Tonepad Corral Debug Help

[mateusborges]

Hello guys, been looking tru other topics about the Tonepad Corral but couldn't find a solution for my issue, so here I am.

1. Bypassed signal working perfectly, once engaged sound passes but at really, really low volume and with almost no mids or highs.
2. Tonepad Corral
3. http://www.tonepad.com/getFile.asp?id=101
4. No mods.
5. No substitutions, however I'm not using the zener, using 9v battery only.
6. Positive ground to negative ground conversion? No.

7.
What is the out of circuit battery voltage? => 9.09
Voltage at the circuit board end of the red battery lead = 8.52
Voltage at the circuit board end of the black battery lead = 0

Q1 - 2N5088
C = 8.42
B = 2.61
E = 3.08

Q2 - 2N5088
C= 3.37
B= 3.53
E= 8.41

Q3 - 2N5088
C= 8.35
B= 2.80
E= 3.14

Q4 - 2N5088
C= 8.26
B= 2.86 - 3.93
E= 2.83 - 4.08

Q5 - 2N5088
C= 6.91 - 7.10
B= ~0.37
E= 0

IC1 - JRC5088
P1 - 4.08
P2 - 4.01
P3 - 4.01
P4 - 0
P5 - 4.04
P6 - 4.06
P7 - 4.07
P8 - 8.23

IC2 - TL022
P1 - 2.49 - 5.59
P2 - 4.06
P3 - 3.46 - 4.93
P4 - 0
P5 - 4.06
P6 - 4.48
P7 - 3.63 - 4.97
P8 - 8.19

IC3 - MN3007
P1 - ~8.10
P2 - ~4.18
P3 - 3.24
P4 - 0.54
P5 - 0
P6 - 4.12
P7 - 3.01
P8 - 3.01

IC4 - MN3101
P1 - 8.08
P2 - 4.12
P3 - 0
P4 - 4.16
P5 - ~0.27
P6 - 7.08
P7 - 2.64 - 2.86
P8 - 0.54

D1 - 1N914
A= ~1.3 - 1.8
K= ~2.6 - 2.8

D2 - 1N914
A = ~2.6 - 2.8
K = ~6.6 - 6.8

All electros read correctly + > -


My soldering sucks, I know. Couldn't find any shorts or bad contacts so far.

Thanks all in advance and sorry about my english.

[antonis]

Hi & Welcome..

At a first glance, almost all (with the exception of D2K - Q5C about 300mV difference) DC voltages look fine..
Take IC3 & IC4 off sockets and repeat measurements..

P.S.
Did you implement any of four Mods ..??
(Especially the Effect Level one..??)

[mateusborges]

Hi & Welcome.

Thanks man! =)

At a first glance, almost all (with the exception of D2K - Q5C about 300mV difference) DC voltages look fine..
Take IC3 & IC4 off sockets and repeat measurements..

Without the chips on it or should I re-socket?

Did you implement any of four Mods ..??
(Especially the Effect Level one..??)

No mods at all.

Thanks for the reply!

[antonis]

Without the chips on it or should I re-socket?

Without chips ..
(only opamps in place..)

Notice if IN-OUT signals are of the same level..

[box]

Hi,
Please check this point
Q2 - 2N5088
C= 3.37   -----(should be ~8.42V)
B= 3.53
E= 8.41----?
it may be the wrong position of the transistor Q2( C=8.42V almost the same as Q1 and Q3).
Regards,
box

[Marcos - Munky]

Welcome, Mateus. Btw, from your name, are you brazilian?

Nice catch, box. From the values, it seems the readings for C and E were just reversed.

1. Bypassed signal working perfectly, once engaged sound passes but at really, really low volume and with almost no mids or highs.

This is something I'd call a "good bad issue". You know there's something wrong, but at the same time you know the most important parts of your circuit are working.

A lack of volume and something messing with the frequencies can be caused by a bad cap, or a cap/resistor with the wrong value. The next step imo should be to recheck all caps and resistors values. Also, do you know how to do an audio probe?

[mateusborges]

Hi,
Please check this point
Q2 - 2N5088
C= 3.37   -----(should be ~8.42V)
B= 3.53
E= 8.41----?
it may be the wrong position of the transistor Q2( C=8.42V almost the same as Q1 and Q3).

Q2
E= 3.50
B= 3.64
C= 8.62

Sorry, measured wrong last time.

Welcome, Mateus. Btw, from your name, are you brazilian?

Thanks man! Yup, from Porto Alegre =)

A lack of volume and something messing with the frequencies can be caused by a bad cap, or a cap/resistor with the wrong value. The next step imo should be to recheck all caps and resistors values. Also, do you know how to do an audio probe?

Yup, gonna cut a cable and do some probing next, also gonna check values and do the measuring w/o chips 3 and 4.

Thanks for the tips guys.

[Marcos - Munky]

Imaginei que fosse brasileiro. Eu moro no Paraná.

Since you know how to do a audio probe test, it may makes things easier. I'd begin with IC1 pin 1, which is the dry signal output and also sends the signal to the delay line. If everything is fine here, then I'd probe the point where R12 and R12 are connected together and the point where R19 and C14 are connected together, to check how is the delay line. And then, if everything is fine, I'd check IC1 pins 6 and 7.

