VersaPulse SELECT User manual

Brand: VersaPulse

Model: SELECT

Type: User manual

VersaPulse

Select™

SERVICE MANUAL

0621-499-01

DEC. 95

This service manual is to be used in conjunction with the operator manual for the product. The

operator manual contains important information regarding instrument description, location of

controls, specifications, and normal operating procedures.

VISIBLE AND INVISIBLE LASER RADIATION.

AVOID EYE OR SKIN EXPOSURE TO

DIRECT OR SCATTERED RADIATION.

CLASS IV LASER PRODUCT

DANGER

HOLMIUM:YAG LASER: 2.1 MICROMETERS

MAX OUTPUT 5 JOULES 250 µs PULSE

Nd:YAG LASER: 1.06 MICROMETERS

MAX. OUTPUT 2 JOULE 350 µs PULSE

DIODE LASER: 650 NANOMETERS

MAX OUTPUT 5 MILLIWATTS

2400 Condensa Street

Santa Clara, CA 95051

(408) 764-3000

VISIBLE AND INVISIBLE LASER RADIATION.

AVOID EYE OR SKIN EXPOSURE TO

DIRECT OR SCATTERED RADIATION.

CLASS IV LASER PRODUCT

DANGER

HOLMIUM:YAG LASER: 2.1 MICROMETERS

MAX OUTPUT 5 JOULES 250 µs PULSE

DIODE LASER: 650 NANOMETERS

MAX OUTPUT 5 MILLIWATTS

in whole or part without the express written permission of Coherent, Inc. Permitted copies must carry the

same proprietary and copyright notices as were affixed to the original.

Please note that while every effort has been made to ensure that the data given is accurate, the information,

figures, illustrations, tables, specifications, and schematics are subject to change without notice.

Coherent and the Coherent Logo are registered trademarks of Coherent, Inc.

Please direct all inquiries about this manual to:

Coherent, Inc.

Technical Support B-35

2400 Condensa Street

Santa Clara, CA 95051

(408) 764-3638

0621-499-01

VersaPulse Select Service Manual Disclaimer 0621-499-01 12/95

DISCLAIMER

Coherent service manuals are written specifically for use by Coherent service engineers who have received

formal training in the servicing of Coherent equipment, and by customers who have taken and passed a

Coherent certification service training course for the equipment being serviced. Information on certification

service training courses offered to customers can be obtained by contacting the Technical Training Coordina-

tor at 800-367-7899.

Coherent does not accept responsibility for personal injury or property damage resulting from the servicing

of Coherent equipment by its customers or by third parties, except where such injury or property damage is a

direct result of Coherent's negligence. Customers, by accepting the service manual, agree to indemnify

Coherent against any claims alleging personal injury or property damage resulting from the servicing of

Coherent equipment by the customer or by third parties, except where such injury or property damage is a

direct result of Coherent's negligence. These limitations include situations where Coherent personnel are

advising customers on the repair of Coherent equipment over the telephone.

The servicing of Coherent equipment by persons who have not passed a current Coherent certification

service training course for that equipment will void Coherent's product warranty.

VersaPulse Select Service Manual Revision Information 0621-499-01 12/95

REVISION INFORMATION

This is the DEC '95 release of the Versapulse Select Service Manual. Contact Coherent Medical Group Techni-

cal Support to determine if this is the most current release of this service manual.

Each page of this manual has a MM/YY date at the bottom. This indicates the release date for the individual

page. Note that when the manual is updated, not all of the pages are necessarily updated, so some pages

may have a MM/YY earlier than the release date for the manual (the release date for the manual is the MM/

YY that appears on the cover and in the first sentence of this revision information page). The following list

provides a complete list of the release date information, by section, for this release of the service manual.

Cover page, copyright page, disclaimer page, this page, table of contents page or pages are all dated with the

release date of the manual (12/95).

SECTION 1 Pages 1-1, 01/94

Pages 1-2, 12/95

SECTION 2 Pages 2-1,4,6 12/95. All other pages 03/94.

SECTION 3 Pages 3-1 thru 3-10 12/95. All other pages, 03/94.

SECTION 4 Pages 4-4 Thru 4-17, 4-22 Thru 4-30, 12/95.

