Rebote 2.5

[mattlee0037]

Ok, so this is the Rebote 2.5 project. Problem is that no signal passes when effect is engaged. It was my friend's failed build that he wanted me to try and debug. Bypass signal is fine, I used an audio probe and got signal up until the TL072 output (pin 7 so just one half) and after that there is no signal, which is pretty early. I was asked to take voltages so here they are

TL072
1- 1.90
2- 1.94
3- 4.74
4- 0
5- 3.80
6- 1.32
7- 1.99
8- 9.56

PT2399
1- 1.69
2- 0.85
3- 0
4- 0
5- 0.86
6- 0.71
7- 1.58
8- 1.59
9- 0
10- 0
11- 0
12- 0
13- 0.1
14- 0.2
15- 0.85
16- 0.85

T78L05
Input 9.56
Gnd 0
Output 1.69

[davent]

The regulator should be putting out 5v so start there, either it's fried or something is miswired to it, short, in backwards...

dave

[mattlee0037]

Yeah I figured that I'll have to order one of those because that was way off spec


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[mattlee0037]

I'm reviving this thread as I threw in my 5v regulator, got the right voltage, but no signal passes as pin 7 of the IC
Voltages
TL072
1- 1.98
2- 1.98
3- 4.75
4- 0
5- 4.52
6- 1.86
7- 1.99
8- 9.5

T78L05
1- 9.50
2- 0
3- 5.01

PT2399
1- 5.01
2- 2.49
3- 0
4- 0
5- 2.83
6- 2.48
7- 0.52
8- 0.6 (going up slowly)
9- 2.49
10- 2.49
11- 2.49
12- 2.49
13- 2.49
14- 2.49
15- 2.49
16- 2.49

[flanagan0718]

I checked mine last night and these voltages seem ok...plus or minus of course. Mine is working too. Is it possible that the 78l05 is backwards? is it a printed board or a vero? A picture is worth 1000 words.

[mattlee0037]

I'll get a pic up tonight. I believe it a tone pad board the regulator has a silkscreen printed for part orientation but I'll check that against the schematic.

[flanagan0718]

If it is the Tonepad Board There are a few jumpers that need to be in place. Make sure those are there. I did an etch of the tone pad layout. I can get it populated in the next day or so and see if i have the same issues or not. I am working off a Vero lay out but i should be able to help you out with this.

[mattlee0037]

Thanks I appreciate the help! I just checked and the jumpers are indeed in there. I suppose I'm at a loss as to why I lose signal at the first IC.... hmm.

[flanagan0718]

Here are some things I would check/try

-Double/triple check the Electrolytic caps. (possible one is backwards)
-Check ICs orientation
-Swap ICs for a new one
-Check Bypass wiring and signal
-Check cap values

Other than that I will Try and populate mine tonight or tomorrow.

[Morgan]

The op amp voltages look pretty weird. The bias on pins 3 and 5 looks fine, which is good, but you should also see around 4.5 volts on pins 1,2, 6, and 7. Like flanagan suggested, I'd try a different op amp - although when they are bad, the voltages usually look weirder than that. If a different op amp gives you the same results, reflow the joints on that puppy (take the op amp out of the socket first). Maybe the signal is just blocked on the output or maybe there is a bad solder joint on one of the components in one of the feedback loops (any component connected to pins 1, 2, 6, and 7).

TL072
1- 1.98
2- 1.98
3- 4.75
4- 0
5- 4.52
6- 1.86
7- 1.99
8- 9.5

[mattlee0037]

You guys are great. I will try all steps tonight and report back with pictures!

[flanagan0718]

here are my working voltages
     78L05
4.91 - top
0.00 - middle
9.01 - bottom

        TL072
4.5 - I--U--I- 9.02
4.5 - I       I- 4.5
4.5 - I       I- 4.5
0.0 - I ___ I- 4.5

      PT2399
4.9 - I--U--I- 2.4
2.5 - I       I- 2.4
0.0 - I       I- 2.4
0.0 - I       I- 2.4
0.0 - I       I- 2.4
2.4 - I       I- 2.4
0.0 - I       I- 2.4
0.0 - I ___ I- 2.4

[mattlee0037]

Ok so the only thing I found was that in the feedback loop is a 470k resistor instead of a 510k resistor (again I didn't build this it's a friends). Anyone want to explain what the feedback loop does and how this would affect it? I should probably learn things

[flanagan0718]

Did you do the "long delay" switch. When I did my vero it wouldn't work with out the switch in the circuit, for whatever reason.


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[mattlee0037]

If you mean the 15k to 10k resistor switch then yes that has been done