Ryobi RY48ZTR75 Service Manual
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Ryobi RY48ZTR75 Service Manual

Riding mower electrical system troubleshooting and testing guide
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SERVICE CENTER ELECTRICAL SYSTEM TROUBLESHOOTING AND TESTING GUIDE
RYOBI RY48ZTR75/100 AND RY48140 RIDING MOWER
Confidential & Proprietary – Property of Techtronic Power Equipment – DO NOT COPY or DISCLOSE

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  • Page 1 SERVICE CENTER ELECTRICAL SYSTEM TROUBLESHOOTING AND TESTING GUIDE RYOBI RY48ZTR75/100 AND RY48140 RIDING MOWER Confidential & Proprietary – Property of Techtronic Power Equipment – DO NOT COPY or DISCLOSE...

  • Page 2: Table Of Contents

    TABLE OF CONTENTS • Testing Headlight Switch • WARNING • Testing Drive Motors • Testing the Drive Speed Switch • ZTR Mower Overview • Testing Drive Motor Hall Sensors • Testing Blade Cutting Speed Switch • Brushless Motors • Testing 48V-12V Converter and fuse •...

  • Page 3: Warning

    WARNING THIS MATERIAL INTENDED ONLY FOR TECHNICIANS TRAINED IN ELECTRICAL REPAIR. Technicians should wear personal protective equipment, such as rubber gloves and safety glasses. Exercise caution at all times. Dangerous voltages /currents are present. This manual assumes knowledge of basic electrical equipment such as DMM (Digital Multi Meter) and clamping Amp Meter to measure voltage, current, resistance, continuity, and diodes.
  • Page 4 OVERVIEW The RYOBI ZTR riding mower is completely electrical, consisting of 4 brushless motors and a controller for each motor: • A brushless motor and controller for each of the 2 blades • A brushless motor/controller to drive each rear wheel. These Drive Motor Controllers also contains the “brains”...

  • Page 5: Brushless Motors

    BRUSHLESS MOTORS Brushless motors operate quite differently than brushed motors, which you may be used to (i.e. a starter motor). A brushed motor can be quickly tested by applying voltage to the two terminals. Brushless motors can be recognized by 3 wires. These 3 wires require a controller to operate them and to turn on these 3 phases in a precise fashion similar to spark plugs firing a 3-cylinder gas motor.
  • Page 6 USING THIS DOCUMENT blue text can be clicked on to jump directly to the page of that topic. (This document is also printer-friendly, so you can have it in front of you while servicing the mower.) If you print this document, we recommend printing it in landscape mode and in color Block Diagram shows the general flow to visualize how the mower is connected and a chart shows general symptoms/solutions for repairs.
  • Page 7 TOOLS NEEDED Sockets and Torx Screwdrivers Wrenches Cross tip 8 mm Flat blade 10 mm 13 mm 14 mm 15 mm 17 mm 19 mm Confidential & Proprietary – Property of Techtronic Power Equipment – DO NOT COPY or DISCLOSE...
  • Page 8 BLOCK DIAGRAM AND CONTROL FLOW Left 5V out RIGHT Head Batteries Neutral Neutral Lights switch switch Main Fuse Accelerator Accelerator Charge Port/lockout/ Drive Speed battery temp Switch 48V to 12V Seat Relay (DC to DC) switch Fuse Brake converter Switch Switch Enables Beeper...

  • Page 9: Troubleshooting: General

    TROUBLESHOOTING: GENERAL • Follow the Block Diagram on the previous page. • Check for loose/bad connections. • Test the easiest components first. (power, key switch, DC-DC converter) • Mower should be fully charged (if possible) • Before disassembly: – Attempt to charge mower (note any error LED indications) –...

  • Page 10: Troubleshooting: Detailed

    TROUBLESHOOTING: DETAILED Use the block diagram as a guide Also refer to the beep diagnostic code chart 1. Verify the battery charger is functional by plugging it into the charge port on the back of the mower and let the mower fully charge.
  • Page 11 TROUBLESHOOTING: DETAILED CONTINUED 8. If the mower will not drive a. Make sure the seat switch is functional and activated. b. Test the angular transducers. Replace if necessary. c. Test the neutral switches. Replace if necessary. d. Test the brake switch.
  • Page 12 DIGITAL MULTIMETER (DMM) Typical DMM (Fluke 87). Note the dial is set to the “DIODE” function. this function will be used in many of the following procedures. Also note where the and black jacks of the test leads are connected to the DMM. If you are unfamiliar with a DMM, please read the section Electronics Tips for the Mechanical Small Engine Technician Confidential &...