All other pages, 01/94

SECTION 5 All pages, 12/95

SECTION 6 All pages, 12/95

SECTION 7 FSB's released for this service manual are listed in the Versapulse Select FSB

Index. Each time an FSB for this manual is released or updated the Index is

also updated and distributed with the FSB. The current Index is placed

behind the single sheet that makes up Section 7, and the FSB's are placed in

order behind the Index. Contact Coherent Medical Group Technical Support

for the date of the most current FSB Index.

SECTION 8 Page 8-1,12, 10/95

Pages 8-2 thru 8-11, 8-13 thru 8-18, 01/94

Pages 8-19 thru 8-30, 08/95

Table Of Contents

DISCLAIMER .................................................................................................................................................. 3

REVISION INFORMATION ........................................................................................................................ 4

1.0 GENERAL INFORMATION ............................................................................................................... 1

1.1 USE OF THIS MANUAL .......................................................................................................................1

1.2 CONVENTIONS USED IN THIS MANUAL.......................................................................................1

1.3 SERIAL NUMBERS ...............................................................................................................................2

2.0 INSTALLATION .................................................................................................................................... 1

2.1 INSTALLATION INSTRUCTIONS......................................................................................................1

3.0 CALIBRATION & ADJUSTMENT .................................................................................................... 1

3.1 OVERVIEW............................................................................................................................................1

3.1.1 Safety Precautions ..................................................................................................................................1

3.2 System Check Out ..................................................................................................................................2

3.3 Energy Monitor and Automatic Laser Calibration ..............................................................................5

3.4.1 Making Test Burns .................................................................................................................................. 7

3.4.2 Adjusting the YAG Channel Optics ....................................................................................................... 7

3.4.3 YAG Channel Check Out and Adjustment Procedure......................................................................... 8

3.5 AIMING BEAM ADJUSTMENT ........................................................................................................ 10

3.6 PERIODIC MAINTENANCE REQUIREMENTS............................................................................13

4.0 THEORY OF OPERATION .................................................................................................................. 1

4.1 INTRODUCTION ...................................................................................................................................1

4.1.1 Operational Overview ............................................................................................................................. 1

4.1.2 Functional Overview ...............................................................................................................................2

4.2 POWER SWITCHING, CONDITIONING, DISTRIBUTION ..........................................................5

4.2.1 Input Power..............................................................................................................................................5

4.2.2 Circuit Breaker on, Keyswitch off .........................................................................................................5

4.2.3 Turn on .....................................................................................................................................................5

4.2.4 Shutdown..................................................................................................................................................6

4.2.5 Low Voltage Power Supplies................................................................................................................... 6

4.3 COOLING................................................................................................................................................ 7

4.4 CONTROL ELECTRONICS .................................................................................................................9

4.4.1 Overview...................................................................................................................................................9

4.4.2 Main Processor ......................................................................................................................................10

4.4.3 Shutter / Footswitch / Remote Interlock Circuits............................................................................... 11

4.4.4 Servo Motor Control Circuit ................................................................................................................ 13

4.4.5 HVPS & PFN Control Circuits ............................................................................................................14

4.4.6 Energy Monitor Circuits.......................................................................................................................17

4.4.7 Touch Screen & Remote Control Circuits...........................................................................................18

4.4.8 Aiming Diode Laser Circuit..................................................................................................................20

4.4.9 Fiber and Blast Shield Position Sense Circuits ...................................................................................21

4.4.10 Service Attenuator Circuit .................................................................................................................. 22

4.4.11 Coolant Temperature and Conductivity Monitoring Circuits......................................................... 23

4.4.12 Low Energy Attenuator Circuit .........................................................................................................24

4.4.13 DC Power Supply Voltage Monitoring Circuits.................................................................................24

4.4.14 Safety Processor....................................................................................................................................25

4.5 FLASH LAMP POWER CIRCUITS..................................................................................................27

4.6 OPTICS .................................................................................................................................................27

4.7 SOFTWARE.......................................................................................................................................... 29

5.0 TROUBLESHOOTING ........................................................................................................................ 1

5.1 OVERVIEW.............................................................................................................................................1

5.1.1 Service Philosophy.................................................................................................................................. 1

5.1.2 Safety Precautions ..................................................................................................................................2

