Utah Medical Products Finesse ESU-110 User manual

Electrosurgical Generator and
Smoke Evacuation System
Service Manual
Catalog Numbers
ESU-110 & ESU-220
Utah Medical Products, Inc.
7043 South 300 West • Midvale, Utah 84047
801.566.1200 • 800.533.4984 USA & Canada

©1994, 2009 by Utah Medical Products, Inc.
Finesse®is a registered trademark of Utah Medical Products, Inc.
The Finesse®Electrosurgical Generator and Smoke Evacuation System
is patented under U.S. patent number 5,160,334.
The contents of this manual may not be reproduced without express
written consent of Utah Medical Products, Inc.
The information contained in this manual was correct at press time.
However, unscheduled changes may have taken place that may ren-
der portions of this manual inaccurate. Please contact Utah Medical
Products, Inc. for updated information if errors or changes in the
contents of this manual are suspected.

Installation 1
Initial Setup 1
Functional Checkout 1
Maintenance 1
Device Description 3
Front Panel Indicators and Connectors 3
Rear Panel Controls and Connectors 5
Specifications 7
General Specifications 7
Supply Voltage & Current Specifications 7
Output Characteristics 7
Smoke Evacuator System 8
Circuit Descriptions 11
Test and Calibration Procedure 15
Complete Calibration Procedure 15
Preventive Maintenance Checklist 20
List of Drawings 22
TABLE OF CONTENTS

INSTALLATION
Initial Setup
Unpack the Finesse®unit from its packing material. Retain the pack-
ing material and box for future use.
Inspect the unit for any visible damage or missing accessories. If
damage is found, contact your Utah Medical Products' representative
for replacement parts.
The unit should be placed on a flat, level surface at working height
within six feet of the operating area.
Connect the footswitch (if used).
Plug the Finesse®unit into an appropriately rated wall outlet.
Functional Checkout
1. Install handswitch pencil into the three-point connector on
front panel. If a non-switching "footswitch" pencil is used,
install this pencil into the port marked with the "active port"
icon on the front panel.
2. Toggle the main power switch to the "on" position. Three
things should happen:
• the green lamp in the power switch should light,
• the red alarm lamp on the front panel should light, and
• an interrupted alarm tone should sound.
3. If the three indicators listed in step 2 above do not occur,
check to verify that:
• the power cord is securely plugged in on both ends,
• the three fuses on the rear panel of the unit are installed,
• these fuses are not blown, and the room outlet is active.
4. Connect a dispersive pad with a single contact surface to the
dispersive pad receptacle on the front panel. The red alarm
lamp should go out and beeping should cease.
5. Briefly operate the cut control on the handswitch. The yellow
"cut" lamp should light, a tone should be emitted from the
internal speaker, and the vacuum pump should come on and
stay on approximately five seconds after the cut control button
is released. If none of this occurs try another handswitch. If
the vacuum motor does not come on, check the position of
the vacuum control switch and the 3-amp fuse on the back
panel.
6. Repeat step 5 above with the coag switch rather than the cut
switch. All operation should be the same except that the blue
"coag" lamp illuminates rather than the yellow "cut" lamp.
7. Repeat steps 5 and 6 above using the cut and coag pedals of
the foot switch. All indications should be the same as they
were using the hand switch.
If any of the above items do not check good, please contact Utah
Medical Products Customer Service for assistance.
Maintenance
Daily Maintenance
At the end of any day that the Finesse®unit is used, the primary fil-
ter, catalog number ESU-501, should be changed. Using a gloved
hand, remove the filter from the front panel by gently pulling and
twisting the filter housing. Discard the filter pack with other medical
disposables.
Cleaning
The Finesse®system exterior may be wiped clean with alcohol or
household spray cleaner applied to a cloth. Do not use acetone.
Do not apply cleaning agent directly to the unit.
The loop and ball electrodes, pens, dispersive pads, and speculum
Finesse Service Manual 1

