Mettler Electronics Sys Stim 206A User manual

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Sys«Stim® 206A
MAINTENANCE MANUAL
AAErrLER E LECTRONICS °
corp.
1333 S. Claudina Street
Anaheim, CA 92805 U.S.A.
Cail toll free: [phone] (U.S.A.)
ог сай: [phone] .
FAX: [phone]
March, 1993 IR6-89

Sys*Stim 206A Maintenance Manual /
Subject | e
A
Abbreviations
Labels
Specifications
章
Precautions
Equipment Description メイ ナ ア エイ イイ イイ イイ イイ で イエ リエ イエ エエ トト さ エ すす ャ キア エナ ャ トド エミ エ マエ ミト エア て エメ エエ て 1
Control Panel Description | . 이 이 늬 아 아 니 아 아 아 마 이 아 아 아 마 아 아 이 아 이 이 라 아 이 이 아 이 이 아 사 이 이
Theory of Operation
Operating Instructions
Routine Maintenance
Fuse Replacement..............ssccrrrerrrire rec carie ri cie zizi e ieniezenino 同 16
Troubleshooting Guide Ne 16
Test Procedures 18
Waveform Diagrams .be sner rese grenene 24
Parts List co. rece ee eee ie eee rienza eni zie cavi vece cieca cieco 25
Sys+Stim 206A Accessory List oocoooococonoconccnnnronoranronennencoracenonranonnraneronananos 31
Drawings and Schematics ee 32
Copyright © 1990 by Mettler Electronics Corp.—Anaheim, CA
Copyright © 1993 by Mettler Electronics Corp.—Anaheim, CA

Sys«Stim 206A Maintenance Manual
INTRODUCTION
Sys«Stim 206A servicing should be done at the factory.
If not possible to return the Sys«Stim 206A to the factory, this service manual may ..
be used to troubleshoot to the major subassembly level. Discrepant subassemblies
can then be repaired at the factory as an alternative to returning the complete
system.
This manual is intended for service technicians who perform preventive and |
corrective maintenance on medical devices using appropriate electronic test and
measurement equipment. It should be read in its entirety before attempting to
service the Sys«Stim 206A. "
For technical assistance, call our Service Department at:
Toll Free: [phone], USA
Phone: [phone]
FAX: ’ [phone]
ABBREVIATIONS
AC - alternating current
DC - direct current
DVM - digital voltmeter
Hz - Hertz (cycles per second)
kohm - Kilo-ohm (1000 ohms)
mA - milliampere (1/1000 ampere)
msec - millisecond (1/1000 second)
mW - milliwatt (1/1000 watt)
psec - microsecond (1/1,000,000 second)
Vdc - Voltage direct current
Vac - Voltage alternating current
W - watts
Recip - Reciprocation
LABELS
The Food and Drug Administration (FDA) requires that medical devices be uniquely
identifiable. To comply with this requirement, the Sys+Stim 206A has a serialized
label unique to each unit.
Please be careful not to damage these labels, especially during servicing actions
such as removing and replacing enclosures.
Include serial numbers when requesting technical assistance.

Sys*Stim 206A Maintenance Manual
SPECIFICATIONS
Line input: 115 VAC ( + 10%), 50/60 Hz
UL listed: Model 206A (Type# 737K) |
Output:
Volts: 0-102V
Milliamps: 0-30 тА DC Continuous
0 - 200 mA {into 500 ohm load)
Narrow pulse
Wide pulse
AC
Waveform Type:
Narrow Pulse Asymmetrical Biphasic Square
Wide Pulse Asymmetrical Biphasic Square
AC
Symmetrical Biphasic Square
DC Continuous Continuous DC
21, 25, 210 Monophasic Square
Frequency: 1-83 pps (Narrow, Wide, AC Pulses or
Pi, P5 OR P10 “DC Continuous’ waveforms)
SURGE Modes:
Narrow, wide, and AC pulses
All up/down ramps fixed at 3 Seconds
F35 6sec.on 18sec. off (35 pps)
F83 6sec.on 18sec. off (83 pps)
On/ Off 1-60 sec. 1-60 sec. (1-83 pps)
Reciprocation Time: 2 - 19 seconds
Fuse: 1 Amp, Fast acting
Treatment Timer Specifications:
Indicator:
The digital time indicator displays set time in minutes and seconds prior to
the start of operation, and time remaining during operation and while in
HOLD. Time is measured during operation oniy.
Accuracy: ‘+ 0.5 minute (at all settings.)
Maximum setting: 29 minutes (preset) É
Continuous: (Timer Bypass)
Automatic stop: When time reaches "0" the output is disabled and
countdown stops.