5.2 INTERIOR ACCESS & PART LOCATIONS .....................................................................................3

5.3 SERVICE MODE .................................................................................................................................12

5.4 FAULT ISOLATION............................................................................................................................14

5.4.1 TURN-ON AND SHUTDOWN FAULT ISOLATION ......................................................................15

5.4.2 "NO FAULT CODE REPORTED" FAULT ISOLATION ...............................................................15

5.4.3 "FAULT CODE REPORTED" FAULT ISOLATION .....................................................................15

6.0 SELECTED PARTS ................................................................................................................................ 1

8.0 SCHEMATICS AND DRAWINGS .................................................................................................... 1

VersaPulse Select Service Manual

0621-499-01 01/94

GENERAL INFORMATION

1-1

1.0 GENERAL INFORMATION

1.1 USE OF THIS MANUAL

This manual contains service instructions for the Coherent VersaPulse Select series of Holmium:YAG surgical

lasers. The content of this manual is intended solely for use by Coherent Medical Group Field Service Engineers

and Coherent trained and certified customer technicians. Coherent, Inc. can not be responsible for service or

repairs attempted by uncertified persons, and the use of this manual by such persons is prohibited.

This manual is to be in conjunction with the Coherent Operator Manual for the VersaPulse Select. The operator

manual contains important information regarding instrument description, location of controls, specifications,

and normal operating procedures.

As necessary, Coherent Medical Group Service Technical Support releases Field Service Bulletins for the

Versapulse Select series. These bulletins supplement the information in this manual. As they are released, the

bulletins become a part of this manual (Section 7).

1.2 CONVENTIONS USED IN THIS MANUAL

Within the text, logic signals that are active low ("notted") will appear inside of slash marks, as illustrated below.

/BRHOK/

These signals are "active", or true, when the logic level is low. When the logic signal /BRHOK/ is low, the BRH

loop is "OK" (complete). When the logic signal /BRHOK/ is high, the BRH loop is not OK (open).

In most of the schematic diagrams such signals are indicated by the more usual solid line above the signal name,

as illustrated below.

The schematics in this manual do not include individual numbers for the logic elements or operational amplifiers

within a single component. For example, U1 below contains two operational amplifiers. The top op amp would

be referred to as U1-1 ( its output is pin 1), and the other would be referred to as U1-7.

BRHOK

GENERAL INFORMATION

1-2

VersaPulse Select Service Manual

0621-499-01 12/95

1.3 SERIAL NUMBERS

Serial numbers for the Versapulse Select are in the format,

MYPHWVXXXX

where M is the month produced

(a is January, b is February, etc..)

Y is the last digit of the year produced

(4 is 1994., etc..)

P is a number indicating maximum system power

(6=60w, 4=45w, 3=30w)

H is the number of laser heads installed (1, 2, 3, or 4)

W is a number indicating the mix of rods installed

(See Below)

V is a number indicating power supply configuration

(1= 208VAC single phase)

XXXX is the number of the laser built

(0001, 0002, etc..)

W: 1= Holmium only

2= Erbium only

3= Nd:Yag only

5= Nd/Ho combo

INSTALLATION

2-1

VersaPulse Select Service Manual

0621-499-01 12/95

2.0 INSTALLATION

2.1 INSTALLATION INSTRUCTIONS

These installation instructions are provided for use by Coherent Service Engineers who have completed

certification service training on the VersaPulse Select. Installation by untrained persons is a potential hazard

to the person or persons doing the installation, others present, and to the equipment itself. In addition,

improper installation is a potential hazard to the user, persons present during use, and patient.

Perform the following steps to install a VersaPulse Select system.

1. Check for proper site set up. This includes proper AC service and adequate space for the console.

AC power configuration: The VersaPulse Select requires 220 VAC ±10%, 50/60 Hz, 30 amp single

phase electrical service. The power cord is a 26 foot cable with 3 conductors. A terminal board

behind the right side cover allows for tapping of the isolation transformer to the setting closest to the

incoming electrical service. The system can be hard wired to electrical service or installed to electrical

service with a plug and receptacle. The plug and receptacle are shipped in the site preparation kit.

Console dimensions and weight: The console measures 39" l x 18" w x39" h. It weighs approximately

325 lbs. A minimum of 18" of air space is required around the unit to provide adequate cooling air

circulation.

