2700-2300 Service Manual Preliminary

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YSI 2300 STAT Plus YSI 2700 SELECT

YSI 2710 Service Manual

Table of Contents

1. Description ......................................................................................................... 1-1

2. Analyzer Mechanical Parts and Procedures ........................................................... 2-1 2.1 Recommended Replacement Parts ................................................................................................. 2-1 2.2 Exploded Views with Parts Lists.................................................................................................... 2-2 2.3 Service Procedures ....................................................................................................................... 2-12

2.3.1 Sipper Mechanism Removal/Installation (See Figure 2.1) ........................................... 2-12 2.3.2 Timing Belt Replacement (See Figure 2.6) .................................................................. 2-12 2.3.3 Optical Sensor Replacement (See Figure 2.6) .............................................................. 2-13 2.3.4 Stir Motor Assembly Removal/Installation (See Figure 2.6)........................................ 2-13 2.3.5 Sipper Board Removal/Installation (See Figure 2.6) .................................................... 2-13 2.3.6 Printer Removal-Installation (See Figure 2.2) .............................................................. 2-14 2.3.7 Keypad and Display Removal/Installation (See Figure 2.2)......................................... 2-14 2.3.8 Sipper Pump Removal/Installation (See Figure 2.5) .................................................... 2-14 2.3.9 Peristaltic Pump Motor Removal/Installation (See Figure 2.1 and Figure 2.8) ............ 2-14 2.3.10 Sipper Alignment Procedures ..................................................................................... 2-15 2.3.11 Door Alignment .......................................................................................................... 2-16 2.3.12 High Voltage Shield Removal/Installation (See Figure 2.8) ...................................... 2-16

3. Analyzer Electronic System .................................................................................. 3-1 3.1 Circuit Descriptions........................................................................................................................ 3-1

3.1.1 Power Supply.................................................................................................................. 3-1 3.1.2 Analog Circuits............................................................................................................... 3-1 3.1.3 Microprocessor ............................................................................................................... 3-2 3.1.4 Stepper Motor Drivers .................................................................................................... 3-2 3.1.5 Bottle Level Sensing....................................................................................................... 3-2 3.1.6 Printer ............................................................................................................................. 3-2 3.1.7 Serial Interface................................................................................................................ 3-3 3.1.8 Interconnect and Sipper Boards...................................................................................... 3-3 3.1.9 Display and Keypad........................................................................................................ 3-3

3.2 PC Boards and Schematics ............................................................................................................. 3-5

4. Service and Repair Tips........................................................................................ 4-1

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5. Turntable Mechanical Parts and Procedures.......................................................... 5-1 5.1 Recommended Replacement Parts ................................................................................................. 5-1 5.2 Exploded Views with Parts Lists.................................................................................................... 5-1 5.3 Service Procedures ......................................................................................................................... 5-8

5.3.1 Sample Wheel Removal/Installation .............................................................................. 5-8 5.3.2 Turntable Drive Hub Removal/Installation .................................................................... 5-8 5.3.3 Bottom Panel Assembly Removal/Installation ............................................................... 5-8 5.3.4 Timing Belt Replacement ............................................................................................... 5-8 5.3.5 Optical Encoder Assembly Removal .............................................................................. 5-9 5.3.6 Optical Encoder Assembly Installation .......................................................................... 5-9 5.3.7 Drive Housing Assembly Removal/Installation ............................................................. 5-9

6. Turntable Electronic System................................................................................. 6-1 6.1 Circuit Descriptions........................................................................................................................ 6-1 6.2 Turntable Main PC Board............................................................................................................... 6-1 6.3 Daughter Board Operation.............................................................................................................. 6-1 6.4 PC Boards and Schematics ............................................................................................................. 6-3

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1. Description

The 2300 Stat PLUS and 2700 SELECT Service Manual is written for service personnel. It contains the major parts and assemblies for the 2300 STAT PLUS and 2700 SELECT analyzers. The manual includes exploded view illustrations, part numbers, disassembly/assembly instructions and other relevant service and repair information.

The manual was developed assuming that the repair person has the appropriate user’s manual nearby. The part numbers for the user’s manuals are as follows:

2300 STAT Plus User’s Manual (printed version) 062861

2700 SELECT User’s Manual (printed version) 062521

2300 STAT Plus / 2700 SELECT User’s Manual (CD version) 577000

1-1

2. Analyzer Mechanical Parts and Procedures

2.1 Recommended Replacement Parts Board Assy, Interconnect 527053 Board Assy, Main Diode, MR751 026071 Diode, LM385Z 060090 Diode, IN4003 066116 Fuse, PCB Mount, 1A 062427 Fuse, PCB Mount, 2A 062428 Fuse Holder, PCB Mount 062617 Regulator, LM323K 061762 Regulator, 7905 062181 Regulator, 7805 030319 Transistor, MJE701 061775 Board Assy, Sipper 527050 Bottle Assy, Cal 110011 Bottle Assy, Supply 110010 Bottle Assy, Waste 110009 Cable Assy, Needle Ground 110052 Display Assy 110051 Keypad Assy 023220 Magnetic Stir Bar 062255 Motor Assy, Peristaltic Pump 110014 Sipper Needle Assy 062502 Printer Assy 527013 Preventive Maintenance Kit 2788 Probe Assy, Enzyme 110923 Pump Assy, Sipper 062506 Pump Head, Peristaltic 061895 Sipper Assy 110926 Cable, Sipper, w/clamp 110925 Motor Assy, Stir 110005 Belt, Timing, Sipper 061959 Motor Assy, Sipper Drive 110055 Optical Sensor 027071 Motor Assy, Vertical Drive 110054 Temp Probe Assy 062265

