Aquaboy v2 debug - only half the expected delay time

[Just1More]

I recently finished an Aqua Puss clone built on madbean's Aquaboy v2 board.  It fired up first go and I managed to borrow an o-scope to do the trimmer setup following the Boss DM2 adjustment procedure.

It sounds good but I can only get about 150ms at maximum delay time with the clock at 6.8kHz.  I'm just trying to work out whether I've done something wrong or if the MN3005 is dodgy.

Here's the voltages at max delay time:

V+: 9.38

IC1 (LF353)
1: 4.68
2: 4.68
3: 4.68
4: 0
5: 4.68
6: 4.68
7: 4.68
8: 9.38

IC2 (SA571N)
1:  1.13
2:  1.80
3:  1.80
4:  0
5:  1.8
6:  1.8
7:  3.0
8:  1.8
9:  1.8
10: 2.99
11: 2.99
12: 1.8
13: 9.38
14: 1.8
15: 1.8
16: 1.13

IC3 (MN3005)
1: 9.38
2: 4.37
3: 5.17
4: 5.18
5: 0
6: 4.37
7: 4.9
8: 0.6

IC4 (MN3101)
1: 8.73
2: 4.38
3: 0
4: 4.38
5: 4.27
6: 4.36
7: 4.31
8: 0.6

Q1 (MPSA18)
E: 3.38
B: 4.24
C: 9.37

Q2
E: 2.4
B: 2.98
C: 9.37

Q3
E: 4.55
B: 5.14
C: 9.38

Q4
E: 3.94
B: 4.53
C: 9.37

Can anyone see anything wrong?  Unfortunately I don't have any other MN3005s to test against and they seem to be pretty well impossible to get now.

Thanks

[anchovie]

Did you buy the MN3005 from Hong Kong via Ebay? Some of those are re-labelled MN3007!

[oldschoolanalog]

You probably got a relabeled (counterfeit) 3008.
Alot of those around these days...

[Just1More]

I got the BBD chip from smallbear towards the end of last year.  I expected it to be OK, but I guess it's possible one slipped through...

[Mark Hammer]

In the old days, when Steve Daniels used to have to score his MN3005s in small lots from here and there, before companies like Beiling and Coolaudio started producing BBDs again, I know Steve used to maintain a Memory Man and test out every single chip by plugging it into the socket.  Given all the changes in the business since that time, I don't know if that is still the practice anymore.

[Scruffie]

In the old days, when Steve Daniels used to have to score his MN3005s in small lots from here and there, before companies like Beiling and Coolaudio started producing BBDs again, I know Steve used to maintain a Memory Man and test out every single chip by plugging it into the socket.  Given all the changes in the business since that time, I don't know if that is still the practice anymore.

Last time they were listed I beleive it stated something along the lines that the chips were not tested but were from a vendour he trusted so I don't think this practice still occurs.

[Mark Hammer]

Given how many he sells now, and how frenetic the business is, I doubt that it is still the sort of thing he can sit and do while watching a Mets game on TV, and gabbing with Judy in the other room.

[Scruffie]

Given how many he sells now, and how frenetic the business is, I doubt that it is still the sort of thing he can sit and do while watching a Mets game on TV, and gabbing with Judy in the other room.

Exactly...

Why don't you give this a read over and see if you can spot anything obviously wrong with it http://www.aeri.com/counterfeits.html

Also, comparisson between a fake and real MN3005
http://pws.cablespeed.com/danielzink/mn3005/3005016.jpg (The odd one out is the real MN3005)
http://pws.cablespeed.com/danielzink/mn3005/3005020.jpg (Once again)
http://www.digitaldestruct.com/images/011.jpg (fake on the left)

[Mark Hammer]

probably all the more reason why it pays to use an MN3205 clone.  Those things can be bought so cheaply, nobody in their right mind would attempt to counterfeit/relabel them.

[Just1More]

Thanks for your responses everyone. I'll have a closer look tonight, but a quick visual inspection doesn't reveal anything obvious.

[oldschoolanalog]

If you decide to keep the chip, try wiping the markings with acetone. As mentioned in the linked counterfeit article.
Please post your findings if you do this.
Of course this will probably eliminate any chance of return/exchange/refund.

[Just1More]

After having a good close look with a magnifying glass under good lighting I can't see anything obviously wrong.  I tried wiping the top with acetone, but the markings are etched and there was no discolouration to the cotton tip I used.

