Aquaboy Big Problem - Need Help (FAKE MN3101-Solved)

[mickey.bellinello]

Hi to all!

I'm Mickey and I've got problems with my Aquaboy.
I've built a lot of pedals so I'm not a newbie. I also done a Deluxe Memory Man delay clone so this isn't the first time I build an analog delay.

The problem is that I got no delay! In bypass mode I get dry sound, when the pedal is engaged I'v got dry sound too. If I turn the knobs no results at all.

If I use a probe to test pin 3/4 of IC3 I only listen a "whii" sound.
I built it yesterday and today I've made some measurement.
Here's the results:

IC1
-----
PIN1 - 4.5
PIN2 - 4.5
PIN3 - 4.5
PIN4 - 0
PIN5 - 4.5
PIN6 - 4.5
PIN7 - 4.5
PIN8 - 9

IC2
-----
PIN1 - 0.85
PIN2 - 1.8
PIN3 - 1.8
PIN4 - 0
PIN5 - 1.8
PIN6 - 1.8
PIN7 - 2.8
PIN8 - 1.8
PIN9 - 1.8
PIN10 - 3
PIN11 - 3
PIN12 - 1.8
PIN13 - 9
PIN14 - 1.8
PIN15 - 1.8
PIN16 - 0.08

IC3
-----
PIN1 - 8.9
PIN2 - 3.99
PIN3 - 6.77
PIN4 - 6.77
PIN5 - 0
PIN6 - 3.95
PIN7 - 4.26
PIN8 - 7.77

IC5
-----
PIN1 - 8.33
PIN2 - 3.95
PIN3 - 0
PIN4 - 3.99
PIN5 - 4.09
PIN6 - 4.15
PIN7 - 4.12
PIN8 - 7.77

The delay chip is an Xvive 3005
The Clock is an MN3101
The Compander is a CoolAudio V571D (I also tried a genuine Panasonic NE570, same results)

As You see I have some very wrong Voltage (I marked the most extreme in red)...
Can someone help me please?

Thanks So Much!

[Scruffie]

Did you audio probe your compander output? It's biased too low, probably the problem.

[mickey.bellinello]

Thanks for Your reply!

I just probe the compander pin7 (OUT1) and I've got signal.

Which parts of the circuits do I check? I'm afraid of PIN8 on both IC3 and IC5. As reference the v must be 0.59, I've got 7.77 on both.

[Scruffie]

Right you are, for some reason I was thinking you'd built the 3205 version.

Where did you get the 3101? I wonder if it's a relabelled 3102.

[mickey.bellinello]

Don't know that there are also a 3205 version.
I bought the pcb directly from Madbean. For the building info I refer to the suggested manual. The Pcb is the blue one, the 2016 version I think.
The 3101 has been bought from Musikding.de site and I don't think it's a fake.. all components came from musikding/banzai so I believe they're genuine..
Are there anything I can do to make it works?

[mickey.bellinello]

Here's a picture of the board:



In case of it would helps...

[zombiesonore]

Hi there.
What I see is that IC5 doesn't produce the good Vgg. And as it get the right voltage on pin 1, I'll check every components attached to IC5: C29 first, R40/41/42, C30, Trimmer and Delay Pot. maybe D2 too?
I guess you don't have any other mn3101 for testing?

[mickey.bellinello]

Hi!
Following your instruction I replaced c30 and c29 with new cap. r40/41/42 are the right value.
Trimmers seem to work. The delay pot is brand new Alpha so I think the problem isn't in it.
I haven't checked D2.
I make a check and the situation is the same. Unfortunately I have only one MN3101.
Do you suggest me to directly buy another one or the problem can be in some other areas of the circuit? Thanks So!

[zombiesonore]

Scruffie is the real guy about BDD circuit so I'll wait his input.
To the limit of my knowledge, I see that IC5 have only one input (pin 1 - Vdd) and it gives 2 important signals: CP1/2 & Vgg.
IC3 cannot works with a bad Vgg and yours his way too high. And it seems that IC5 have a good input Vdd so I guess the problem is with it.
It happen to simply have bad mn3101 even with a good source like banzai or musikding, it happened to me.
If you can't buy another one, and if you are in Europe, I can send you one for test purpose.

[madbean]

You MN3101 is actually an MN3102. How do I know? MN3102 produces the correct Vgg voltage for the MN3205 without any external circuitry. The correct Vgg voltage for an MN3205 is 14/15 of Vd.

Your voltages: 8.33Vd, 7.77Vgg

8.33 * 14/15 is 7.77!

This trick might work or it might not: ground pin 8 of your fake MN3101 to see if you can get delay out of the MN3005. If not, get yourself an genuine MN3101 and your problem should be solved.

[madbean]

You MN3101 is actually and MN3102. How do I know? MN3102 produces the correct Vgg voltage for the MN3205 without any external circuitry. The correct Vgg voltage for an MN3205 is 14/15 of Vd.

Your voltages: 8.33Vd, 7.77Vgg

8.33 * 14/15 is 7.77!

This trick might work or it might not: ground pin 8 of your fake MN3101 to see if you can get delay out of the MN3005. If not, get yourself an genuine MN3101 and your problem should be solved.

BTW: the correct Vgg voltage for the MN3101 in this case should be Vd*(1-14/15) = 8.33*0.067 = 0.56v

[mickey.bellinello]

Thanks so much!!!

I never thought that a serious supplier can have fake goods.
I've ordered from another supplier a new mn chip. It will arrive mid week.
I'll try it with it and I'll tell You.

Zombiesonore I really appreciate your offer. I'll try the new chip and I'll tell you if your chip is needed. I live in Italy (Europe). And thanks so much again

[Scruffie]

I just grabbed a MN3101 from my parts box and the voltage divider is made from a 14.5k & 1.2k resistor... so you could put a 100R resistor from pin 8 to pin 3 of the '3101' to get the right voltage.

[mickey.bellinello]

Thanks So Much Scruffie! I've just soldered a 100R between pin 3 and 8 of the mn3101.
This evening I'll give a test. 

[mickey.bellinello]

Here I am!

I tried soldering the 100R. The check at pin 8 is +-0.6V.
I tried to probe the mn3005 output but there are the same wiiii sound.
By the end of the week I'll receive a genuine mn 3101 ( I asked to the supplier and it has confirmed that is genuine.Let' hope!).
I'll update You soon and thanks again for support!