The system requires approximately 2.5 gallons of deionized water for its closed loop cooling system.

The coolant must be added as described in this procedure.

Complete specifications for the VersaPulse Select are included in the VersaPulse Select Operator

Manual. Contact Technical Support in Palo Alto, CA, if there are any questions concerning site

preparation.

2.) Check the crate/carton for any shipping damage.

INSTALLATION

2-2

VersaPulse Select Service Manual

0621-499-01 12/95

LIFTING BAR (2)

Rear lifting bolts

(2, 5/8ths)

Front lifting bolts

(2, 3/4ths)

As the bolts turn, the lifting bar is raised or lowered. The system

ships with the lifting bar up. The bar must be lowered and removed,

then the system is rolled down the wooden ramps to remve it from

the crate base.

Removable

wooden ramp (2)

FIGURE 2.1 SHIPPING CRATE

Accessories

CARDBOARD SIDE COVER

CARDBOARD TOP COVER

STRAP

WOODEN

BASE

FOAM

WOODEN RAMPS

03/94

INSTALLATION

2-3

VersaPulse Select Service Manual

0621-499-01 12/95

The shipper is responsible for any damage to the system in shipment. If the crate/carton appears to

be damaged, report the damage to the customer and shipper.

3.) Remove the console and accessories from the crate.

Refer to drawing 2-1. Remove the straps, remove the top cover, remove the side cover, remove the

protective foam, remove the accessories box, then locate and remove the two wooden ramps stored in

the base. Lower the lift plates (2) by turning the bolt at each end of each lift plate (5/8" and 3/4"

bolts). Loosen the bolts all the way, then remove the bolts and lift plate. Remove the front fence from

the base by removing the four wing nuts that secure it to the base. Install the ramps onto the base,

then roll the unit down the ramps.

4.) Move the system to its installation location.

The VersaPulse Select rolls best when pushed from the front handles. The front wheels swivel, the

rears wheels do not.

6.) Open/remove covers and do a visual inspection of the interior.

Refer to Section 5 for information on removing the covers. Open the front cover, then remove the top

and two side covers. Inspect the interior carefully for loose or broken electrical connections, loose or

broken plumbing connections, or any indication of shipping damage.

7.) Set up for site AC.

Measure the voltage of the site electrical service at the point where the VersaPulse Select will be

connected. The three connections include an earth ground and two hot mains. Measure line voltage

across the two hot mains. Mains voltage must be between 200 and 240 VAC, 50/60 Hz. Confirm that

the circuit is rated for 30 amps.

The isolation transformer has two secondaries: one operates the turn-on circuitry and the other

provides AC to the low voltage power supply, display power supply, fan and pump. These

secondary loads (not the turn-on circuitry) are rated for 220 VAC supply input. The isolation

transformer is tapped to allow a range of AC line inputs ( 200 to 240 VAC) to be stepped up or down

to result in a secondary voltage at or near 220 VAC to these secondary loads. The various taps on the

isolation transformer are wired out to terminal board TB1 on the right side on the system. The

tapping is done by changing the connections at the terminal board.

ISOLATION

XFORMER

(primary)

MAINS ( from F2)

120

100

120

100

MAINS (from F1)

POWER CORD

TB1

MAINS TO CIRCUIT BREAKER

EARTH GROUND TO

GROUNDING STUD

03/94

FIGURE 2-2 TB1 TAPPING

INSTALLATION

2-4

VersaPulse Select Service Manual

0621-499-01 12/95

8.) Connect to AC service.

CAUTION: Once connected to site electrical service lethal voltages are present inside the unit. The

AC power is present at the circuit breaker, main contactor and isolation transformer. In addition, the

isolation transformer secondary outputs are hot. Review and understand the safety subtopic in

Section 5 before proceeding.

The system can be hard wired to electrical service, but is more typically connected by a plug to an

electrical outlet.

If the system is to be hard wired, the customer must provide an electrician to wire the cord end into

the electrical service outlet.

If the system is to be plugged into an electrical receptacle, the appropriate receptacle should already

be installed by the customer's electrician. The installing engineer connects the plug to the end of the

VersaPulse Select electrical cable.

9.) Add coolant.

