LESS THAN STANDARD SEPARATION WHEN SMA LANDED ON RWY OCCUPIED BY PRECEDING SMA.

Narrative

FIRST ACFT (VFR) TURNED FINAL (3 MI) FROM LEFT BASE. SECOND ACFT (IFR) WAS TOLD TO WIDEN OUT ON RIGHT BASE AND FOLLOW FIRST ACFT. SECOND ACFT HAD FIRST ACFT IN SIGHT; EST 3/4 TO 1 MILE BEHIND. TWR CTLR TURNED ATTN TO WEST SIDE OF FIELD WHERE 2 ACFT WERE ENTERING RIGHT TFC ON RIGHT XWIND; 3 OTHERS IN PATTERN (27R). THESE CONFLICTIONS WERE FIXED AND SEQUENCE SET. ACFT #1 HAD LANDED AND WAS TURNING OFF RWY 27L ONTO A CLOSED TAXIWAY 1400' FROM APCH END. HE WAS INSTRUCTED NOT TO TURN ON THAT TAXIWAY; AND TURNED BACK-DOWN THE RWY. AT THAT POINT ACFT #2 WAS SEEN ON THE RWY ABOUT 200' FROM #1. #2 WAS TOLD #1 WAS CONTINUING ON THE RWY AND TO SLOW DOWN. #2 SAID HE SAW #1 AND FOLLOWED HIM OFF THE RWY. THE #2 ACFT GOT WITHIN 75' OF EACH OTHER. #2 WAS NOT CLRED TO LAND. CONTRIBUTING FACTORS; CLOSED TXWY 'R'; LATE AFTERNOON SUN AND HAZE; COMBINED POSITIONS(LC1 AND LC2) BRITE OUT OF SERVICE. POSSIBLE REMEDIES; SPLIT POSITION; TEACH PLTS NOT TO LAND WITHOUT CLRNC; INCREASED CTLR AWARENESS; A BRITE RADAR THAT WORKS.