I was supposing that, setting a sine wave with Amp at 2.5V I would have on the scope a wave with 2.5V p-p, while on the manual I have just seen within the example that the p-p value showed on the screen is 5V, so the amplitude should only be related to a semi-wave.
Unless explicity stated, it is IMO never perfectly clear wheter "amplitude" is supposed to mean peak-peak or semi-wave (or even something else). Yet another difference makes the terminatinion impedance. With no load you get 2.5V semi-wave, but when you terminate the output with 50 Ohm, you'll indeed see your expected 2.5V
pp, due to the 50 Ohm output impedance of the AWG. It all depends...
... Found that the 150ohm resistor at pin 2 of EL5166 was in short circuit, so changed with a new one. After that the things were better, but not exactly as expected. I checked the outputs from DAC and levels were ok, so I decided to change the feedback resistor on the output opamp. From 560 to 186 ...
That's odd. If things are off by say 10..20%, then it is still plausible, but factor 3 isn't.
Is everything related to the AWG populated as in a geniune 2D72?
Are the various 0 Ohm resistors replaced with the actual values as well?
Are the 49.9 Ohm (68X) resistors from the DAC outputs to GND present?
What DC voltage do you measure from DAC pin 17 to GND, and from pin 18 to GND?
What is the value of your R
set resistor, from DAC pin 18 to GND?
When you set the AWG to rectangle with amplitude=2.5V and offset=0V, what peak-to-peak voltages do you measure on the two DAC outputs?
Expected are about 500mV
pp on one output, and about 850mV
pp on the other one.
EDIT:
I have added photos of a genuie 2D72.
Regards,
gf