working through a schematic. But, since you are tracing the audio on your actual board, you can do it from the layout image directly. You just listen to the audio at each pin starting with the input. When you can't hear it, that part and parts near by and their associated solder joints are suspect. You do need to know what your output pins are on your parts. Like you need to know that pin 5 is the output pin on the LM386. You can get that from the schematic or the spec sheet.
So, you trace the audio from the input to pin 2 on IC1, and then you come out pin 5 of IC1. From there you go to C4 and then R3, ... etc.
dang! I see also! you have an '09 etching! I was looking at a '10 version. looks like you had it right the first time! this is the '10 version
Quote from: TreeSlayer on June 17, 2013, 11:01:36 PM
dang! I see also! you have an '09 etching! I was looking at a '10 version. looks like you had it right the first time! this is the '10 version
I think though that his regulator should still be the other way around. The layout to the regulator still looks the same in both docs. It's just the regulator image that's different.
Edit (for clarity):
The input pin should still be to the left on both the '09 and '10 docs.
Quote from: RobA on June 17, 2013, 11:05:15 PM
Quote from: TreeSlayer on June 17, 2013, 11:01:36 PM
dang! I see also! you have an '09 etching! I was looking at a '10 version. looks like you had it right the first time! this is the '10 version
I think though that his regulator should still be the other way around. The layout to the regulator still looks the same in both docs. It's just the regulator image that's different.
Edit (for clarity):
The input pin should still be to the left on both the '09 and '10 docs.
I tend to agree. i'm trying now to compare the two. here's something that might be of intrest for diagnosing. I built one of these and it's a tremendous help! it's the "Tiny Tester" http://www.jmkpcbs.com/JMK_PCBs/Store.html
That could be very helpful. I've got a signal generator built into my computer's audio interface that has been very helpful. But, it's a pain to use. One of these would be much nicer.
Oh man, sorry for the confusion. I thought I had the newer version of the build doc as it has the fizz lift on it and the one that TreeSlayer posted above doesn't.
The tone generator seems really useful. I'll get one orders soon.
In the meantime please could someone tell me how to hook up my test rig to use the audio probe? Do I just hook everything up as normal or do I have to unclip the Out wire so that the signal goes through the probe? I'm not at home so can't try it out.
Thanks again.
Hey guys. Here is the doombutter v1 build doc
Quote from: Haberdasher on June 18, 2013, 11:02:57 AM
Hey guys. Here is the doombutter v1 build doc
Thanks for the link. Now I'm even more confused because the the other '09 one says v2 in the title but is actually this one which is clearly ver.1 in the doc.
Oh well, it doesn't matter. This is clearly the one we are working on here.
Quote from: RobA on June 18, 2013, 11:17:59 AM
Quote from: Haberdasher on June 18, 2013, 11:02:57 AM
Hey guys. Here is the doombutter v1 build doc
Thanks for the link. Now I'm even more confused because the the other '09 one says v2 in the title but is actually this one which is clearly ver.1 in the doc.
Oh well, it doesn't matter. This is clearly the one we are working on here.
Yep this is the one I've been been building (using one of your great etches). I might have screwed another one up!
Seems like theres a few versions of this circuit loating around.
Quote from: Guybrush on June 18, 2013, 06:48:53 AM
...
In the meantime please could someone tell me how to hook up my test rig to use the audio probe? Do I just hook everything up as normal or do I have to unclip the Out wire so that the signal goes through the probe? I'm not at home so can't try it out.
Thanks again.
No problem on the version. I think we have the right doc to go by now for your build and all is cool that way.
Did you check R3? If that one is off, there won't be any audio coming out.
As far as using your audio probe goes, I don't have a built probe, so what I'm saying here is based on my assumptions about how yours works. I assume you have an output jack that's got a decoupling cap before it and connections for ground and the probe? If so, you'd just hook up the ground of your probe to the ground network of the pedal and then use the probe to contact the different parts/pins. You shouldn't need to disconnect the pedals output jack. Just not having anything plugged into would essentially do that anyway even if you did have to.
