Tonepad CE-2 debug

[Fuzzy-Train]

I thought I wasn't going to get this done for a while but my uncle gave me the day off today  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. 

[Andre]

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.

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

[Fuzzy-Train]

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.

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 

[Victor]

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.

[Fuzzy-Train]

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

[Victor]

I guess you're right. I was not aware of its real function in this pedal. 

[Fuzzy-Train]

That's cool... any help is appreciated.

[Fuzzy-Train]

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

[jonathan perez]

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!

[zeta55]

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

[Phorhas]

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

[jonathan perez]

mine have 72s as replacements and it sounds great.

[Fuzzy-Train]

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 

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.

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.

[jonathan perez]

yup, im pretty sure it has to be polarized

[Fuzzy-Train]

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 

[jonathan perez]

electrolytics.

place an order on mouser? got any electronic stores around?

[Fuzzy-Train]

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???

[Fuzzy-Train]

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.

[jlullo]

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

[Fp-www.Tonepad.com]

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