FISCHER MD-1a Product manual

Table of Contents
Description ...............................................................Page 2
Installation................................................................Page 2
Panel Controls ..........................................................Page 3
Device Specifications ...............................................Page 4
Device Maintenance .................................................Page 4
Device Inspection.....................................................Page 5
Assembly Parts List..................................................Page 8
Schematic Diagram ..................................................Page 9
MODEL MD-1a Galvanic Unit
Technical Reference Manual
CONTENTS
FOR PROFESSIONAL USE ONLY
FISCHER
Rev. 7/96
Rev. 12/04
Page 1

MD-1a Galvanic Unit
The Model MD-1a Galvanic Unit offers a versatile approach to the use of Galvanic (DC)
current in certain medical applications employing anaphoresis, cataphoresis, or
iontophoresis. It is designed for use by physicians in a clinic setting, and generates an
adjustable, filtered DC current from normal AC line voltage. Standard accesssories supplied
with the unit include:
(1) Dual Patient Cordset (red and black cords) p/n 15-0003
(2) 3" x 6" Wet pad electrodes p/n 12-0019
(1) Iontophoresis Trays (OPTIONAL) p/n 13-0020
TYPICAL INSTALLATION
Locate the Galvanic Unit near a treatment area where all controls are easily accessible. Plug
the line cord into a 110-115 volt A.C. grounded wall receptacle (220 volt operation is
available on special order only).
DO NOT USE "CHEATER" OR ADAPTER PLUGS. PROPER GROUNDING IS
ESSENTIAL FOR SAFE AND PROPER OPERATION OF THIS DEVICE. The MD-
1a is equipped with a “hospital grade” plug to ensure reliable grounding, although the plug
will fit typical grounded receptacles. Because of its light weight and small size, the MD-1 is
very portable. When relocating the unit for use, however, always be sure it is properly
grounded.
Insert the dual-prong plug at one end of the patient cordset into the front panel jacks; the red
jack is always positive with respect to the black (negative). The plugs at the opposite ends
of each cord should be firmly plugged into the accessory electrodes to be used for
treatment.
! PRECAUTIONS
CAUTION: PRODUCES HIGH VOLTAGE. Always exercise care and follow safety
procedures when operating or servicing this device.
Disconnect the power cord when servicing the unit to reduce the risk of shock hazard.
Avoid contact with in-circuit capacitors which may retain a high voltage charge.
Wait at least 3 minutes after disconnecting from power source to allow circuit components
to fully discharge before performing any service.
Do not move or carry the unit by any attached cords.
Do not subject the machine to excessive shock or vibration; do not use or store in places
where termperature is over 105 degrees, or in high humidity.
Page 2

Description of Model MD-1a panel controls
DC MILLIAMPERE METER
This analog meter indicates actual current flow, in DC Milliamperes, through the connected patient
circuit. A reading can only be obtained when a resistive load is applied between output jacks and the
INTENSITY knob is adjusted.
METER SCALE SWITCH (0-10 and 0-50)
This switch selects the meter scale to be used for indicating current flow. Read from the TOP range
(0-10) when the switch is in the "0-10" position, and from the BOTTOM range (0-50) when in the "0-
50" position. This switch does not change the level of output, only the meter scale. Use the "0-10"
scale for a more accurate reading when using currents less than 10 milliamperes.
ACTIVE LAMP
This red LED will glow ONLY when the Galvanic Unit detects both a completed patient circuit and
active current flow. This lamp does not indicate a power-on condition, but only current activation.
POWER SWITCH
Press the LOWER edge (marked "1") of this rocker-type switch to turn ON the Galvanic Unit. The red
colored top edge of the switch will be exposed when the power is turned ON.
INTENSITY KNOB
Adjust this knob to set the desired current level to be applied to the patient. The actual current is
indicated on the "DC MILLIAMPERES" meter when the patient circuit is completed. Since current flow
is dependent upon the patient circuit resistance (which varies with electrode contact area and skin
moisture), only the meter reading can provide an accurate indication of current level - the INTENSITY
knob position may vary.
POLARITY REVERSAL SWITCH (Applies to units made after 1/1/2005)
Press the left side for normal (NOR) polarity (red jack is positive), or the right side for reverse (REV)
polarity (black jack is positive). Use this switch to reverse polarity instead of swapping the patient cord
plugs. Always return the INTENSITY to “0” before changing polarity.
OUTPUT JACKS
Two "banana" jacks allow connection of patient cords to the machine. The RED jack (marked "+") is
always positive with respect to the BLACK (negative) jack. The supplied Dual Patient Cordset uses a
single, dual-prong plug at one end to allow quick connection or reversal of electrode polarity as
needed. Always insure that the plug is securely attached to the output jacks during treatment.
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Page 3