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2.2 Exploded Views with Parts Lists

Figure 2.1 Front Components

2-2

Ref YSI Part No. Qty Description

1 062287 1 Bezel, Support 2 023029 1 Housing 3 062357 1 Paper Cover Assy 4 062506 1 Pump Assy, Sipper 5 062279 1 Panel Assy, Side 6 062235 1 Bulkhead 7 062502 1 Sipper Needle Assy 8 110926 1 Sipper Mechanism 9 061895 2 Pump Head, Peristaltic 10 062236 1 Baseplate 11 062321 1 Cable Assy, Cal, White 12 062319 1 Cable Assy, Waste, Red 13 062320 1 Cable Assy, Supply, Black 14 110010 1 Bottle Assy, Supply (061971 bottle only) 15 110009 1 Bottle Assy, Waste (061982 bottle only) 16 110011 1 Bottle Assy, Cal 17 062247 1 Bracket Assy, Cup Carrier 18 110050 1 Carrier Assy, Cup 19 023008 1 Spring, Cup Carrier 20 062241 1 Motor Shield 21 062292 1 Latch, Door (not shown) 22 062418 1 Spacer, Door Latch (not shown)

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Figure 2.2 Operator Panel Assembly


1–2 110048 1 Keypad/Display Assy (includes Ref 1 and 2) 1 110051 1 Display Assy 2 023220 1 Keypad/Backplate 3 062414 1 Clamp, Tear Bar 4 527013 1 Printer Assy 5 023001 1 Bezel 6 070910 1 Tear Bar 7 061671 1 Print Head 8 062421 1 Cable, Print Head

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Figure 2.3 Stir Motor Assembly


1 110005 1 Stir Motor Assembly

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Figure 2.4 Sample Chamber Assembly


1 110923 2 Probe Assy, Enzyme (includes Ref 9) 2 061944 1 Electrode Housing, Black 3 110049 1 Chamber, Sample (includes Ref 2 and 6) 4 062255 1 Stir Bar, Magnetic (not shown) 5 062265 1 Probe Assy, Temperature 6 062174 1 Electrode Housing, White 7 110056 1 Chamber Assy, Waste 8 062305 1 O-Ring, Chamber 9 077803 2 Probe Sleeve 10 062543 1 O-ring, Temperature Probe (not shown)

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Figure 2.5 Sipper Pump Assembly


1 110057 1 Motor Assy, Sipper Pump 2 061946 1 Frame, Sipper Pump 3 061950 1 Drive Hub 4 038237 1 Dowel Pin 5 062259 1 O-Ring 6 062522 2 O-Ring 7 027070 1 Optical Sensor 8 062503 1 Body, Sipper Pump, with Tubes 9 062498 1 Spacer 10 062499 1 Cap, Screw Housing 11 062512 1 Housing, Sipper Pump 12 062500 1 Plunger, Sipper Pump 13 060476 1 Mount, Adhesive

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Figure 2.6 Sipper Mechanism

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1 062171 1 Guide Assy, Sipper Needle 2 061967 2 Bearing, Flanged 3 062362 1 Spring, Cal Well Ground 4 027071 1 Optical Sensor 5 110005 1 Motor Assy, Magnetic Stirrer 6 061897 2 Bearing 7 061076 1 Pulley, Timing Belt 8 023045 1 Bracket, Idler 9 023046 1 Roller, Idler 10 061928 1 Plate, Motor 11 061927 4 Standoff, Alum. 12 110054 1 Motor Assy, Vertical Drive 13 061954 1 U-Joint 14 110055 1 Motor Assy, Horizontal Drive 15 061990 1 Bracket, Sensor 16 110053 1 Photosensor Assy 17 061924 1 Flag, Rotary Sensor 18 061923 1 Pulley, Modified 19 061959 1 Belt, Timing 20 061961 1 Washer, Thrust 21 061930 2 Block, Spacer 22 061932 1 Plate, Main Frame 23 527050 1 Board Assy, Sipper 24 062176 1 Shroud Assy 25 061926 1 Flag, Sensor 26 023047 1 Post, Roller Retainer 27 023051 1 Screw, Shoulder, Idler 28 061956 1 Screw, Sipper Needle Mounting 29 061994 2 Thumbnut, Sample Chamber (not shown) 30 061969 2 Stud, Sample Chamber (not shown)

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Figure 2.7 PC Boards and Cables


