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DIY Stompboxes => Building your own stompbox => Topic started by: Fuzzy-Train on April 12, 2007, 07:39:15 PM

Title: Tonepad CE-2 debug
Post by: Fuzzy-Train on April 12, 2007, 07:39:15 PM
I thought I wasn't going to get this done for a while but my uncle gave me the day off today  :icon_mrgreen: :icon_mrgreen: but only after I got there lol

http://www.tonepad.com/getFile.asp?id=101

I did the vibrato, and depth intensity mods (switchable 47pf and 100pf caps for depth), I used a 1N4001 instead of the RD11EB, and a Tl072 instead of the TL022 (both subs have been said to work in previous threads) Other than that no other subs were used, and all the parts are what they should be.

I'm getting sound and the depth pot works, but the rate pot does nothing. EDIT: oh... and there seems to be no "chorus'ing" effect.

I've never taken IC voltages before so I'm not sure how to do it so I just did them like this:
1 5
2 6
3 7
4 8

It's a big one... get ready. My battery at the time was at 8.98v

IC1

1 6.79
2 6.79
3 6.70
4 0 (I'm assuming this should actually be reading something)
5 8.94
6 6.79
7 6.79
8 6.76

IC2

1 8.24
2 3.60
3 4.13
4 0
5 8.93
6 1.40
7 4.11
8 3.60

IC3

1 8.83
2 4.54
3 6.03
4 0.58
5 6.25
6 6.25
7 4.51
8 0

IC4

1 8.82
2 4.5
3 0
4 4.54
5 0.58
6 2.77
7 7.79
8 0.32

Q1

E 5.74
B 4.40
C 8.94

Q2

E 6.06
B 5.89
C 8.94

Q3

E 5.84
B 4.80
C 8.93

Q4

E 2.92
B 2.87
C 8.82

Q5

E 0
B 0.40
C 7.27

D1

A 1.36
K 2.80

D2

A 2.80
K 7.36

D3

A 0
K 8.99

Thanks in advance for the help.  :icon_wink:
Title: Re: Tonepad CE-2 debug
Post by: Andre on April 13, 2007, 05:23:59 AM
Quote
I've never taken IC voltages before so I'm not sure how to do it so I just did them like this:
1 5
2 6
3 7
4 8

The pin order of an 8 pin IC is like this:
     _____
1 -| º      |-8
2 -|        |-7
3 -|        |-6
4 -|____ |-5

The voltages on all of the pins of IC1 except Vcc and GND appear to be little to high. (6.8V instead of 4.5V.)
You might want to adjust trimmer VR3 until the voltage on pin 3 of  IC 1 reads about half of the battery voltage.
But, since VR3 also adjusts the bias of the BBD IC 3, the final adjustment of VR3 needs to be done by ear or by using an oscilloscope.

Furthermore the voltage on pins 2 and 5 of IC2 in the LFO circuit  should also be half of the battery voltage, so 4.5V instead of 3.6V.
I'm not sure if this will stop the LFO, but maybe you can check R33 and R34 for the right value.

Also the measured B and E voltages on the transistors are wrong, but since you say you are getting sound, I think you've mixed up the B and E voltages.

I can measure all voltages on my CE-2 for you, but since I'm at work right now, this will have to wait until about 9 tonight.

Quote
I'm getting sound and the depth pot works, but the rate pot does nothing. EDIT: oh... and there seems to be no "chorus'ing" effect.

What happens when you use the depth pot?

Maybe the LFO works, but the BBD bias is wrong, in which case you won't hear any sound from the BBD.
If you not already did, you could slowly turn VR3 all the way and listen for the chorus to start.

Hope this helps.

André



Title: Re: Tonepad CE-2 debug
Post by: Fuzzy-Train on April 13, 2007, 05:35:09 PM
I needed to make a few changes:

I scrapped the mods for now (until it can actually work) and just used fixed components instead (82pf for C22, and a 47k for R21.) The pots I had were actually bad... they were supposed to be 100k, but for some reason one registered 48k and the other 10k... WTF... I had soo many problems with my last order but this one takes the cake. So I replaced those with working, and checked 100k pots.

I also forgot the most important part on my first post. I'm getting high pitched oscillation that's controlled by the rate pot.. goes higher and lowere depending on which way I turn it.

Here are my new voltages after I set IC1 to 4.5 like you said and I'm using the pin layout you showed me as well:

IC1

1) 4.52    8 ) 8.92
2) 4.53    7) 4.52
3) 4.47    6) 4.53
4) 0        5) 4.49

IC2

1) 4.51    8 ) 8.91 
2) 4.41    7) 4.11
3) 4.29    6) 2.53
4) 0        5) 4.41

IC3

1) 8.81    8 ) 3.78
2) 4.50    7) 3.78
3) 2.85    6) 4.47
4) 0.58    5) 0

IC4

1) 8.81    8 ) 0.58
2) 4.49    7) 3.09
3) 0         6) 7.36
4) 4.49    5) 0.88


(I might be getting confused on the pinout for these.. but the B is right either way)
Q1 

E 3.65
B 2.93
C 8.89

Q2

E 8.88
B 3.16
C 2.85

Q3

E 8.87
B 2.34
C 2.13

Q4

E 3.36
B 3.25
C 8.77

Q5

E 6.57
B 0.57
C 0

D1

A 1.57
K 3.09

D2

A 3.09
K 6.55

D3

A 0
K 8.85

Furthermore the voltage on pins 2 and 5 of IC2 in the LFO circuit  should also be half of the battery voltage, so 4.5V instead of 3.6V.
I'm not sure if this will stop the LFO, but maybe you can check R33 and R34 for the right value.

