Module Tester Calibration


#1

My module tester seems to work fine, but when trying to calibrate using the Offset trimmer, I cannot get the output below 8.38V when it should be 1V.
the gap between v/oct is correct
Help!


#2

It’s not a calibration problem, you have a wrong part somewhere.

Check R6, R10, or maybe the voltage reference.

Does the voltage reference generate -4.096V as it should?


#3

R6 and R10 are correct, which is the voltage reference?


#4

sorry, it’s late the LM4040 is giving out -10.10V


#5

Wrong LM4040? There are different versions available with different reference voltages.


#6

Yes, you’re using the wrong part.


#7

ok thanks, i’ve re ordered the part listed on the bom


#8

You mean the BOM had an error? Or that you’ve now bought the exact part listed on the BOM? Because I confirm that the references published on the BOM are correct. So if it’s a mistake digikey/Mouser/Farnell did when they shipped your order, try to see if they can send you the correct part for free!


#9

I had used a part from a bag labelled LM4040, turned out I had the correct Mouser part still in a sealed bag. I’ve replaced it but now the display no longer works?


#10

the voltage ref now reads -4.11V


#11

but the module tester no longer works


#12

Voltage check?


#13

IC9 got super hot and the power supply died before I had a chance to take any measurements


#14

Then you had a short somewhere…


#15

it was the power cable that leads out to the module, now I have to find another psu, took me ages to find the last one.
Thanks for your help Olivier


#16

Hi,
I have about the same problem. I’m beginner and I’m learning to read the schema. when I’m measuring CV OUT, so i still have a value of 4.35 V, I turn potentiometer as I want.


#17

Oliwerwhite,there are plenty of books for beginners,i was absolute beginners 1 year ago,and now ,with books (how to read schems,electronics for beginners,etc…)its a lot easier!
If you are intereseted to go more “inside” electronic : there is a great book called “the art of electronics electronics” from Paul Horowitz,there are 3 editions.Dont hesitate to buy books its a great help even if you think its not for U ,consider it.Its the bible!


#18

mutantjf, thank you very much for the great type.