Pretty much, probing for audio through the audio path is just hooking up an output at each point. The only thing you really need to account for is that signal might be biased at the point you are listening to it, so your probe needs the decoupling cap that I assume is already there.
If you can send me a link to the docs for your test rig, I can look and see if there is anything else to note about how to use it.
So...
I just nipped home from work and hooked the circuit back up to my test rig with the idea of using my audio probe on it (thanks for the advice RobA) and the bloody thing worked! I've no idea what changed but I'm getting sound loud and clear. Baffling! There is still something wrong though as the internal LED is not lighting up which will obviously be having an affect on the effect if you catch my drift? If I tap the circuit/wires etc the LED occaisional lights up for a split second which leads me to believe I have a bad connection/solder joint somewhere. Does this sound possible?
On a related note, what does the LED/LDR 'do' to the effect? As I have said the LED isn't lighting up but the effect seems to be working somewhat without it.
Thanks again!
Yes if you are tapping wires/components and getting intermittent signal then it is most likely a bad solder joint/connection. It may be a good idea to reflow all solder joints. Looking at your pics, besides some possible bridges, it also appears you may have some cold joints as some look dull and "balled" up. You should be striving for a nice, shiny hershey-kiss solder joint.
Making progress, your getting signal :)
Maybe you've discovered some new form of self healing silicon? ;D
Seriously though, that is good. I've never built this effect, so I have no idea what it's supposed to do.
From the schematic, I'm guessing it's a bit of an amp sim/overdrive with a delay whose delay time is modulated by the volume envelope of the guitar.
The LM386 must be working at least somewhat because you wouldn't get any audio otherwise.
The PT2399 could easily have been damaged when the regulator was smoking.
It would be a good idea to check the voltages on the power pins of the chips and the regulator to see where you are at.
Definitely check your joints for the LED. Particularly look at the Track pot's joints and C3.
One question about the solder joints, are you using lead free solder? I ask because there are two things to consider. The first is that a lead free solder is harder to see a cold joint with. It tends to look frosted even when the joint is good. The second point is that if you are using lead free solder, you need to use a higher temp with your iron to get good flow.
Sometimes my testing rig goes stupid on me too.
Quote from: jimilee on June 18, 2013, 01:29:56 PM
Sometimes my testing rig goes stupid on me too.
I was wondering if it was my test rig. It was the first thing I built so I might open it up and have a look at how bad my soldering is!
Quote from: RobA on June 18, 2013, 01:17:47 PM
One question about the solder joints, are you using lead free solder?
Yes I am. I was using leaded stuff and started to get a tight chest so switched to lead free some time ago. I bought a much better soldering iron yesterday and did some work on another board last night at 400C/750F. Is that going to be hot enough to get nice solder joints with lead free?
Quote from: RobA on June 18, 2013, 01:11:30 PM
It would be a good idea to check the voltages on the power pins of the chips and the regulator to see where you are at.
Will do. Where can I find what the voltages of the IC should be? I can't see them on the schematic.
Sorry for all the questions. I've only built 3 relatively simple pedals before and I'm encountering a lot of 'firsts' with this build. There's always more to learn!
Quote from: jimilee on June 18, 2013, 01:29:56 PM
Sometimes my testing rig goes stupid on me too.
Sometimes I go stupid on me ;D. That's when it gets really fun debugging.
;D
Quote from: Guybrush on June 18, 2013, 01:36:22 PM
...
Quote from: RobA on June 18, 2013, 01:17:47 PM
One question about the solder joints, are you using lead free solder?
Yes I am. I was using leaded stuff and started to get a tight chest so switched to lead free some time ago. I bought a much better soldering iron yesterday and did some work on another board last night at 400C/750F. Is that going to be hot enough to get nice solder joints with lead free?
400 should be good. Different lead free solders behave differently, so that's a bit of a learning process too. I'm still working on figuring what works best here too. I just got a new lead free solder that I hope to test this week. It is a bit more challenging to work with the lead free, but I think it is worth it.
Quote
Quote from: RobA on June 18, 2013, 01:11:30 PM
It would be a good idea to check the voltages on the power pins of the chips and the regulator to see where you are at.