They're both 10k... the way it should be.

I can measure all voltages on my CE-2 for you, but since I'm at work right now, this will have to wait until about 9 tonight.

That would be fantastic... I'm dead set on getting this thing working tonight so I'm not going out or anything.

Quote
I'm getting sound and the depth pot works, but the rate pot does nothing. EDIT: oh... and there seems to be no "chorus'ing" effect.

What happens when you use the depth pot?

It was almost like a subtle tone knob for a guitar.. but not as intense. Now it's not doing that anymore since I changed things... as mentioned above.

Maybe the LFO works, but the BBD bias is wrong, in which case you won't hear any sound from the BBD.
If you not already did, you could slowly turn VR3 all the way and listen for the chorus to start.

Hope this helps.

André

Tried that today and it didn't work.

Thanks for the help so far... anybody else ever had to debug their CE-2... don't be shy now, any help will be appreciated.

Thanks again  :icon_wink:
Title: Re: Tonepad CE-2 debug
Post by: Victor on April 13, 2007, 08:43:59 PM
I used a 1N4001 instead of the RD11EB

uh-oh. that's not right, I guess. You should use a proper zener diode, no ordinary diode here. :)
Title: Re: Tonepad CE-2 debug
Post by: Fuzzy-Train on April 13, 2007, 09:32:00 PM
You sure?

http://www.diystompboxes.com/smfforum/index.php?topic=54105.0

http://www.diystompboxes.com/smfforum/index.php?topic=48104.0

http://www.diystompboxes.com/smfforum/index.php?topic=53177.0
Title: Re: Tonepad CE-2 debug
Post by: Victor on April 13, 2007, 09:55:36 PM
I guess you're right. I was not aware of its real function in this pedal.  :icon_redface:
Title: Re: Tonepad CE-2 debug
Post by: Fuzzy-Train on April 13, 2007, 11:00:45 PM
That's cool... any help is appreciated.
Title: Re: Tonepad CE-2 debug
Post by: Fuzzy-Train on April 14, 2007, 01:08:47 AM
Well I just spent the past hour going over each joint in case or bad connections and it's still doing the same thing: high pitched oscillation (like a fuzz factory oscillation) with no chorus effect whatsoever.

If one of the IC's were bad/faulty would I even be getting voltages? I'm starting to think that maybe an IC is blown or just doesn't work.... they're socketed BTW, and I removed them whenever I soldered/desoldered anything on the board.

I guess I won't be able to get it working today... I'm soo friggin' tired... 'night
Title: Re: Tonepad CE-2 debug
Post by: jonathan perez on April 14, 2007, 02:13:21 AM
i had that problem. the same one!

what cap have you got for the depth? if its around 40pF youre good, but over 100 pF will start to bring in that squeel.

also, when i had that problem, it was because of a bunch of solder bridges...

clean up your solder!
Title: Re: Tonepad CE-2 debug
Post by: zeta55 on April 14, 2007, 03:08:06 AM
I'd take my guess on the TL022 replacement you've got there.
When I built my Boss VB-2 clone wich also asks for the TL022 as the LFO generator, I tried a few other dual opamps, the only one that got the the LFO working was a TL272 as a substitute.

/Krister

Title: Re: Tonepad CE-2 debug
Post by: Phorhas on April 14, 2007, 03:24:23 AM
Yes, it's most likely the LFO IC by the sound of it. I had the same with a chorus once and these LFOs are pretty selective with parts you use
Title: Re: Tonepad CE-2 debug
Post by: jonathan perez on April 14, 2007, 03:36:28 AM
mine have 72s as replacements and it sounds great.
Title: Re: Tonepad CE-2 debug
Post by: Fuzzy-Train on April 14, 2007, 04:27:15 PM
For the depth cap I have an 82pf in there right now.

I just spent the past 45min-hour looking over my joints and I can't find a single solder bridge... I even cleaned up the flux residue between pads just in case that would create a bridge. Still doesn't work.

I'm using a TL072 which was said to be a working LFO in the CE-2

http://www.diystompboxes.com/smfforum/index.php?topic=52924.0
http://www.diystompboxes.com/smfforum/index.php?topic=47254.0
http://www.diystompboxes.com/smfforum/index.php?topic=48722.0

I feel so beaten  :icon_frown:

Man the guy who was working for boss who created this thing must've been a huge geek, a genius or both... I'd go with both. :icon_wink:

One thing I noticed is that for C2 the bottom pad is a square pad (meaning positive) ... was that supposed to be a polarized cap? Cause I just have a regular wima in there.

