Aquaboy Deluxe 2013

[ricardoruben]

Hi!

I decided to try to succesfully debug an Aquaboy Deluxe from 2013 that I have.  Back then, it didn't made any sound.
I bought a pair of BL3208B  to replace the ones that I had (I always supected that they were defective).

But I started the calibrating process and found out that there is no sound on pin3 of the IC3. And also, no sound at all on the pins 1 or 7 of the IC1. I'm quite sure that the LF353 it's bad, and I'm searching for a replacement at this moment.
I didn't put the IC4 on the board, but if I plug the pedal to an amp there is a high pitch squeal that changes with the rate pot and delay.

Is there any guide of how the voltages should be on all the ICs, so I can compare with the ones that I have?
So far i now that the pin 7 of each BBD should be in the 6-8v range. (https://www.madbeanpedals.com/forum/index.php?topic=30810.msg297061#msg297061)

[thomasha]

The squeal is probably the clock for the BBDs, since the BBD is not on the board and there is no signal the output must be getting it from somewhere. Once the circuit works it probably will disappear.

The LF353 is a dual OpAmp, as the TL072 or the 4558, is there a special reason for using a different Opamp there? You could probably debbug it with the previous two and once the LF arrives put it in place.

The voltages depend on your supply, the BL3208B only works at a max. voltage of 10v, the higher voltages are for the MN300* chips. So I guess you are powering it with 9v, right? Check if you connected the right jumpers, since the *32** chips also have different pinouts than the MN30** chips (basically GND and V+ are inverted and the output resistor is connected to V+ or GND, not in this sequence necessarily).

What I normally do is, I use the voltages that are available (link) and scale it by the highest voltage and multiply it by the voltage I am using. This way you can have a rough estimation of the voltage that you should see. That means, if the BBD at 15v has 6-8v (8/15*9=4.8v) what makes sense, since it is approx. what I have on my dirtbag running at 9v with the v3205s. Normally it is a little higher than V+/2, around 4.9 to 5.1v, so that you cannot use VD. 

Before you install the BBDs check the signal all the way until pin 7. Then check the voltages of the BBDs (clock pins are roughly at V+/2). The input and output pins can have different voltages, since the chip is not installed (no load).

Good luck mate!

[ricardoruben]

The only reason why I'm thinking on changing the LF353 (for another LF353) it's because I don't hear anything audioprobing the pin 7 of the IC1. At least some sound should be reaching out that op amp and into the BBD, right?

Thanks for the reply! It's good to know that the squeal won't be there when I place the BBDs on the board.

[thomasha]

Yes, right.
I just suggested, that if you don't have the LF353 you could test another dual opamp just to check if it works or if there is a bad solder joint somewhere.