  • Page 13: Component Locations

    COMPONENT LOCATIONS Charge port Seat Switch Access panel Beeper (under seat) DC-DC Controllers converter Neutral “zero” Brake Switch Switches Headlights Accelerator transducers Confidential & Proprietary – Property of Techtronic Power Equipment – DO NOT COPY or DISCLOSE...

  • Page 14: Controller And Label Locations

    CONTROLLERS AND LABEL LOCATIONS (Shown with passenger leg panel removed) As a note the RY48140 will have 3 deck motor controllers with 2 being Secondary and 1 as a Primary “Deck Motor Controller” “Drive Motor Controller 2” “Deck Motor Controller” “Drive Motor Controller”...

  • Page 15: Main Battery Connection

    MAIN BATTERY CONNECTION The main battery disconnect is located directly under the seat access cover. It may take considerable pressure to separate the halves. If you can not separate by hand, you may need a blunt instrument to push in the hole in the direction indicated. NOTE THAT ONE HALF OF THE CONNECTOR IS SCREWED TO THE FRAME AND WILL NOT MOVE.
  • Page 16 MAIN FUSE 1.Disconnect main battery connection IMPORTANT: If the main fuse is blown, find the source of problem before replacing fuse 2. Open the plastic box to access main fuse. 3. Set DMM to Resistance Ω symbol on DMM • Measure were indicated to the left. •...
  • Page 17 CHARGING PORT Two Different Charging Ports The Charging port on the Right is the Gen 2 The Charging port on the Left is the Gen 1 charger. charger. Note the Different indexing plugs. Make sure when ordering charging port or charger they are the same type.
  • Page 18 BATTERY VOLTAGE TEST 1. Set DMM to “DC Volt” mode. Note: If a valid voltage cannot be 2. Turn mower on. read, the electronics built into the charge port may be bad. In this 3. Pull PTO switch up (Power Take Off/Blade Engage knob) to load the battery for event, find the blue connector more accurate measurement.
  • Page 19 SEPARATING CONNECTORS Many of the connectors are sealed together with heat shrink tubing. To separate the connectors, soften the heat shrink with a heat gun, then peel the heat shrink tubing off with pliers as shown. Heat Connector Connector When reassembling connectors, be sure to apply new heat shrink tubing and shrink with a heat gun to protect against elements and hold the connections together.

  • Page 20: Control Panel

    CONTROL PANEL Main Power Key Switch (Power Take Off) Headlight switch Low Speed Cut Button Low Speed Button Fuel Gauge/ Hour Meter USB Charger Confidential & Proprietary – Property of Techtronic Power Equipment – DO NOT COPY or DISCLOSE...

  • Page 21: Testing Pto Switch

    TESTING PTO SWITCH 1. Mower Power OFF Note: Make sure spade plugs 2. DMM set to measure Resistance are secure. They should be 3. Insert DMM probes where indicated. When red button is locked in place and should PULLED OUT, the switch is CLOSED (very LOW resistance or not come loose if the wires continuity) are pulled on.
  • Page 22 TESTING THE RMO SWITCH 1. DISCONNECT MAIN POWER FROM MOWER. 2. Set DMM to “Diode” mode. 2.5V Touch leads where indicated. LED should light (polarity of probes does not matter). 4. Set DMM to Resistance mode. Switch is normally open (N.O.).
  • Page 23 TESTING THE CRUISE SWITCH 1. Disconnect Main Power from Mower. 2. DMM set to “Diode” mode. 6.4V 3. Touch the leads where indicated. LED should light 4. Set DMM to Resistance mode. This is a latching switch. 5-6V Pressing the buttons alternates between open and closed. Confidential &...

  • Page 24: Testing Headlight Switch

    TESTING HEADLIGHT SWITCH 1. Disconnect Main Power from Mower. 2. DMM set to “Diode” mode. 3. Touch the leads where indicated. LED should light 4. Set DMM to Resistance mode. This is a latching switch. Pressing the buttons alternates between open and closed. Confidential &...
  • Page 25 TESTING DRIVE SPEED SWITCH AND CUTTING SPEED SWITCH • This test procedure is the same as the headlight switch procedure. • The only difference is these switches are momentary. • When the button is held in, the switch is closed. •...