1 062341 1 Cable Assy, Display 2 062366 1 Cable Assy, Printer 3 110230 1 Board Assy, Main, 2300S 3 110231 1 Board Assy, Main, 2300D 3 110232 1 Board Assy, Main, 2700S 3 110233 1 Board Assy, Main, 2700D 4 023235 1 Door, Rear 5 062293 3 Cable Assy, 10 In. 6 110925 1 Cable Assy, Sipper, 24 In. w/clamp 7 023000 1 Door, Front 8 527055 1 Board Assy, Turntable Daughter 9 062553 1 Cable, Auxiliary Connector 10 062552 1 Cable, Main/Daughter Board 11 062594 2 Spacer, Daughter Board 12 062593 2 Standoff, Daughter Board 13 023011 1 Plate, Side 14 023002 1 Hinge, Door, Front 15 060005 1 Logo, 2300 STAT Plus 15 062497 1 Logo, 2700 SELECT 16 060004 1 Window, Door, 2300 STAT Plus 16 062511 1 Window, Door, 2700 SELECT

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Figure 2.8 Rear Components


1 110014 2 Motor Assy, Peristaltic Pump 2 527053 1 Board Assy, Interconnect 3 062417 1 Shield, High Voltage 4 062291 1 Transformer, Signal A41-25-10 5 062315 1 Cable Assy, RS232 6 062224 1 Switch Assy, Reset 7 062388 2 Jack Socket 8 061694 1 Transformer A41-80-24 9 061679 1 Hinge, Continuous, Rear Door 10 062597 1 Filter, Power Line 11 062553 1 Cable Assy, Auxiliary 12 000802 4 Foot, Rubber 13 028110UL 1 Cord, AC, 110V (not shown) 14 028111 1 Cord, AC, 220V (not shown)

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2.3 Service Procedures 2.3.1 Sipper Mechanism Removal/Installation (See Figure 2.1)

1. Unplug instrument. 2. Remove tubing connected to waste tube and to bottom of cal well. 3. Remove three screws which secure motor shield. 4. Pull motor shield forward and remove. 5. Remove probe assemblies (including temperature electrode) from the side(s) and

back of sample chamber. NOTE: When working with single channel units, the blank plug does not need to be removed.

6. Disconnect plugs at locations J-6, J-7, J-8, J-9, J-12, and J-13 on interconnect board, releasing sipper mechanism cables.

7. Loosen (DO NOT REMOVE) two 5/16 mounting nuts located between upper and lower plates of mechanism.

8. Slide mechanism to the left approximately 3/8" and pull forward while feeding wires through hole in case.

9. Repair, or replace entire sipper mechanism. 10. Reverse steps 1–8 to reinstall sipper mechanism. NOTE: Figure 3.1 shows

component connections to interface board.

2.3.2 Timing Belt Replacement (See Figure 2.6) 1. Remove sipper mechanism as described in "Sipper Mechanism Removal". 2. Loosen idler pulley to relieve belt tension. 3. Remove 4 screws which secure block spacers to lower plate. 4. Manually turn U-joint to raise needle to its upper limit. NOTE: Maintain needle

at its upper limit throughout the rest of this procedure. If needle is left in chamber, it could be damaged if mechanism is moved horizontally.

5. Loosen top 2 hex screws on U-joint, releasing acme screw. 6. Carefully remove lower plate. 7. Remove 2 screws which secure sensor mounting block to upper plate. 8. Remove sensor mounting block. 9. Use a firm pull to remove spur gear (hex screws, used only on old instruments,

do not need to be loosened). 10. Replace worn belt with a new one 11. Reverse steps 2–9 to reassemble sipper mechanism. 12. Check and adjust alignment of sensor flag (Horizontal Alignment, steps 2 - 8). 13. Check and, if necessary, adjust sipper needle alignment before resuming

instrument operation.

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2.3.3 Optical Sensor Replacement (See Figure 2.6) 1. Remove sipper mechanism as described in "Sipper Mechanism Removal". 2. Remove 4 screws (2 on top, 2 on bottom) that secure optical sensor mounting

block to upper and lower plates of sipper mechanism. 3. Slide mounting block from between upper and lower plates. 4. Remove 1 screw securing sensor to mounting block. 5. Remove optical sensor. 6. Reverse preceding steps with new sensor to reassemble instrument. 7. Realign needle after reassembly. Confirm correct needle alignment before

resuming instrument operation.

2.3.4 Stir Motor Assembly Removal/Installation (See Figure 2.6) 1. Remove motor shield as described in "Sipper Mechanism Removal", steps 1–4. 2. Remove two screws which secure stir motor assembly to top plate of sipper

mechanism. 3. Disconnect stir motor assembly cable connector at interconnect board (J7). 4. Pull stir motor assembly downward and remove. 5. Replace stir motor assembly. 6. Reassemble by reversing steps 3–5. 7. Power instrument, and operate stir motor to check alignment. If operation is

noisy, loosen two screws holding motor assembly to top plate, shift motor assembly position, and retighten screws. Continue to step 8 when motor operates without excessive noise.

8. Reinstall motor shield to complete reassembly.

2.3.5 Sipper Board Removal/Installation (See Figure 2.6) 1. Make sure sipper needle is above sample chamber. 2. Unplug instrument and remove motor shield as described in "Sipper Mechanism

Removal" Steps 1–4. 3. Disconnect two cable connectors on sipper board. 4. Remove sipper board mounting screw; lift and remove sipper board assembly. 5. Remove sipper board from shroud and replace. 6. Re-install shroud/board assembly and cables (Reverse operations of steps 3 and

4). 7. Turn spur gear to put needle in manual (sample) position. This is necessary in

order to view sensor flag/sensor alignment in the next step. 8. Manually turn U-joint to raise needle to maximum height, making sure sensor

flag travels through optical sensor on sipper board. If necessary, adjust sensor flag so that the flag is centered in optical sensor (Vertical Alignment, steps 2–4).

