Basically I just finished a cry baby gcb 95 on vero and I hooked it up. To no surprise it didn't work and later I found out it was a faulty switch. Still dosent work. When I say 'dosent work' I mean it works normally and no tone is lost which is the point of bypassing however when I engage the effect, I get nothing. Imagine unplugging your guitar when your amp is on and you get no sound but the faintist buzz (because of the amp). This is what im experiencing. I have ran a blade several times through the tracks and made sure it is wired up correctly but it still dosent work. Any feedback or advice would be amazing! Like I say I have built many pedals before so I know it shouldnt be my soldering, maybe the caps? Thanks
Aran
Hey Aran,
The problems could be quite a few, and the real key is to narrow down the issue by eliminating the things it isn't.
I'm going to move this thread over to the tech help area, and I recommend that you read the thread below for some debugging ideas. For instance, do you know you're getting power to the right places? Are you sure you have your signal going in and out of the pedal properly?
The tool you really need at this point is a good audio probe. If you haven't built yourself one, and you plan to build pedals, you should build one asap.
http://www.madbeanpedals.com/forum/index.php?topic=902.0 (http://www.madbeanpedals.com/forum/index.php?topic=902.0)
Jacob
Yeah ive got it wired up properly e.g two wires going to out and pos wire going to circuit etc. I cannoit yet find an issue but on the bright side the mpsa18 trannie I have spare from the order, now is in my seamoon funk machine and makes it sound so much better. Anyways It might be the inductor? Im using an axial 500 mh. Cheers
Aran
Quote from: aran.e666 on December 04, 2014, 08:55:29 PM
Yeah ive got it wired up properly e.g two wires going to out and pos wire going to circuit etc. I cannoit yet find an issue but on the bright side the mpsa18 trannie I have spare from the order, now is in my seamoon funk machine and makes it sound so much better. Anyways It might be the inductor? Im using an axial 500 mh. Cheers
Aran
Please read the entire topic Jacob linked to. It contains instructions for what we need to help you troubleshoot your project.
Without that information, it's like calling someone on the phone and saying that you've got a letter that doesn't make any sense, but they don't have a copy of the letter and you won't even tell them what the letter says. All anyone can do is guess. Maybe they'll get lucky and describe exactly what's wrong, but how likely do you think that is?
I guess il describe the problem then. So I guess it could be the input jack since its old but I have probed the wiring, checked it over 11 times and I see no fault. With the vero I have ran a blade down each strip and used a magnifying glass to cgeck and it looks ok. Maybe its the inductor, its axial. The values are all right and like I said its all wired up right because it bypasses nicely but dosent engage when I select the effect. But it could be the pot wiring but I have done it as specified on the schem.
Aran
Quote from: aran.e666 on December 04, 2014, 09:33:22 PM
I guess il describe the problem then. So I guess it could be the input jack since its old but I have probed the wiring, checked it over 11 times and I see no fault. With the vero I have ran a blade down each strip and used a magnifying glass to cgeck and it looks ok. Maybe its the inductor, its axial. The values are all right and like I said its all wired up right because it bypasses nicely but dosent engage when I select the effect. But it could be the pot wiring but I have done it as specified on the schem.
Aran
Look, I'm not trying to be a jerk, but again, please READ the post Jacob linked to and follow the instructions. It has a FORMAT for your post. It tells you to take VOLTAGES using your multimeter. It suggests taking PICTURES of both sides of the board. It provides numerous other diagnostic steps you should take and document before you post a tech help thread. Among other things that might not be obvious, you haven't linked to the schematic or even the
layout you're working from.
We're all friendly here and many of us enjoy helping, but seriously, read the post and provide the information that Brian and Jacob instruct you to post. Until you provide all of it, we are just guessing and can offer no useful advice. Help us help you.
Well in the UK it is 11pm so im going off for the night but tomorrow I will take voltages, pics of the board and post the layout etc.
Quote from: aran.e666 on December 04, 2014, 11:00:24 PM
Well in the UK it is 11pm so im going off for the night but tomorrow I will take voltages, pics of the board and post the layout etc.
Great! The key is figuring out where the signal stops. If the wiring is correct, than the signal is stopping somewhere on the PCB, so we need to figure out what's wrong.
9 times out of ten it's a simple mistake, and you'll be up and running in no time. Get us those voltages and be prepared to learn how to audio probe your PCB.
Jacob
Ok the voltages read - dc = 9.26v
Q1 C-8.22v B-2.14v E-3.36v
Q2 C-7.73v B-1.04v E-3.37v
Q3 C-7.54v B-5.23v E-6.81v
Could you share the layout you're working from, and some good pictures of the guts of your pedal? We need to see your wiring, and your circuit and layout will be a big help in determining if your voltages are correct.
