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Mn3005 voltages on aquaboy

Started by nunonaos, May 25, 2017, 10:15:16 PM

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nunonaos

Hello, I measured the voltages in my mn3005 and they are similar to what is in the instructions pdf for the aquaboy build.
But.. I checked the data sheet of the mn3005 and pin1 theoretically should be ground (0v) and pin 5 should be 9v. But in the instructions pdf it says pin 1 should be 9v and pin 5 should be 0v.

Maybe the xvibe version of the mn3005 has to be placed in reverse? Can I try it?

I noticed this because I don't have delay, only clean signal, and so I started checking voltages...

I don't have an audio probe yet, so for now just voltages...

Any help?

Thanks

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madbean

MN3005 were designed for positive ground so when used as negative ground the power and ground pins are switched as well as the pulldown resistors on the outputs.

It only takes a few minutes to make an audio probe so I suggest doing that then probe the input and outputs of the MN3005 to see if that is the problem area.

nunonaos

Quote from: madbean on May 26, 2017, 12:01:59 AM
MN3005 were designed for positive ground so when used as negative ground the power and ground pins are switched as well as the pulldown resistors on the outputs.

It only takes a few minutes to make an audio probe so I suggest doing that then probe the input and outputs of the MN3005 to see if that is the problem area.
Ok thanks.i will make a probe and test it.thanks

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nunonaos

Ok, so no audio signal in any pin of ic3 (mn3005). I have audio (no delay) at output jack.
Any suggestions to where I should audio probe next?

Thanks

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Boba7

Quote from: nunonaos on May 26, 2017, 07:04:31 PM
Ok, so no audio signal in any pin of ic3 (mn3005). I have audio (no delay) at output jack.
Any suggestions to where I should audio probe next?

Thanks

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Just follow the signal coming out at pin1 of Ic1 until you lose it! Could be the compander, a transistor. Look at the schematics and follow as best as you can the signal path, it's not too complicated.
Hope you get it to work!

nunonaos

Quote from: Boba7 on May 27, 2017, 11:50:14 AM
Quote from: nunonaos on May 26, 2017, 07:04:31 PM
Ok, so no audio signal in any pin of ic3 (mn3005). I have audio (no delay) at output jack.
Any suggestions to where I should audio probe next?

Thanks

Sent from my XT1562 using Tapatalk

Just follow the signal coming out at pin1 of Ic1 until you lose it! Could be the compander, a transistor. Look at the schematics and follow as best as you can the signal path, it's not too complicated.
Hope you get it to work!
I was doing that just now and I believe the problem it's in the ne570.
Pin 6 on the ne570 has a clear input but none of the other pins have good signal...only low volume distorted signal...

Are there any alternatives to ne570 or does it has to be exactly that chip?

Thanks

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madbean

I wouldn't go changing the NE570 until you know what the problem is. Take some voltage measurements, double check the part values to make sure they are correct (R13, R14, C10, C12), double check your soldering and reflow if needed. You should have a fairly large signal coming out of pin7. If everything looks correct and you still don't have signal from pin7 then it could be the IC. Another 570 or an SA571 might be called for.

nunonaos

Quote from: madbean on May 27, 2017, 01:09:00 PM
I wouldn't go changing the NE570 until you know what the problem is. Take some voltage measurements, double check the part values to make sure they are correct (R13, R14, C10, C12), double check your soldering and reflow if needed. You should have a fairly large signal coming out of pin7. If everything looks correct and you still don't have signal from pin7 then it could be the IC. Another 570 or an SA571 might be called for.
Ok.i will recheck those resistances and caps,thank you.

I also believe that the most probable problem is my own errors, not the components error :)

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nunonaos

I rechecked and still no sound out of pin 7.
Another question, should I have audio signal on r29?
I have audio in one end of r10 but not in the other, then on r29 no sound.
And what about probing the mix pot, should I have sound?

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madbean

Without signal through the comapander you won't have anything on the Mix pot or R29.

What are your voltages on the NE570? Can you please provide a pic of that area?

nunonaos

Pics

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nunonaos

Voltages on the ne570

1-1.85
2-1.42
3-1.42
4-0
5-1.48
6-1.35
7-0.26
8-1.83
9-1.83
10-8.81
11-1.24
12-1.24
13-9.38
14-1.83
15-1.83
16-0.79


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madbean

Some of those voltages are way off. Pin 7 should be closer to 3v. Pins 10 and 11 should be the same but somehow you have completely different voltages (could you have measured those two incorrectly?) Where did you get the NE570 from?

nunonaos

Quote from: madbean on May 27, 2017, 03:36:35 PM
Some of those voltages are way off. Pin 7 should be closer to 3v. Pins 10 and 11 should be the same but somehow you have completely different voltages (could you have measured those two incorrectly?) Where did you get the NE570 from?
I got ne570n from retroamplis.es
It's a Spanish online store.

I rechecked and pin 10 has that high voltage. And pin 7 is very low. can it be something with my other components or it's more probable to be from the ne570?

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nunonaos

The ne570 wasn't sitting perfectly in the socket. With a little force pin 10 went to the 3v range...
Still pin 7 has the same voltage as before

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