ENTERED RESTRICTED AIRSPACE.

Narrative

WHILE ON A ROUTINE VFR FLT FROM THE CINCINNATI BLUE ASH ARPT TO READING; PA; I PASSED THROUGH A PART OF R5503A DUE TO THE FACT THAT THE RNAV RADIO I WAS NAVIGATING BY EXPERIENCED A MALFUNCTION OF SEVERAL DEG. I HAD BEEN RECEIVING ADVISORIES FROM INDY CENTER AFTER MY DEP FROM BLUE ASH BUT WAS TERMINATED BY THE CENTER DUE TO TFC SATURATION IN HIS SECTOR. I CONTINUED FLYING EBND NAVIGATING TO A POINT (RNAV) SLIGHTLY NW OF THE YORK (YRK) VOR ON A RADIAL WHICH WOULD KEEP ME JUST S OF THE RESTR AREA. AFTER FLYING FOR SEVERAL MINUTES; AN FGT JOINED MY LEFT WING. AT THIS TIME; I CHKED MY CINCINNATI SECTIONAL CHART TO CONFIRM MY RNAV WAYPOINT AND INBND COURSE TO THE POINT. I FOUND NO ERROR. HOWEVER; WHEN I CROSS-CHKED MY POS WITH MY #2 RADIO; I FOUND MY POS WELL N INTO THE RESTR AREA. I TURNED S IMMEDIATELY AND PROCEEDED DIRECTLY TO THE YORK VOR IN ORDER TO VACATE THE AREA. THE NEXT CENTER CTLR CONFIRMED THE AREA WAS ACTIVE WHEN I CONTACTED HIM FOR FURTHER ADVISORIES. I CONTINUED TO READING W/O FURTHER INCIDENT WHERE I HAD THE VOR-RNAV UNIT INSPECTED. THE RADIO WAS FOUND IN SUBSTANTIAL ERROR BOTH IN THE ACFT AND WHEN LATER TESTED BY AN AVIONICS REPAIR STATION AND SUBSEQUENTLY REPAIRED.