Device Name: MD-1a
Manufacturer: R.A. Fischer Co., Inc.
Power Source: AC line
110-115 VAC 60 Hz
Fuse Rating: 3/8 Amp, Type 3AG
Number of Output Modes: 1
Mode Type: Direct Current (DC)
Constant Current: No
Constant Voltage: No
Minimum Output Voltage: 0.0 VDC
Maximum Output Voltage: 150 VDC (no load)
Minimum Output Current: 0.0 DCma
Minimum “Active” Current: 1.0 DCma (load dependent)
Maximum Output Current: Load dependent:
50 DCma (meter FS) w/nominal 1K load
78 DCma direct short
Output Short Circuit Duration: 1 minute
Line Current Isolation: Split bobbin transformer (UL #E63829)
Automatic Trip overload: N/A
Patient Override Control: N/A
Indicator Display: Unit Functioning (Active lamp)
Current Level (analog DC milliameter)
Meter ranges: 0-10 DCma w/0.2ma resolution
0-50 DCma w/1.0ma resolution
Meter Accuracy -20% to +20% FS
Timer/Auto shutoff: N/A
Typical Leakage current: Chassis: 10 uA
Electrodes: 5 uA
Maximum Leakage current: Chassis: 50 uA
Electrodes: 50 uA
Standards: UL-544 Patient Connected or equivalent
Electrical Safety Certification: Los Angeles Electrical Testing Laboratory
Application #249247
Note: Output specifications measured at 115VAC line voltage
DEVICE SPECIFICATIONS
The Model MD-1a does not require specific periodic maintenance beyond regular
inspection of the device and accessory cords. Refer to the following page for
recommended inspection procedures.
DEVICE MAINTENANCE
Page 4

The factory recommends inspecting this device according to the following schedule.
Inspections may be performed at other intervals as required by maintenance personnel
at the installation site, but in no event should the interval between inspections exceed 24
months.
Visual Device Inspection
Period: Annually (12 months)
Line Cord and plug:
◊ Inspect for insulation wear, broken wires, exposed wires, loose Heyco grip
◊ Inspect for bent or broken plug spades, bent or broken ground connection
◊ Replace line cord upon evidence of wear or breakage
Panel Controls:
◊ Inspect for damaged or worn panel controls.
◊ Rotate Intensity control knob to check for positive stops at Minimum and Maximum.
◊ Tighten Intensity control knob if knob is loose.
◊ Check integrity of Output Jacks and replace if corrosion or cracks are evident.
◊ Verify operation of “Active” LED by applying a 1K to 10K ohm load across Output
Jacks and rotating Intensity knob. LED should be off at Minimum intensity setting and
turn on at a setting of 1-2 on the knob.
◊ Verify operation of Polarity Reversal switch (applies to units made after 1/1/2005).
Switch in “REV” position will reverse polarity at red & black panel jacks..
◊ Verify operation of Meter by applying a 1K to 10K ohm load across Output Jacks and
rotating Intensity knob. Confirm at both meter scales (0-10 and 0-50) with a nominal
output setting of 10 DCma as indicated on the meter.
Cabinet:
◊ Inspect case for evidence of cracks or breakage.
◊ Ensure that bottom panel screws (4) are tight and front and panels are properly
seated in the housing (only necessary if unit has been opened for access to circuitry).
Visual Electrode Inspection
Period: 6 months
Electrodes and Cords:
◊ Inspect patient cords (red and black) for evidence of wear, broken wires, exposed
wires or corroded banana jacks
◊ Replace patient cords regularly (12-24 months) or if wear is evident.
◊ Inspect dual plug at one end of cords; tighten allen screw if necessary to clamp
internal wire.
◊ Inspect electrodes (wet pads or Iontophoresis trays) for evidence of breakage or
corrosion. Replace if necessary.
DEVICE INSPECTION
Page 5

