16 Installation Note N5225-90105• W29 (N5245-20017) A31 port 4 receiver coupler to front-panel REF 4 SOURCE OUT• W18 (reuse) (N5245-20111) A32 port 2 receiver coupler to W17• W38 (N5245-20037) Port 3 RCVR C IN to A28 mixer brick (C)• W44 (N5245-20020) REF 3 RCVR R3 IN to A28 mixer brick (R3)• W12 (reuse) (N5245-20109) A29 port 1 receiver coupler to W11• W20 (N5245-20099) Port 1 CPLR THRU to A33 port 1 coupler• W24 (N5245-20098) Port 3 CPLR THRU to A34 port 3 coupler• W26 (N5245-20015) A34 port 3 coupler to front-panel Port 3 CPLR ARM• W23 (N5245-20051) A30 port 3 receiver coupler to front-panel Port 3 SOURCE OUT• W25 (N5245-20016) A30 port 3 receiver coupler to front-panel REF 3 SOURCE OUT• W37 (N5245-20041) Port 1 RCVR A IN to A27 mixer brick (A)• W22 (N5245-20014) A33 port 1 coupler to front-panel Port 1 CPLR ARM• W19 (N5245-20039) A29 port 1 receiver coupler to front-panel Port 1 SOURCE OUT• W42 (N5245-20007) REF 1 RCVR R1 IN to A37 reference mixer switch• W41 (N5245-20006) A37 reference mixer switch to front-panel REF 1 SOURCE OUT• W43 (N5245-20009) A37 reference mixer switch to A27 mixer brick (R1)• W21 (N5245-20110) A29 port 1 receiver coupler to A37 reference mixer switch* Figure 1 on page 12 shows two screws that attach the reference mixer switch to the test set deck. At thistime, torque these two screws to 9 in-lbs.• W14 (reuse) (N5245-20043)A30 port 3 receiver coupler to W13• W16 (reuse) (N5245-20044)A31 port 4 receiver coupler to W15Install the Ribbon CableTo see an image showing the location of this cable, click the Chapter 6 bookmarks “Bottom Ribbon Cables andWire Harnesses, 4-Port, Option 401” in the PDF Service Guide1 . New parts are listed in Table 1 on page 7.If not already done, connect the reference mixer switch ribbon cable ( 8121-0966) as follows:• A23 test set motherboard J554 to A37 reference mixer switch1. See “Downloading the Online PNA Service Guide” on page 5.