I don't know about the electronics but here's how I would remove the rust:
I researched this for weeks and here’s how I removed the rust in my tank:
If real bad, add a cup of nuts and bolts and shake vigorously till the big chunks are gone, empty out.
Put 50/50 mix of phosphoric acid (under $10 / gal. at tractor supply) & water in tank, swish around, rotate occasionally and let work for at least 8 hrs.
Always Add ACID TO WATER-NEVER Add Water to Acid
Rinse with water
Next fill it with a solution of water and a small amount of baking soda to neutralize the acid. After 15 minutes, rinse the tank with water again
Fill the tank immediately with a Water/Baking Soda solution. ˝ box of baking soda in full tank of water
Immediately rinse with 1 qt gas with some heat or WD-40(1 oz. per gal)
Next rinse with pre mix- gas 25:1 2 cycle oil, swish around.
Used acid can be diluted and sprayed into garden.