Electrical Device Inspection
Period: Annually (12 months)
Line Voltage,Ground Integrity:
◊ Measure line voltage supplied to the device . Accept: 105-120 VAC
◊ Confirm reliable ground connection by ensuring line receptacle is 3-prong grounded
type and ground integrity is intact. Accept: Ground OK
◊ Measure device ground wire resistance between line plug ground contact and the
screw near the Heyco cord grip on the rear panel. Accept: 0 to 1.0 ohm
Nominal reading is .1-.2 ohms. IMPORTANT: Do not make this measurement
between line plug ground contact and front or rear panel surfaces; these panels are
anodized and will not conduct.
Chassis and Patient Leakage:
◊ Measure ground leakage between line and chassis using an approved Electrical
Safety Analyser. Use screw head near the Heyco cord grip on the rear panel for
chassis connection. Accept: Less than 50uA
IMPORTANT: Do not make this measurement between line and front or rear panel
surfaces; these panels are anodized and will not conduct.
Nominal readings appear below for reference.
Normal Polarity-Normal Ground: 5 uA
Reverse Polarity-Normal Ground: 5 uA
Normal Polarity-Open Ground: 10 uA
Reverse Polarity-Open Ground: 10 uA
◊ Measure patient lead leakage between line and red and black Output Jacks using an
approved Electrical Safety Analyser. Accept: Less than 50uA
Nominal readings appear below for reference.
Normal Polarity-Normal Ground: 5 uA
Reverse Polarity-Normal Ground: 5 uA
Normal Polarity-Open Ground: 5 uA
Reverse Polarity-Open Ground: 5 uA
Dielectric Strength Test (OPTIONAL):
◊ Apply 1250 VAC, 60 Hz between line and chassis ground for 60 seconds using an
approved Dielectric Withstand Tester, with Cutoff current set to 1.0-2.0 ma.
◊ Apply 1250 VAC, 60 Hz between line and patient leads (red and black jacks) for 60
seconds using an approved Dielectric Withstand Tester with Cutoff current set to 1.0-
2.0 ma. Accept: No Breakdown
IMPORTANT: Observe safety precautions when conducting dielectric strength test.
Do not return to service any device which has failed the withstand test as it may have
become internally damaged. This test is optional and does not need to be conducted
annually.
DEVICE INSPECTION
Page 6