However, the fact that you're getting power to the PCB is a very good sign. Perhaps knowing if you have signal at the input and output of the PCB (not the switch, the actual PCB) that would help. The best approach is tracing backwards from the output to where the audio stops, then you'll know where to start.
Jacob
Quote from: jkokura on December 06, 2014, 10:22:07 PM
Could you share the layout you're working from, and some good pictures of the guts of your pedal? We need to see your wiring, and your circuit and layout will be a big help in determining if your voltages are correct.
And the schematic the layout was from.
Without more information, the best I can say is that there are very few situations where the emitter of a BJT being used as an amplifier or buffer can possibly be higher than the base voltage. It should be .7V lower as a rule. Therefore, you've missed a connection, shorted a connection, or failed to make a cut on the vero.
Ok il try and send a few pics, I see what you mean with the voltages. Thanks
Aran
Heres sadly the best shot of the guts
That's a tremolo layout.
Jacob
Oh god clicked wrong pic (epic facepalm) :-[
Also just so you can compare, this might help
Take it out of the box and take pictures of both sides of the PCB. Unless or even if it worked before putting it in the enclosure, you cannot troubleshoot a pedal when it's in a box.
Your emitters of Q1 and Q2 are the same. That's not possible. Q2 should be nearly at ground potential, perhaps half a volt. I would bet that if you pulled out your multimeter and set it to continuity, you would find that they're connected, which would indicate that you did that cut wrong -- and where there's one cut wrong, there are many.
Is this your first veroboard build?
Okay thank you il send a pic of the base. I bet thats where I went wrong. Thanks
Aran
After following your advice midwayfair, I found a bridge which I must of made when I pushed the board back in since there was a long lead left but now it bypasses like it should and when the effect is engaged, all I get is very quiet fuzz/distortion. To hear this I had to crank up my amp to almoast max volume!
Aran
Also have I wired the pot right?
Aran
No. You wire the pot to Wah 1&2 as per the layout you attached.
Also as per Jon's comment above, you need to check the emitters of q1&2, they should not be connected...
Ok so does the 3rd lug not go to output? Also il quickly check if q1 and 2s emmiters are connected. Thanks
Aran
You can get away with much, much, much less solder, the potential bridges on there look to be pretty extensive, you'll need to check each individual copper segment against all those around with a meter set for contnuity to ensure there's no shorts.
Good luck!
dave
edit;added clarity
Yeah I thought that too, I checked with a magnifying glass and ran a very sharp Stanley knife blade through EVERY track like 20 tines atleast, any other ideas? Thanks
Aran
Quote from: aran.e666 on December 07, 2014, 09:13:24 PM
Yeah I thought that too, I checked with a magnifying glass and ran a very sharp Stanley knife blade through EVERY track like 20 tines atleast, any other ideas? Thanks
Aran
Everyone's eyes suck at detecting shorts, no matter how much you magnify it. You can't see the electrons.
Use a multimeter set to continuity to check. And use the schematic, not just the layout.
My multimeter is quite strange bacause it sometimes picks up continuity then it loses it so I might not see it so il give that a shot but I really cant see anything wrong with how ive wired it offboard etc. Thanks
Aran
Quote from: midwayfair on December 07, 2014, 09:17:01 PM
Quote from: aran.e666 on December 07, 2014, 09:13:24 PM
Yeah I thought that too, I checked with a magnifying glass and ran a very sharp Stanley knife blade through EVERY track like 20 tines atleast, any other ideas? Thanks
Aran
Everyone's eyes suck at detecting shorts, no matter how much you magnify it. You can't see the electrons.
Use a multimeter set to continuity to check. And use the schematic, not just the layout.
Yes, i should have said check for shorts/continuity with a meter. I'll fix that.
If you can't rely on your meter for checking continuity you're sunk, you need a new one!
Im back, just found a link with my meter and stupidly broke a wire, il be back in a min when ive soldered it back. Cheers
Aran
:'( it bypasses and engages the effect but it acts as a volume pedal again
Aran
the PCB out AND the pot lug three both go to the switch. I have not built a wah before, and this layout lists two outputs, which confused me. I went and looked at a schem to see that this does indeed have two outputs that must be connected.
Found several more links but still to my suprise it still just controls the volume only :-\
The Boomerang is a wah that when switched off acts like a volume pedal. It has something to do with taking the inductor out of the signal. I'm not %100 sure, but it would indicate you either have a bad inductor or some other error on the PCB.
Jacob
Yeah I have a 500mh axial inductor. Is this okay? Thanks
Aran
So I cut the tracks again and now it dosent engage. This pedal I literally f*cked. I hope I can find a way. What il do is get the voltages again and compare them. When I put the voltages tell me if they seem strange. Thanks
Aran
New voltages q1-q3 c 9.15v b2.39v e3.73, c8.95v b- e-, c9.14v b0v e-
Aran
After everything I have came to conclusion that it is a faulty mobo. I will have order some vero and some caps unless I can diagnose it!
Aran