Title: Re: Tonepad CE-2 debug
Post by: jonathan perez on April 14, 2007, 04:49:48 PM
yup, im pretty sure it has to be polarized
Title: Re: Tonepad CE-2 debug
Post by: Fuzzy-Train on April 14, 2007, 04:52:59 PM
SOB... they really need to specify this type of stuff on the tonepad site.

So that means I need a tantalum cap right? OF which I don't have any  :icon_lol:
Title: Re: Tonepad CE-2 debug
Post by: jonathan perez on April 14, 2007, 04:58:42 PM
electrolytics.

place an order on mouser? got any electronic stores around?
Title: Re: Tonepad CE-2 debug
Post by: Fuzzy-Train on April 14, 2007, 05:02:10 PM
Electro? You sure?

It's a .47uf cap, do electro's go that small? I couldn't find a .47uf polarized cap on SmallBear that wasn't tantalum???
Title: Re: Tonepad CE-2 debug
Post by: Fuzzy-Train on April 14, 2007, 05:11:14 PM
D'oh... mouser has 'em.

I believe it's this one, correct?

http://www.mouser.com/search/ProductDetail.aspx?R=140-L50V.47-RCvirtualkey21980000virtualkey140-L50V.47-RC

There's a store a little ways out of town I can go to... I'll call them up. Hopefully there still open but I doubt it.

EDIT: nope there closed on weekends dangit. I'll just go after work on monday.

Thanks for help everyone, hopefully by monday it'll be working.
Title: Re: Tonepad CE-2 debug
Post by: jlullo on April 14, 2007, 05:46:37 PM
hey buddy, i've got a bunch of them.. if you don't want to pay for shipping for just one electro, pm me with your address.. i'd be more than happy to drop one in the mail for free
Title: Re: Tonepad CE-2 debug
Post by: Fp-www.Tonepad.com on April 14, 2007, 10:03:42 PM
Hi, got your email, here's some things you can try out.

C2... shouldn't be a problem if it's non polarized, but if using a polarized one, the square pad is the positive, otherwise it doesn't matter.

Sounds like an LFO issue. I've had lfos not working due to a number of things, maybe the IC is the problem, also the pots can be a problem, I've had to replace new pots because they were faulty.

You can try an audio probe and listen for signal at R13 and C10.

If you have an analog multimeter you should be able to see the oscilation produced by the lfo (measuring volts at r35 for example), with a DMM it's harder to see but you can if you turn the lfo speed really slow.

To succeed in troubleshooting a large complex circuit you need to break it down to smaller circuit blocks, with the audio probe, dmm and analog mm, you're set to search for signs of working/not working parts of the ckt.

Make sure you got your offboard wiring correct too. you'll want the grounds connected to the ground on the pcb (check offboard wiring diagrams at tonepad for info on this).

Also, a couple of good resolution pictures could help us find the issue troubling you.

I hope this helps
Title: Re: Tonepad CE-2 debug
Post by: Fuzzy-Train on April 15, 2007, 05:09:24 PM
Thanks... Francisco or Matt?... whichever posted.

I guess I won't be needing that electro cap jlullo...

While desoledring and soldering many times I accidently lifeted a pad... but it was a graound pad and luckily it was right next to another ground pad so I just extended the lead of that resistor and bridged it to the other ground. That wouldn't cause any problems would it?? I circled that part in one of the photos.

You sure it would just be the LFO IC that's faulty? Cause I'm going to try and get another TL072, and I wonder if I should get replacements for all the IC's just in case. Also, other then heat, what could make an IC stop working?

I tested my pots, and although one measured 90k they both funtion like they're supposed to.

All my wiring was right. It's kind of hard to mess up wiring with the silkscreened board, but I checked again and it all looks right.

I tested  the voltage of R35 while rotating the depth pot and here's what I got: The lead going to the jumper = 3.22 to (as I rotated it) 3.49 and the lead to the pot = 4.02 to 4.37
I also did this to R32 and got: Lead to pot = 4.41 to 4.42 and the lead going to C19 = 2.54 to 4.11. What all this means I don't know LOL, but maybe someone can make something of it.

Here are some pics:
(some parts of the board look scratched up because I was cleaning the flux off, but I didn't damage anything while doing that)

(http://img403.imageshack.us/img403/3421/img1167ns4.th.jpg) (http://img403.imageshack.us/my.php?image=img1167ns4.jpg)

(http://img410.imageshack.us/img410/773/img1168fn7.th.jpg) (http://img410.imageshack.us/my.php?image=img1168fn7.jpg)

(http://img265.imageshack.us/img265/2427/img11691122rf9.th.jpg) (http://img265.imageshack.us/my.php?image=img11691122rf9.jpg)
Title: Re: Tonepad CE-2 debug
Post by: Fuzzy-Train on April 16, 2007, 09:36:21 PM
Well, I just tried it with a NE5532P chip from my Rebote 2.5 (the Rebote actually calls for a TL072 so it has the same pin out) and it's still doing the same thing... high pitched oscillation squeal that's controlled by the rate pot, and it goes higher and lower depending on which way I turn it.