9. Reinstall motor shield and power instrument.

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10. Confirm correct sipper needle alignment; adjust if necessary.

2.3.6 Printer Removal-Installation (See Figure 2.2) 1. Unplug instrument. 2. Remove printer paper. (Cut paper between supply roll and printer slot, then pull

remaining paper from top of printer.) 3. Unplug cable connectors J-15 and J-16 on interconnect board and J-9 on main

board. 4. Remove two screws directly above supply and waste bottles which secure bezel

and operator panel assembly to shelf, and pull bezel assembly from instrument. (See Figure 2.1).

5. Remove 4 screws which mount printer assembly to bezel. Note position of ground wire, if installed, for reassembly.

6. Service or replace printer assembly. 7. Reverse preceding steps to reassemble instrument.

2.3.7 Keypad and Display Removal/Installation (See Figure 2.2) 1. Remove printer as described in "Printer Removal", steps 1–5. 2. Remove 4 nuts which secure Keypad/Display Assembly to bezel. 3. Remove 4 screws securing display to backplate of keypad. 4. VERY carefully pry around display to remove it from the keypad adhesive. Do

NOT bend or twist the display! 5. Replace display and/or keypad. 6. Reverse above steps to reassemble.

2.3.8 Sipper Pump Removal/Installation (See Figure 2.5) NOTE: Seal replacement does not require pump removal.

1. Unplug instrument. 2. Unplug sensor and motor wire connectors J-3 and J-5 on interconnect board. 3. Remove tubing from sipper pump fittings. 4. Remove 2 screws (one each; directly above and below sipper pump head) which

secure pump to case. NOTE: Support sipper pump motor in rear of instrument while removing screws.

5. Pull pump head through mounting panel opening, and remove pump assembly from rear of instrument. NOTE: Be careful not to damage pump head fittings.

6. Service or replace sipper pump. 7. Reverse steps 1–5 to reassemble. NOTE: Tubing from sipper tube should be

attached to fitting nearest front of pump.

2.3.9 Peristaltic Pump Motor Removal/Installation (See Figure 2.1 and Figure 2.8) 1. Unplug instrument.

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2. Remove 2 screws on front of pump head and pull pump head off. NOTE: Tubing does not need to be removed.

3. Remove 2 nuts that hold motor to case in back of instrument. Remove motor. 4. Inspect black rubber washers that go between wall and motor. Washers that are

broken, cracked, or brittle must be replaced. 5. Install new motor, leaving nuts slightly loose. NOTE: When installing new

motor, confirm that black rubber washers are in place between motor and wall. PERMANENT MOTOR FAILURE MAY RESULT IF RUBBER WASHERS ARE NOT PRESENT.

6. Reinstall spacer (if previously installed) and pump head, leaving screws loose. 7. Power-up instrument. 8. Exercise motor in diagnostic mode to allow self centering of pump. 9. Tighten pump head screws and pump motor nuts while motor is running. If

binding occurs, loosen screws and nuts, and recenter.

2.3.10 Sipper Alignment Procedures The sipper mechanism is built with photosensors to detect vertical and horizontal movement. For proper operation, the mechanical components of the sipper mechanism must be correctly aligned with these photosensors and each other. Refer to Figure 2.6 to identify and locate components when performing the following procedures.

Vertical Alignment 1. Place needle in manual (sample) position and at maximum height. (See Sipper

Board Removal/Installation, steps 1,2,7 and 8). 2. Loosen the sensor flag mounting screw. 3. Adjust flag so it passes through center of slot in photosensor (located on sipper

board). 4. Tighten sensor flag mounting screw. 5. Reinstall motor shield and repower instrument. 6. Confirm correct sipper needle alignment; adjust if necessary.

Horizontal Alignment 1. Remove sipper mechanism as described in "Sipper Mechanism Removal". 2. Raise needle to its upper limit by manually turning U-joint. NOTE: Maintain

needle at its upper limit throughout the rest of this procedure. If needle is left in chamber, it could be damaged if mechanism is moved horizontally.

3. Locate and loosen two set screws that secure sprocket to main shaft. 4. Turn sipper carrier to "Home" position (Tip of needle is over sample chamber.).

Confirm correct position by placing a pin (A spare Allen wrench will work.) through alignment holes in the main frame plate and the base of the sipper carrier.

5. Rotate sprocket until set screws are oriented facing the left side and front of sipper mechanism.

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6. Place Allen wrench in left facing set screw and turn sprocket until wrench contacts front of left hand spacer block (Figure 2.6, Item 21).

7. Tighten both set screws, then remove pin from alignment holes in sipper carrier and main frame plate.

8. Reinstall aligned sipper mechanism 9. Check needle alignment; adjust if necessary.

2.3.11 Door Alignment Align the front door by adjusting hinge on right hand side of instrument. The catch (vertical positioning) can also be adjusted by loosening the two nuts on catch, located on inner left hand side of cabinet. Catch tension is also adjustable via two screws on top/bottom of catch.

