ATX SMT UNAUTH PENETRATION ON MOA.

Narrative

I RECEIVED THE IFR CLRNC FROM LAS VEGAS BUT WAS INFORMED PRIOR TO DEP THAT THE DEST HAD BEEN CHANGED TO SAN JOSE; CA. AFTER SWITCHING FREQS TO LOS ANGELES CENTER; I ADVISED THEM OF MY DEST CHANGE. I RECEIVED THE FOLLOWING CLRNC. CLRED TO SAN JOSE VIA BTY 126 DEG RADIAL BTY V105 LIDAT DIRECT HYP DIRECT SJC. I HAD BEEN TOLD TO RPT LIDAT INTXN; AS OAKLAND CENTER RADAR IN THAT AREA WAS APPARENTLY NOT WORKING. AFTER RPTING LIDAT; I BEGAN A LEFT TURN TOWARDS HYP USING THE AUTOPLT TO TURN THE ACFT. I HAD PROGRAMMED HYP IN THE RNAV (263 DEG RADIAL/178 NM). UNKNOWN TO ME AT THE TIME; I MAY HAVE INADVERTENTLY ROTATED THE COMPASS CARD OF THE HSI AS I TURNED THE HDG BUG (IT IS POSSIBLE TO DO THAT IN THIS ACFT). BECAUSE OF THE POSSIBLE COMPASS ERROR; I BELIEVE I MAY HAVE TURNED TOO FAR BACK TOWARDS THE S. AT THE SPD I WAS TRAVELING (APPROX 205 KTS); I WOULD HAVE DEVIATED 20 NM OFF WHAT MY DIRECT COURSE SHOULD HAVE BEEN WITHIN ABOUT 6 TO 8 MINS. AS THE COMPASS BEGAN SLOWLY SLAVING ITSELF BACK TO THE PROPER MAGNETIC HDG; I WAS IN FACT ON A DIRECT COURSE TOWARDS HYP; EXCEPT MY COURSE LINE WAS ABOUT 20-25 NM S OF THE COURSE LINE I SHOULD HAVE BEEN ON. I DID ENTER A MOA; BUT DID NOT ENTER ANY RESTR AIRSPACE. WHEN I WAS HANDED OFF TO THE NEXT CENTER CTLR; HE THEN REQUESTED THAT I CALL THEM UPON REACHING MY DEST.