Could it be that the dots on my IC's are not in the same place as the layout... If I knew more about IC's I'd switch them around to see if it makes it work, but I'm afraid of damaging them.

Anybody?
Title: Re: Tonepad CE-2 debug
Post by: Fp-www.Tonepad.com on April 17, 2007, 01:26:30 AM
they seem to be in the right orientation.

Did you check the oscilating voltage (voltage reading, black probe to ground, red probe to...) the output of the LFO.

I asked you to...

You can try an audio probe and listen for signal at R13 and C10. (research on what an audio probe is if you don't know)

If you have an analog multimeter you should be able to see the oscilation produced by the lfo (measuring volts at r35 for example), with a DMM it's harder to see but you can if you turn the lfo speed really slow. (black probe to GROUND, red probe to R35)

That info would really help.
Title: Re: Tonepad CE-2 debug
Post by: Auke Haarsma on April 24, 2007, 06:23:17 AM
Not to hijack this thread...but I've build the CE-2 on breadboard and have about the same voltage readings as posted in this topic. Those seem ok to me.

But here's the problem:
-I get a distorted, delayed sound (this is a matter of setting the trimpot, if I understand correctly)
-and, more importantly, I get a pitched constant tone with a pulsing swirl to it. It does respond to the rate pot and depth pot. Could anyone point me where to look for the cause of this noise? There's no chorussing going on btw.

I have oscilliating voltages at the lfo, so that seems ok.

I made one mistake...instead of connecting IC4 pin 8 to ground I put it to 9v... corrected that, but I don't know if that could have caused any damage.
Title: Re: Tonepad CE-2 debug
Post by: Andre on April 24, 2007, 07:47:53 AM
Quote
and, more importantly, I get a pitched constant tone with a pulsing swirl to it. It does respond to the rate pot and depth pot. Could anyone point me where to look for the cause of this noise? There's no chorussing going on btw.

It seems like your BBD clock frequency is to low (within audible range).
That's the constant tone with pulsing swirl (lfo modulation) you hear.

Check if you have used 47pF for C22, and if so check all components connected to pins 5 and 7 of IC4.

Quote
I made one mistake...instead of connecting IC4 pin 8 to ground I put it to 9v... corrected that, but I don't know if that could have caused any damage.

Pin 8 IC4 (MN3101) is Vgg output for the BBD and should not be connected to ground, but to pin 4 of IC3 (MN3007).
Since you can hear the BBD clock and a delayed sound,  I think neither IC3 or IC4 are damaged.

Good luck.

André

Title: Re: Tonepad CE-2 debug
Post by: Auke Haarsma on April 24, 2007, 08:06:12 AM
thanks, I may have forgotten C9.... will check that when I get home ;)
Title: Re: Tonepad CE-2 debug
Post by: Auke Haarsma on April 24, 2007, 11:38:25 AM
thnx to Andre! Not only did I forget C9, I also put a wrong cap in C22 indeed! (100 nF...don't ask why, I don't know). Put 47pf in there, and the constant tone is gone! Experimented some, but I have max depth and no added noise with 330pF, so I'll stick to that.

Only problem left is that it distorts. Is that a matter of fine tuning? Heavy stummin on sc or normal strumming on humbuckers results in distortion. Any tips?
Title: Re: Tonepad CE-2 debug
Post by: John Lyons on April 24, 2007, 11:48:43 AM
Ok, I have "NoNothings" CE-2 here and this is what I get.
Slight signal whine variable with speed pot, distorted output, Very sight chorus with no modulation. (may just be the guitars signal modulated by the whining tone)

I get signal at r13 and C10
There is no modulation at pin 7 of IC2.

Voltages: (with 9.6 supply)

IC1
1) 5v   5) 5                  Q1
2) 5   6) 5                    E 4.6
3) 5   7)5                     B 5
4) 0   8) 9.6                 C 9.6

IC2
1) 4.8   5) 4.5              Q2
2) 4.8   6) 4.8v             E 4.9
3) 4.5   7) 4.5               B  5.4
4) 0      8) 9.6               C 9.6


IC3                             Q3
1) 9.6   5) 0                 E 4.7
2) 4.9   6) 4.8              B 5
3) 4.6   7) 4.8              C 9.6
4) .64   8) 4.8

IC4                             Q4               Q5
1)  9.6   5) 0                E  4.7           E  0v
2) 4.8    6) 8.6             B  4.2            B  0v
3) 0       7) 3                C  9.6          C  8.5
4) 4.8    8) .6


I'm not sure about Q5. There should be some voltage on the base correct?
I have a TL072 in the IC2 position. I've tried another one but with no oscillation still.
I don't have a TL022 here to try
The board is soldered cleanly and there are no solder bridges.

Where should I check?