2.3.12 High Voltage Shield Removal/Installation (See Figure 2.8) 1. Unplug instrument. 2. Unplug three cable connectors at positions J-1, J-12, and J-14 on interconnect

board. 3. Lay cables over main board assembly. 4. Remove 2 screws which secure shield to case. 5. Carefully lift and move shield towards rear of instrument, being careful not to

pinch any wires. 6. Perform service as needed in area exposed by shield removal. 7. Reverse steps 1–5 to reinstall shield. NOTE: Feed wires carefully through slots at

each end of shield. Wires must not be pinched between shield and instrument housing (case).

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3. Analyzer Electronic System

This section describes the YSI 2300 Stat PLUS and 2700 SELECT electronic circuits. The circuit descriptions are followed by board layouts and schematics.

3.1 Circuit Descriptions 3.1.1 Power Supply

Mains power is selectable to either 115 or 230 volts alternating current at the power switch assembly in the back of the instrument. When set to 115 volts, each transformer's primary windings are connected in parallel. When 230 volt operation is selected, the primary windings of each transformer are connected in series. The secondaries of both transformers are connected to the main circuit board through connector J15.

The secondary of the main transformer is connected to a full wave center tapped rectifier, D13 and D14, and capacitive filter, C64 and C65, to provide the unregulated DC power at about 17 volts. U33 reduces and regulates this supply to five volts for use by the digital circuitry, and U34 reduces and regulates this supply to five volts for use by the analog circuitry. The unregulated power is also distributed through fuses F1 through F6 to the motor driver circuits.

The secondary of the second transformer is connected to a full wave bridge rectifier, D15 through D18, and capacitive filter C58, to provide the unregulated DC power for the negative supply. U35 reduces and regulates this power to provide the negative five volts for the analog circuitry. An LED will be lit whenever the digital five volt supply is powered.

3.1.2 Analog Circuits The analog circuitry polarizes the probes and amplifies the nanoampere current signals to an appropriate voltage for conversion to a digital number.

U30 and its associated circuitry is a differential dual channel front end amplifier for the enzyme probes. Each front end amplifier is a mirror image of the other up to the signal multiplexer, U29. The black chamber amplifier uses sections B and C of U30, and the white chamber amplifier uses sections A and D. For discussion the amplifier for the black chamber will be described. Section C senses the potential of the reference electrode of the probe in the black chamber and generates an output voltage seven hundred millivolts greater then the reference electrode to use as the probe polarizing voltage. Section B of U30 drives the working electrode with the polarizing voltage and also converts the probe current to a voltage with a gain of five millivolts per nanoampere.

Chamber temperature is sensed by the RTD connected to J4. The RTD in combination with R65 forms a half bridge circuit whose output increases with increasing temperature.

Under software control of signals MUXA and MUXB, U29 directs the signals from either chamber amplifier, the RTD half bridge, or signal common to the

3-1

programmable gain differential amplifier. U28 sections C and D, U27, and resistors R72 through R78 form a programmable gain differential amplifier. The output from the differential amplifier is fed into the input of a dual slope integrating analog to digital converter, U32. A 3.5 volt reference for the analog to digital converter is derived from a bandgap reference, D32, and amplifier U28A.

Voltage converter U31 generates the negative supply voltage for U29 and U30 from the battery when power is off. Switching from the regulated analog power supply to the battery backup supply is provided for by diodes D26 through D29.

3.1.3 Microprocessor The controller architecture uses an 8-bit NSC800 microprocessor (U14). The system clock is derived from an 8 MHz oscillator controlled by X1. An octal latch (U9) separates the addresses from the data for use by the memory. The program code is stored in a 64K byte EPROM (U11), and program variables are stored in static RAM (U12). The memory is divided by a memory decoder section in the 22V10 PAL (U6) that generates the chip select signals for the ROM and RAM. A 68HC68T1 type real time clock, (U13) keeps time of day, controls power to the battery backup circuits and generates a power up reset signal. The power up reset signal and reset button signal are combined in U6 to get reset signal for the CPU. The I/O device selects are generated by U5.

3.1.4 Stepper Motor Drivers Each winding of the sipper arm stepper motors is connected to a 3717 type motor driver (U21-U24). Motor current is regulated by a current chopping technic to a value programmable by the I1 and I0 input pins connected to port A of U26, and current direction is controlled by the PH pin connected to the upper half of port B. The lower half of port B controls the sipper pump with a ULN2803 motor driver, U25. Pumps are controlled from port C with transistor drivers Q4 through Q6.

3.1.5 Bottle Level Sensing Timer zero in U20 is used to generate a 16 kilohertz square wave clock that is filtered by R23 and C42 to remove the higher frequency harmonics. This clock is routed to one of the four level sensing amplifiers on the Interconnect and sipper arm boards by U18. The return signal from the appropriate level sensing amplifier is also selected by U18 and is sent to rectifier detector circuit, U17C, D6, D7, R6 and R7. The detector signal is filtered by R4 and C30 to remove high frequencies before it goes to a comparator, U16. The comparator output will stay at logic high until the detector signal is greater then the voltage from the digital to analog converter, U19 and U17A. The output of the digital to analog converter is also used to adjust the speed of the chamber stirring with U17B, Q1 and Q2.