Add coolant (deionized water) to the fill reservoir. The coolant will drain out of the fill reservoir and

into the main reservoir. The system uses approximately 2.5 gallons of coolant. Most of the coolant

can be added at this time - until the fill reservoir level stays up. The system coolant level will be

"topped off" after the system is turned on (in a later step).

9.) Initial power application.

CAUTION: Once the circuit breaker is turned on lethal voltages are present throughout the system.

With the side covers still removed, turn on the electrical service and turn on the circuit breaker on the

VersaPulse Select. Wait a few minutes, observing for any indication of failure of mains or turn-on

components.

10.) Initial turn on.

CAUTION:

• The system will fire during the turn-on sequence if SW3 (Autocal) on the CPU PCB is up

and the BRH plug is installed. Only those persons required should be present during this

portion of the installation

• The cooling fan blades are not covered. The fan is located on top of the heat exchanger. It

operates whenever the system is turned on. Keep tools, system parts and body parts clear of

the fan blades.

Turn the keyswitch to the START position, then release it to the ON position. The system will go

through its start up sequence. Observe for normal start up, and for any indication of leaks in the

cooling system.

INSTALLATION

2-5

VersaPulse Select Service Manual

0621-499-01 12/95

11.) Add coolant.

With the system turned on, top off the fill reservoir. Cycle the machine off and on several times,

adding coolant as necessary until the fill reservoir level stays up to approximately half full as the

system runs.

12.) Operational and Safety Checkout.

Attach a test fiber, remote interlock plug, and footswitch, then check system operation as follows:

a.) Footswitch, remote control (if included) and remote interlock plugs connect properly to jacks.

b.) Fiber attaches to the fiber port.

c.) Touch screen display matrix is operating properly.

d.) Touch screen inputs are functional.

e.) Remote control (if installed) display and input buttons are functional.

f.) Aiming beam responds to off, low, medium, and high settings.

CAUTION: The remaining operational tests include firing the system and attempts to fire the system

with one disabling condition. Select a low power setting and direct the test fiber output into a

calibrated power meter.

g.) Fire into the meter for several seconds, noting the power reading on the meter.

i.) Confirm that the total energy display value has incremented, then confirm that the value clears

back to zero when RESET is touched.

j.) Disconnect the footswitch and confirm that the "ATTACH FOOTSWITCH" message appears on the

display.

k.) Reconnect the footswitch, then disconnect the fiber and confirm that an "ATTACH FIBER"

message appears on the display. Depress the footswitch and confirm the system will not fire.

l.) Reconnect the fiber, then disconnect the remote interlock plug and confirm the " REMOTE

INTERLOCK" message appears on the display.

m.) Reconnect the remote interlock plug, then go to STANDBY. Depress the footswitch and confirm

the system will not fire.

n.) Pull the blast shield out, then confirm the "REPLACE BLAST SHIELD" message appears on the

display. Depress the footswitch and confirm the system will not fire.

o.) Reinsert the blast shield.

03/94

INSTALLATION

2-6

VersaPulse Select Service Manual

0621-499-01 12/95

13.) Confirm the power calibration.

Connect a good test fiber onto the fiber port and direct the fiber output towards the head of your

calibrated power meter, then, for each operating point, fire the system into the meter, confirming that

displayed power remains within ± 10% of the power indicated on the meter (typically, the power

calibration will be much more accurate than ±10%). If the power calibration is not better than ±10% at

all operating points, refer to Section 3 for instructions on system calibration.

14.) Check the fiber focus using a test fiber.

Two test fibers are shipped with the system. Check the fiber focus as described in Section 3, topic 3.2,

step 3.

15.) Replace all covers and prepare the system for demonstration to the customer.

16.) Demonstrate the system installation to the customer.

17.) (for U.S. Field Service) Fill out and mail the "self mailer" installation quality audit report.

CAL & ADJUST

3-1

Versapulse Select Service Manual

0621-499-01 03/94

3.0 CALIBRATION & ADJUSTMENT

3.1 OVERVIEW

This section includes a System Checkout Procedure, Energy Monitor Calibration Procedure, a YAG Channel

Adjustment Procedure and an Aiming Beam Adjustment Procedure. The procedures assume the reader has

successfully completed a Coherent service training course on the Versapulse Select series.