Thanks

John
Title: Re: Tonepad CE-2 debug
Post by: Auke Haarsma on April 24, 2007, 11:53:49 AM
I have mine still on the breadboard. I have an Tl072 as IC2. You should see some voltages going up and down at pin 7 ic2.
Distortion is probably misbiasing (that's how I cured most of my distortion, but not all, see above). You can quite easily fine tune this with an audio probe at pin 8 of IC3. You should hear quite some modulation there. If you need any speficic measurements from me, let me know.
Title: Re: Tonepad CE-2 debug
Post by: John Lyons on April 24, 2007, 12:15:04 PM
The thing is that I am not getting and modulation fron IC 2. (Pin 7)


John
Title: Re: Tonepad CE-2 debug
Post by: Andre on April 24, 2007, 12:24:03 PM
Here's the voltages of my CE-2:

(http://www.xs4all.nl/~jvcn0028/pictures/CE-2%20Voltages.jpg)

André
Title: Re: Tonepad CE-2 debug
Post by: Auke Haarsma on April 24, 2007, 12:24:37 PM
edit: -nvm- wrong reading of dmm
Title: Re: Tonepad CE-2 debug
Post by: John Lyons on April 24, 2007, 01:03:52 PM
Thanks Andre for posting your voltages

Those are close to the voltages I get. With the exception of Q5 which I have (C) 8.5v (B) 0v and (E) 0v
I guess I'll try to rebuild the oscillator section and hope that I can find a bad part or value.

I do get a fixed chorus sound but no oscillation. The distortion is still on hard stummed chords though. The trimmer cured a little of it...

John


Title: Re: Tonepad CE-2 debug
Post by: Auke Haarsma on April 24, 2007, 01:26:04 PM
Q5 for me:
C: 9v
b: 0.13 V
e:0.02

hth
Title: Re: Tonepad CE-2 debug
Post by: John Lyons on April 24, 2007, 05:14:08 PM
I measured all the resistors in the Oscillator (TL072) and they measure fine. Replaced the .1uf  cap and still no oscilation.
The voltages are right but it will not oscillate. Anyone think of another place to check? Is there anything other than the TL072 section that would prevent oscillation?

Still get the fixed chorus type sound.

Thanks

John

Title: Re: Tonepad CE-2 debug
Post by: Andre on April 24, 2007, 07:09:23 PM
Although the measured voltages prove me wrong and you say the board is cleanly soldered could you please check this:
If you have a look at the picture of the copper side of the PCB you can see some shiny stuff between one of the depth pot's lugs and one of the pins of R34 which connects to ground. Could this be some drop of solder which does not really short to ground, but maybe act as a capacitor to ground ? It's in the upper left corner of the PCB.

It's probably nothing but I just thought I'd mention it.

André
Title: Re: Tonepad CE-2 debug
Post by: Fuzzy-Train on April 24, 2007, 07:24:36 PM
(http://img264.imageshack.us/img264/1525/untitled11222gj0.jpg) (http://imageshack.us)

Is that what you're talking about.

Since John has the board I can't say for sure, but I don't think there's a bridge.
Title: Re: Tonepad CE-2 debug
Post by: John Lyons on April 24, 2007, 09:14:55 PM
Woohoo!
I was cleaning the bottom of the board in order to take some pics and I started resoldering a couple possible cold solder joints.
Cleaned the flux off the board and it fired up. The cold solder joint was it i'm sure.

Here are a couple pics and a sound clip since I already had them ready to go.
Thanks folks for ther help. I'm glad I found the problem because the voltages were right and I wasn't sure where else to check.


CE-2 sound clip (http://www.mrdwab.com/john/CE-2-demo.mp3)



(http://www.mrdwab.com/john/CE-2.jpg)

(http://www.mrdwab.com/john/CE-2bottom.jpg)





John

Title: Re: Tonepad CE-2 debug
Post by: Fuzzy-Train on April 24, 2007, 09:36:41 PM
OOOOOOOOHHHH YEEEAAAH!!!!!!  :icon_mrgreen:

*NoNothing doing the safety dance*

You are a god my good man... I can't believe it was a cold joint, I went over all my joints, desolderd, and then resolderd them and it still wasn't working. ???

That's awesome man just awesome... any idea which component lead was the culprit?

That clip sounds great... I'm sooo excited to get it back and get that suker in it's case. :icon_mrgreen: :icon_mrgreen:

Thanks again man.
Title: Re: Tonepad CE-2 debug
Post by: Andre on April 25, 2007, 03:16:33 AM
Now that's good news  :icon_biggrin:

Quote
Is that what you're talking about.

Yes, that's the one.

Have fun with your new toy.

André

Title: Re: Tonepad CE-2 debug
Post by: Fp-www.Tonepad.com on April 25, 2007, 03:35:00 AM
 ;D
Title: Re: Tonepad CE-2 debug
Post by: Auke Haarsma on April 25, 2007, 04:36:42 AM
nice!

Did you solve the 'distortion' too?
Title: Re: Tonepad CE-2 debug
Post by: John Lyons on April 25, 2007, 10:48:53 AM
Yes, somehow the distortion cleared up as well...!

By the way. Thanks Andre. Pretty much started the clean up which led to the resordering everything which brought it back to life.
Lesson: When it doubt resolder everything. Should have known that.

John
Title: Re: Tonepad CE-2 debug
Post by: wui223 on May 08, 2007, 05:47:30 AM
Sorry for hijacking and reviving this old thread. I am debugging a BOSS CE-3.

