UNINTENTIONAL LOW ALT CIVIL FLT.

Narrative

I DEPARTED RHV FOR A NIGHT FLT OVER THE S SAN JOSE AREA. I DEPARTED RWY 31R AT RHV EXITING THE PATTERN ON R DOWNWIND FLYING AT 1100 FT MSL. I SPOTTED TFC THAT WAS ON FINAL FOR RWY 31R AT RHV AND COMMUNICATED WITH HIM ON THE RADIO TELLING MY RELATIVE POS TO HIM AND HE DID THE SAME. I CONTINUED FLYING SWBOUND STAYING CLR OF SJC'S CLASS C AIRSPACE. I WAS GOING TO FLY OVER NEAR THE FOOTHILLS AND THEN BACK TO RHV. ON THE WAY OVER THERE; I SAW THE POLICE HELI PATROL NEAR THE DOWNTOWN AREA. ABOUT SW OF THE ARPT (SJC) I LOST VISUAL CONTACT WITH THE POLICE HELI. I WANTED TO REGAIN VISUAL CONTACT AS TO KEEP CLR OF THE AREA THAT HE IS PATROLLING; BECAUSE EVENTS ON THE GND MAY CAUSE HIM TO SHIFT HIS LOCATION SUDDENLY AND EXTRA DISTANCE WOULD GIVE ME TIME TO REACT IF NEEDED. I STARTED A BACK TURN TO THE R CIRCLING TO SEE IF I COULD REGAIN VISUAL CONTACT. A SHORT TIME AFTER I STARTED CIRCLING MY INST LIGHTS WENT OFF. I LEVELED OUT OF MY TURN AT THE SAME TIME CHKING MY BREAKERS AND SWITCHES. I THEN BUMPED THE SWITCH PANEL AND THE INST LIGHTS CAME ON THEN OFF. I THEN REACHED UNDER THE SWITCH PANEL AND STARTED PUSHING ON THE WIRING THINKING THERE MAY BE A BAD CONNECTION; AND THE INST LIGHTS CAME BACK ON. I THEN REALIZED I HAD LOST SOME ALT. I ADDED THROTTLE AND PULLED UP INTO A CLB AND DECREASED MY ALT WHEN I STARTED TO REGAIN MY ALT; AT THIS POINT I WAS APPROX SEBOUND. AS I LEVELED OUT; I GOT A VISUAL ON THE POLICE HELI. HE WAS OFF TO MY R. I THEN STARTED BACK TO RHV WHEN I SMELLED BURNING WIRES. SO I TURNED OFF THE EQUIP SWITCHES AND OPENED THE VENT AND WAITED TO SEE IF THE SMELL WOULD GO AWAY; BY THEN I WAS NEARING THE SILVER CREEK AREA AND TURNED NWBOUND FOR A STRAIGHT IN LNDG ON RWY 31R; UPON LNDG I TAXIED OVER TO MY TIEDOWN.