The System Check Out, Topic 3.2, is an operational check of the system. It confirms that the system turns on

properly, responds properly to operator inputs, provides the full range of pulse energies and pulse rates, delivers

average power within ±10% of the displayed average power, delivers the multiplexed YAG beam into the center

on an attached fiber, and provides an adjustable aiming beam through the fiber. It also checks system coolant level

and consumables (i.e., air filter, DI filter and particulate filter).

The Energy Monitor Calibration Procedure, Topic 3.3, calibrates the voltage output of the three energy monitor

circuits to the field service engineer's calibrated power meter.

The YAG Channel Adjustment Procedure, Topic 3.4, is done when the System Check Out Procedure indicates

a problem with one or more of the YAG channels. It provides adjustment procedures for the channel cavities and

relay optics.

Aiming Beam Adjustment, Topic 3.5, provides information on adjusting the aiming beam optics to get the aiming

beam out through the fiber. See Section 6 for required tools.

3.1.1 Safety Precautions

Lethal voltages and laser emission are the primary dangers to the servicing engineer. In addition to the general

safety precautions which always apply when working on electronics and lasers, the servicing engineer must be

aware of the following specific precautions:

Only Coherent certified VersaPulse Select Service Engineers should attempt any service on this

system.

Even with the keyswitch and the breaker in the "OFF" position there are potentially lethal voltages

present inside the console. Always disconnect the main electrical service before working on the

console.

12/95

CAL & ADJUST

3-2

VersaPulse Select Service Manual

0621-499-01 03/94

Storage capacitors inside the system are capable of holding a lethal charge, even after power has

been removed from the unit. A charge level indicator bulb located on the PFN PCB mounted across

the top of the main storage capacitor flashes at a rate proportional to the level of charge on the main

charging capacitor. Do not rely on this indicator to determine that the main charging capacitor has

been discharged. Before contacting the main charging capacitor, disconnect the system from primary

power and use a shorting probe to discharge the capacitor to ground.

Do not touch the YAG Cavity Module when the system is on - IT IS A SHOCK HAZARD. The

YAG Cavity Module is electrically isolated from the chassis and can be at a voltage potential much

higher than ground.

Whenever the footswitch is pressed a single pulse is fired immediately, before the shutter opens,

to dump any charge remaining on the charge capacitor. The laser cavity that fires is the one directly

opposite the one that the servo mirror is pointing towards. The energy is dependent upon how much

charge remains on the capacitor. Since the relay mirror is not directed towards the channel, the beam

will be directed away from the first turning mirror (usually towards the mounting screws for the

plano mirrors on the OC wall.

The Ho:YAG, Er:YAG and Nd:YAG laser light is invisible to the human eye. Because the YAG

laser energy can not be seen, there is no visible indication of the primary or reflected beam. Eye

protection that attenuates the Ho:YAG, Nd:YAG and Er:YAG wavelengths to a safe level must be

worn by all persons in the area of the laser system, whenever the laser is being serviced.

The YAG laser light and its reflections are potential burn hazards and can ignite flammable

materials. Use extreme caution when operating the system with covers opened or removed. The

covers contain the beam and reflections safely within the console. Only those persons required

should be present during servicing, and eye protection that safely attenuates the Ho:YAG, Nd:YAG

and Er:YAG wavelengths must be worn by all present.

The Ho:YAG, Er:YAG and Nd:YAG laser light and its reflections are potential hazards to the eye.

Use extreme caution when operating the system with the covers opened or removed. The covers

contain the beam and reflections safely within the console. Only those persons required should be

present during servicing and eye protection that safely attenuates the Ho:YAG, Er:YAG and Nd:YAG

wavelengths should be worn by all those present.

3.2 SYSTEM CHECK OUT

This system check out confirms that the laser is functioning properly.

1.) Open the front door and defeat the door interlock, then turn the system on and allow it to go through

autocalibration. After autocalibration is completed, place the system in service mode.

If the system fails to pass autocalibration, there is something wrong; continue on to step 2 to gather

more information about why the system failed autocalibration.

12/95

CAL & ADJUST

3-3

Versapulse Select Service Manual

0621-499-01 03/94

2. Check rod calibration values.

Go to the second service screen and note the cap voltage values displayed for each of the four

channels at minimum (low point) and maximum (high point).