Sys*Stim 206A Maintenance Manual >
PRECAUTIONS
1. Line supply voltage is present inside the enclosure, and present on exposed
components after back housing is removed and line cord is connected to the
line supply. DISCONNECT LINE CORD PRIOR TO REMOVING BACK COVER.
2. Servicing should be performed by qualified technicians using appropriate
calibrated test equipment.
3.
Use
grounded
wall
outlets
only.
|
4. Adhere to standard safety practices for troubleshooting and servicing
electronic equipment.
5. To insure continued conformance to specifications and applicable safety
standards, the Sys+Stim 206A should be performance checked and safety
tested at least once each year.
6. USE OF CONTROLS OR ADJUSTMENTS OR PERFORMANCE OF i
PROCEDURES OTHER THAN THOSE SPECIFIED HEREIN MAY RESULT IN 1
HAZARDOUS EXPOSURE TO ELECTRICAL ENERGY. a
7. Do not operate the Sys*Stim 206A in close proximity with operating shortwave
or microwave diathermies.
8. Replace line fuses with same type and rating as specified in the list of
specifications and on printed circuit board nest to the fuses to avoid risk of fire
and component damage.
9. Primary circuit components must be replaced with factory- specified É
components to insure compliance with UL-544 safety standard for medical and
dental equipment. -

Sys*Stim 206A Maintenance Manual
EQUIPMENT DESCRIPTION
The Sys«Stim 206A is a portable, microprocessor controlled, digital, dual channel,
electrical neuromuscular stimulator that has three pulse modes and a DC
Continuous mode. Additional features such as surge options, reciprocation and
reverse polarity are also available.
The injection molded ABS plastic enclosure is divided into two halves, a front half
and a back half. Electronics circuitry and indicator subassemblies are assembled
into the front enclosure half. The back enclosure half provides a protective cover
and base that is removed by means of four Phillips head screws.
There are three printed circuit boards in the Sys+Stim 206A: the RFI, Display and
Main circuit boards. The RFI board is a small PCB consisting of two fuses and a
line filter. The Display and Main circuit boards contain most of the operating and
power supply circuits. Each of these subassemblies is described in the Theory of
Operation section of this manual. |
The membrane touch control panel incorporates multilayer laminated design
minimizing knobs and dials, and facilitating equipment operation.
Displays consist of 7-segment LED's, green LED's, and a beeper signal to indicate
control operation, end of treatment time, and output cutoff.
The Sys*Stim 206A is constructed and safety tested in compliance with UL-544,
"medical and dental equipment standard for safety”.

Sys*Stim 206A Maintenance Manual
TIME
MINUTES SECONDS
@ PEAK VOLTS
@ MILLIAMPS
CURRENT
NARROW
PULSE
CONTINUOUS
o
o LN |sunce
一 REVERSE
=
O
OFF
INTENSITY PULSE FREQUENCY
MAXIMUM
SYS eSTIMO
1 206A 2
CHANNEL
©
Control and Display Panel

Sys*Stim 206A Maintenance Manual
DESCRIPTIONS OF CONTROLS, INDICATORS
AND DISPLAYS
1. TIME Display
The
TIME display indicates selected time, time remaining and elapsed time. It also
displays "On" and "Off" when on/off times are selected for variable surge cycles.
"CH2" is displayed for 5 seconds every 30 seconds when channel 2 output is
indicated by the METER display.
2. TIME Selector
The TIME selector is a ten key pad. To input 1 minute press "1" to get "1.00" in the
time display. For 10 minutes, press "1" then "0" to get "10.00" in the TIME display.
From 1 to 29 minutes may be input. Seconds cannot be input, but during
operation the TIME display shows time in minutes and seconds.
3. GO
GO starts the output. When pushed, time counts down, the METER display
becomes active, and Stimulation current is available at the ELECTRODE JACKS.
Both INTENSITY controls must be rotated fully counterclockwise for GO to activate.
If time does not begin to change, check position of these controls and adjust
accordingly. "Err1" will be displayed if these controis are not returned to the zero
position.
4. HOLD
HOLD temporarily suspends operation. Timer is frozen at time remaining, or time
elapsed, when HOLD is pressed. METER returns to zero and outputs are
terminated. All previously selected parameters are maintained. INTENSITY controls
must be returned to zero prior to resuming operation. New operating parameters
may be selected while in HOLD.
5. TIMER BYPASS
TIMER BYPASS is used when preset time is not desired. It obviates the need to
input time. TIME display shows elapsed time alternating with flashing dashes
during operation. Elapsed time is shown in even seconds and restarts at 0.00 after
each 100 minute time period.
6. MAIN POWER SWITCH
THE MAIN POWER SWITCH is a rocker type switch which, if depressed to the left,
applies power to the unit.
7. INTENSITY CONTROLS
Dual control knobs permit intensity adjustment of both channels. The lower knob
adjusts the intensity for channel 1 and the upper knob adjusts the intensity for

