Aquaboy troubleshoot - old version

[TNblueshawk]

I debated whether to start this thread based on what I just realized this morning but I think I will to confirm a few things at least.

I'm building the old version of the aquaboy, with DD and Mod boards run at 18v with a Road Rage. So I fired it up. Bypass and indicator LED work fine. Kick it on, bypass still working fine  . No delay and no mod = no dice. Usually I get a dead signal when I mess something up. Anyway, I'm doing the usual inspection. Took a bunch of voltage readings and realize something is just not right at the R-19. I'm getting 18v off the RR and into the PCB 9v pad. I get 17.2v going into the first leg of R-19. Great. Of course I clipped that pin off the regulator so no lead is in there. I put the base pin into the ground pad on the PCB. But then I get nothing on the output of R-19. I guess the explains why nothing is going to the MN3005's.

For kicks I took voltages at the Mod board and I'm getting 18v into the 9v pad which is good but I'm getting no modulation. I get nothing on the output pad on the Mod board and I get various readings that fluctuate on the IC TL072. It ranges from 4v to 12v depending on what pin you are on and finally 17.3v on pin 8. I had also hooked up an LED in series to get a pulsing LED to satisfy my childish "I like pusling lights" craving. Nothing there.

So, I'm going over everything this morning before I post and then I realize. I was using a TO92 volt reg 78L05 and not a 78L15   This of course explains a lack of voltage I am assuming.  I was so used to using that value I just spaced on it and didn't catch the "1". The bummer is I don't have a 78L15 in a TO92 package. However I do have it in that beast of a part in the TO220 but of course the tranny sockets won't accomodate that regulator.

- Anyway, am I correct to assume that is a huge problem?
- There is one thing I'm curious about though. Taking a reading of just the socket at R-19 I get close to 18v at the input. . But when I take a reading of the output of R-19 I get nothing? Should I not be getting close to 18v since they are connected on the PCB?
- Also, given I had the wrong voltage regulator I get the the DD board not working. But should I still not have gotten modulation especially given I was getting 18v to the 9v pad on that board?


Thanks for any help and thoughts ont this. I'm all ears on any opinions on anything on this. I'll post a few picks in anticipation of needing to further troublehsoot  

[madbean]

You are going about this the wrong way. You need to install an LM7815 on the Road rage board (the T0-220 type) to get a regulated 15v supply to the PCB. R19 can be anything between 22R and 100R---the values doesn't matter too much. You do not want to supply 18v to the Aquaboy and try to regulate it on that PCB. A 78L15 is not going to supply sufficient current to power the Aquaboy with two MN3005.

You need to break something like this down into manageable steps first instead of hooking everything together and hoping for the best. Install the regulator, confirm it puts out 15v. Remove the double delay board and MN3005. Hook the power supply up to the AB board. Measure the supply pins on the ICs and the socket for the MN3005 to confirm you are getting power to them. At this stage, I would only hook up one MN3005 on the AB PCB and confirm that delay is passing, but I guess that depends on whether or not you have the clock and bias trims on there. If delay is passing then hook up the double delay board and bias. Hook up modulation last and test.

This kind of thing is too complicated to just wire everything up without doing proper testing of supply and voltages first. When you break it down like this, you give yourself a much better opportunity to debug as you go along.

[TNblueshawk]

Ok, let me stop here and pause to look at this build. The reason I was regulating at R-19 was this discussion http://www.madbeanpedals.com/forum/index.php?topic=3756.0. All we talked about was R-19 or at least that is how I read it and still read it. So call me crazy and call me confused as it wouldn't be the first time but can you see where I got that from?

So if I was to regulate at the RR board to 15v using the TO220 package then that means no where else on the board would see 18v right?

I was going for 18v based on other recommendations that the circuit might run/sound better at this voltage, sans the 15v split off of course. But I'm fine with 15v as this is close enough for my ears I'm sure.

[madbean]

Ahh, okay I see what you are getting at now (I had forgotten about that discussion). Yes, you could run the circuit at 18v and then Vdd at 15v only (remembering that the MN3005 has a max Vdd supply of +/-15v). I don't think that is going to offer any real advantage, though, esp. considering you are not going to get 18v exactly off a charge pump. It will probably be closer to 17.5 or so. Which ever way you decide to go, do use the correct type of regulator and try wiring it the way I mention here: www.madbeanpedals.com/forum/index.php?topic=3756.msg36736#msg36736

Get the power thing sorted out first, and try to get your BBDs passing delay. Then we can tackle the modulation

[TNblueshawk]

Thanks Brian. Frankly I like the idea of putting the regulator on the RR board and putting a resistor in R19 as that would simplify things and I would still be pushing 15v which I'm going to declare close enough for me at this point 

I will take a step back and go one step at a time as you suggest.

[madbean]

Thanks Brian. Frankly I like the idea of putting the regulator on the RR board and putting a resistor in R19 as that would simplify things and I would still be pushing 15v which I'm going to declare close enough for me at this point 

I will take a step back and go one step at a time as you suggest.

Cool. Hope it did not sound like I was picking on you...

[TNblueshawk]

Honestly? At first I thought man, maybe he thinks I just half assed this and threw it together, but then I sat back and realized you are just telling me my approach is wrong and I need to step back and go slow with all the pieces parts which is what I should have done rather than hook it all up at once and see. I'm just appreciative for the help and perspective. Between gtr2 and you I will and have come away with some knowledge on this build that I did not have previously. So, it's all good and thanks for such cool projects to challenge me 

[TNblueshawk]

Well got it running. I went with the 15v regulator on the RR board and all is well. Well sort of. I was able to find out two of my MN3005 were bad. I have two good ones however so all is well. I wasn't able to dial it in though as the phone rang and I got taken away for the night.

The mod board doesn't seem to do much. I think I'll start a new thread just for that though.

Thanks Brian.