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Let's get the collective wisdom rolling My M20J is fresh out of the avionics shop after installing a G3X panel. Last week when I flew it, the R wing fuel gauge stopped working. Well the fuel senders are old and I am contemplating a switch anyways. The very next flight, when I tried to start the engine I turned the key the plane seemed like the battery was low. I thought it was odd but maybe I spent a little too long updating the navdata with the engine off. I started it with an external source and went flying. Everything seemed normal so I took it on a 2hr XC flight. Today, flying back home I experienced the same behavior and had to use and external source to start up. Now, both COMM radios had an interference of a quick rhythmic "popping" sound. Additionally, in cruise I could see the ammeter was showing some crazy readouts, going from -30 to -290 amps!!! After I landed the ammeter showed a reasonable +2 amps. I tried turning on and off various systems and lights to see what I could find but no clue. Nothing particular happened. I suspect something is shorting the system and draining the battery. Perhaps the fuel sender line (it may have nothing to do with the electrical problem but what the hell)? Any thoughts? Here are some pictures.

Hi, We recently did the annual on our M20K 252 and noticed that the boost pump would only run with the high boost switch on but not the low boost switch: - Checked the switch and boost pump regulator and found that there is a short on cable #2 from the regulator (the yellow cable is somewhere connected to GND). The short has actually damaged the big transistor on the regulator board (a PMD17K100). - Now the challenge comes: where is the short between cable 2 and GND. -> Anyone who has seen similar issues with the low boost pump?, any hints on how to find the short? Thanks, M252