Sys«Stim 206A Maintenance Manual
channel 2. Both controls must be fully counterclockwise before initiating
operation.
8. ELECTRODE JACKS
There are two output jacks marked "1" and "2" to indicate respective output
channels.
9. METER DISPLAY
Indicates peak output voltage in the NARROW, WIDE and AC modes; milliamps in
the DC CONTINUOUS. PEAK VOLTS and MILLIAMPS green LED's under the
METER display indicate which units are displayed. Channel 1 output is displayed
except when "CH2" is shown in the TIME display.
Indicates surge codes (L11, L13, H13, P1, P5, P10, etc.) and variable On/Off times
in SURGE mode during initial treatment parameter selection. In HOLD, or when
timer counts down to zero, the selected SURGE code returns.
10. NARROW PULSE MODE
NARROW PULSE waveform is an asymmetrical biphasic square pulse. Phase
duration is 100 microseconds one way, 400 microseconds the other at 1/4
amplitude to provide zero amperes net DC current flow. The green LED next to the
NARROW PULSE key is lit when this mode is selected.
11. WIDE PULSE MODE
WIDE PULSE MODE waveform is an asymmetrical biphasic square pulse. Phase
duration is 300 microseconds one way, 1200 microseconds the other at 1/4
amplitude to provide zero amperes net DC current flow. The green LED next to the
WIDE PULSE key is lit when this mode is selected.
12. AC MODE.
AC waveform is a symmetrical biphasic sguare pulse. Each phase duration is 300
microseconds at egual amplitude, opposite polarity. Net DC current flow is zero
amperes. The green LED next to the AC key is lit when this mode is selected.
13. DC CONTINUOUS. MODE.
The first time DC CONTINUOUS is selected, output is continuous and in one
polarity only. CAUTION: APPLICATION OF CONTINUOUS DC (GALVANIC)
CURRENT CAN PRODUCE SKIN IRRITATION. USE EXTREME CARE. Black lead is
negative, red lead is positive. Output is displayed in milliamps.
Note: Continuous DC is output through CH 1 only.
14. SURGE CONTROL
Activating SURGE allows the operator to select preset or variable On/Off times of
1-60 seconds for use with NARROW PULSE, WIDE PULSE and AC modes.
Activating SURGE with DC CONTINUOUS provides monophasic pulses at three