I've uploaded some pics of the chip.  They are just taken with my phone, but I think you can see clearly enough.  If it is a fake it's a damn good one 

[Scruffie]

Yeah that's a damn good fake if it is one... there is only one thing I can question, the legs... i'm not sure about them, they look a bit too short, not tinned enough and the ends are flatter where as most I see have pointier tips... although it could have been removed from something else I suppose.

Everything else looks good, Large semi circular indent at the front, circle indent on the top, larger circular indent on the base, nice edging, engraved as you say... you'd need a micrscope to get in closer and check for other imperfections.

Here's an image of the legs comparisson of a real chip to a fake (the Real is at the forefront of the image) http://pws.cablespeed.com/danielzink/mn3005/300504.jpg

[Mark Hammer]

Maybe it's a dumb question, and I do not wish to offend by underestimating your chops, but is there any chance you have measured either the clock rate or delay time wrong?  I ask, because if you simply doubled 150msec, and factored in the usual component tolerance issues, 300msec delay is not far off from what one would expect from a well-functioning Aqua-Puss.

[danielzink]

After having a good close look with a magnifying glass under good lighting I can't see anything obviously wrong.  I tried wiping the top with acetone, but the markings are etched and there was no discolouration to the cotton tip I used.

I've uploaded some pics of the chip.  They are just taken with my phone, but I think you can see clearly enough.  If it is a fake it's a damn good one  

Two things:

#1: I really don't like the looks of those legs....as scruffie said - all my legit 3005's have very shiny - "roundy" tinned sort of legs.

#2: The lettering. Was the lettering white before you hit it with the acetone ? all my 3005's have white lettering - all of 'em....

Dan

[danielzink]

After having a good close look with a magnifying glass under good lighting I can't see anything obviously wrong.  I tried wiping the top with acetone, but the markings are etched and there was no discolouration to the cotton tip I used.

I've uploaded some pics of the chip.  They are just taken with my phone, but I think you can see clearly enough.  If it is a fake it's a damn good one  

Two things:

#1: I really don't like the looks of those legs....as scruffie said - all my legit 3005's have very shiny - "roundy" tinned sort of legs.

#2: The lettering. Was the lettering white before you hit it with the acetone ? all my 3005's have white lettering - all of 'em....

Dan

new/more pics:






Dan

[Just1More]

Two things:

#1: I really don't like the looks of those legs....as scruffie said - all my legit 3005's have very shiny - "roundy" tinned sort of legs.

#2: The lettering. Was the lettering white before you hit it with the acetone ? all my 3005's have white lettering - all of 'em....

Dan

The acetone treatment didn't change the appearance at all.  There was no white lettering - just the engraved markings.

[Just1More]

Maybe it's a dumb question, and I do not wish to offend by underestimating your chops, but is there any chance you have measured either the clock rate or delay time wrong?  I ask, because if you simply doubled 150msec, and factored in the usual component tolerance issues, 300msec delay is not far off from what one would expect from a well-functioning Aqua-Puss.

No offence taken at all Mark and a perfectly reasonable question.  Given the the good reputation of the supplier, I was thinking it's at least a 50/50 proposition that I've done some thing wrong.

At maximum delay time I measured the clock frequency at pins 2 and 6 on the MN3005 using my DMM.  At once stage I dimed the clock trim just to see how much delay time I could coax out of it.  The repeats sounded severely distored, but I just got 300ms.  As for measuring delay times, I just matched the repeats by ear with a digital multi-effect unit which shows the delay time.

[jbgron]

Hi guys,

I read this thread this morning and it confirmed what I'd been thinking all along.  My DM-2 build also only has half the delay time!  I'm lucky enough to have an original Boss DM-2 so the first thing I did when I got home from work was to swap the MN3005 ICs.  Its like chalk and cheese, a REAL MN3005 sounds awesome, has more than double the delay time and is far less prone to distortion on the repeats.

I bought my MN3005 from eeedesigner on eBay, http://stores.ebay.com.au/eeedesigner  BEWARE!!

Here is a pic of my two ICs, the fake is on the right.



I'm contacting eeedesigner and asking for a refund and reporting him to eBay of course.

Cheers

jbgron

[Just1More]

At least you know the cause now. I'm going to see if I can find someone locally who has a MN3005 based delay and try my chip in a known good unit and see what we come up with. Should confirm it one way or the other.