  • Page 26: Testing Fuel Gauge/ Hour Meter

    TESTING FUEL GAUGE/ HOUR METER Percent Charge remaining Approximate charge remaining Total hours of use (mower must be on Continuously for a minimum Turn Mower switch ON. of 6 minutes for time to change) Set Volt meter to “DC VOLTS”. Measure battery voltage between and Black wire (below, left) Measure battery voltage between Black and...

  • Page 27: Testing Key Switch

    TESTING KEY SWITCH 1. Set DMM to DC Volts 2. With Power switch OFF, measure battery voltage where indicated 3. With Power ON, measure approx. 0V where indicated 48V DC Note this switch operates at To measure Switch with wires disconnected: Set DMM to measure continuity OFF position: No continuity between green and red wire.

  • Page 28: Testing Usb Port

    TESTING USB PORT The USB port is marked “+” (yellow wire) Note: The “+” spade lug is larger than the “-” lug and “-” (black wire). *USB operated 11.5v-12.5V nominal 1. Power ON Mower. power IN, 5V OUT. The LED indicates 2.

  • Page 29: Testing The Neutral "Zero" Switches

    TESTING THE ZERO SWITCHES A zero switch is located at the base of each steering arm Confidential & Proprietary – Property of Techtronic Power Equipment – DO NOT COPY or DISCLOSE...
  • Page 30 TESTING THE NEUTRAL SWITCHES 1. Set meter to measure continuity and connect probes 2. With switch NOT pressed, measure No continuity 3. With switch pressed, measure continuity 4. Make sure wires and connector are in good shape and wires don’t pull loose Note: the switches are pressed when the steering arms are in the out position Confidential &...

  • Page 31: Testing Headlight Assembly

    TESTING HEAD LIGHT ASSEMBLY POSITIVE ”+” “-” NEGATIVE To test Headlight module independently: 1. Power on Mower. 2. Turn on Headlights. Disconnect Headlight from wire harness. 3. Set DMM to measure DC Volts. 1. 2. Supply 12V to the connector as shown above. 4.
  • Page 32 TESTING ANGULAR TRANSDUCER Test for Voltage at Harness 1. Set DMM to measure DC Volts. 2. Disconnect Accelerator connector. 3. Turn mower on. 4. Measure 4-5V between red and black wires on harness. 4.25V typical To Test Transducer Independently: 1. Set DMM to measure DC Volts. 2.

  • Page 33: Testing Brake Switch

    TESTING BRAKE SWITCH 1. Turn Power Off. 5.4V nominal when plunger depressed 2. Disconnect brake switch connector. 3. Measure voltage at the contacts. To test brake switch independently: 1. Power OFF Mower. 2. Set DMM to measure Resistance. contacts 3. Connect DMM leads to black and red contacts. Plunger Continuity when plunger is NOT pressed.

  • Page 34: Testing Beeper

    TESTING THE BEEPER Test by disconnecting connector and connecting 12V “+” to red wire and “-” to black ground wire of beeper. Or put mower in Reverse. This should cause beeper to activate. To measure the voltage at the harness: 1.

  • Page 35: Testing Seat Switch

    TESTING THE SEAT SWITCH 1. Power Mower OFF. 2. Set DMM to measure Resistance. 3. Disconnect seat switch connectors. 4. Measure continuity when switch is pressed. 5. Measure very high resistance when switch is released. 0-.2 Ohms nominal continuity when pressed To Measure the harness: 1.
  • Page 36 CONTROLLER LOCATION The only difference between the RY48ZTR’s and the RY48140 it that there are 3 deck controllers One primary and two secondary controllers Confidential & Proprietary – Property of Techtronic Power Equipment – DO NOT COPY or DISCLOSE...