The HVPS maximum output is 1500 VDC, so each rod must be capable of making its

maximum pulse energy (high point) at less than 1500 VDC. Typical values at high point are

from 1280 to the low 1400's. Typical voltages for low point are in the 700 to 900 VDC range.

For Nd:YAG the typical values at high point are from 500 to 800 VDC, and typical low point

values are from 200 to 400 VDC.

As the rod temperature increases (during use), its output will tend to drop off for a given cap

voltage. The software compensates for this effect, so as the rod temperature increases, it is

normal to see the cap charge voltage required at a particular pulse energy increase. Since the

system goes through its autocalibration at turn on, when the rods tend to be cooler, the cap

charge voltages found during autocal will tend to be lower than those that might be required

during sustained, high duty cycle operation. Thus, a channel with a cap charge voltage in the

mid to high 1400's @ 2.8 Joules at turn on may require a cap charge voltage higher than the

HVPS can provide to make 2.8 Joules during operation.

If the system has failed to complete autocalibration or channel performance appears poor, perform

the YAG Channel Adjustments (Topic 3.4).

3. Inspect debris shield and clean/replace as required.

4. Check the power supply voltages, coolant temperature and coolant conductivity.

5. Check the fiber focus using a test fiber.

If the system passes autocalibration and channel performance appears normal (service screen min/

max cap charge values are good), check for proper alignment of the beam into the fiber. This is done

using a special test fiber (0621-675-01). The fiber proximal end is coated with a red ink (Berol 8800

red marker) that records an impression of the YAG beam footprint where it enters the end of the

fiber. The laser is fired into the test fiber, then the fiber end is examined using a hand held 100X

microscope. A good alignment will result in a "concentric" footprint, i.e., the footprint will be

approximately centered in the fiber core and be well away from the cladding that surrounds the fiber.

a.) Install a test fiber in the 100X fiber examination microscope and examine its surface to confirm that

it is unused.

b.) Install the test fiber at the fiber port, then turn on the system and go to service mode.

c.) Turn on all the rods, select 850 cap volts and a pulse rate of 20 Hz.

d.) Fire the laser for approximately one second.

12/95

CAL & ADJUST

3-4

VersaPulse Select Service Manual

0621-499-01 03/94

e.) Remove the fiber and examine it in the microscope. The burn and cladding will be easily

visualized if the other end of the test fiber is pointed towards a light source. The burn should be

approximately centered in the fiber optic and be well away from contact with the fiber cladding, as

shown in the drawing below. If the system fails this check, perform the YAG Channel Adjustments

(Topic 3.4.).

* If spot size is large, check individual YAG channels for proper alignment. Spot size should be less

than 210 µm in diameter and no closer than 70 µm from the cladding.

6. Confirm the calibration

Once the system passes steps 1 through 3, attach an Infratome fiber (nonsterile fibers for service

purposes are available through Technical Support) to the fiber port and direct its output into a

calibrated power meter. Go to user mode and fire the system to confirm that the measured power (as

seen on the power meter) is within ±10% of displayed average power across the range of pulse

energies and pulse rates.

7. Check consumable parts. Replace as necessary.

Check/replace the air filter. The air filter is mounted on the bottom of the system, held in place by a

removable bracket. A dirty filter should be cleaned or replaced.

Replace the DI filter after 6 months of use, or when the system has coolant conductivity faults.

Check/replace the coolant particulate filter. Replace the filter when it is visibly discolored.

8. Perform functional and safety checks.

a.) Attach a fiber.

ACCEPTABLE

NOT ACCEPTABLE

Examining the test fiber end with the 100x microscope - The footprint will not always be circular,

but it should be approximately centered in the fiber and away from contact with the cladding.

Cladding

Core

Footprint

FIGURE 3.1 EXAMINING THE TEST FIBER BURN

12/95

CAL & ADJUST

3-5

Versapulse Select Service Manual

0621-499-01 03/94

b.) Confirm that the aiming beam is visible at the fiber output and that the aiming beam intensity

properly responds to touch screen intensity control.

c.) Place the system in STANDBY, then depress the footswitch. Confirm the system does not fire.

d.) Go to READY and fire the system a number of times, verifying that the system displays the

cumulative energy. Stop firing, then press "clear" and verify the counter returns to zero.

e.) Unplug the footswitch and verify the system goes to STANDBY and displays "Attach footswitch".

f.) Open the front door and verify the system shuts down. Defeat the interlock and confirm that the

system turns back on.

g.) Remove the fiber optic. Verify that the system goes to STANDBY and "Attach fiber" is displayed.

