MN3005 Aquaboy - no delay

[badgerific]

I've got 20 "MN3005"s here which I purchased from ebay and the seller is no longer registered which makes me think they're fake. I bought an aquaboy board to test these chips before before buying any dirtbag boards/parts and after building it up and trying to bias it it doesn't seem to work.

The clock trimmer and delay knob change the amount of high pitched noise as described in the build doc but the bias trimmer doesn't seem to make any difference.

Here's some pictures of my board:





The only substitution I made was to use a 25k trimmer for bias instead of 22k. Is this my problem?

Another thing I've noticed is that my "MN3005" gets pretty hot after it's been connected to power for a little while (9V).

Anyone have any suggestions?

[jkokura]

What direction did you put the jumpers?

Jacob

[Scruffie]

I'm sorry to say but that chip looks terribly fake, I could be wrong but... I don't think I am...

[Loztboy]

Is this the refurbished MN3005 from the seller with e-bay id "paul_freejazz"
Mine looks exactly the same, I have not tested mine yet...

[badgerific]

What direction did you put the jumpers?

Jacob

Running along the length of the chips rather than across as shown in the doc for MN3005.

I'm sorry to say but that chip looks terribly fake, I could be wrong but... I don't think I am...

Apparently they're pulls from karaoke machines and the tops where sanded and stamped because they looked untidy but I have a feeling you may be correct

I payed £80 for 10 and then when I tested them in my MN3008 DMM they didn't work so I emailed the seller and he sent me out another 10 without hesitating so I only payed for half of them but still £80 is a lot to spend on non working ICs even if I have 20 instead of 10.

Is this the refurbished MN3005 from the seller with e-bay id "paul_freejazz"
Mine looks exactly the same, I have not tested mine yet...

Yeah it certainly is, let me know how you get on with testing yours. Hopefully we haven't been ripped off but the fact that he's no longer on ebay worries me.

[jkokura]

Have you tried all your chips? Or just one?

Jacob

[badgerific]

Only two so far, going to give the others a go tomorrow. I've checked over my parts and joints and it all seems okay to me. The main thing I think that could be wrong is the 25k bias trimmer.

[madbean]

That particular chip looks fake, I'm sorry to say.

[badgerific]

If I pull one of the MN3008s from my deluxe memory man and drop it in will that be acceptable to test the board is all done properly or will I break something?

[gtr2]

Did you check your voltages at the "mn3005"?

Did you check to see if you're getting an audio signal at pin 7?

I've had a fair share of genuine mn3005's in my hands and that one looks bogus.  But you should be sure things are correct before subbing other bbd's.

Josh

[badgerific]

Did you check your voltages at the "mn3005"?

Did you check to see if you're getting an audio signal at pin 7?

I've had a fair share of genuine mn3005's in my hands and that one looks bogus.  But you should be sure things are correct before subbing other bbd's.

Josh

I haven't checked the voltages. Will give that a go now. What voltages should I be looking for?

Will also check the signal at pin 7 and report back.

Cheers to everyone for the help


Edit:

Got audio at pin 7, louder than the input and the clock noise is present too which changes when i adjust the delay pot.

Voltages are as follows:

Pin1: 8.32
Pin2: 4.04
Pin3: 0.37
Pin4: 0.36
Pin5: 0
Pin6: 4.03
Pin7: 1.33
Pin8: 1.17

[Loztboy]

I got my last part for the dirtbag(chargepump) today, and wil test the mn3005's (same as you got) tonight.

[badgerific]

Awesome, I have my fingers crossed for you

[Loztboy]

Mine does not work. I get a clean signal, but no delay. Tried audioprobing pin 3 still just a clean non delayed signal.
They get a little hot also.

I ordered two new ones from dalbani.co.uk (http://www.dalbani.co.uk/catalogue/product_details.php?id=20198)
I read some posts on FSB that they are real.

[Scruffie]

Hot = Bad

Sorry guys... looks like you got fakes, not even relabelled 3008s.