tubing/ reducer are supplied as single patient use items. Cleaning
and/or resterilization of these items should not be attempted.
Annual Maintenance
The primary internal filter, catalog number ESU-700, should be
changed on an annual basis.
To change the internal filter:
Remove the three button head screws running along the top
edge of the rear panel of the Finesse®unit, using a 5/64" hex
key. Gently pull the top cover up and away from the front
housing.
Release the front filter adapter from the front housing by
removing the three externally visible button head screws with a
5/64" hex key. Gently pull the adapter away from the front
panel. With a gloved hand, remove the used primary internal
filter by pulling it away from the vacuum motor inlet. Note the
original positioning of the filter. Dispose of the used filter as
you would dispose other medical disposables.
Insert the new filter onto the vacuum motor inlet in the same
orientation as the previous filter. Replace the front filter
adapter onto the front housing, taking care to verify that the
primary internal filter inlet seats properly into the front filter
adapter. Secure the front filter adapter to the front panel by
replacing the three button head screws.
Replace the top cover onto the chassis by inserting the lip on
the front of the cover into its locator slot in the front housing
and then drop the rear of the top cover into place. Align the
three screw holes and replace the three button head screws.
For the care and performance of your Finesse®electrosurgical unit,
the Emergency Care Research Institute (ECRI) recommends the estab-
lishment of a program for inspection and preventive maintenance.
ECRI Procedure/Checklist 411 recommends that minor inspections
should be performed every six months and major inspections should
be done on an annual basis.
Information on the ECRI Procedure/Checklist can be obtained by
calling ECRI at [phone] or visiting www.ecri.org.
Finesse Service Manual
2

DEVICE DESCRIPTION
The Finesse®unit consists of two major modules, the electrosurgical
generator and the smoke evacuation system. A single power switch
controls both modules; the smoke evacuation system is automatically
switched on and off relative to footswitch or handswitch activation of
the electrosurgical generator.
Figure 1. Finesse®front panel connectors and indicators
Front Panel Indicators and Connectors
Connectors and indicators on the Finesse®front panel are shown in
Figure 1 and subsequently described.
1. Vacuum Level Switch. This three-position rocker switch con-
trols the smoke evacuation system flow rate.
The upper, or "normal" position runs the vacuum motor at a
level that is sufficient to draw the smoke plume away from the
surgical site during the LETZ®procedure.
The lower or "high" position of the switch runs the vacuum
motor at a higher speed, creating a flow rate approximately
40% greater than the normal setting with the same tubing con-
figuration. This setting should be used whenever the distal
smoke removal tube has a very small diameter, or in any other
circumstance where the smoke is not being completely
removed.
The smoke evacuation system motor can be disabled by setting
this switch to the center "off" position (designated by "0").
The vacuum system does not have an activation switch of its
own. It is turned on automatically by internal circuitry when-
ever the cut/blend or coag modes are activated, and shuts off
after a delay of five seconds from the time the electrosurgical
generator output is deactivated. In addition to its conven-
ience, this intermittent operation is beneficial to the life of the
filters and to the vacuum motor itself.
2. Cut/Blend Indicator Lamp. This yellow lamp is illuminated
whenever cutting or blend voltages are applied to the active
lead. Illumination of this lamp is accompanied by an audio
tone having a pitch lower than the tone heard during a fault in
the dispersive electrode monitoring circuit or during operation
in the coag mode.
3. Main Power (on/off) switch. This switch must be turned on to
enable all functions of the instrument. A green light internal to
the switch illuminates when the unit is powered on.
4. Cut/Blend Output Control Knob and Indicator. This knob is
used to specify the output level desired for the intended cut.
The adjacent digital readout indicates the output setting.
Due to line voltage and thermal variations, it is normal for the
number displayed on the digital indicator to vary by one or
two digits while the control knob is stationary. While this vari-
ation truly reflects the relative output setting, it is of no clinical
significance and will not affect cutting quality.
The cut mode display can be continuously adjusted between
"05" and "99". In general, higher output levels are required for
thicker or wider loop electrodes or for deeper submersion of
Finesse Service Manual 3

