Re: 2445A calibration

maxim.vlasov@...
 

On Mon, Oct 15, 2018 at 09:29 PM, Chuck Harris wrote:


Also, it sounds a little to me like you don't understand that
Tek used the opamp as the "pass transistor" for the -1.25 and
+1.36 reference power supplies.
Thank you Chuck, but now I understand in every little detail how the reference is generated and distributed all across the o-scope including the programmatic values and the expected convergence DC point after finding the DAC code and running the smal simulation.

I had to give the thorough test and find the explanation to whatever was discovered. IMHO, the problem is related to the operation or the calibration of the ADC/DAC since it fails one of automated routines. Now since the hypothesis about the bad reference distribution is dead, then I'll go with the raster step. If the raster step is OK, then then I had to pass the 1st and 11th graticules after the DAC ref current calibration. Otherwise I'll have to go back to the multichannel DAC/ADC and continue checking the sample&hold caps, muxers and the rest.

I'm advancing slowly (have not more than 40 mins per day), so please be patient with me.

Thank you,

Maxim

Join TekScopes@groups.io to automatically receive all group messages.