= AST RESEARCH, INC. TECHNICAL BULLETIN # 1205 6-6-95 = AST DESKTOPS DISPLAYING GARBLED TEXT PROBLEM AST desktop systems may display garbled text and error message "03:02" at boot-up. CAUSE Noise on the Non-Maskable Interrupt (NMI) lines causes a false NMI to be generated. SYSTEMS AFFECTED AST PART NUMBER AND DESCRIPTION 501196-XXX BRAVO 4-25S 501197-XXX BRAVO 4-33 501198-XXX BRAVO 4-50D 501199-XXX BRAVO 4-66D 501233-XXX BRAVO 4-33S 501243-XXX ADVANTAGE! PLUS 2 486-33 501244-XXX ADVANTAGE! PLUS 2 486SX 501245-XXX ADVANTAGE! PLUS 2 486SX 501246-XXX ADVANTAGE! PLUS 2 486DX2 501275-XXX ADVANTAGE! PLUS 2 486SX 501276-XXX ADVANTAGE! PLUS 2 486SX 501290-XXX BRAVO 4-25S 501291-XXX BRAVO 4-33S 501292-XXX BRAVO 4-33 501293-XXX BRAVO 4-50D 501300-XXX BRAVO 4-33S 501303-XXX BRAVO 4-33 501304-XXX BRAVO 4-25S 501341-XXX BRAVO LC 4-33 501346-XXX BRAVO 4-33S 501415-XXX ADVANTAGE! PLUS 3 486SX 501416-XXX ADVANTAGE! PLUS 3 486DX2 501417-XXX ADVANTAGE! PLUS 2 486DX2 501418-XXX ADVANTAGE! PLUS 3 486SX 501419-XXX ADVANTAGE! PLUS 3 486DX 501445-XXX ADVANTAGE! PLUS 3 486DX2 501461-XXX BRAVO 4-66D 501560-XXX BRAVO 4-25S 510300-XXX BRAVO 4-33S 510303-XXX BRAVO 4-33 510304-XXX BRAVO 4-25S SOLUTION A .33 PF capacitor has been added to the system board between pins 12 and 13 at location U21. The solution is to replace the system board. See part numbers and revision below. CAUTION This modification should be performed ONLY by a qualified service technician. It is strongly recommended that this change be completed by an AST Authorized Service Center. In no case will AST Research, Inc. be liable for damage to the system and its components, or loss of data caused by improper modification. PREREQUISITES A full backup of all data on the hard drive in the computer is strongly suggested. TIME REQUIRED 30 minutes. STATUS VERIFICATION The revision level of the AST Riser card can be identified by observing the revision letter at the end of the nine-digit part number located on the solder side of the card. PARTS REQUIRED AST PART NUMBER DESCRIPTION REVISION 202560-000 PCBA MBD ALC2/BLC2 X24 or higher 202560-001 PCBA MBD A/BLC2 4-25S X22 or higher 202560-012 PCBA MBD A/BLC2 4-33 X23 or higher 202560-013 PCBA MBD A/BLC2 4-33 X24 or higher 202560-014 PCBA MBD A/BLC2 4-33 X24 or higher 202560-015 PCBA MBD A/BLC2 4-33 X24 or higher 202560-017 PCBA MBD A/BLC2 4-50D X24 or higher 202560-018 PCBA MBD A/BLC2 4-50D X25 or higher 202560-019 PCBA MBD A/BLC2 4-50D X25 or higher 202560-021 PCBA MBD A/BLC2 4-66D X28 or higher 202560-022 PCBA MBD A/BLC2 4-66D X29 or higher 202560-023 PCBA MBD A/BLC2 4-66D X29 or higher 202560-024 PCBA MBD A/BLC2 4-66D X26 or higher 202560-027 PCBA MBD BLC2 4-33 X17 or higher 202560-028 PCBA MBD BLC2 4-50D X19 or higher 202560-030 PCBA MBD A/BLC2 4-33 X20 or higher 202560-031 PCBA MBD BLC2 4-66D X10 or higher 202560-100 PCBA PIII X16 or higher 202560-101 PCBA MBD A/BLC2 4-25S X21 or higher 202560-102 PCBA MBD A/BLC2 4-25S X21 or higher 202560-103 PCBA MBD A/BLC2 4-33S X22 or higher 202560-104 PCBA MBD A/BLC2 4-33S X22 or higher 202560-105 *PCBA MBD A/BLC2 4-33 X09 or higher 202560-106 *PCBA MBD A/BLC2 4-33 X09 or higher 202560-107 *PCBA MBD A/BLC2 4-50D X10 or higher 202560-108 *PCBA MBD A/BLC2 4-50D X10 or higher 202560-109 *PCBA MBD A/BLC2 4-66D X13 or higher 202560-110 *PCBA MBD A/BLC2 4-66D X13 or higher 202560-111 *PCBA MBD A/BLC2 4-66D X11 or higher 202560-112 PCBA MBD B 4-25S X16 or higher 202560-113 PCBA MBD B 4-33S X16 or higher 202560-600 PCBA MBD ALC2/BLC2 X09 or higher TOOLS REQUIRED Standard computer tools. INSTALLATION PROCEDURE Refer to the system Hardware Maintenance Manual. Removal and replacement of system "Field Replaceable Units" (FRUs) should only be performed according to the installation procedures approved and prescribed by AST Research, Inc. Remove the Riser card according to procedures approved and prescribed by AST Research, Inc. CHECK-OUT PROCEDURE To verify proper operation of the system upon completion of this change, follow the setup and test procedures described in the AST User's Manual. NOTE Warranty reimbursement for this change requires prior AST Research, Inc. approval. The warranty on this system will become VOID if this change is completed by ANYONE other than an AST Authorized Service Center.