the cutting electrodes in the tissue. These principles are dis-
cussed in the “Principles of Electrosurgery” section of the
Finesse®Operator's Manual.
As mentioned in the safety warnings of the operator's manual,
this knob should not be turned up to correct an apparent
power output deficiency without first verifying that all connec-
tions are in good order and the patient dispersive electrode is
still properly applied.
5. Coag Indicator Lamp. This blue lamp is illuminated whenever
coag voltage is applied to the active lead. Illumination of this
lamp is accompanied by an audio tone having a pitch lower
than the tone heard during a fault in the dispersive electrode
monitoring circuit but has a pitch higher than the tone heard
during operation in the cut mode.
6. Coag Output Control Knob and Indicator. This knob is used
to specify the output level desired for the intended coag oper-
ation. The adjacent digital readout indicates the output set-
ting.
Due to line voltage and thermal variations, it is normal for the
number displayed on the digital indicator to vary by one or
two digits while the control knob is stationary. While this vari-
ation truly reflects the relative output setting, it is of no clinical
significance and will not affect coagulation quality.
The coag mode display can be continuously adjusted between
"05" and "75". Smaller or finer electrodes require a lower set-
ting and larger electrodes will require a higher setting. Lower
settings on this knob may be used for desiccation coagulation.
The principles of coagulation by desiccation and fulguration
are explored in the “Principles of Electrosurgery” section of the
Finesse®Operator's Manual.
7. Patient Dispersive Electrode Receptacles. Three sets of dis-
persive pad receptacles are provided to accommodate the dis-
persive pad cable configurations that are commonly available.
The left-most socket pair is provided to take two redundant
leads out to a dispersive electrode. If either of these leads has
broken continuity, or if either lead is omitted, the red patient
alarm warning lamp in the center of the terminal block illumi-
nates and current from the generator is automatically shut off.
The center dispersive pad connector is a phone plug that
accommodates the phone plugs provided with many of the
available pads. Redundant leads are used, and the continuity
sensing circuit warns of a compromised dispersive electrode
connection.
The right-most rectangular socket is compatible with most of
the remainder of the available pads. Like the other two recep-
tacles, it accommodates dual-conductor cables.
8. Patient Alarm Indicator Lamp. This red lamp is illuminated
whenever the generator is disabled due to one of the following
conditions:
1) Incomplete redundant dispersive electrode connections
(accompanied by intermittent high-pitched alarm tone);
2) Simultaneous activation of both cut and coag modes
("cross-key") (accompanied by continuous high-pitched
alarm tone); or
3) Activation of the output safety circuit (accompanied by a
continuous high pitched audio tone).
The output safety circuit continuously monitors the output of
the generator and will disable the system when an unexpected
discrepancy between the displayed output setting and the out-
put power is detected. The main power switch must be tog-
gled off to clear this condition.
9. Monopolar Handswitch Receptacle. This connector consists
of three banana sockets which accommodate most of the
reusable and disposable hand-switching electrosurgical pens
that are available.
The left-most of the three sockets, marked with the "active
port" icon, accommodates a non-switching pen for monopolar
Finesse Service Manual
4

cutting loops, balls, and other surgical tools. When these pens
are used, the electrosurgical current must be activated by a
footswitch connected to the footswitch connector on the rear
panel of the unit.
10. Mode Select Switch. This switch allows the selection of the
appropriate mix of cut and coagulation activity for the per-
formed procedure.
In the cut mode, a continuous sinusoid voltage is applied to
the surgical tool in use. If the loop wire diameter is small
enough, it will cut through tissue very cleanly with very little
surface heating that would stop bleeding.
In the blend modes, the same loop electrode will cut cleanly
through the tissue while the surface of the cut is heated to
accomplish a degree of coagulation. "Blend 1" produces slight
coagulation, whereas "Blend 2" and "Blend 3" produce succes-
sively higher degrees of coagulation.
In switching between these modes the total output delivered
to the surgical tool is maintained at a constant setting as set by
the output control knob above the switch. Further information
useful in selecting blend modes is given in the “Principles of
Electrosurgery” section of the Finesse®Operator's Manual and
the “Technical Data” section of this manual.
11. Smoke Filter Connection. This connection, the large circular
structure on the face of the front panel, accepts the external
disposable filter pack which provides first- and second-stage
particulate removal and odor adsorption.
Rear Panel Controls and Connectors
Controls and connectors on the Finesse®rear panel are shown in
Figure 2 and are described below.
Figure 2. Finesse®rear panel connectors
1. Footswitch Connector. This connector accommodates two-
pedal footswitches designed to separately control cut and coag
modes.
2. AC Power Cord Connector. This connector is a three-contact
connector for use with high quality three wire power cords.
3. Fuse Sockets. These three sockets house the fuses that pro-
vide overcurrent protection for the Finesse®unit. They are
labeled with the appropriate fuse specifications for these cir-
cuits. Use only the correct fuses as specified by these labels.
4. Audible Tone Volume Control. This control adjusts the vol-
ume of the cut and coag mode activation tones. Due to inter-
national regulatory requirements, alarm tones are not affected
by this control, and are not adjustable.
Finesse Service Manual 5