Problem is: no chorus effect,only clean sound from output. I read up the threads about CE-2 for some ideas to repair mine.

For CE-3 the BBD driver is MN3102 and BBD is MN3207, the LFO is working fine as i got fluctuation voltage on the output of IC5(LFO chip).

But i found out voltage reading at MN3102 pin 8(Vgg out) is 6.65v but the pin 4(Vgg) of MN3207 is mere 0.30v. BTW these 2 pins are connected directly. Anyone got any idea?

Thanks.
Title: Re: Tonepad CE-2 debug
Post by: Andre on May 08, 2007, 06:29:33 AM
I think it's crucial to find out why you measure different voltages at pin 4 of IC3 and pin 8 of IC4.
What happens if you just short those pins?
Furthermore the Vgg of 6.65 Volt is quite low.
Since Vgg is 14/15 Vdd, Vdd should be 7.125V in this case.
What is the voltage at pin 1 (Vdd) of IC4 ?

André
Title: Re: Tonepad CE-2 debug
Post by: wui223 on May 08, 2007, 06:57:03 AM
pin 1 at IC4 is 7.18v but my battery is 8.88 when measured. The different voltages at pin 4 of IC3 and pin 8 of IC4 is now solved, it happened that leg 8 of IC4 is not connected to PCB due to broken pin. But now the voltage at pin 4 IC3 still not same with pin 8 IC4 but closer.
Title: Re: Tonepad CE-2 debug
Post by: Andre on May 08, 2007, 09:22:50 AM
Quote
But now the voltage at pin 4 IC3 still not same with pin 8 IC4 but closer.

Given the fact that the distance between those pins is really short, you should really get the same values on both pins (within 0.1 V).
Other then that, I think the voltage at pin 1 of IC4 should be approx. 0.6 V less the the battery voltage, and not 1.7 Volts.

Could you measure the voltages at the pins of transistor Q7?
Maybe you can "audioprobe" the circuit and check where the audio stops.

André








Title: Re: Tonepad CE-2 debug
Post by: wui223 on May 10, 2007, 03:50:45 AM
I check the Q7, the emitter voltage is 7.00v while my battery 8.24v

I check pin 8 of IR9022 gives 7v also while from the schematic i got from this forum, it should share the same voltage supply as the other opamps (IC1 , IC2). This pedal is original so i wonder what is wrong here. Anybody ?
Title: Re: Tonepad CE-2 debug
Post by: Andre on May 10, 2007, 04:27:03 AM
The schematic is wrong.
If you check the layout you will see that pin 8 IC5 is also connected to the emitter of Q7, so this means that the LFO, BBD and BBD clock are all fed by Q7.
Maybe this is done to prevent LFO ticking.

André
Title: Re: Tonepad CE-2 debug
Post by: wui223 on May 10, 2007, 05:53:05 AM
I read up the MN3007 datasheet, the VDD is suggested -15v. But i measure my CE-2 got something like +7~8v.

Can anyone explain ?
Title: Re: Tonepad CE-2 debug
Post by: Andre on May 10, 2007, 06:18:34 AM
By reverse wiring the power pins Vdd & Gnd of both the BBD and BBD clock, you avoid the need of a negative powersupply with positive ground.
If you check the Supply Voltage Characteristics in the 3007 datasheet you will see that it will work from -5 V up to -16 V.
However signal to noise ratio will be worse and THD will be little more at lower supply voltages.

André
Title: Re: Tonepad CE-2 debug
Post by: wui223 on May 10, 2007, 08:32:43 AM
Surprisingly, from the schematic i got now. CE-2 is wired like Andre said.
But CE-3 is different story, the Vdd connected to Q7 while ground is ground, mean positive supply neg ground.

Is it the mistake in schematic ?
Title: Re: Tonepad CE-2 debug
Post by: Andre on May 10, 2007, 08:47:50 AM
No, I think you overlooked the fact that CE-2 uses MN3007 (negative power) and the CE-3 uses MN3207 (positive power)

André
Title: Re: Tonepad CE-2 debug
Post by: wui223 on May 10, 2007, 09:40:35 AM
Yes just found out the fact. So i come to a dead end now, what to check next if the voltage on all IC is correct ?

CE-3 i can get clean signal in bypass and effect mode, but CE-2 i get no signal at all so i guess the FET switching might be faulty. Do i need to replace all FETs in the bypass circuit?
Title: Re: Tonepad CE-2 debug
Post by: wui223 on May 10, 2007, 10:15:27 AM
I use audio probe to check my CE-3. Below is result:

pin 1,7 of IC1 pin 1 of IC2 got audible signal.
pin 3 of MN3207 got audible signal.
pin 7,8 of MN3207 and pin 7 of IC2 no audible signal.
IC5 give ticking sound (LFO ticking?)

My questions:
1. pin 7,8 of MN3207 is output so i guess i should expect audible signal?
2. pin 7 of IC2 no audible signal means bad IC ?or is it related to question 1?

