TANDY 1000 SX (250-1051) Math Coprocessor Faxback Doc. # 1187 There is a socket on the main logic board at location U33 for the math co-processor. Remove jumper E3-E4 to initialize math co-processor. Use an Intel 8087 Math Co-Processor. Note: Refer to Faxback Doc. # 9002 for the specific Catalog Number to order this part.