Finesse Service Manual
6

SPECIFICATIONS
General Specifications
Dimensions: 14.0" (35.6 cm) W x 14.2" (36.1 cm) D x 7.1"
(18.0 cm) H
Weight: 22 lbs. (10.0 kg)
IEC Classification: Class I, Type CF
EU Directive: Compliant with 93/42/EEC (Medical Device
Directive) (ESU-220 only)
Mode of Operation: Continuous operation with intermittent load-
ing (10s/30s)
Supply Voltage & Current Specifications
The Finesse®unit can be obtained in either a 115 VAC (catalog no.
ESU-110) or 230 VAC (catalog no. ESU-220) configuration.
Supply Voltages (voltages are AC rms)
Nominal Voltage: 115 volts 230 volts
Regulated Range: 100-130 volts 200-260 volts
Operating Range: 90-140 volts 180-280 volts
Frequency: 45-65 Hz 45-65 Hz
Output Power vs. Supply Voltage
Within the Regulated Range listed above, the output power into a
500Ωload remains within ±15% of the power delivered at the cen-
ter of this range in cut and blend modes and ±30% in coagulation
mode.
Maximum Supply Current and Power (total)
115 V model 230 V model
Idle State: 0.5 A, 60 W 0.3 A, 70 W
Cut Mode: 6 A, 690 W 4.5 A, 1035 W
Coag Mode: 6 A, 690 W 4.5 A, 1035 W
Overcurrent Protection
The Finesse®115 V model is protected by a 6.25 amp slo-blo fuse in
each lead to the primary winding of the main power transformer.
The Finesse®230 V model is protected by a 4 amp slo-blo fuse in
each lead to the primary winding of the main power transformer.
Output Characteristics
Output Frequencies
The frequency of the interrupted waveforms is 450 kHz ± 50 kHz.
Interrupted patterns for blend and coagulation modes repeat at 28
kHz ± 3 kHz.
Output Values at Maximum Settings
Mode SettingaDuty CyclebMax Voltaged
Cut 99 100% 1000
Blend 1 99 62.5% 1925
Blend 2 99 50% 2050
Blend 3 99 37.5% 2200
Coag 75 c3500
a Output Setting specified is power in watts, plus or minus 15%, deliv-
ered into a 500Ωpatient load.
b Duty Cycle is ratio of burst duration to burst-plus-rest duration.
c Coag pulse consists of two high voltage cycles followed by lower
amplitude ringout for about 10 μsec, repeated at 28 kHz.
d Maximum voltage is peak-to-peak, open circuit. Lower values are
permitted.
Floating Patient Leads
The dispersive and active leads are RF isolated as defined by
ANSI/AAMI standard HF-18/1993.
Output Power vs. Load
Output display is calibrated to be relative power in watts at a load of
500Ω.
Finesse Service Manual 7

The negative-feedback output stage limits the output voltage under
high resistance loads. The same feedback circuit attempts to main-
tain the output voltage under low resistance loads so that the cutting
characteristics are quite uniform throughout the entire cut. See
Figure 3 and Figure 4 for output power vs. load data for cut, blend
and coag modes. Cut mode maximum output power is 150 watts at
200Ωpatient load.
Output Power vs. Displayed Setting
The output of the Finesse®unit increases linearly with adjustment of
the front panel output settings. Figure 5 and Figure 6 show the typi-
cal output power of each of the five modes over the full control
range. Both curves shown indicate output at 500Ωload resistance.
Output Safety Circuit Specifications
The Finesse®system is equipped with a safety circuit that monitors
the output signal levels and disables all unit functions when the out-
put exceeds the expected "nominal" output. The alarm system can
only be reset by turning off the main power switch.
The output safety alarm system will activate if the output voltage
exceeds 180 volts rms or exceeds the nominal output voltage by
50%, whichever is greater.
Audible Tone/Alarm System
Volume: 65 dBA min @ 1m (3.3 ft)
Frequency: Cut 0.8 kHz nominal
Coag 1.5 kHz nominal
Alarm 3.0 kHz nominal
Smoke Evacuator System
Supply Voltages (all voltages are AC rms)
Nominal Voltage: 115 volts 230 volts
Operating Range: 90-140 volts 180-280 volts
Frequency: 45-65 Hz 45-65 Hz
Maximum Supply Current and Power
At the Nominal Voltage, the maximum supply current is 2 amps.
Maximum supply power for the ESU-110 is 230 watts and for the
ESU-220 is 460 watts.
Overcurrent Protection
The smoke evacuation motor is protected by a 3 amp fuse in the hot
lead.
Air Flow vs. Supply Voltage
At a supply voltage within the Regulated Range, the air flow through
a new disposable filter coupled to a 15 cm long 7 mm ID tube is not
less than 100 liters per minute (3.5 cubic feet per minute) at the
"high" setting and not less than 70 liters per minute (2.5 cfm) at the
"normal" setting.
Smoke Evacuation Duration
The smoke evacuation system will begin running immediately on
activation of the electrosurgery module and remain running five sec-
onds after the output power is deactivated.
Disposable Filter Cartridge
The Finesse®Filter Pack, catalog number ESU-501, consists of a
pleated HEPA paper filter followed by a compartment containing
activated charcoal.
Filter Life
The Finesse®Filter Pack, to ensure total elimination of odors between
procedures, should be replaced on a daily basis. However, the
three-stage filtration system has been tested to effectively remove
odors and particles for up to 15 electrosurgical procedures. Over a
period of time the external disposable filter pack can be a source of
odor and possible viral contamination. Therefore, it is recommend-
ed that the external filter pack be changed every day or after 15 pro-
cedures if more than 15 procedures are performed in a single day.
Finesse Service Manual
8