[antonis]

Imaginei que fosse brasileiro. Eu moro no Paraná.

Νόμιζα ότι ήσουν Βραζιλιάνος. Ζω στον Παναμά. 
(much better now..)

[Marcos - Munky]

Nice one, Antonis! It actually looks way better, greek alphabet is very beautiful in my opinion. Just one small thing, according to google translator Παναμά is Panama, but I live in Paraná (google translator told me it's Παράνα), which is a brazilian state. Both Panama and Paraná are written very similar to each other, and are pronounced very similar to each other. Think on Van Halen's Panama chorus but with different consonants .

Now you gave me an idea, an enclosure with words written in greek would look very cool.

[mateusborges]

Good news!
Sorry about the long delay, finally got a new mix to work in and had to dive into it, it's being really hard living out of record production now a days.
Back to the chorus, thanks a lot for the inputs, got the new measures, gonna post 'em asap.

[mateusborges]

New measures, without MNXXXX chips, marked in bold.

1. Bypassed signal working perfectly, once engaged sound passes but at really, really low volume and with almost no mids or highs.
2. Tonepad Corral
3. http://www.tonepad.com/getFile.asp?id=101
4. No mods.
5. No substitutions, however I'm not using the zener, using 9v battery only.
6. Positive ground to negative ground conversion? No.

7.
What is the out of circuit battery voltage? => 9.09 -> 7.97
Voltage at the circuit board end of the red battery lead = 8.52 -> 7.71
Voltage at the circuit board end of the black battery lead = 0 -> 0

Sorry had no new battery to test it, only the old one.

Q1 - 2N5088
C = 8.42 -> 7.84
B = 2.61 -> 2.42
E = 3.08 -> 2.92

Q2 - 2N5088
C= 8.62 -> 7.82
B= 3.64 -> 3.23
E= 3.50 -> 3.08

Q3 - 2N5088
C= 8.35 -> 7.78
B= 2.80 -> 2.61
E= 3.14 -> 2.86

Q4 - 2N5088
C= 8.26 -> 7.74
B= 2.86 - 3.93 -> 2.50 - 3.60
E= 2.83 - 4.08 -> 2.62 - 3.78

Q5 - 2N5088
C= 6.91 - 7.10 -> 7.70
B= ~0.37 -> 0
E= 0 -> 0

IC1 - JRC5088
P1 - 4.08 -> 3.80
P2 - 4.01 -> 3.80
P3 - 4.01 -> 3.75
P4 - 0 -> 0
P5 - 4.04 -> 3.78
P6 - 4.06 -> 3.80
P7 - 4.07 -> 3.80
P8 - 8.23 -> 7.78

IC2 - TL022
P1 - 2.49 - 5.59 -> 2.34 - 5.22
P2 - 4.06 -> 3.83
P3 - 3.46 - 4.93 0 -> 3.25 - 4.62
P4 - 0 -> 0
P5 - 4.06 -> 3.82
P6 - 4.48 -> 3.24
P7 - 3.63 - 4.97 -> 3.43 - 4.69
P8 - 8.19 -> 7.68

D1 - 1N914
A= ~1.3 - 1.8 -> ~1.29 - 1.8
K= ~2.6 - 2.8 -> 6.65

D2 - 1N914
A = ~2.6 - 2.8 -> 6.65
K = ~6.6 - 6.8 -> 7.63



Yeah, soldering sucks, freaking parkinsons, but still can't find any shorts.

[mateusborges]

Still can't find the problem gonna work in the audio probe next, any ideas where should I start listening to?
Thanks.

[Fender3D]

I can't understand why Q1 and 3 emitters are higher than their bases, unless you're testing with a very low input impedance DMM....
Time foir signal probe...

[mateusborges]

I can't understand why Q1 and 3 emitters are higher than their bases, unless you're testing with a very low input impedance DMM....
Time foir signal probe...

Any suggestions for points I should probe?
Thanks!

[PRR]

I can't understand why Q1 and 3 emitters are higher than their bases, unless you're testing with a very low input impedance DMM....

mateusborges, what meter are you using? Make and model? Link? Link to specs? Is it a $7 needle-meter or a $20 digital meter?

[Fender3D]

Any suggestions for points I should probe?

Start from C1 then check all active stage outputs...

[mateusborges]

I can't understand why Q1 and 3 emitters are higher than their bases, unless you're testing with a very low input impedance DMM....

mateusborges, what meter are you using? Make and model? Link? Link to specs? Is it a $7 needle-meter or a $20 digital meter?

Heya,
it's a very cheap model unfortunately.
Foxlux FX-MD.




Sorry, couldn't find an english version.

[PRR]

> it's a very cheap model unfortunately.  Foxlux FX-MD.

It's OK. (Much better than I started with.) That basic machine with minor differences of name, color, and settings is ALL over Amazon, eBay, and the various Asian selling sites; and I am sure in local stores everywhere. (The cut-down model has been seen as Harbor Freight's $3 bonus.)

Specs are semi-universal language: for AC Volts (Tension Alternate) the meter loads the circuit like a 450k resistor; for DC Volts (Tension Continuous) it is like 1 MegaOhm. (It says "greater than" but if it was much more, it would cost more.)

The loading is "just enough" to give the low Base voltages you report. So they are probably OK except when you poke them. The Emitter voltage is a better guide and that looks good.