Author Topic: First time on Keithley 2000  (Read 10185 times)

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Offline Kjelt

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Re: First time on Keithley 2000
« Reply #50 on: September 05, 2016, 07:12:43 am »
There is no need to desolder U136 EEPROM to read or write to it. I know with other Keithleys (2001, 2002) you can hold the RESET line to stop the MCU working and can play about with the EEPROM at will, but with the 2000/2015 that doesn't work. (Something to do with Tri State?). Thankfully all you have to do is remove the firmware PROMs U156/U157 from their PLCC sockets and switch on and the U136 is your oyster.
Thanks for this tip, for backing up the calibration data that is a very good workaround.  :-+
For experimenting with the data in the eeprom that would not be so handy (for me that is).
You have to pull out the proms, flash the chip, put back in the proms and see what happened over and over again.
I rather put wires on the board than to remove those plcc's each time from their socket, I hate those plcc tools to remove them, I was glad I ordered 5 SST39F020 because I damaged one in  pulling it out the programmers socket (not zif obviously) since my expensive device programmer with multi plcc zif socket malfunctions:

What I actually would have loved is a small emulator with second individually program input, than you can fast and easy experiment with all the data.
Since the ic's are so cheap I think I might build a small breadboard with switches for I2C lines and Vcc. Oh well no time for now, will be on my todo list as future project  :)

Now - firmware change from A19 or A20 does destroy your calibration.
Honestly I do not know the advantages for upgrading any further. The only problem I had was psychologically that both 2000 units had a different firmware on power up A05 and A06, that bothered me.
If they are both A19 I am pretty happy as is, if someone can explain me why the A20 would be superior or have advantages I would like to know that. But as you said you have to recalibrate it and then figure out what changed and how to go back to the correct calibration.

Paying twice $200 for calibration is not for me, I rather spend it on new gear. Manually tweaking the calibration so it gets better (compared to a dmm on work or known chemical voltage cells) would be awesome, esp. if I get both units read exactly the same.

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