Finesse Service Manual 9
Figure 3. Typical output
power vs. load resistance
for cut and blend modes
Figure 4. Typical output
power vs. load resistance
for coag mode
Figure 5. Typical output
power vs. output setting
for cut and blend modes
Figure 6. Typical output
power vs. output setting
for coag mode

Third-Stage Internal Filter
The Finesse®Internal Filter, catalog number ESU-700, is a pleated
ULPA filter element.
Filter Life
Annual replacement is recommended.
Combined Filter System
Particle Removal Efficiency
In laboratory tests, spherical particles with a mean diameter of 0.1
microns were removed with a minimum efficiency of 99.999%.
Finesse Service Manual
10

CIRCUIT DESCRIPTIONS
Note: Schematics for the Finesse®generator will be made available
on request to qualified technical personnel.
Power Supply
The power supply for all electronic functions is derived from the
input line supply through a multi-winding transformer mounted on
the floor of the unit. Circuits are conventional, non-switching sup-
plies using bridge rectifiers, electrolytic filter capacitors, and series
regulators. Except for the line connections, transformer, and fuses, all
DC power supply components are mounted on the power supply
board (see functional diagram on page 28 and assembly diagram on
page 24).
The 200 volt supply furnishes power to the preamplifier and final
output stages. This supply is not actively regulated; however the
volt-amp capacity of the transformer itself is sufficient to maintain
sufficient voltage under load to provide the set cutting or coag out-
put, and the preamplifier and output stages are feedback regulated at
the RF level so that the variation in cutting output over a large
change in supply line voltage is small.
The 30 volt regulated DC supply begins with a 28 volt rms secondary
winding on the main power transformer winding. A bridge rectifier
with a capacitor input filter converts this to approximately 40 volts
DC for use by both the 30 volt and 15 volt regulators. The 30 volt
regulator is a three terminal linear regulator.
The 15 volt regulated DC supply for powering the CMOS logic chips
also uses the 40 volt bridge with a three terminal linear regulator. A
resistor between the regulator and the 40 volt unregulated supply
protects it from excessive current in the event of a shorted compo-
nent.
The five volt regulated supply furnishes power to the LED display
devices on the display board. A 5 volt regulator chip is fed from a
separate winding on the main power transformer.
Output Level Control and Display
The cut/blend and coag modes of operation are separately controlled
with parallel circuitry. However, only the operation of the cut/blend
control circuit will be described.
The desired output for cutting is set by turning the cut/blend output
control knob on the front panel until the digital output indicator dis-
plays the correct value. Voltage from the front panel potentiometer
is routed to the A-D input on the digital display board. R3 in this
path is provided to set the display to read "99" at the fully clockwise
setting of the front panel knob.
The A-D converter converts the adjusted voltage at this point to a
digital value which can be manipulated by the main display proces-
sor. A linearization curve is programmed in the processor for each of
the cut and three blend modes so that the proper output control
level is presented digitally to the D-A converter at any setting from
the front panel.
The D-A converter translates the output of the processor to an analog
voltage which, after some additional scaling, will act as drive to the
power generation circuits. Two potentiometers on the logic board
allow for offset and gain adjustment of this voltage. A summing
amplifier at the output of the D-A converter provides a means for
amplifying, attenuating, or offsetting the control voltage and, also,
provides a mixing point for subtraction of the voltage signal fed back
from the generator output.
The adjusted output voltage, mixed with the feedback signal, is rout-
ed to individual variable-gain buffer amplifiers that are provided for
setting the drive levels of each mode in final calibration. The outputs
of these power level control amplifiers are connected to a bank of
transistor switches which act to select the proper voltage for each
selected mode of operation and present it to the DC-AC converter.
These transistor switches are logically controlled by signals from the
mode switch on the front panel and by the cut/blend and coag acti-
vation signals from the power board.
The DC-AC converter is a FET chopper whose drain voltage is the
conditioned output control DC voltage and whose gate is driven
Finesse Service Manual 11