Sys+Stim 206A Maintenance Manual
different phase durations. The green LED next to the SURGE control is lit when
SURGE is selected.
Repeatedly press the selected waveform key (NARROW PULSE, AC or DC
CONTINUOUS pulsed) until desired surge code is displayed in the METER. A 15
second period is available after treatment is initiated in all surge modes (except DC
CONTINUOUS) to allow the operator time to adjust the intensity of the output to
the patient. When 15 seconds have elapsed, the intensity will ramp down and the
preset Off time will begin the selected surge program. SURGE codes are listed
below.
NARROW PULSE, WIDE PULSE AND AC
Code Up Ramp On Time Down Ramp Off Time Frequency
F35 3 sec. 6 sec. 3 sec. 18 sec. 35 pps
F83 3 sec. 6 sec. 3 sec. 18 sec. 83 pps
On» 3 sec. 1-60 sec 3 sec. 1-60 sec. (Use PULSE
FREQUENCY control)
Input time with 10-key pad. METER displays ON time. Pressing GO after entering
OFF time enables TIME selector and GO key.
DC CONTINUOUS xx
Code Phase Duration Maximum Frequency
Pl 1 millisecond 83 pps
PS 5 milliseconds 83 pps
P10 10 milliseconds 83 pps
** PULSE FREQUENCY control is enabled in pulsed DC. The waveform is a
monophasic square wave.
15. REVERSE POLARITY
Polarity may be reversed at any time before, during or after operation. The LED
next to this key indicates normal polarity when off (black = negative). REVERSE
POLARITY is enabled when using DC CONTINUOUS, NARROW PULSE and WIDE
PULSE.
|
16. PULSE FREQUENCY CONTROL
This control varies pulse frequency form 1 - 83 pps in all pulsed modes except
preprogrammed surge cycles. It is disabled in DC CONTINUOUS. Frequency
increases with clockwise rotation. A green LED next to the Frequency control is on
when pulse energy is at the output(s) and blinks at a rate proportional to the
selected frequency.
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Sys*Stim 206A Maintenance Manual
17. RECIP OPTION
This option alternates selected pulsed currents between the two channels for 2 to
10 seconds each. A distinctive detent is felt when control is rotated past the on/off
point. Setting the desired time at 2 to 10 seconds provides output at CH 1 for that
period of time followed by output for the same amount of time on CH 2. Up and
down pulse ramps of 0.5 second are provided in RECIP.
RECIP is disabled if SURGE or DC continuous is selected, and can not be disabled
after treatment has been initiated.
Rotate RECIP control fully counterclockwise past the distinctive detent when
reciprocation is not required.
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Sys«Stim 206A Maintenance Manual
THEORY OF OPERATION
1. POWER SUPPLY
The power supply consists of a line transformer that supplies AC power to the +5
volt, +12 volt, -12 volt and +40 volt supplies, full wave rectifiers for each of
supplies and three 3-terminal regulators for the +5, +12 and -12 supplies. The +40
volt supply is unregulated.
2. CONTROL CIRCUITRY
The control circuitry is made of following sections:
A. Microprocessor, Reset circuit, Crystal and UVEPROM
These parts make up the heart of the microcontroller. The 8 MHz
crystal provides the System clock that allows the microcontroller to
run and the UVEPROM contains the program firmware that controls
the action of the controller, The reset circuit allows the voltage and
clock freguencies to stabilize within the microcontroller before allowing
it to run the program that is stored in the UVEPROM.
7 Segment Display Driver
The display is controlled by the microprocessor used PORTA and
decoder to seguence the display strobes and drives the individual
segments from a latch. The output of the latch is connected to high
current driver that supplies current to the LED segments. The function
indicator LED are also driven in this way.
The Membrane Keyboard Interface.
The membrane keyboard is a 7 by 3 switch matrix. The rows are
strobed with display strobes 0 through 6 and the columns are
monitored by PORTA bits 0, 1 and 2.
The Dual D-A Converter 」
The D-A converters along with the intensity pots for channels 1 and.2
produce an output voltage between 0 and 5 volts for each channel that
is used to control the output voltage of the high voltage generator.
The 8-Bit Latch
This latch is used to output waveform control signals for both
channels and also to output signals to the buzzer and to the frequency
indicator LED.
3. HIGH VOLTAGE GENERATOR
The high voltage generator is made up of the following sections:
A.
Voltage Controlled Dual Output Power supply
The heart of the output power supply is a switch mode pulse width
modulation control chip. The output of the chip switches on a power
FET that draws current from the +40 volt unregulated supply through
the primary of a step-up transformer. So as the pulse width at the
12