Thanks for any input.
Title: Re: Tonepad CE-2 debug
Post by: Andre on May 10, 2007, 10:23:55 AM
I suggest you use an audioprobe to find out where the audiosignal stops.

Quote
but CE-2 i get no signal at all so i guess the FET switching might be faulty. Do i need to replace all FETs in the bypass circuit?

In the CE-2 schematic I have there is only 1 FET which switches the effect signal to the output.
The dry signal is not switched, but has to pass Q1 and both opamps of IC1.

So I think it's not the bypass circuit, but maybe some power problem.
Have you checked the CE-2 voltages against my CE-2 voltages posted earlier in this thread.
My CE-2 is a Tonepad build, but I don't think that'll make a difference.

As far as your CE-3 concerns, I'm out of ideas. I'd love to have this thing on my desk and help you out, but I think distance will be a problem.

André






Title: Re: Tonepad CE-2 debug
Post by: Andre on May 10, 2007, 10:27:08 AM
Your post crossed mine, so forget about the first line
Title: Re: Tonepad CE-2 debug
Post by: Andre on May 10, 2007, 10:42:53 AM
Quote
My questions:
1. pin 7,8 of MN3207 is output so i guess i should expect audible signal?
2. pin 7 of IC2 no audible signal means bad IC ?or is it related to question 1?

1. Yes
2. Not necessary.

There can be 2 other reasons:

1. Misbiasing of the input (Have you tried rotating VR-3 ?)
2. Absence of BBD clock

I can't think of an easy way to check the BBD clock without an oscilloscope however.
Anyone ?

André


Title: Re: Tonepad CE-2 debug
Post by: wui223 on May 10, 2007, 11:02:19 AM
Yes, i rotate VR3 to set bias but no chorus sound all the way from min to max setting.
Where can i find info about the BBD clock? is it the MN3102 u talking about ?
Title: Re: Tonepad CE-2 debug
Post by: wui223 on May 10, 2007, 09:30:47 PM
Finally got the CE-2 chorusing. But still one problem to be solved. The effect once switch on, the chorus effect is there in both bypass and effect mode. I guess the flip-flop circuit is faulty, anyone?

PS: i found my mind split to two since working on both CE-2 and CE-3 at the same time  :icon_cry:
Title: Re: Tonepad CE-2 debug
Post by: Andre on May 11, 2007, 03:25:45 AM
Does the LED switch on and off ?

If so, the flipflop's OK.
Check if there's a voltage change at the gate of the FET if you hit the switch.
If there is, your FET's broken, otherwise you could check R49, C28 and D4.

What stopped the CE-2 from chorussing in the first place ?

André
Title: Re: Tonepad CE-2 debug
Post by: wui223 on May 11, 2007, 10:19:38 AM
Does the LED switch on and off ?

If so, the flipflop's OK.
Check if there's a voltage change at the gate of the FET if you hit the switch.
If there is, your FET's broken, otherwise you could check R49, C28 and D4.
André

Which FET are u refering to?

Quote
What stopped the CE-2 from chorussing in the first place ?

I overlooked a connection problem which i think i am so stupid to make such a mistake
Title: Re: Tonepad CE-2 debug
Post by: Andre on May 11, 2007, 10:50:13 AM
In the CE-2 schematic diagram I have there is only 1 FET and it's labelled Q9.

André
Title: Re: Tonepad CE-2 debug
Post by: wui223 on May 14, 2007, 04:26:30 AM
Thanks Andre, finally fix the CE-2. Now the CE-3 is still dead, anymore idea?

And how to check the BBD clock ?i might seek for scope at uni lab
Title: Re: Tonepad CE-2 debug
Post by: loulouloudaurat on October 28, 2010, 10:18:56 AM
Hello everybody,
I know this is an old topic, but I would like to have some help debugging my CE-2 clone coming from tonepad; in bypass or not I only have input signal: where I sgould hear the chorus effect, I don't hear it, only the guitar signal... I removed all the bypass stuff but the problem is still there, the 3pdt is not guilty. Now I'm searching for an error but I don't find anything. I've resoldered every pin, lifted the eigth pin of IC4...
Thanks for replying :)
Title: Re: Tonepad CE-2 debug
Post by: Andre on October 28, 2010, 03:30:08 PM
These are the voltages I measured on my Tonepad CE-2.
I've posted them earlier, but they got lost when I switched from one internet provider to another.
Please let us know the differences between those and your voltage readings.
(http://i752.photobucket.com/albums/xx161/andre_schaap/CE-2Voltages.jpg)

Title: Re: Tonepad CE-2 debug
Post by: loulouloudaurat on October 29, 2010, 05:54:51 AM
thanks a lot for this, I'm happy somebody replyed as fast!
excuse my bad english, I'm a french guy!
I'll check voltages when i'll have time :)
thanks again!
Title: Re: Tonepad CE-2 debug
Post by: loulouloudaurat on October 29, 2010, 12:34:40 PM
hey, I've got news: I had time enough to measure ICs voltages: here they are:
IC1:
1)2.69              8)8.56 
2)2.69              7)2.67 
3)2.65              6)2.68
4)0                  5)2.67

