Yusynth ADSR (New version) issues

[Crowhill]

Hi All, I am having a problem with the Yusynth ADSR (v.2)

I have read the various posts regarding other people´s issues with this particular ADSR, and have tried to troubleshoot the problem myself, but to no avail. I will describe the issue and the steps I have taken to remedy the problem.

Schematic here: http://yusynth.net/Modular/Commun/ADSR/ADSR555-FINAL.gif

Issues:
- Attack , There is no attack, on the contrary, when I increase the attack, I get no release
- Decay, no decay, no matter how i twiddle the knob
- Sustain, the sustain level is 8v no matter if i increase or decrease the pot.
- Release works fine, albeit that Sustain messes it up.
- And of course the LED is illuminated all the time, but gets brighter when i push the trigger button. This is not really a big issue for me, as I recall a solution for this elsewhere on the forum.


Troubleshooting so far:
- I have checked for solderblobs and shortcircuits on the PCB. I have removed all flux between tracks.
- Probed the TL074 and the 7555 for correct voltages on the power input pins.
- Checked all components for correct values and orientation.
- As the A,D and S pots are wired to the pcb, and not soldered directly, I have probed the pots and connectors to make sure that there are no broken crimps on cables. Also there is good connectivity between male and female JST connectors.
- After reading https://electro-music.com/forum/viewtopic.php?highlight=adsr&t=70344 I probed my 7555 on pin 7 and 8, and both are reading 11.6v
- I am getting 11.6v on pin 4 of the tl074 and -11.8v on pin 11

The reason I am getting 11.6v is because my power supply is fed by a 12vAC wallwart, and I reckon I am losing some voltage over the 7812 and 7912 voltage regulators, but surely, the half a volt loss couldn't make such a difference, no?

I really could do with some additional troubleshooting steps, as I would love to get this circuit working



cheers, and thanks in advance,
Dave.

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[Crowhill]

Believe it or not but I had a 75558p (Opamp)in the timer socket. Doh!

[PHOBoS]

those simple mistakes can sometimes be the hardest to spot.

also