Sys*Stim 206A Maintenance Manual
output of the chip increases, the amount of Power applied to the
transformer is increased, thus the voltage produced on the secondary
increases and the feedback voltage is increased. The control voltage
comes from the D-A converter and the maximum output from the
converter is adjusted at setup to cause 102 volts at the patient output.
The minimum output is 1 volt.
A % amplitude low voltage output slaved to the high voltage output is
provided.
Current control of the supply is limited to 30 mA when the current
limit defeat signal from the microcontroller is not present. This limit is
active only in the DC mode. The AC pulsed modes can produce pulse
currents up to 200 milliamps.
B. HI/LOW Voltage Select Switch
Either one of the power supply voltages can be selected for the patient
output with the HI/LOW Voltage Select signal. This signal can turn on
a FET switch that connects the higher voltage to the voltage to the
patient output or it can turn off the switch so that 1/4 voltage appears
at the output.
C. | Voltage and Current Sense
Patient applied voltage and current are read by the microprocessor's
analog to digital converter inputs, and the binary number that is read
by the processor then converted to decimal is the voltage and current
that is being sensed.
D. Output Switches
The bridge configuration of the FET switches develops the square wave
output and the polarity reversal of the device. Q8 and Q9 for CH1, and
Q20 and Q21 for CH2 work together for one current direction while Q5
and Q6 for CH1, and Q17 and Q18 work in the opposite direction.
‘Only one pair for each channel can be on at a time.
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Sys+Stim 206A Maintenance Manual
OPERATING INSTRUCTIONS
1. Before Starting.
Review control/ display descriptions and precautions. Verify line cord and
electrode cable connections.
2.. Energize.
Depress MAIN POWER rocker switch to the left.
3. Reset Intensity.
Set both intensity controis fully counterclockwise.
4. Input Time
Select operating time with 10-key pad. Maximum time to enter is 29 minutes.
If greater than 29 minutes is entered, "Err2" is displayed in TIME window
when GO is pressed. TIME display should show time selected, e.g., if ”5” is
pressed TIME display shows "5.00". A tone is produced when any key is
pressed to verify activation.
It is not necessary to input a specific time to operate ME 206A. For an
indefinite time, select TIMER BYPASS prior to pressing GO.
5. Select waveform.
Default is NARROW PULSE. Other options include WIDE PULSE, AC and DC
CONTINUOUS.
6. Select optional duty cycles.
Press SURGE or turn on RECIP control to select an On/Off duty cycle. Details
of the operational characteristics of each option are shown below.
SURGE - available in NARROW PULSE, WIDE PULSE, AC, and DC
CONTINUOUS. Press waveform switch repeatedly until desired surge code
appears in the METER display, SURGE codes are described on page 10, item
15. SURGE sequences are given below.
NARROW PULSE, WIDE PULSE, AC
Press desired mode
Press SURGE __ ---+--~-------------------------- > F35 in METER
Press mode key ------------~-------------------- > F83 in METER |
Press mode key --------------------------------- > ON in TIME
Enter 1-60 on key pad -------------------------- > 1-60 in METER
i Press GO ----.- non > OFF in METER
i Enter 1-60 on key pad -------------------------- > 1-60 in TIME
; Press GO anno > TIME shows entered time.
i
METER
shows
"Adj."
|
| DC CONTINUOUS
| Press ーーーーーーーーーーーーーーーーーーーーーーーーーーーー ニ ーーーーーーーーーーー > DC CONTINUOUS
Press SURGE----------------------------------- > "P 1º in METER
Press DC CONTINUOUS __------------------ > "P 5" in METER
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Sys*Stim 206A Maintenance Manual
Press DC CONTINUOUS ----------------- > "P10" in METER
When desired duty cycle code is displayed, proceed to step 7.
RECIP - rotate RECIP control clockwise to the on position. Reciprocation
times of 2-10 seconds may be selected. NARROW PULSE, WIDE PULSE and
AC may be selected when RECIP is activated. RECIP cannot be activated at
same time SURGE is selected and may not be deactivated during treatment.
7. Select Pulse Frequency
Set desired frequency using PULSE FREQUENCY knob. PULSE FREQUENCY is
active when pulse waveforms are selected, in SURGE ON/OFF program, and in
RECIP. It is disabled in DC CONTINUOUS except for pulse options.
8. Connect Electrode Cabies (or dummy loads)
Attach electrodes to electrode cables by inserting cable pins or banana
connectors into electrode jacks. (See TEST PROCEDURE for dummy load
description.)
9. Begin Operation
After all operating parameters are set, press GO.
"Errl" is displayed if both intensity controls are not adjusted fully
counterclockwise. Rotate both intensity controls to reset and press GO to
clear error and continue.
"Err2" is displayed if time greater than 29 minutes is entered. Enter time less
than 30 minutes and press GO to clear error and continue.
"Err4" is displayed if no time entered and TIMER BYPASS not selected.
- 10. Set Intensity.
Adjust output intensity to desired level using dual intensity control knobs.
Rotate the lower control knob only to adjust Channel 1, and the upper knob
for channel 2. DC CONTINUOUS intensity is shown in milliamps. Intensity for
all other modes is given in volts. The LED indicators below the METER are lit
either to the left of Peak Volts or Milliamps, whichever is being displayed.
11. Operation Interrupt.
If changes are desired while equipment is running press HOLD to suspend
operation. Reset intensity by rotating both intensity controls fully
counterclockwise before pressing GO to restart operation.
12. Reversing Polarity
Electrode polarity may be reversed at any time during operation by pressing
the REVERSE POLARITY key. The black electrode will change from negative to
positive while the red electrode will change from positive to negative when
REVERSE POLARTIY is selected.
13. End of Operation Time
When operation time elapses, a buzzer will sound. TIME and METER displays
return to zero and output terminates.
` 15