3.1.6 Printer Printer data is transferred through port A of U4, and printer control signals are connected to port C. The remainder of U4's pins are used to control the analog gain, multiplexing and analog to digital circuits.

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3.1.7 Serial Interface The serial interface is implemented with an NSC858 UART, U1. The RS-232 level signals are generated by U2 and U3.

3.1.8 Interconnect and Sipper Boards All four capacitive level sensing preamplifiers work by the same principle. An excitation signal is fed through an R-C network to the noninverting input of the amplifier. The level sensing probe is capacitively coupled to the center of the R-C network. When the probe capacitance to ground is high enough, the excitation signal is shunted away from the amplifier and its output drops.

3.1.9 Display and Keypad The display and keypad are controlled from U15. Port A is used for the 8-bit data to and from the alphanumeric liquid crystal display module. Part of port B is used for the display interface control lines, and the rest of port B is used for the column scan lines in the keypad matrix. The rows of the keypad matrix are connected to port C. Timer zero of U15 drives a charge pump circuit, U7, to generate the display contrast voltage.

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3.2 PC Boards and Schematics These schematics and drawings are representative only. Your instrument may be different.

Figure 3.1

2300/2700 Block Diagram

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Figure 3.2

Main PC Board Layout

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Figure 3.3 Main PC Board, Sheet 2

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Figure 3.4

Main PC Board, Sheet 3

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Figure 3.5

arMain PC Bo d, Sheet 4

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Figure 3.6

Main PC Bo d, Sheet 5 ar

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Figure 3.7


3-11

Figure 3.8


3-13

Figure 3.9


3-14

Figure 3.10

Interconnect PC Board

3-15

Figure 3.11

Inte t 1 rconnect PC Board, Shee

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Figure 3.12

Interconnect PC Board, Sheet 2

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Figure 3.13

Sipper PC Board

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Figure 3.14

Sipper PC Board, Schematic

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Figure 3.15 Keypad Pinout

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4. Service and Repair Tips

Error: "Sipper/Needle Interference" This error message is usually caused by an intermittent break (or open) in the sipper cable. The sipper cable (YSI #110925) is the blue ribbon cable which is connected to the main sipper mechanism. This cable is easy to replace, however, we recommend the replacement be done by a qualified service technician.

Other causes of this error include a faulty sipper board assembly or possibly a fluid leak. Also, verify the unit (2300 or 2700) is connected to a properly grounded AC outlet.

Error: "Sipper Pump/Motor Failure” or “Sipper Homing Error" If the fuse holder (rear case of instrument) is installed backwards, sipper pump/motor failure will occur. Verify the installation of the fuse holder using the pictorial in your instruction manual. If the fuse holder is installed correctly and the preventative maintenance was recently done on the sipper pump, try the following procedure:

Unplug the 2300/2700 and remove the screws on the back panel.

Lower the back panel and look close of the sipper pump. On the back of the pump there is a black "hub" which, when turning, moves the sipper pump plunger in and out.

On the hub, there is a thin disc which goes through a U-shaped optosensor. Rotate the hub manually and visually make sure the disc is not contacting the optosensor. This will cause the error!

If the disc is rubbing the optosensor, loosen the hex screw on the hub. Re-position the hub so that the disc is "centered" in the optosensor. Re-tighten hex screw.

If the problem still persists, try placing a thin film of grease on the back of the white sipper pump base and on the threads of the sipper pump plunger.

If the sipper pump appears "dead" and does not make any noise, check the circuit board mounted fuse labeled F6 on the main PCB.

Error: "Vertical Motor Failure/Jam" If the main fuse holder (back side of instrument) is installed backwards, it will cause the vertical motor errors. The index mark can be difficult to see. If at one point the fuse holder is removed, it is very easy to install it backwards. The "220 - 240V" stamped mark should be closest to the AC line cord for 110-120 volt operation. When installed backwards, the instrument will power the logic circuits and run some of the other motors, even though the voltage is low.

The sipper cable (blue ribbon cable attached to sipper board) is intermittent, this also can cause vertical motor errors. This cable is easily replaced, however, we recommend this be done by a qualified service technician.

Another cause for this error is the positioning of the sipper needle ground cable. This cable must be installed such that its crimp connector is parallel with the sipper needle (flange). If it is not, the crimp may come into contact with its own connector while attempting to reach its "home" position.

ly at the BACK

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Error: "Final Baseline" Among the most common causes of this error are enzyme membranes, high sample concentrations and buffer pump tubing problems. If a new membrane was recently installed, it may take several hours before complete baseline stabilization has occurred.

cently replaced, do this first unless there is an obvious

are e buffer pump will not be able

Error compartment or bottle

f

Erroris normally caused by

mode, make sure the tip of the sipper is 1/16th of an inch above the cone in

If the membrane has not been releak on the system.

Secondly, replace the buffer tubing if necessary. This tubing should be replaced every 2 to 6 months, depending on the calibration frequency and the number of samples thatpresented to the unit. If the tubing has "flattened" out, thto pump the correct amount of buffer through the system to flush the sample chamber.