IC2:
1)0.75~7.72)     8)8.47 
2)4.40~4.08)     7)2.3~6.2
3)0~6.5             6)2.40
4)0                  5)4~4.40

IC3:
1)7.52              8)0 
2)5.57~5.62      7)0
3)0.88              6)0
4)0.88              5)0

IC4:
1)7.51              8)0.77 
2)3.82              7)2.29~2.94
3)0                  6)6.43~6.70
4)5.56~5.61     5)0.31~0.43

there are a lot of weird measures... I hadn't time enough to check trannys, anyway here we see that there is a problem.
thank you for your help.
Title: Re: Tonepad CE-2 debug
Post by: loulouloudaurat on November 03, 2010, 06:51:43 AM
nobody here?
Title: Re: Tonepad CE-2 debug
Post by: Govmnt_Lacky on November 03, 2010, 08:56:43 AM
If I were you I would hook up to a dedicated 9.0V power supply and remeasure your voltages. Also include the voltages at the transistors (Q1-Q5).

Also, pictures of your build on both the component and solder side will help a lot!


Good Luck  ;D
Title: Re: Tonepad CE-2 debug
Post by: Projectile on November 04, 2010, 02:50:23 AM
yup, im pretty sure it has to be polarized

You seem to have a lot of posts here, so I would expect you to know your stuff, but sorry that sounds like complete rubbish. Never in my life have I ever seen a polarized cap that wasn't simply used because of space, cost, or availability issues. Why would you ever NEED a polarized cap in a circuit? That just seems utterly ridiculous.
Title: Re: Tonepad CE-2 debug
Post by: Projectile on November 04, 2010, 02:52:19 AM
yup, im pretty sure it has to be polarized

You seem to have a lot of posts here, so I would expect you to know your stuff, but sorry that sounds like complete rubbish. Never in my life have I ever seen a polarized cap that wasn't simply used because of space, cost, or availability issues. Why would you ever NEED a polarized cap in a circuit? That just seems utterly ridiculous.

EDIT: Didn't realize this post was so old. Nevermind, my bad.
Title: Re: Tonepad CE-2 debug
Post by: Txiske on November 19, 2010, 07:56:16 AM
Hi!
I build this pedal about a year ago and then I gave as a present to a friend... and now I've built it again. But I have a problem, when it is switched on nothing happens, it just sound the same as it wasn't on. And if I twick the trimpot, when it's the full way it doesn't sound anything. Don't know where could be the problem, because I get good sounding signal, but with no chorus effect. The only changes I've made are R21-39K, Rin-1M and R32-470k. When I did it a year ago it sounded perfectly the first time but now... If anyone could know were the problem is...
Title: Re: Tonepad CE-2 debug
Post by: Txiske on November 19, 2010, 10:31:08 AM
Hi again!
After checking everything again and again... I noticed that there was a bridge between 2 tracks!!! :icon_surprised:
So I repaired that and, there is the chorus!!! Now just adjust the trimpot and maybe I make some mod...
Title: Re: Tonepad CE-2 debug
Post by: Devilll on September 08, 2011, 06:55:48 PM
Hi!

Could someone help me? I built the CE-2, but it acts strange.
I hear the strait signal and some noise, The noise is a poppin thing which reacts for the speed and depth knobs. I think the LFO-s working right maybe. But why do I hear it?
I tried audio probe. I hear the signal on IC3 pin 3, but on pin 7 and 8 I got the noise.
I tried to replace IC2, IC3, IC4, but the result was the same.
If I don't leave R38 out, it blows IC4.
Title: Re: Tonepad CE-2 debug
Post by: Projectile on September 09, 2011, 12:26:56 AM
R38 is pretty important. You can't just leave it out of the circuit and expect it to work. Start with figuring out what's wrong there.

Did you buy your mn3007 and mn3101 chips from reputable supplier? There are a lot of junk ones floating around on ebay. 

Also, it sounds like you have 2 separate problems. One is noise bleed from the clock, and the other is that you have no signal from the BBD circuit. I'd focus on getting the BBD circuit working first and worry about the noise later. The noise bleed is likely just a lead dress issue.
Title: Re: Tonepad CE-2 debug
Post by: Devilll on September 09, 2011, 04:42:36 AM
I bought the MN3007 and MN3101 from smallbear.
I know R38 is important, but when I put it inside the circuit, it kills my MN3101. It gives about 8 Volts
Title: Re: Tonepad CE-2 debug
Post by: Projectile on September 10, 2011, 04:00:18 AM
I bought the MN3007 and MN3101 from smallbear.
I know R38 is important, but when I put it inside the circuit, it kills my MN3101. It gives about 8 Volts

Well, then you obviously have a problem there. I used an MN3101 from smallbear with the tonepad layout to build a ce2 just a few days ago and it works fine.
Title: Re: Tonepad CE-2 debug
Post by: Govmnt_Lacky on September 10, 2011, 08:04:42 AM
Check for the following:

1) Values of resistors around IC4
2) Orientation of D1 and D2
3) Solder bridges around IC4 and its supporting components.

Good Luck  ;D