Sys*Stim 206A Maintenance Manual
1. The SYS«STIM 206A may be-cleaned with a damp cloth. The line cord should
be disconnected before cleaning unit. In case of stubborn dirt, a gentle
household cleaner may be sprayed on the cloth and then wiped on the unit. If
this method is used, remove cleaner residue with damp cloth.
2. Electrode cables ARE NOT autoclavable.
3. Replace electrodes and cables upon any sign of wear, tear or corrosion to
ensure proper operation.
4. Standard electrical safety checks should be performed annually.
1. Two line fuses located on the RFI board are used. Fuse replacement requires
removal of the back enclosure. Use only the same fuse type and rating for
replacement to protect against fire hazard.,
2. Iffuse replacement becomes necessary, the unit should be checked for proper -
operation prior to placing it back in service.
SYMPTOM CHECK
1. Nothing lights when main power Is line cord connected to outlet?
switch is turned on.
2. When GO is pressed nothing Reset the unit. Reprogram treatment
happens; time does not increment parameters. Press GO to restart up or.
down, intensity cannot be adjusted operation. :
and no output.
3. In DC CONTINUOUS, when GO is Verify electrode cable connections, or
pressed, time increments up or dummy loads in properly.
down, but intensity cannot be and no output.
adjusted.
4. During operation, previously This is normal.
selected treatment parameters
cannot be changed.
5. "Errl" in TIME display. Reset intensities to zero and press GO.
6. "Err2" in TIME display More than 29 minutes entered. Enter
correct time or press TIMER BYPASS
ROUTINE MAINTENANCE
and press GO.
16

Sys*Stim 206A Maintenance Manual
7. "Err3" in TIME display. On/Off time more than 60 seconds
entered. Enter time < 60 seconds.
8. "Err4" in TIME display. No time entered. Enter time or press
: TIMER BYPASS and press GO.
Refer to test procedure for other error codes. If problem is not addressed above, or
if additional troubleshooting guidance is desired, call [phone].
The distributor who sold the Sys+Stim 206A should be able to assist you with a
loaner unit during warranty service.
17

Sys*Stim 206A Maintenance Manual
TEST AND CALIBRATION PROCEDURE
Equipment/ Material Needed
5 MHz dual channel oscilloscope.
DVM
1 kohm/2 W.test load.
Leakage (safety) tester
Hipot tester.
EZ-hook to Ez-hook jumpers (2).
AWN
1. Procedure:
Visual Inspection.
a. Check for signs of damage, poor connections, missing or loose
components, reversed components, solder discrepancies, etc.
b. Look for discoloration of components and PCB's caused by overheating
or short circuits.
c. Look for loose or missing hardware.
2. Power supply.
i a. Verify proper interconnection between PCB assembly and front case.
| b. Set intensity to minimum and frequency to maximum.
| c. Plug unit in and turn it on.
(1) TPland TP4 should be +5 VDC + 0.3.
(2) | TP2 should be +12 VDC + 0.3.
(3) TP3 should be -12 VDC + 0.3.
(4) TP5 and TP6 are ground.
d. Turn unit off.
3. Current Limit
a. Perform the following for each channel. Before testing CH2, press
hidden button #1 (located one inch to right of Current LED) twice to be
in test mode and turn RECIP pot on.
(1) Install 1k load in series with not load mono plug. Put DVM
] across patient output; red probe to center, black probe to
i outside.
(2) Press hidden button #1 twice, press DC CONTINUOUS, enter
time, and press GO.
(3) Set Voltage adjust pot's, R26 (CH1), R89 (RH2)} to mid- position.
(4) Put DVM in DCA mode, 200 mA range.
(5) Slowly increase intensity to maximum.
(6) Observe DVM and front panel meter.
18

