7.6.22 Klystron Tube V1/Focus Coil L1. The following procedures describe how to remove the klystron tube and focus coil and install replacement units. It is not necessary to remove the focus coil to remove the klystron. However, the klystron tube must be removed before replacing the focus coil.

7.6.22.1 Equipment Required.- The following special equipment is required to
remove and install the klystron tube:

Name                                                         Quantity

Torque wrench, 3/8 in. drive,                       1
30-200 in. lbs

Drive extension bar,                                    1
3/8 in. x 6 in.

Drive adapter, 3/8 in.                                  1
to 1/4 in.

Hex head driver, 1/4 in.                            1
drive, 3/16 in.

Allen wrench, 3/16 in.,                               1
modifed

Torque wrench, 5/16 in.                             1
open end, 5-15 in. lbs

4x4x15-inch wood block                             2
(for temporary focus
coil pallet)

Chain fall, 1/2 ton, special                            1
lift (10 ft)

Plate sling                                                     1

Klystron tube container (empty)                   1

Locking/sealing compound                     As required

Lubricant, silicon grease                        As required

Oil tank dolly                                                  1

Waveguide gasket                                           1

Screwdriver set, flat tip                                   1

Screwdriver set, Phillips                                  1

Waveguide dust cover                                    1

Wrench set, open end                                    1
 
 
 

7.6.22.2 Preliminary Operations/Safety Precautions.- Proceed as follows:
 
 

Failure to perform the transmitter power-down procedure in paragraph 3.4.1.2 could cause serious injury or death.

During handling, be extremely careful that high-voltage ceramic seal is not struck or scratched, and no side pressure is exerted on the metal terminals of the klystron. Never lift the klystron tube by the output waveguide. Never allow the tube to rest on the cathode terminal.

1. Perform paragraph 3.4.1.2, steps 1 through 4a to place transmitter in maintenance mode.

2. Set waveguide pressurization unit UD6 ON/OFF switch to OFF.

3. Set power distribution panel no. 2 circuit breaker CB8 to OFF.

4. Remove transmitter center bay door and right bay outer door.

5. Perform right-bay key interlock procedure per paragraph 3.3.1.1.

Use the grounding stick provided to ground the terminals to be disconnected before touching them. High voltage could be present even after primary power is shutoff due to capacitors in the circuit. Failure to comply could result in serious injury or death.

7.6.22.3 Removal Procedure.- The following paragraphs describe how to remove klystron tube V1 and focus coil L1. See figure 11-21, sheet 1 and proceed as follows.

7.6.22.3.1 Removing Cables and Waveguide.- Proceed as follows:
 
 

 
 

1. On top of modulator pulse assembly A12, ground out terminals E7A, E7B, E8A, and E8B with grounding stick provided.
 
 

 

2. From cabinet right bay, remove screws and associated hardware securing cover over oil tank leads A7E18 through A7E21, and lift cover away. See figure 11-21, sheet 1, view A, and figure 11-22. Perform modulator pulse assembly A12 access procedure paragraph 7.7.2.3 to gain access to the hardware securing the cover to leads A7E18 through A7E21.

3. Use grounding stick to ground terminals A7E18, A7E19, A7E20, and A7E21 on oil tank.

4. Disconnect leads from terminals A7E18, A7E19, A7E20, and A7E21 on oil tank.
 
 

 

5. Disconnect connector A7Pl from oil tank interface assembly jack AlA1J1. See figure 11-21, sheet 2, view B.

6. Loosen screws securing oil tank interface assembly A7A1 to oil tank terminal block, and lift assembly enough to expose terminals on oil tank terminal block.

7. Ground all terminals on oil tank terminal block, and disconnect leads from terminals A7E1, A7E4, A7E5, and A7E16. See figure 11-21, sheet 2, view C.

8. On exterior of oil tank interface assembly A7A1, remove safety cover on terminal board A1TB3.

9. Disconnect leads terminals TB3-1A and TB3-2A from terminal board A1TB3.

10. Disconnect connector L1P1 from focus coil connector L1J1.

11. Tie disconnected terminal leads and cables clear of interface assembly A7A1 to gain access to work area.

12. Place interface assembly A7A1 in place on oil tank assembly terminal block. Do not replace hardware.

13. Disconnect exhaust air manifold from focus coil by loosening four captive screws on right side of manifold.

14. Disconnect exhaust air stove pipe duct from klystron tube cooling shroud by loosening hose clamp closest to klystron (lower of two hose clamps).
 
