Easy Vibe problems

[ohm1163058]

Last week I built an easy vibe and I am having a bit of a hard time figuring out why the Oscilator is not working, I have gone and searched the forum for info and I have not been able to figure out what the problem is yet. I built the circuit from RG Keen's layout using TL072 opamps. I am pretty sure the tone section of the circuit works as I can run a torch by each LDR and it well change tone and such. The two leds at the bottom of the board are on, and the drive and depth pots do very the insensity of the leds for the LDR's. I have gone over the board several times looking for solder bridges and missing links, but have not had much of any improvement, I did though on accident install the polarized caps backwards(sense corrected), I do not know if I fried one and that is effecting the oscillator or not. Here is the voltage readings for the opamps, in RG's order.

-Battery 8.5v (yes I know it is half dead)

     IC1     IC2       IC3    IC4
--------------------------------
1  3.8    4.5-7.7    3.8    1.3
2  3.8      3.8        3.8    3.8
3  1.9      3.8        3.8    3.8
4    0         0           0      0    (good sinse it is ground)   
5  3.8      3.8        3.8    3.8
6  3.8      3.8        3.8    3.8
7  3.8      3.8        3.8    3.8
8  8.5      8.5        8.5    8.5

Any help would be appriciated as I would love to have it working and be able to play with it.

[spudulike]

Did you try the search function ?

In this thread I posted the volatages of my working easyvibes ...

http://www.diystompboxes.com/smfforum/index.php?topic=40414.msg289975#msg289975

... and also pointed out a problem with the pcb artwork.

And in this thread I posted a cleaned up schematic with voltages at specific points

http://www.diystompboxes.com/smfforum/index.php?topic=40553.msg291427#msg291427

To help I've repeated the schematic...

[ohm1163058]

Thanks that should help with testing. I did go and do a search and read through a bunch of posts, did not see that one though. Are you saying two if the bias doides are improperlly labled on the layout? Should I try reversing them?
Thanks again.

[ohm1163058]

My bad I see what you mean with the diodes.

[ohm1163058]

I figured out that I was also not reading some of the voltages right for the IC's. I also figured out that the output pins U2-1 and U4-1 are not changing like they should, I think my diodes might not be in right.

[spudulike]

Schematic edited - now correct.

This shows the traces with power, ground, and vref highlighted.

[ohm1163058]

I went over the board again and cant find anything. I checked c7 and it was reading 120nF instead of 100 so I replaced it with a different one that was reading 99nF, just a little closer, but still no luck. I went and read the pin 1 voltages on IC2 and 4 and they are both reading 8.5 volts which is obviously wrong and also I took readings off the rate pot and is does not seem to effect the voltage at all, it reads 3.8 volts on all three lugs no matter the position of the shaft is this normal, resistance changes like normal though. I wish I was still in school, on summer break, if I was I would hook the thing to a O-scope and see if I could see the oscillator working.

[ohm1163058]

Got it to work, I went over the board about half a million more times with a hobby knife and cleaned it up some more and it is working. In hind sight I should have printed another board, as the one I used was not that great, seems like I was constantly finding bad traces and tight gaps. Thanks Spudulike for all the help, the highlighted board diagram was a big help, made it easier to follow the traces and find things. Now I just need to put it in a box and play with it