Electrical Device Inspection (Continued)
Period: Annually (12 months)
Device Output:
PRELIMINARY SETUP:
• Plug line cord into a grounded receptacle and press the bottom edge of the POWER
switch to turn on the MD-1a (red portion of power switch will be visible). Note that the
red “ACTIVE” LED will NOT be lit unless a patient circuit is completed between the
Output Jacks and current is flowing.
• Attach the dual patient cordset to the Output Jacks and make all measurements
between the red and black banana plugs at the end of the cordset using a series load
resistance of 1K ohm rated at 3 watts or more. (A 2 watt resistor may be used for
short duration measurements).
OUTPUT MEASUREMENTS:
◊ Measure Minimum output using a DC milliameter in series with a 1K load resistance
and Intensity control knob set to its minimum position. This measurement simply
confirms that there is no unintended output current with the Intensity knob at its
minimum (zero) position. Accept: 0 DCma
◊ Measure Maximum output using a DC milliameter in series with a 1K load resistance
and Intensity control knob set to its maximum position. Note that the MD-1a can
produce approximately 50 DCma at this this setting, which will require a resistor rated
at 2.5 Watts or higher. Accept: 40-58 DCma
◊ Verify meter reading on 0-10 scale. With a 1K load resistance, set the METER
SCALE switch to the 0-10 position and adjust Intensity until the the meter settles on a
reading of 10ma (full scale). Measure the actual current using a DC milliameter in
series with the load resistance. Accept: 8.0-12 DCma
◊ Verify meter reading on 0-50 scale. With a 1K load resistance, set the METER
SCALE switch to the 0-50 position and adjust Intensity until the the meter settles on a
reading of 20ma. Measure the actual current using a DC milliameter in series with the
load resistance. Accept: 16-24 DCma
NOTE: The MD-1a incorporates circuitry to slowly ramp the output current to its set value
when a load resistance is detected. Therefore, you must allow several seconds for the
output current to stabilize before making these measurements.
AC RIPPLE (OPTIONAL):
◊ Measure the AC ripple present in the output current by connecting an isolated ground
oscilloscope in parallel with the 1K load resistance. Adjust Intensity for a metered
output of 20 DCma (using 0-50 scale) and observe the AC component (ripple)
superimposed on the DC waveform. Accept: 0-.5 Vpp (2.5%)
Note: Output specifications measured at 115VAC line voltage
DEVICE INSPECTION
Page 7

Part No. Item Description Quantity
12-0019 3 x 6 Wet Pad 2.00
15-0003 Dual Patient Cordset 1.00
21-0019 TIP31B Transistor 1.00
21-0023 2N4124 Transistor 1.00
21-0028 1N4004 Diode 3.00
21-0033 V130LA2 Varistor 1.00
21-0038B 3N255 Diode Network 1.00
21-0044 TIP47 Transistor 1.00
21-0045 1N4749 Zener Diode 1.00
23-0015 MV5053 Red LED 1.00
23-0029 Modutec T1S 1ma Meter 1.00
27-0012 LM324 Quad OP-Amp IC 1.00
31-0028 6.8K ohm 1/4W Resistor 1.00
31-0030 10K ohm 1/4W Resistor 4.00
31-0037 3.9K ohm 1/4W Resistor 1.00
31-0044 150 ohm 1W Resistor 2.00
31-0045 220K ohm 1/4W Resistor 1.00
31-0046 8.2K ohm 1/4W Resistor 1.00
31-0050 750 ohm 2W Resistor 1.00
31-0062 100K ohm 1/4W Resistor 1.00
31-0075 330K ohm 1/4W Resistor 1.00
32-0004 1K 3 1/4W Ceramic Resistor 1.00
38-0004 10K 2W 53C3 Pot. 1.00
41-0013 100uf 100V Electrolytic 1.00
41-0015 100uf 250V Electrolytic 2.00
41-0033 33uf 25V Tantalum 1.00
45-0015 .005uf 50V Ceramic Disc 1.00
45-0006 .001uf AC By-pass 1.00
45-0006A .001uf AC By-pass CSA 2.00
54-0021 ST-4-120 Transformer 1.00
61-0015 62021221 Rocker Switch 1.00
61-0015a 62022221 DPDT Switch 1.00
61-0018 DPST Mini Curvette Switch 1.00
65-0001 Black Banana Jack 1.00
65-0031 3AG Fuse Holder 1.00
65-0039 Red Banana Jack 1.00
65-0056 47745 Crimp Socket 10.00
65-0076 36 Pin "BergStik" 0.30
65-0082 10 Pin Contact Housing 1.00
66-0014 #10 Red Crimp Lug 3.00
67-0020 Hospital Grade Line Cord 1.00
68-0024B MD-1a PCB Rev B 1.00
69-0004 3/8 Amp Slo-Blow Fuse 1.00
77-0004 Varflex #6 HO tubing 1.50
81-0048 TS-1/MD-1 Cabinet 1.00
83-0022B MD-1A Front Panel 1.00
83-0059 MD-1A Rear Panel 1.00
88-0046 Universal Knob 1.00
91-0026 Fuse Repl. Label 1.00
91-0003 Serial Number Plate 1.00
PARTS LIST
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