Pork Barrel bother

[juansolo]

Built a pork barrel and have hit a bit of a wall.

Chorus can be heard but only when you turn the pot. Pointing at a problem with the oscillator. Probing around the only issue we can find that looks wrong is that the voltage on pin2 of ic2, where you'd expect 4.5v is 0.9v. We've replaced the two resistors at r31 and r32 in case there are issues there and can find no problem. It's got 9v going into r31, and very little coming out. For the life of me I can't find a short anywhere.

Any ideas?

[juansolo]

Maracas has got the oscillator running. Looks like the was an invisible short on the ic. Still doesn't work mind you so we'll bite the bullet and get the ics from small bear and give it another go. Not given up yet.

[juansolo]

...and lo, from now on Marauder will be known as Maracas. Bless iPad autocorrect for it is awesome

[bigmufffuzzwizz]

That means you got it working!? My hat's off to you, or is it your cleggy? 

[Scruffie]

Are these ICs from Ebay then? What does Pin 8 of the 3101 read... I recall a problem with the ebay 3101s.

[Haberdasher]

...and lo, from now on Marauder will be known as Maracas. Bless iPad autocorrect for it is awesome

Maracas, eh?  Reminds me of a certain Zappa tune.

[juansolo]

Not working but the oscilator is oscilating (which is wasn't before). There was a bloody invisible bridge there somewhere that Cleggy found. I've given up looking long before this point. It's clicking away happily now.

I suspect the usual suspects are duff. They came from Das Musicding who are usually very good. I've bitten the bullet and ordered a shedload of ICs from smallbear. They be here in a few weeks, then we'll try again.

[juansolo]

We changed the ICs and the result is the same

I noticed that the oscillator stops oscillating when the depth pot is at maximum, and only starts when turned down.  Anyone got any ideas?

Can someone give us the voltages on the ICs and transistors to compare when the depth at maximum.

[LaceSensor]

We changed the ICs and the result is the same

I noticed that the oscillator stops oscillating when the depth pot is at maximum, and only starts when turned down.  Anyone got any ideas?

Can someone give us the voltages on the ICs and transistors to compare when the depth at maximum.

If you don't get an answer til Thursday remind me with a pm and I'll do voltages for you on my v2 board

[marauder]

An interesting development.

As the problem seems to be with the depth pot, I disconnected pin 1 from it, and it now choruses.  Of course, the depth doesnt change with the pot, but at least it's pointing us in the right direction, those voltages would still be great, if you could check them at min and max depth.

[bigmufffuzzwizz]

I just finished one which I could grab the voltages for you guys, I just need to get it from my buddy's house. 

[lloyd17]

Have you tried swapping out the depth pot? I chased problems on my PB for two hours on Saturday until figuring out I had a faulty speed pot. If nothing is posted I'll try to get some voltages up tonight after work. Gotta open mine up and replace an LED. How I got two different colors in there is beyond me..

[marauder]

Tried another pot, and the result is the same.

[LaceSensor]

Here are my voltages. Battery wasnt fresh, but the effect works, so hope this helps.
I rounded up to 1 decimal point as my DMM isnt great anyway.

Left side is min ,right side is max

TL062
1 - 0-6.7 / 2-5 fluctuating
2 - 3.8 / 3.8
3 - 2-5 / 4-5 fluctuating
4 - 0 / 0
5 - 3.6 / 3.8
6 - 2.1 / 3/5
7 - 1.8-5.2 / 3-4 fluctuating
8 - 7.3 / 7.6

4558D

1 - 4.6 / 4.8
2 - 4.7 / 4.8
3 - 4.7 / 4.8
4 - 0 / 0
5 - 4.7 / 4.8
6 - 4.7 / 4.8
7 - 4.7 / 4.8
8 - 7.4 / 7.8

MN3101

1 - 7.4 / 7.6
2 - 3.8 / 3.9
3 - 0 / 0
4 - 3.8 / 3.9
5 - 0.3 / 0.3
6 - 6.5 / 6.6-6.7
7 - 2.45 / 2.4 - 2.6
8 - 0.5 / 0.5

MN3007

1 - 7.3 / 7.6
2 - 3.8 / 3.9
3 - 4 / 4.1
4 - 0.5 / 0.5
5 - 0 / 0
6 - 3.7 / 3.9
7 - 4.2 / 4.4
8 - 4.2 / 4.4

ps I subbed a couple parts in my build, for the nearest value

[marauder]

That's really helpful mate.

I can tell ours isn't right, as the reference voltage on the TL062 drops to less than 1V when the depth is max'd.  It's correct at around 4.5V at minimum.

I like the little millennium boards for DPDT switches, I assume they are the ones which Mark made.  Thanks for those.