Aquaboy Deluxe / v3205 Biasing

[enepdivad]

Hello all,

This is my first post on this forum, as I have usually been able to find an answer to my questions by simply searching past posts.  Many thanks to all of the experienced people on here who are willing to help out.

This time I'm having trouble finding an answer, so I figured it may be prudent to ask...

My issue is this:
I'm building two Aquaboy Deluxes, each with v3205 BBDs, v3102 clock, and v571 compander.  I had a somewhat difficult time finding the v3205 chips because Smallbear is out of stock.  I ended up ordering them from a place called Build Your Own Clone.

Anyway, now that I have finished one of the ABDXs (the other is close to finished), I have begun the process of testing and biasing before boxing them up.  At first things were going pretty well.  I removed IC4 and was able to get nice clean delay signal on pins 3 and 4 of IC3 after fiddling with both the "clock" and "bias1" trimpots.
But when I moved on to the second step, repeating the process on IC4, I hit a road block.  After replacing IC4 and probing, I was unable to get any signal at all on it's 3rd and 4th pins, no matter what I did with the "bias2" trimpot.  I even tried fiddling with the clock a little bit (after each small turn of the clock I would sweep through the entire range of "bias2").  Still nothing.
At this point, since I have extra chips from the second build, I tried swapping out IC4.  Still couldn't get it to pass a delay signal.
Then I decided to go back to step one, but test each chip in the IC3 position to see what I would get.  What I found was this:  The only v3205 chip I could get to pass a delay signal in the IC3 position was the first one I had tried.  I tried to perform the same operation on the other three with no success.

So my assumption is that I have three non-working v3205 chips and one working one.  But I don't know.

Is there anything I should try before looking for replacements?  Is there any way of objectively testing each of these chips?  Is there something I'm missing in the biasing process?  I'm kind of stuck at this point and after looking around, the only place I can find v3205 chips at the moment is from Banzai Music, and they are in Germany.
If anybody has any insights on this, I would greatly appreciate the help.  I will attempt further testing this evening and will let you all know if anything changes.

Thanks,
-David

[alanp]

Have you got in contact with BYOC?

[Stomptown]

I would definitely contact BYOC.  Their customer service is great so I'm sure they will work with you.  The question is, are you sure you didn't damage them by inserting them into IC4???   

[Scruffie]

Did you ESD handle them? They are static sensitive (also I hope BYOC shipped them in anti-static packaging or they could be at fault).

They're possibly not dead though, just not biasing up right, stick the working one in so that it passes delay, note the voltages and then stick one of the 'dead' chips in and note the voltages for that and post them up.

[enepdivad]

Hello all,

Thank you for your responses.  I was able to work on the ABDX a bit this weekend and I have come to the conclusion that I fried the chips due to improper handling.  Basically, when I tried to re-create my original success with the one working chip, I couldn't get it to pass a delay signal anymore either.  BYOC sent the chips in an anti-static bag and since I seem to have been able to destroy one chip that was working originally, I'm guessing I am at fault for the rest too.  I was trying to be careful, working in an uncarpeted area and touching a grounded chasis before and after touching each part, but I guess this is not enough.

On that note, I'm working on getting some replacement v3205s but before I do, what would you recommend for ESD handling?  Do I have to go to the extent of buying an anti-static mat and wrist strap?  Are there some economical alternatives?  Or is this an area where you get what you pay for?

Thanks all,
-David

[peAk]

wow, interesting to read stories like this because I never ground myself and I don't ever worry about handling ICs

I guess we have so much humidity over here, that something like this would be pretty rare.

Sorry to hear your story