TM 55-2840-241-23 Change 19          5-25 (5) With the engine at 100% N2 and the com- pressor bleed valve closed, set the friction lock on collec- tive and rotate the twist grip to flight idle and let N1 stabi- lize. The bleed valve should be fully open. (6) Slowly rotate the twist grip toward open. Re- cord the N1 speed at which the compressor bleed valve starts to close. (7) Continue rotating the twist grip and record N1 speed  at  which  the  compressor  bleed  valve  is  fully closed. (8) Compare the recorded N1 speeds for figure 1-8. Clean the compressor bleed valve (refer to para 7-7) if range of figure 1-8 is not met and retest. Replace the bleed  valve  if  it  does  not  operate  within  the  range  on figure 1-8. b.  Removal.   (1) Disconnect the compressor discharge pres- sure sensing tube (1, figure 5-13) at compressor bleed valve (5). (Disconnect tube at the diffuser scroll pressure probe elbow only if necessary.) (2) Remove three nuts (9,12), bolts (6,10) and washers (7, 11); remove valve (5) and gasket (8). Discard the gasket. (3) If valve is to be replaced, remove  lockwire, loosen jam nut (3) and unscrew elbow (2) from the bleed valve. Discard preformed packing (4). c.  Installation. (1) Install compressor bleed valve (5) and new gasket (8) on mounting flange. Retain with three nuts (9, 12), bolts (6, 10) and washers (7, 11). Figure  5-15.  Anti-icing Valve Lever Repair Apply antiseize compound (item 15, table  2-2) to the bolts. The 1/4-28 bolt goes in the left hole (looking forward). Tighten nut on 1/4-28 bolt to 70-85 in. lb. and the other two nuts to 35-40 in. lb. (2) Lubricate preformed packing (4) with oil (item 7, table  2-2)  and place on elbow (2). Install the elbow in the bleed valve. Do not tighten the jam nut. (3) Attach     compressor     discharge     pressure sensing tube (1) to valve elbow (2). Tighten coupling nut to 80-120 in. lb. Tighten jam nut (3) to 55-80 in. lb. Section  V.   IGNITION SYSTEM 5-34.   Scope. Ignition system servicing includes replacing and test- ing the ignition exciter, spark igniter and igniter lead. 5-35.   Ignition Exciter.   a.  Removal.   WARNING The  ignition  unit  contains  a  very  small amount  of  radioactive  material  (cesium- barium 137) and normally requires no han- dling     precautions.     However,     severely damaged   units   that   have   been   broken open,  must  be  handled  with  forceps  or lead   gloves   and   disposed   of   in   accor- dance with TB 43-0108 and AR 11-9. WARNING To prevent personnel injury due to electri- cal   shock,   ensure   ignition   system   has been off at least five minutes before dis- connecting any leads. Ground leads to en- gine using an insulated screwdriver. (1) Remove nut (1, figure 5-16) and washer (2) and disconnect power input lead from the exciter (3). (2) Disconnect igniter lead (18) from the exciter. (3) Remove three nuts (4) and washers (5) se- curing exciter (3) to the gearbox housing. Remove the exciter. b.  Inspection.   (1) Visually inspect for general condition of excit- er,  input  power  terminal,  and  igniter  lead  connector. Nicks,  dents,  etc.  are  acceptable  if  damage  does  not extend  through  the  case  or  cover.  Bent  or  misaligned electrical connector is acceptable if the connector base is not excessively distorted, bulged, or cracked. The con- nector ends must assemble properly with no evidence of internal damage.