 
 

15. Disconnect connector W1P1 from ion pump high voltage connector V1J1 on klystron tube V1.
 
 

 
 

16. Remove rigid coax W1O4 connected between rf attenuator AT1J2 and rf drive input connector XV1P2 on klystron tube V1.

17. Disconnect rf output waveguide flange on klystron tube V1 from arc detector A6, and place dust cover on klystron waveguide opening.
 
 

 
 

18. Disconnect three grounding straps on top of oil tank A7 (one strap on each rear corner and one on right front corner).

19. Remove tuner adjusting tools from focus coil L1.
 

7.6.22.3.2 Transferring Oil Tank to Oil Tank Dolly.- See figure 11-21, sheet 3 and proceed as follows:

1. Set oil tank dolly in place at threshold of transmitter cabinet center bay. See figure 11-21, sheet 3, view E.

2. Adjust dolly height and horizontal position, as necessary, to engage dolly alignment tabs in cabinet rails.

3. Connect dolly cabinet hooks to transmitter cabinet and tighten wing nuts.

4. Remove  wheel chock from left front oil tank carriage wheel. See figure11-21, sheet 3, view D.

 
5. Lift safety stop and use oil tank handle to pull klystron tube and oil tank assembly out of cabinet and onto dolly. See figure 11-21, sheet 3, views D and F.

6. Insert dolly wheel stop pin. See figure 11-21, sheet 3, view E.
 
 
 

If the front of the transmitter cabinet is obstructed, the oil tank assembly may have to be rolled to a clear area before disassembly can continue. Before releasing the dolly from the cabinet, refer to paragraph 7.7.1.4.1 to drain the oil from the oil tank. Disconnect oil hoses from heat exchanger and wires from A7TB1 and A7TB2 at the rear of the oil tank.

7.6.22.3.3 Klystron Tube V1 Removal Procedure.- Proceed as follows:
 
 

1. Remove hardware securing x-ray shield to focus coil and remove x-ray shield from focus coil L1. See figure 11-21, sheet 4, view G.

Never lift klystron tube V1 and focus coil L1 together. To prevent damage to klystron tuning gears, make sure tuner adjustment tools have been removed from klystron before lifting klystron.

2. Attach chain fall to eyebolt provided in shelter overhead in front of transmitter cabinet. See figure 11-21, sheet 4. Then attach plate sling to chain fall hook.

To prevent sling from separating from klystron, make sure three nuts holding sling hooks are tight. (Recommended torque is 25 foot-pounds.)

During tube extraction, proceed slowly making sure sling hooks do not damage klystron shroud and klystron is entirely supported by sling hooks and eyebolts.

The hook hardware should be lubricated and checked for free play before use. Take care not to bump or damage the waveguide components or vacuum pump connection.

3. See figure 11-21, sheet 4, view H. Attach two lifting sling hooks to two eyebolts on klystron tube V1.

4. Align chain fall directly over klystron tube V1 by adjusting eyebolt in shelter overhead and oil tank assembly A7.

5. One person should steady klystron while a second person operates chain fall to carefully extract klystron tube V1 from focus coil L1.

Dielectric oil is a skin irritant. Avoid prolonged skin contact. Breathing oil vapors for a prolonged time is hazardous. Make sure the area is adequately ventilated. Oil on floor is slippery and hazardous to maintenance personnel.

On ingestion of dielectric oil, get medical attention. On eye contact, flush with water for at least 15- minutes, and get medical attention. Frequent or prolonged skin contact should be avoided. Inhalation of vapors or oil mist may irritate lungs.

Good industrial hygiene practice requires the use of effective ventilation to remove any dielectric oil vapors and mist. Skin contact is minimized by use of rubber gloves and oil resistant, nonabsorbent clothing. After working with lubricants, wash thoroughly with soap and water before eating or smoking. Change clothing soaked with oil, and reuse only after laundering.

6. Once klystron tube V1 is clear of focus coil L1, transfer oil tank assembly A7 from dolly to cabinet (refer to paragraph 7.6.22.4.3). Place removed klystron in klystron shipping container.

7. Place dust cover over klystron waveguide opening.

8. Make sure 0-ring was extracted with klystron. If 0-ring slipped off, recover it from oil tank.

9. Mop up oil that may have dripped from klystron during transfer.

10. If it is not necessary to remove focus coil L1, proceed to paragraph 7.6.22.4.2 for klystron installation procedures.

