APCH CTL USING CTR RADAR HAD POOR QUALITY.

Narrative

WHEN I ARRIVED AT WORK FOR MY SHIFT; DULLES WAS IN A CENRAP OP. THIS MEANS OUR RADAR WAS OUT TO MAINT AND THE CTR RADAR AND CTR SEPARATION WAS BEING USED. THE PRESENTATION WAS UNACCEPTABLE. ALL A/N'S WERE FLICKERING; AND THE LAST 2 CHARACTERS OF THE 'H' FUNCTION WERE MISSING. (EXAMPLE: A C130 WOULD REFLECT 'C1' IN THE SCRATCH PAD. THE AIRSPD WAS ALSO AFFECTED. AN AIRSPD OF 230 KTS WOULD SHOW '2' IN THE SCRATCH PAD. THIS LACK OF INFO MADE ACFT TYPE AND AIRSPD UNUSABLE.) (WHILE WORKING S ARR SECTOR; I HAD 2 TARGETS TOTALLY DISAPPEAR N OF BRVVOR. ACR X AT 10000 FT AND ACFT Y AT 800 FT.) I LOST ALL A/N'S; VIRGILES AND SPLATS (*) ON THESE ACFT. (CTR RADAR DOES NOT SHOW 'SKIN HITS' ON ACFT. IT ONLY GENERATES A TARGET BASED ON THE XPONDER CODE.) ANOTHER ACFT AT 6000 FT ROUTED CSN DIRECT MRB AND WAS HANDED OFF TO W ARR. THE AIRPLANE TOTALLY DISAPPEARED FROM MY SCOPE AS WELL AS W ARRS. LATER; WHILE WORKING DEP SCOPES; I WATCHED THE OP. I OBSERVED 2 ACFT ON FINAL TO RWYS 19R/L DISAPPEAR OFF SCOPE. (1 - ACFT ABOUT 4 MI N OF AML; 2 - BE35 OVER RINKS OM.) ADDITIONALLY I HAD RECEIVED A POINTOUT ON A HEF PRACTICE APCH (A CESSNA OF SOME TYPE) AND THE NEXT TIME I LOOKED; THE ACFT DISAPPEARED TOTALLY. WITH THE VOLUME OF TFC; AND THE INTRAILS THAT WE HAD; THIS WAS AN UNSAFE OP; TO SAY THE LEAST. THE AREA SUPVR REMARKED TO ME; 'THIS IS THE WORST CENRAP PRESENTATION I'VE EVER SEEN.'