PCS 100 Calibration fails

Indeed, you may do the fine tuning by editing the parameters of the WinDso.ini.
To get the trace and the ground symbol align on the screen you have to change the parameter:

Ch1_pos0=127

Reduce it first to 117 for example.

The trace position on the screen changes when the value of the Ch1_pos0 is modified.
To get the trace back to the middle line at the program startup, you have to change the parameter:

offs_1=133

Reduce the value in little steps until trace position OK.

You may also reduce the movement of the trace when you switch from 3V to 1V by changing the parameter:

V1_offs1=-1

Try values -2 or 0 first.

Wonderful!
I have found the following values and this is all right!
ch1_pos0=109, offs_1=138 and V1_offs1=0

I have tried to find a NXP, Philips type: 74AHC1G66GW (package SOT353) with no success. I have called all big electronic sailors in Paris area… but I didn’t find any (and I don’t want to buy 1000 of them!).
As this is very small, would it be possible that you send me 1 (or 2) by mail?
If I had one, I could solder it.

Again thank’s so much for your brillant help.

Nice that the manual editing of the WinDso.ini parameters helped you to get the scope settings OK.
About the analog switch IC4:
I have forwarded your request to the Velleman product support team. I hope they can help you to get the 74AHC1G66GW.

I wish you a happy new year.

I did not receive any feedback from the Velleman product support team…
I wish they can send one circuit.

If you are bored waiting for to get those parts, one possibility may be to try to order some samples of the 74AHC1G66GW direct from the NXP.
Their sample policy is here:
nxp.com/policy/policy.php?nc12=935268459125

[quote]THIS SERVICE IS ONLY OPEN TO CUSTOMERS WHO HAVE DIRECT PURCHASING AGREEMENTS WITH NXP.
If you do not have a direct account with NXP our network of global and regional distributors is available and equipped to support you with NXP samples. You can locate the NXP authorized distributor of your choice here. [/quote]

You may ask from this sales office:
nxp.com/profile/sales/europe/#France

Or some of the distributors listed here:
nxp.com/profile/sales/europe_dist/#France

Good luck.

Thank you for your information.
I am going to contact them.