from the high frequency waveform generator. This converter is trans-
former coupled to the base of the output preamplifier which, in turn,
drives the final output stage.
Waveform Generation
Each of the cut, blend, and coag modes are distinguished from each
other by the voltage waveforms delivered to the output terminals.
All of these waveforms are originally derived from a 450 kHz square
wave oscillator on the logic board. In the pure cut mode, the
unmodified 450 kHz square wave is applied to the gate of the chop-
per FET in the DC-AC converter. In the blend modes and in the
coag mode, the continuous square wave is interrupted for various
durations. Blend 1 removes 6 cycles of every 16 for a duty cycle of
62.5 percent. Blend 2 removes 8 cycles of 16 for a duty cycle of 50
percent. Blend 3 removes 10 of 16 for a duty cycle of 37.5 percent,
and the coag mode removes 15 of 16 for a duty cycle of 6.25 per-
cent.
Cycle removal for these functions is accomplished using a ripple
counter, an array of gates, and a D-type flip flop. The 450 kHz oscil-
lator is disabled unless either the cut/blend switching circuit or the
coag switching circuit is active.
RF Power Amplification
After the variable-amplitude, output-control voltage is converted to
AC by the DC-AC converter, the resultant RF signal is transformer
coupled to the input of the preamplifier and amplified in two stages
to the level necessary for performing electrosurgery. The preamplifier
consists of a bipolar power transistor with collector-to-base local
feedback and a transformer coupled to the final output stage. With
the exception of the power transistor itself, which is mounted on the
back panel heat sink, all components of the preamplifier are mount-
ed on the RF power board.
The final output stage uses four parallel power transistors mounted
on a fan-cooled internal heat sink. Other components of this circuit,
which consist of biasing resistors, output transformer, and output
coupling capacitors are mounted on the RF power board.
The RF output is coupled to the active and dispersive output termi-
nals through an output transformer with series capacitors in both
leads. This results in an output which is RF isolated from ground and
which is incapable of conducting low frequency currents which may
cause serious neuromuscular stimulation in the patient.
Feedback Circuit
Feedback control of the output is provided to 1) limit the maximum
open circuit output voltage, 2) regulate the output to optimum levels
under various cutting conditions, and 3) diminish the sensitivity of
the cutting output to line voltage variations. The output voltage is
detected by a high frequency bridge rectifier connected across the
secondary of the output transformer. This rectifier produces a DC
output which is proportional to the peak RF voltage across the output
terminals. This proportional voltage is applied to the LED input of a
opto-isolator device, and the emitter voltage from the isolator is fed
back to the cut/blend gain and offset control amplifier on the digital
display board.
With this circuit in place, an increase in the output, caused by a
decrease in load current or any other cause, will be detected and
subtracted from the output control signal, which will, in turn, result
in less drive to the preamplifier and, therefore, less change in the
output. Conversely, any attempted decrease in the output voltage
will be suppressed by the opposite action.
The degree of feedback control is adjustable using R333 on the
power board. This resistor is adjusted as part of the factory calibra-
tion procedure. It is interactive with the power gain adjustments.
Changing it without corresponding adjustment of the gain will result
in miscalibration of the generator.
Function Switching Circuits
The commonly available hand switches for electrosurgery have three
wire connections to the generator with two single pole switches for
cut/blend and coag. The active lead to the electrosurgical imple-
ment is the common wire for both switching functions. To maintain
RF isolation of the generator output, it is necessary that the hand
Finesse Service Manual
12