11. If tube will be out of oil tank for extended period, cover oil tank opening to keep dust and other foreign matter out of tank.

7.6.22.3.4 Focus Coil L1 Removal Procedure.- After removing klystron tube V1, seefigure 11-22 and proceed as follows:
 
 

1. Remove filter and filter bracket from air intake side of focus coil, (see figure 11-22).
Filter Assy.      Filter Assy. Removed

2. Remove manifold clip assembly, clip gasket, and two spacers from exhaust side of focus coil.
Manifold Clip Assy.         Manifold Clip Assy. Removed

3. Remove mounting flange hardware from focus coil base.

4. Attach lifting sling to chain fall hoist lifting hook and three eyebolts on focus coil.
 

To avoid personal injury and equipment damage, use a lifting mechanism rated for at least 500 pounds. Make sure shelter eyebolt will withstand the anticipated load.

Support the removed focus coil with wooden blocks, when it is placed on a dolly to protect the tube that extends below the coil mounting base.
5. Lift focus coil L1 clear of oil tank and transfer oil tank from oil tank
dolly to cabinet (refer to paragraph 7.6.22.4.3). Lower focus coil onto
dolly using wood blocks to protect tube extension. Roll focus coil away
from transmitter cabinet.

Keep dust and other foreign matter out of oil tank opening to prevent dielectric oil pollution.

7.6.22.4 Installation Procedures.- The following paragraphs describe how to install focus coil L1 and klystron tube V1. If only klystron tube V1 has been removed, proceed to paragraph 7.6.22.4.2.

7.6.22.4.1 Focus Coil L1 Installation Procedure.- See figure 11-22 and proceed as follows:
 
 

To avoid personal injury and equipment damage use a lifting mechanism rated for at least 500 pounds. Make sure shelter eyebolt will withstand the anticipated load.
1. Attach lifting sling to replacement focus coil L1.
 
 



CAUTION
Take care not to damage the stud bolts on top of oil tank.














2. With chain fall, lift focus coil L1 and place in position. Transfer oil tank to oil tank dolly (refer to paragraph 7.6.22.3.2). Place focus coil on oil tank assembly A7 using attaching hardware, and remove sling.

3. Tighten focus coil holdout bolts sufficiently to compress lock washers.

4. Attach air intake bracket using locking/sealing compound on studs, flat washers, and nuts.

5. Torque air intake bracket nuts to 40-inch-pounds maximum.

6. Install filter in bracket.

7. Attach manifold clip assembly, clip gasket, and two spacers using locking/sealing compound on studs, flat washers, and nuts. Torque nuts to 40-inch-pounds maximum.

7.6.22.4.2 Klystron Tube V1 Installation Procedure.- Proceed as follows:
 
 

Avoid touching the ceramic portion of the tube. All ceramic portions of the tube should be examined to make sure they are clean and dry. Check that there are no foreign particles of any kind between the flange and ceramic window.

Examine klystron tube, and if necessary, install 0-ring while the klystron tube is still in the transport cart.

1. Lubricate 0-ring on replacement klystron tube V1 with small amount of silicon grease.

2. If necessary, transfer oil tank from oil tank dolly to transmitter cabinet (refer to paragraph 7.6.22.4.3).

3. See figure 11-21, sheet 4, view H and figure 11-22. Attach lifting sling between chain fall and eyebolts on klystron tube V1 as shown.

Two people are required to remove the klystron from the shipping container. One person should grasp the lower end of the tube. The other person should grasp the upper portion of the tube, exercising care not to lift on the rf output waveguide flange.

During klystron extraction, proceed slowly making sure the sling hooks do not damage the klystron shroud, and the klystron is entirely supported by sling hooks and eyebolts. Take care not to bump or damage the waveguide components or vacuum pump connection.

4. Raise klystron tube V1 above focus coil Li and transfer oil tank assembly A7 to oil tank dolly (refer to paragraph 7.6.22.3.2). Line up tuning ports on klystron tube V1 with holes in focus coil L1.
 

5. Lower klystron slowly guiding it carefully in place in focus coil.
 

6. When klystron is seated in focus coil, remove lifting sling.
 

The klystron produces dangerous X-radiation during operation. Never modify or alter klystron or other transmitter components that might decrease radiation shielding. Never operate transmitter unless all shielding is in place. X-ray exposure can occur without personnel being aware, and serious personal injury or death may occur as a consequence at some later date.
7. See figure 11-21, sheet 4, view G. Install x-ray shield on focus coil L1.