: "Bottle Errors" All reagent and waste bottles must be in the instrument bottleerrors will likely occur. The level sensing depends on capacitive sensing to "ground". Ithe errors still occurs, cleaned the bottles and the bottle compartment area where the bottom of the bottles rest. Placing a paper towel underneath the bottles can also cause this error. Finally, verify the instrument is plugged into a GROUNDED AC outlet.

: "Sample Chamber Overflow" This error is limited to early versions of the Model 2300 STAT. It either an intermittent sipper cable (Blue ribbon cable connected to sipper board) or an improperly adjusted sipper needle. When performing the sipper needle alignment in the SERVICEthe sample chamber. This should be adjusted to 1/16" during the FINE alignment of the sipper needle. The sipper cable (blue ribbon cable attached to sipper board) can be replaced easily, however, we recommend this procedure be done by a qualified service technician.

4-2

5. Turntable Mechanical Parts and Procedures

5.1 Recommended Replacement Parts Belt, Timing 061959

Board Assembly, 2710 527056

Stepper Driver 062160

Cable, Interconnect 062557

Diode, Light Emitting 062554

Encoder 062548

Indexing Fixture 062560

Motor Assembly 062571

5.2 Exploded Views with Parts Lists

Gear/Pulley Assembly 061076

Spring, Garter 062569

Switch Assembly, Reset 062602

Wheel, Sample 062611

Wrench, Hex 062600

The exploded views and parts lists on the next several pages will help you identify individual components, if you need to order parts from YSI.

5-1

Figure 5.1 2710 Turntable Assembly

5-2


1 062592 1 Housing Assembly, Bottom 2 062563 1 Housing Assembly, Drive 3 062611 1 Wheel, Sample 4 062567 1 Housing, Top 5 062578 1 Drive Hub 6 062560 1 Indexing Fixture 7 062569 2 Spring, Garter 8 062557 1 Cable, Interconnect 9 062603 1 Cable Assembly, Encoder 10 061642 2 Screw, Set, Hex Socket 11 001280 4 Nut, Hex, Lock 12 001790 4 Screw, Mach., 6-32 13 002670 4 Washer, Lock, #6 14 062600 1 Wrench, Hex, T-Handle

Figure 5.2 2710 Turntable Accessories

5-3

Figure 5.3 2710 Bottom Housing Assembly

5-4


1 062568 1 Housing, Bottom 2 062602 1 Switch Assembly, Reset 3 061758 1 Guard, Switch 4 527056 1 PC Board Assembly 5 062554 1 Light Emitting Diode (LED) 6 061732 1 Connector, Plug, 3 Conductor 7 062440 2 Terminal, Crimp 8 000802 4 Foot, Rubber 9 001280 4 Nut, Hex, Lock 10 001710 4 Screw, Machine, 6-32 11 002670 4 Washer, Lock, #6

5-5

Figure 5.4 2710 Drive Housing Assembly

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1 062564 1 Housing, Top Drive 2 062572 1 Bearing, Flanged 3 061076 1 Gear/Pulley Assembly 4 061959 1 Belt, Timing 5 061923 1 Pulley, Modified 8 062573 1 Bearing, Flanged 9 062565 1 Plate, Drive 10 061673 4 Screw, Machine, 8-32 11 062575 1 Shaft, Main Drive 12 062548 1 Encoder, Optical 13 001710 2 Screw, Machine, 6-32 14 062571 1 Motor Assembly, Drive 15 002680 4 Washer, Lock, #8 16 002670 2 Washer, Lock, #6 17 062585 1 Collar, Shaft 18 001036 2 Screw, Set, 6-32 19 006755 2 Screw, Machine, 2-56 20 002690 2 Washer, Lock, #2

5-7

5.3 Service Procedures 5.3.1

ntly side

l the wheel

the Drive Hub.

5.3.2 ntable D Remova nstallatio Removal".

the Main Drive

3. Slide t Hub up off the M

5.2, Sample Wheel ub Align . Adjus

5.3.3 Bottom Panel Assembly Removal/Installation 1. Unplug the instrument. 2. Remove the Drive Hub as described in "Turntable Drive Hub Removal". 3. Remove the 4 screws and the 4 lock washers that secure the Bottom Panel

Assembly to the Top Housing. 4. Carefully remove the Top Housing, disconnecting the Encoder Cable from

location J-7 and the Motor Cable from location J-1 on the PC Board. 5. Reverse steps 2 through 4 to reinstall the Bottom Panel Assembly.

5.3.4 Timing Belt Replacement 1. Remove Bottom Panel Assembly as described in "Bottom Panel Assembly

Removal". 2. Remove the 4 nuts that secure the Drive Housing Assembly to the Top Housing. 3. Slide the Drive Housing Assembly off the mounting studs in the Top Housing. 4. Remove the 4 screws that secure the Drive Plate to the Top Drive Housing. 5. Carefully remove the Drive Plate. 6. Use a firm pull to remove the Spur Gear (hex screws do not need to be loosened). 7. Replace worn belt with a new one. 8. Reverse steps 2 through 7 to reassemble the mechanism.

Sample Wheel Removal/Installation 1. Grasp the wheel firmly with both hands and raise it straight up. Rock ge

to side, if necessary. 2. To reinstall, slide the Sample Wheel down over the Drive Hub unti

stops. 3. Gently rotate the wheel until it drops into the indexing slot of

Tur rive Hub l/I n 1. Remove Sample Wheel as described in "Sample Wheel2. Loosen the two set screws in the Drive Hub, releasing it from

Shaft. he Drive and ain Drive Shaft.

