Hello Everyone,
I was trying to fix some stubborn buttons on my 34401A multimeter. In my frustration, I shorted something
I shouldn't have and now the front panel is dead. Taking inspiration from user qu1ck, I am considering a project to replace the front panel with my own custom design.
https://www.eevblog.com/forum/repair/hp-34401a-dmm-with-leaking-segments/msg3953096If I'm able to get a prototype working, I was thinking I could add even more features such as sd card data logging and wireless connectivity.
I have another working 34401A at my disposal to sniff out the serial communications to the front panel.
From my current understanding, the logic levels of the serial communications are 0V and 5V, and floating with respect to earth. Is it safe to connect my knockoff Salee logic analyzer to the main board? Since my laptop would be refrenced to earth, the gnd on the meter would become earth refrenced.
Another question I have is, which power rail would provide the most power to my system, and is it acceptable to use a switch mode power supply for increased efficiency? I see that there is +- 18V, as well as the filament AC rail straight from the transformer, originally for the VFD filaments. Do you think this could provide enough current?
I still have a lot to research on my own but I wanted to start a thread to collect criticism and feedback since I know there are many 34401A experts on this forum.
Thank you for your time,
mower