7.6.22.4.3 Transferring Oil Tank from Dolly to Transmitter Cabinet.- Proceed as follows:
 
 

Ensure that all hoses, cables, and wires are free and will not be damaged during placement of the oil tank assembly into the cabinet.

1. See figure 11-21, sheet 3, view D. Remove wheel stop pin and push klystron tube V1 and oil tank assembly A7 into transmitter cabinet until oil tank is seated against rear wheel stop.

2. Install wheel chocks on left front oil tank carriage wheel.

3. See figure 11-21, sheet 3, view E. Loosen wing nuts on dolly cabinet hooks, unhook dolly from cabinet, and roll dolly away from transmitter cabinet.

Careful alignment between the output flanges of the klystron and connecting waveguide components is essential to prevent arcs. Errors in alignment can result in window failure and damage to klystron tube V1.

1. Remove klystron waveguide dust cover.

2. See figure 11-21, sheet 2, view B. Connect arc detector A6 to klystron tube waveguide flange using a new rf gasket. Leave flange screws loose at this time so that waveguide can be purged.

3. Set RDA power distribution panel no. 2 circuit breaker CB8 to ON.

4. Set waveguide pressurization unit UD6 ON/OFF switch to ON. Wait 10 minutes after waveguide pressurization unit UD6 is turned on to allow waveguide to purge properly.
 
 



NOTE

Waveguide flange hardware should be torqued to 50 inch pounds maximum.. Torque waveguide flange screws to 50 inch pounds in sequence shown in figure 7-1. Check for pressure integrity and correct any leaks before proceeding with installation.

6. Connect three grounding straps to top of oil tank. One strap is connected on right front; the remaining two are  connected to rear corners.

To avoid arcing and corona damage, make sure that no other wires are within 1 inch of high voltage connection A7E 1 when wires are installed and the interface box is replaced.

 
7. See figure 11-21, sheet 2, view C. Lift oil tank interface assembly A7A1 high enough to gain access to terminals on oil tank terminal block. Connect leads to terminals A7E1, A7E4, A7E5, and A7E16 at same locations as noted in paragraph 7.6.22.3.1 step 8.

8. On exterior of oil tank interface assembly A7A1, connect leads to terminal board terminals TB3-1A and TB3-2A.

9. Install safety cover on interface assembly A7A1TB3.

10. Replace exhaust air manifold to focus coil exhaust air manifold bracket and tighten four captive screws.

11. Connect L1J1 to L1P1 on focus coil L1. Route this lead through interface assembly box when setting box in place over oil tank terminal block.

To avoid a cabinet door interlock alarm when the transmitter is powered up, make sure that oil tank interface assembly A7A1 is firmly seated.

12. See figure 11-21, sheet 2, view B. Set oil tank interface assembly A7A1 in place over oil tank terminal block, and secure it with eight screws and associated hardware.

13. Connect oil tank interface assembly jack A7A1J1 to connector A7P1.

14. Reconnect coaxial cable connector A7J7 to oil tank interface TP2.

15. Connect exhaust air stove pipe duct to klystron tube cooling shroud and tighten stovepipe duct clamp.

16. Connect ion pump high voltage connector J1 on klystron tube V1 to plug W1P1.

17. Install rigid coaxial W104 between RF drive input connector XV1P2 on klystron tube and RF attenuator AT1J2.

18. See figure 11-21, sheet 1, view A. Connect high voltage leads to terminals A7E18, A7E19, A7E20, and A7E21 at same locations as noted in paragraph 7.6.22.3.1 step 4.

19. Install cover over high voltage terminals.

20. Reinstall Modulator Pulse Assembly A12 in accordance with paragraph 7.7.2. 15.

21. Replace klystron tuning tools.

22. Check oil level at oil tank sight glass, and refer to paragraph 7.7. 1.4.6 to replace oil, if necessary.

23. Close right bay inner door and use key to lock right bay inner door.

24. Replace and close right bay outer door.

25. Return interlock key to HIGH VOLTAGE POWER circuit breaker CBl lock.

26. Replace and close center bay door.

 
1.  Refer to RDA Maintenance Manual NWS EHB6-510, Chapter 6 and perform oil dielectric strength test.

2.  Perform final Power amplifier procedures in paragraph 7.8.5.