4. Reverse steps 2 and 3 to install the Turntable Drive Hub. 5. Check nt of the rntable "h tion alignme Tu ome position" (See Sec

/Drive H ment) t, if necessary.

5-8

5.3.5 Optical Encoder Assembly Removal scribed in "Bottom Panel Assembly

DO NOTSIN

of the Encoder. ur Gear until

5. the setscrew holding the Encoder Wheel Hub to the Main Drive Shaft. plate.

. late

Drive Shaft.

5.3.6 Optica tallation s. tter

3. Wheel Hub

e end of the hex wrench. x

wise

.

5.3.7 Dri ation Panel Assembly

2. Remove the 4 nuts that secure the Drive Housing Assembly to the Top Housing. 3. Carefully remove the Drive Housing Assembly from the studs in the Top

Housing Assembly. 4. Reverse steps 1 through 2 to reinstall the Drive Housing Assembly.

1. Remove Bottom Panel Assembly as deRemoval".

2. Using a flat blade screwdriver, rotate the center slot of the Encoder Cap counterclockwise until the dot on the cap is aligned with the single dot on the Encoder case.

ROTATE THE ENCODER CAP COUNTERCLOCKWISE PAST THE GLE DOT POSITION.

3. Insert a .035" hex wrench into the body4. While maintaining a slight pressure on the hex wrench, rotate the Sp

the hex wrench seats in the Encoder Wheel Hub set screw. Loosen

6. Carefully snap the Encoder body off the Encoder Base7. Carefully slide the Encoder body off the Main Drive Shaft8. Remove the 2 screws and the two lock washers that secure the Encoder Basep

to the Drive Plate. 9. Slide the Encoder Baseplate off the Main

l Encoder Assembly Ins1. Remount the Encoder Baseplate onto the Drive Plate and tighten the screw

Note, an alignment tool slipped over the Main Drive Shift can be used to beposition the baseplate.

2. Slide the Encoder body onto the Main Drive Shaft. Push the hex wrench into the Encoder body, seating it in the Encoder set screw.

4. Apply a downward force on th5. Tighten the set screw while continuing to apply a downward force on the he

wrench. 6. Remove the hex wrench by pulling it straight out of the Encoder body. 7. Snap the Encoder body onto the Baseplate, locking all 4 snaps. 8. Using a flat blade screwdriver, rotate the center slot of the Encoder cap clock

until the dot on the cap is aligned with the 2 dots on the Encoder case. 9. Replace the Bottom Panel Assembly

ve Housing Assembly Removal/Install1. Remove Bottom Panel Assembly as described in "Bottom

Removal".

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6. Turntable Electronic System

6.1 Circuit Descriptions The 2710 Turntable electronic system consists of two electrical printed circuit (PC) boards. One board is located inside the 2300/2700 Analyzer. This board is referred to as the "Daughter Board" of the 2300/2700 Main PC Board. The second board is located inside the 2710 Turntable and is referred to as the Main PC Board (of the 2710).

Refer to Figure 6.1, Schematic of 2710 Main PC Board and to Figure 6.2 2300/2700 Daughter Board Location for additional information.

6.2 Turntable Main PC Board The 2710 Turntable is powered by the shielded Interconnect Cable from the 2300/2700. Approximately 16.5 VDC at 1 ampere maximum is provided through fuse F2 on the 2300/2700 Main PC Board, through the Daughter Board and Interconnect Cable, and then into the 2710 Main PC Board. This voltage is then used to drive the turntable motor, and is regulated by VR1 to provide +5 VDC for logic power.

All functions such as motor operation, positioning and communication are handled by the microcontroller. Data between the 2300/2700 and the 2710 are transmitted in serial format. An optical encoder is used to sense the position of the turntable sample wheel. These data are then interpreted by the microcontroller and sent to the 2300/2700.

6.3 Daughter Board Operation The Daughter Board is a microcontroller based PC board that is used to handle the communications and translation between the 2300/2700 and the 2710 Turntable. The microcontroller, Motorola 68HC705, performs the operations of serial to parallel conversion and handles the handshaking and timing functions. This is done by making use of the ROM inside the 68HC705 and the flexibility of the programmable serial and parallel ports.

Power and data are provided to the Daughter Board from the 2300/2700 via the ribbon cable connected at J-10 on the 2300/2700 Main PC Board and J-20 on the Daughter Board. Data are sent out to the Turntable Main PC Board via J-21 on the Daughter Board, which is connected to the 2300/2700 Auxiliary Port connector. A 15 conductor shielded cable carries the signals from the 2300/2700 to the 2710 Main PC Board.

6-1

Figure 6.1

ghter Board Location 2300/2700 Dau

6-2

6.4 PC Boards and Schematics

Figure 6.2

2710 Main PC Board Layout

Figure 6.3

2300/2700 Daughter Board Layout

6-3

Figure 6.4

2710 Main PC Board Schematic

6-5

Figure 6.5

2300/2700 Daughter Board Schematic

6-6

2700-2300 Service Manual Preliminary

Documents

Transcript of 2700-2300 Service Manual Preliminary