AquaBoy - no delay & strange MN3005 chip

[deadTalash]

Got an 3005 chip from Polida, and it looks very strange (like fake) Proper voltage is applied and i hear an audio signal at the leg 7 too, but at the legs 3 and 4 i only hear noise. Is it really fake chip or it could be trouble with 3101 or something else?
I'm also going to post some photos of my mn3005 chip if necessary

[madbean]

Can you take a pic of the MN3005? One that shows the top and pins? I might be able to tell you if it is fake.

[deadTalash]

sure, here are the photos


it's really hard to see the letters on it

[madbean]

This actually looks legit. Some of them have indented borders, but I have some without them. This doesn't mean it isn't fake, though.

But, you are hearing some output at pins 3 and 4, correct? Even if it is noise, a fake chip would not produce any output at all I'm guessing.

Do have the ability to measure clock frequency on pins 2 and 6? If not, what about audio probing---do you get a high pitched whine at those points?

[pickdropper]

For what it's worth, I recently bought 4 chips from Polida.  3 of them worked fine and the 4th had the same exact problem that you have.  I tested all of them in a working Dirtbag and I couldn't get the 4th to bias, regardless of where the bias control was set.

I sent the bad one back.  Supposedly he is going to send a replacement, but I am not holding my breath.

[deadTalash]

Yes, I hear the noise at pins 3 and 4. On pins 2 and 6 I hear very high pitched sound comin' from mn3101, adjustable by CLOCK trimmer. I can not measure an exact frequency value but I guess it's about 9-10Khz.
Pickdropper, - same thing, bias trimmer makes no effect. Did your chips look like that?
What do you think guys? Is it my mistake or it's better to ask for replacement?
P.S. guys sorry for my poor english

[madbean]

You are getting clock signal. 10kHz would be correct depending on where the clock trimmer is at. If setting the clock trim at the halfway mark and adjusting the bias trim does not give you any delayed output then there are two possibilities. 1- bad chip 2-some other problem like a solder bridge at the outputs, etc.

If you feel #2 is not the case I'd say see if you can get a replacement. For me, I have a DM-2 build that I keep around just for the purpose of testing BBDs. It's one that I know works perfectly so if I have a questionable chip, I just toss it in there and bias it up. Of course, that's not necessarily the most efficient or practical way to do it, but it is very convenient

[deadTalash]

I'm sure everything is soldered correctly, but I really can't get no delayed output(  I'll try to find working thing to test my BBD. Also I have workin' MN3007, what do you think about usin' it instead of 3005 to make sure there is no other problems?

[pickdropper]

Yes, I hear the noise at pins 3 and 4. On pins 2 and 6 I hear very high pitched sound comin' from mn3101, adjustable by CLOCK trimmer. I can not measure an exact frequency value but I guess it's about 9-10Khz.
Pickdropper, - same thing, bias trimmer makes no effect. Did your chips look like that?
What do you think guys? Is it my mistake or it's better to ask for replacement?
P.S. guys sorry for my poor english

I don't have them in front of me, but I seem to remember that some (if not all) of the good ones looked just like the bad one.

[Scruffie]

I'm sure everything is soldered correctly, but I really can't get no delayed output(  I'll try to find working thing to test my BBD. Also I have workin' MN3007, what do you think about usin' it instead of 3005 to make sure there is no other problems?

Workin' MN3007 would do, probably sound like crap but it should work to test if you can jam a daughterboard or run some wires from the breadboard.

Make sure the pinouts are the same... can't remember.

[deadTalash]

Thank you guys! I'll tell you about my experiments with 3007  a week later because I'm far from my place

[spaceboss]

I've had good experiences with Polida. Given the prices are reasonable, I've expected that 1 out of 4 chips will be bunk.

Their 3007 and metal can LM308 prices are great.

James

[deadTalash]

Guys, here is some new information. The  sound I hear at the output pins of 3005 chip  (3 and 4) is the same high-pitched sound that mn3101 generates sensitive to the clock trimmer and DELAY pot, but a little more quiet. Is it helpful?

[deadTalash]

guys, workin' mn3007 behaves exactly THE SAME way like mn3005 does. Can not find any mistakes in soldering. Only thing is  I replaced electrolythic 1uf caps with non-polar film ones. Scope shows signal frequency at 10 khz and higer as I adjust CLOCK trimmer

[Scruffie]

guys, workin' mn3007 behaves exactly THE SAME way like mn3005 does. Can not find any mistakes in soldering. Only thing is  I replaced electrolythic 1uf caps with non-polar film ones. Scope shows signal frequency at 10 khz and higer as I adjust CLOCK trimmer

If the MN3007 works and your build still doesn't then let's not rule the 3005 out yet.

Voltages are needed to make any real judgements/diagnostics.