Replace the fiber optic and verify that the fault clears.

h.) Remove the blast shield. Verify that the system goes to STANDBY and "Install blast shield" is

displayed. Replace the fiber and confirm that the fault clears.

i.) Check the operation of the keyswitch. It should turn the system on, turn the system off, and only

be removable when the system is switched off.

j.) Confirm that the emergency off button shuts the system down.

3.3 ENERGY MONITOR AND AUTOMATIC LASER CALIBRATION

The energy monitor calibration adjusts the three energy monitor circuits to output 2.2 volts per Joule of energy

as measured on a calibrated power meter at the output of an attached fiber. The automatic laser calibration (also

referred to as "autocalibration" and "autocal") is run to allow the system to determine and store the capacitor

voltages required to provide the maximum and minimum pulse energies for each rod.

1. Set up.

Open the front door of the VersaPulse Select and defeat the door interlock. Connect a known good

test fiber to the fiber port and direct its output into a calibrated power meter. Connect an oscilloscope

probe to CPU PCB TP2 (ENERGYI).

2. Turn on the system and go to service mode.

3. Turn off three rods, leaving one on. Select 40 Hz, then go to READY.

4. Adjust the cap voltage for a fiber output of 10 watts (1 Holmium head).

Fire the laser into the power meter, adjusting cap voltage up/down to get 10 watts of average power

at the power meter. Once the charge voltage is set to provide a consistent power meter reading of 10

watts, stop firing and leave the cap charge at that setting.

12/95

CAL & ADJUST

3-6

VersaPulse Select Service Manual

0621-499-01 03/94

The system software has a 2.2 volts/Joule conversion factor written into it, so the energy monitor

circuit must be calibrated to output 2.2 volts for a 1 Joule pulse. With 40 Hz selected, but only one

rod on, the actual pulse rate will be 40/4 = 10 Hz. Since 1 Watt= 1 Joule/sec, 10 Watts = 10 Joules/

second,i.e. each pulse is 1 Joule.

5.) Calibrate ENERGY II.

Attach the scope probe to TP3.

Fire the laser, adjusting CPU PCB R8 to adjust the amplitude of the positive pulses on the oscilloscope

screen to approximately 2.22 volts (the pulse will be about 2 mseconds in width, with a relatively

"square" profile). Once the pulses are of the correct amplitude, release the footswitch.

6.) Calibrate ENERGY I

Move the probe to TP2, then adjust as in step 5 above, using CPU PCB R7.

7.) Calibrate ENERGY III

Move the probe to TP4, then adjust as in step 5 above, using CPU PCB R9.

8.) Turn all the rods back on, then confirm the calibration.

Turn the system back on (CPU PCB SW3 in its up position so the system will go through its

autocalibration), then fire the laser into the power meter across its range of operating points,

confirming that delivered power as measured by the power meter is always within ±10% of selected

power.

3.4 YAG CHANNEL ADJUSTMENTS

When properly adjusted the YAG channel will meet each of the following three criteria.

•␣The cavity HR will be positioned to direct the YAG output to the center of the first relay mirror, and

the cavity OC will be positioned to provide maximum power for that HR position.

• The first relay mirror and second (plano) relay mirror will direct the YAG energy off the two

folding mirrors so that it is centered through the wedge optic apertures and centered into the

proximal end of the fiber.

• Each YAG beam will be coaxial with the other YAG channels, confirmed at the second wedge optic

aperture and at the fiber port.

The adjustment procedure for a single channel follows. The procedure is a complete check out and alignment for

a single channel. The procedure is meant to be done in the order given, from beginning to end.

12/95

Page is loading ...

VersaPulse SELECT User manual

Brand: VersaPulse

Model: SELECT

Type: User manual

Download PDF

report

VersaPulse SELECT User manual

VersaPulse SELECT User manual

Other documents