Will do. Where can I find what the voltages of the IC should be? I can't see them on the schematic.
Sorry for all the questions. I've only built 3 relatively simple pedals before and I'm encountering a lot of 'firsts' with this build. There's always more to learn!
No problem with the questions, it's what this section of the forum is all about.
Good question on the voltages. You usually need to take them from a known working pedal. Good circular catch there huh? (Really you could work it out theoretically or simulate it, but that's going to be a pain.) But, for the supply voltages, which is where you need to start, you can see it on the schematic. Mainly you want to look at the voltage on the regulator, LM386, and PT2399 to start. Pin 3 of the regulator should be close to 5 volts which feeds pin 1 of the PT2399 and this should be at 5 volts too. Pin 6 of the LM386 should be close to 9V (whatever is at pin 1 of the regulator and the output of D1). It should really be at about 0.6V less than your input voltage.
Thank you so much.
Is this the correct method to test voltages:
- Hook circuit up to test rig and power up.
- Clip or hold black DMM probe onto ground wire.
- Touch red DMM probe to point on circuit that needs to be tested.
- Take reading.
Will the reading settle and be definate or may it wander a little?
Thanks
Yep, that would be the process.
The reading stability depends on the pedal. Some can wander or pulse if there is an element that changes how much power it draws (like LED's in an LFO based circuit). Sometimes the voltage on a pin will move quite a bit as in the pins on IC's in an LFO.
I guessing that these power supply pins should be pretty stable.
I've got home re-flowed all the joints and it's working perfectly.
Thank you for everyone's help. I may not have had to use all the advice given but I've learnt tonnes from all your help.
Hi-5s all round.
Time to start on the mods now!
Cheers guys!
Excellent! Congrats on the build.
Awesome feeling
Spoke to soon...
I was playing around with it on my test rig and it just stopped working.
I'm getting sound but no effect. Theinternal LED isn't lighting at all and the knobs aren't working. Ha.
EDIT:
I tool some voltage readings. They don't mean much to me but could anyone please tell me if they look correct?
Regulator:
1: 8.56
2: 0.03
3: 4.8
IC1:
1: 1.34
2: 10.2
3: 0.02
4: 0.02
5: 3.92
6: 8.57
7: 4.27
8: 1.35
IC2:
1: 4.78
2: 2.39
3: 0.05
4: 0.05
5: 0.00
6: 0.01
7: 0.27
8: 0.39
9: 2.39
10: 2.39
11: 2.39
12: 2.39
13: 2.39
14: 2.38
15: 2.39
16: 2.39
Phew.
Well that sucks. But, look at it this way, you'll be able to celebrate getting it fixed twice now.
The good thing is that you know the LM386 is good and that the audio path is good from there to the output.
Is the blend knob working like a volume pot?
One thing to note is that the LED is tuned on by the guitar signal from the LM386. It could be very faint and still be doing it's job.
Go back to checking the voltages at the PT2399 and then trace the audio at pins 16 15 14 13 and around R5. Then listen at lug 3 of the blend pot and trace back from there to the PT2399.
I'm assuming that you still should get delayed audio even if the LED/LDR aren't working. So you should focus on the PT2399 first. If I'm wrong about that, hopefully someone will let us know.
Im no master builder BUT...
How can you have a higher voltage (10.2) on Pin 2 of IC1 than you have going into the pedal/circuit :o
I'd say you have something going on in that area ;)
Are you sure that pin 2 reading wasn't in mV?
The one that really stands out to me is pin 6 on the PT2399. Does this vary at all when you move the depth or delay pots? I would use my DMM to check and see if pin 6 has continuity to ground.
I re-checked and some of the voltages were the same and some were different. I had a dig in my parts box and found I had a spare of each chip. I swapped them both out and hey-presto all's well again! Perfectly screwed up delay goodness.
Fingers crossed that'll be the end of it!
Thanks again!
Well Yeah! again :D. It is very likely that the earlier voltage problems caused problems for the PT2399. I'd guess the LM86 might be good though and I'd test it in the circuit to see.