I lost another 3 hours to debug it, with no great luck.
What I did:
1. I relinked the J201 with R36/R37 (I thought that the 1M resistor is important for the bias of IC1) and the strong noise that I had before was gone

...anyway, the thresold pot doesn't seems to do something very serious

2. After that I was able to hear a very weak flanger-ish signal "behind" the dry signal (the same sound you can obtain with a BF-2 into an amp at a high volume and no guitar in the input of BF-2)...so I think that the LFO it's working...this sound can be altered using Speed/Manual/Depth/Enhance pots
3. With the Speed at maximum (or very close to) I can hear a very clear (and enough loud) "detuned chorus"-like sound...and I was able to identify it: it's the same sound that you can obtain disconnecting the dry signal from a chorus/phaser (I never built a flanger before, only choruses/phasers) ...let's say it's a "vibrato" sound...it's OK now to assume that MN3007 it's working (it's the only one that I have)?
Anyway, for my last try to debug it, can you solderman please tell me what I must to hear at the outputs of the opamps?
I made some tests and that's what I obtained:
0. all op-amps and MN3007 are OK (tested in clones of MXR Distortion+/Small Clone)
1. pins 1 and 7 of IC1: a strong clear dry signal
2. pins 8 and 14 of IC1: a strong distorsed signal
3. pins 1 and 7 of IC3: a strong clear/distorsed signal
4. pin 3 of BBD: a strong clear signal
5. pins 7/8 of BBD: a strong distorsed signal (with the Bias trimpot maximized)
6. pin 7 of IC4 (2b-2c): a strong signal (I don't remeber if it was clear or distorsed)
7. pin 1 of IC4 (2b-2c): a weak whistle signal (maybe this is a problem...)
Thank you very much!