switching circuit be electrically isolated from ground. To achieve this
result, optical isolators are driven by op amp comparators between
the hand switch wires and the generator logic elements. Between
periods of surgical activity the comparator outputs are low and the
optical isolators stay in the "off" condition. When one of the two
handswitches is activated, the corresponding comparator toggles high
and the optical isolator switches "on". When current flows through
either of these optical isolators, the various gates that activate the
450 kHz oscillator, select the appropriate output control voltage, pro-
duce the correct cut/blend or coag waveforms, and activate the vac-
uum motor, are enabled.
The footswitch operates an isolated circuit that is identical to the
handswitching circuit.
Downstream of the first level cut/blend and coag gates, another pair
of gates are used which are disabled in case of cross key activation.
This blocks output from the generator when both cut/blend and coag
switches are simultaneously activated and generates a high pitch tone
on the speaker.
Besides their functional purposes, the signals generated by the
switching logic circuits also trigger the visual and audible indications
of their operation. The logic board contains a group of switching
transistors that control the indicator lamps, amber for cut/blend, and
blue for coag. They also select the appropriate tone outputs from a
frequency divider driven by an audio frequency oscillator which,
together, constitute the audio frequency generator block. These tone
signals are routed to a FET which drives a speaker mounted on the
front panel. The lowest pitch tone denotes cut or blend. The next
higher pitch tone denotes coag, and the highest tones are reserved
for cross key, patient alarm, and output alarm functions.
Vacuum Motor Control Circuit
The vacuum motor circuit is activated by either the cut/blend or coag
switches. A voltage representing either cut/blend or coag operation
is applied to the trigger input of a timer chip connected in a mono-
stable mode. The output of the timer turns on a solid-state relay
which controls the current to the vacuum motor. At an adjustable
interval after cessation of output activation, the timer output goes
low and the vacuum motor is shut off. The nominal delay for turn-
off is five seconds which is adjusted by R102 on the logic board.
Patient Alarm Circuit
The patient alarm circuit monitors the continuity between the two
parallel leads that are used to connect the dispersive pads to the gen-
erator. If either lead breaks or is otherwise compromised such that
the impedance between the two leads becomes greater than about
300 ohms, the generator shuts down and both visual and audible
alarms are produced.
Detection of the patient safety alarm condition is accomplished by a
transistor with a transformer in its collector circuit whose secondary is
connected between the two dispersive pad leads. The base of the
transistor is driven with a square wave at approximately 44 kHz.
When the dispersive leads are intact, the secondary of the trans-
former in the collector circuit is shorted. If this circuit opens or
develops a high impedance, an AC potential is produced on the sec-
ondary. This is rectified and applied to an optical isolator which,
when turned on, activates a number of gates that shut down the RF
waveform generator, turn on the red alarm indicator lamp on the
front panel, and generate a high-pitch interrupted beep signal in the
audio frequency generator.
Output Alarm Circuit
An output alarm circuit is included to prevent excessive output
power in the event of a generator malfunction. This circuit is a
direct copy of the controlled output feedback circuit described previ-
ously. The circuit monitors the generator output and sends a signal
directly to the microprocessor, where it is compared to pre-pro-
grammed values in a table. Should the output exceed conditions
that are considered normal with respect to the output setting, the
microprocessor will disable all unit functions and enable the audio
alarm circuit. The Finesse®system must be shut off to clear this
problem.
Finesse Service Manual 13

Overheat Protection Sensor
The Finesse is equipped with a temperature sensor that interrupts
one leg of the AC line in the event of a rear panel overheat. The
sensor opens at a nominal temperature of 160oF and is not
adjustable. The sensor is mounted on the rear panel near the output
transistors.
In the event of an overheat condition, all functions will cease and the
green lamp inside the main power switch will turn off. The unit will
automatically reset after about 30 to 45 seconds.
Under normal clinical conditions, the unit should perform without
any activation of the thermal shutdown sensor. However, during cal-
ibration and testing of the unit, the technician should allow for occa-
sional cooling down of the rear panel to avoid the shutdown.
Finesse Service Manual
14

TEST AND CALIBRATION
PROCEDURE
Complete Calibration Procedure
This procedure is intended as a protocol for functional testing and
calibration of the Finesse®electrosurgical generator and smoke evac-
uation system. It should be conducted in whole or in part whenever
malfunction or miscalibration is suspected. If the problems encoun-
tered are correctable by the adjustments contained in this procedure,
the adjustments should be made and the generator should be con-
sidered suitable for clinical use. If the problems cannot be thus cor-
rected, more thorough testing or parts replacement may be neces-
sary. In such a case the user technician should note the step or steps
in this procedure that cannot be accomplished as described, note the
measurements actually obtained where applicable, and contact
Customer Service at Utah Medical Products for further assistance or
to make arrangements for factory repair.
CAUTION: The procedures described herein require understanding
and skill in electronics technology. They should be performed only by
qualified electronic or biomedical technicians who understand the ter-
minology and recognize the various components of radio frequency
power circuits. Attempts to carry out these procedures by unqualified
personnel may result in human injury or equipment damage.
EQUIPMENT NEEDED:
• Allen wrench set
• Oscilloscope with two high voltage probes and line iso-
lation transformer
• Digital multimeter
• Electrosurgical analyzer, such as Fluke/DNI 454A
• Safety analyzer, such as Bio-Tek model 170
• AC Hi-Pot Tester
• Handswitch and cable
• Footswitch and cable
• Jumpered dispersive cable with rectangular plug
• 900Ωjumper
1.0 VISUAL AND MECHANICAL INSPECTION
1.1 Remove the top shell of the Finesse®and inspect the interior.
Verify that all connectors are fully seated, that the vacuum
motor is properly secured to its shock mounts, and that all
boards and components attached to the chassis are solidly
mounted.
1.2 Verify that the internal smoke filter is properly aligned with the
pump intake with no discontinuity or visible leaks in the vacu-
um connections.
1.3 Correct all observed mechanical problems by reseating con-
nectors and/or tightening mounting screws as needed.
2.0 INITIAL UNIT SETUP PROCEDURES
CAUTION: The input power connections have an AC voltage of 120
volts or 240 volts, and the collectors of the power transistors, as well
as several points on the circuit boards, have DC voltages in excess of
200 volts. During application of output power, the voltage between
the active and dispersive terminals or circuit components connected
to these terminals may be as high as 2000 volts peak-to-peak at high
frequencies. To prevent shocks or burns, avoid touching any bare
metallic objects, wires, or connections.
CAUTION: Use of an oscilloscope on the Finesse®generator requires
that the oscilloscope be fully isolated from the main power line by a
transformer. Failure to properly isolate the oscilloscope could result in
extensive damage to the Finesse®generator and/or oscilloscope.
NOTE: Reference to board level components will be as follows:
1 - 99 display board
101 - 199 logic board
201 - 299 power supply board
301 - 399 RF power board
Finesse Service Manual 15