” Sys*Stim 206A Maintenance Manual
(7) - Set current adjust pot's, R33 (CH1) and R97 (CH2), for 30 mA +
.2 Von DVM.
(8) Decrease intensity to minimum, jumper R66 (CH1) and R116
(CH2), then slowly increase intensity until over-current circuit is
triggered. Shutdown should occur prior to reaching 75 mA, Err5
is displayed in time display. Turn unit off and remove jumpers.
(9) Turn unit on, press hidden button #1 twice and set intensity to
maximum. Check for 30 mA on DVM in DC CONTINUOUS.
(10) Adjust current sense pot's, R62 (CH1) and R113 (CH2) for 30 mA
on front panel meter.
Voltage Adjust. (Perform this test one for each channel.)
(1) Press HOLD. Select NARROW PULSE. Install 1 kohm/2 W load
in output jack. Press GO and set intensity to maximum.
(2) Connect scope across output load. Set AMPL/DIV to 20 V and
time/DIV to .2\1 ms.
(3) Adjust R26 (CH1) and R89 (CH2) for 102 V + 2 V peak on
oscilloscope.
(4) Adjust R42 (CH1) and R106 (CH2) for 102 V + 2 Von front panel
meter.
4. Waveform Verification. (Perform this test once per channel)
a. Select NARROW PULSE. Set oscilloscope TIME/DIV to 2 ms. Verify
pulse interval, leading edge to leading edge, is about 8 ms (28 ms for
35 Hz).
Set frequency to minimum. Verify pulse interval is about 1 ms.
Refer to Figures 1 through 6 for pulse mode diagrams. Set oscilloscope
time/div to .1 ms when checking pulse 1, .2 ms for pulses 2 and
3, 1 ms for pulse 4, and 2 ms for pulses 5 and 6.
Select each pulse mode and set intensity to maximum. Verify pulse
widths and amplitudes conform to applicable figure (1 through 6) for |
each mode.
Press HOLD. Decrease intensity. Press SURGE, NARROW PULSE and
GO.
Set intensity to maximum and verify pulses come up and remain for a
15 second adjustment period. Also verify that intensity linearity and
amplitude are the same in SURGE as they are in regular pulse modes.
Verify SURGE envelope (35 and 83 Hz) agrees with timing table below.
Use a timepiece with a second hand t to obtain applicable ratios and
frequencies.
19

Sys*Stim 206A Maintenance Manual
RATIO CODE FREO UP RAMP ON DOWN RAMP OFF
1:3 F35 35 Hz 38 6s 3S 18S
1:3 F83 83 Hz 38 68 38 18 $
Table 1 Timing.
5. Channel Reciprocation Test.
a. Set oscilloscope to dual trace and chop mode
b. Select a pulse mode, Install 1 kohm test load in both output jacks.
Check RECIP pot off (fully counter- clockwise). Turn both intensity
knobs and frequency knob to maximum. Channel 2 output pulse
should follow channel 1 pulse, but never at the same time.
ο. Turn RECIP pot clockwise until it just clicks on. The output pulse
should alternate from channel 1 to channel 2 at a 2 second rate.
d. Turn RECIP pot fully clockwise. The rate at which channels alternate
should decrease to a 10 second rate.
6. Front Panel Functions
a. Press HOLD and each mode switch to verify all green LED's work.
Buzzer sounds for every membrane and mode key that is pressed.
b. Alternately press DC CONTINUOUS and AC PULSE. Verify that peak
volts indicator LED goes on for AC PULSE and that milliamps indicator
LED goes on for DC CONTINUOUS.
c. Press NARROW pulse mode, TIMER BYPASS, and GO.
d. Press HOLD and verify that timer and pulses stop.
e. Turn intensity to minimum, press SURGE and verify ratio indication
on power meter. Press GO and verify timer restarts.
f. Press HOLD and SURGE to get out of SURGE mode. SURGE LED
should go out. Press O, 1 and GO. Verify that timer counts down from
1 minute to O and buzzer sounds for last 2 seconds.
g. Press HOLD and hidden button #1. Time and voltage displays should
simultaneously sequence, 1 through 9, while function indicator LED's
light in sequence from top to bottom followed by pulse frequency LED.
Press HOLD to exit from test mode.
h. Verify membrane switch and program checksum.
(1) Press hidden button #2 located directly below hidden button #1.
(2) Press keys in following sequence: 1,2,3,4,5,6,7 ,8,9, GO, O,
HOLD, TIMER BYPASS, NARROW PULSE, WIDE PULSE, AC, DC
CONTINUOUS, SURGE and REVERSE POLARITY. If test
successful, a 4-digit checksum is shown in time display. Use
checksum to verify proper program is installed in unit. Exit by
pressing HOLD.
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