2.1 Connect unit to AC power With the main power switch off,
verify that the neon lamp is not lit. Then, switch the unit on
and verify that the lamp lights.
2.2 Verify that the unit is now making a high pitched beep with a
1 second repetition rate and the red alarm lamp is lit.
2.3 Plug the dispersive pad connector dummy or a dispersive pad
into the dispersive pad connector and verify that the alarm
condition is canceled.
2.4 Connect black lead of multimeter to TP103. This will serve as
the ground reference for all measurements.
2.5 Plug the power cord into the receptacle. Also plug in the
footswitch, the handswitch pen and the dispersive pad plug.
2.6 Switch the unit on. Verify that the green light in the switch is
on and that the displays light. No other indicator lights should
be on and the unit should not beep.
2.7 Verify regulated 5 volts on pin 1 of J203 measures 4.5 to 5.5
volts.
2.8 Verify regulated 15 volts on pin 2 of J203 measures 13.5 to
15.5 volts.
2.9 Verify regulated 30 volts on pin 4 of J203 measures 28.5 to
31.5 volts.
2.10 Verify unregulated 200 volts on pin 12 of J203 measures 170
to 205 volts.
3.0 INITIAL SETUP OF CONTROL CIRCUITS
NOTE: ADJUSTMENTS MADE IN THIS SECTION SHOULD NOT BE
NECESSARY FOR PREVIOUSLY CALIBRATED SYSTEMS. IF ADJUST-
MENTS IN THIS SECTION ARE MADE, THE FINESSE SYSTEM CALIBRA-
TION PROCEDURE SHOULD BE FOLLOWED IN ITS ENTIRETY. IF
ONLY POWER OUTPUT RECALIBRATION IS DESIRED, PROCEED TO
STEP 6.6.
3.1 Adjust the vacuum motor delay by pressing the cut switch
momentarily. The vacuum motor will start and should stay on
for five (5) seconds. Adjust R102 until a five second delay is
achieved.
3.2 Turn the cut mode output setting adjustment knob fully clock-
wise. Adjust R3 to make the cut display read '98'. Then adjust
R3 so that the cut display jumps to '99', then add ¼ turn in the
same direction.
3.3 Turn cut mode output setting knob fully counter clockwise.
Verify that the display reads '05'.
3.4 Turn the coag mode output setting adjustment knob fully
clockwise. Adjust R2 to make the coag display read '74'. Then
adjust R2 so that the cut display jumps to '75', then add ¼ turn
in the same direction.
3.5 Turn coag mode output setting knob fully counter clockwise.
Verify that the display reads '05'.
3.6 Set cut mode output setting to '99' and coag mode output set-
ting to '75'.
3.7 Measure TP105 and adjust R164 to read zero (0) volts.
3.8 Measuring cathode of D102, adjust R163 to read 12 volts DC.
3.9 Verify voltage on D102 varies as you adjust the cut mode out-
put setting knob.
3.10 Set cut mode output setting to '99'. Measuring the voltage at
TP104, follow steps 3.11 - 3.14.
3.11 Set mode to "CUT". Adjust R142 to 12 VDC.
3.12 Set mode to "BLEND 1". Adjust R144 to 10 VDC.
3.13 Set mode to "BLEND 2". Adjust R146 to 10 VDC.
3.14 Set mode to "BLEND 3". Adjust R148 to 10 VDC.
3.15 Measure voltage at D107. Voltage should be zero (0). Press
cut switch and verify that the voltage jumps to approximately 9
Finesse Service Manual
16