  • Page 37: Testing Primary Blade Motor Controller

    TESTING PRIMARY BLADE CONTROLLER Test for short circuit: Disconnect all connectors to Primary Controller. Temporarily touch a wire between “+” and “-” wires to drain capacitance. Set meter to Resistance Mode. Connect DMM probes to heavy red wire (power) and heavy black (ground) wire to check for short circuit Typical resistance: 1.46M Check resistance of controller output:...
  • Page 38 TESTING SECONDARY BLADE CONTROLLER Test for short circuit: Disconnect all connectors to Secondary Controller. Temporarily touch a wire between “+” and “-” wires to drain capacitance. Set meter to Resistance Mode. Connect DMM probes to heavy red wire (power) and heavy black (ground) wire to check for short circuit.
  • Page 39 TESTING DRIVE CONTROLLER Test for short circuit: Set meter to Resistance Mode. Connect DMM probes to heavy red wire (power) and heavy black (ground) wire to check for short circuit. Nominal resistance: 750K Ohms Check resistance in controller output: Set DMM to Resistance Mode. Check continuity between any two terminals (heavy Yellow and heavy green for BATT + BATT -...
  • Page 40 TESTING PRIMARY AND SECONDARY DECK MOTORS 1. Disconnect Motor from controller. 2. Set DMM to Resistance mode. 3. Measure between any 2 pins. 4. Measure between other pins. 5. Measurements should be nearly identical. Nominal resistance .1 Ohm Confidential & Proprietary – Property of Techtronic Power Equipment – DO NOT COPY or DISCLOSE...

  • Page 41: Testing Drive Motors

    TESTING DRIVE MOTOR 1. Set DMM to Resistance mode 2. Measure resistance between heavy green and heavy yellow wire. 3 Measure resistance between heavy green and heavy blue wire. 4. Measurements should be nearly identical. Nominal resistance: 0.1 Ohm Heavy motor Drive Hall sensors phase wires...

  • Page 42: Testing Drive Motor Hall Sensors

    TESTING DRIVE MOTOR HALL SENSORS IN MOWER Note: power should be ON, and rear wheels raised so they can be rotated by hand. Set DMM to “DC Volts” 1. Touch red probe to red wire. 2. Black probe to black wire. 3.
  • Page 43 TESTING 48V TO 12V (DC-DC) CONVERTER Testing Converter Fuse: 1. DISCONNECT MAIN POWER. 2. Check continuity of fuse. 3. If fuse is bad, replace only with same type and Amperage. Testing Converter: 1. Turn mower on. Set DMM to “Volts” 2.
  • Page 44 RELAY BASICS Relay A relay consist of an electromagnet and a switch, controlled by the electromagnet, within a single package +12V When 12V is supplied to the two small terminals on the left of the relay, it causes the switch to close and supply 48V to the mower. It is standard practice to add a diode across the electromagnet to Diode Electromagnet...

  • Page 45: Testing Relay

    TESTING RELAY General rules of thumb: Relay 1. When you turn on mower, you should hear a “clunk” when the relay engages. and also when you turn off the mower +12V and the relay disengages. 2. If headlights work, the relay is good 3.
  • Page 46 TESTING RELAY 1. Power Mower ON. 2. Set DMM to “DC Volts”. 3. Check for 12V on the small terminals (under the black caps). 4. Check for approximately 39+V on the large terminals (under the red caps). Alternate method to test relay independent of mower: 1.

  • Page 47: Testing Relay Diode

    TESTING RELAY DIODE Diode Test: Turn Mower OFF. 2. Unbolt one leg of diode to disconnect from the circuit. 3. Set DMM to “Diode”. 4. Connect lead at arrow, black lead at Diode black arrow. DMM should read approx 7V. and black leads.

  • Page 48: Testing Charge Port And Interlock

    TESTING CHARGING PORT AND INTERLOCK Turn mower on. Turn headlights on. Connect a jumper wire as shown. (any insulated wire will do.) Green charge LED should glow as shown. Mower should shut down (relay clicks, headlights go out). Remove the jumper wire. After a few seconds, the mower should come back on(relay clicks) and headlights light again.

  • Page 49: Testing The Battery Charger

    TESTING BATTERY CHARGER 1. Refer to photos on next page for this procedure 2. Disconnect main battery connection. 3. Disconnect the blue charger wire connector 4. Connect the red alligator clip to the charger plug. 5. Connect the 2 black alligator clips to the other 2 plugs on the charger connector 6.
  • Page 50 CHARGER ERROR CODES CODE MEANING SOLUTION Check charger/ mower connection and remove any Charge Enable Fault: May indicate poor contact at the charger connector or the One red flash debris. Allow hot batteries to cool, Then try charging battery temp is too hot (Greater than 122 F again.
  • Page 51 TESTING TEMPATURE SENSOR • Disconnect the plastic connector • Set DMM to measure RESISTANCE. • At room temperature, measurement should be approx 10K Ohms. • As the sensor is heated, the resistance will decrease. • If sensor is not connected, the charger will blink an error code.
  • Page 52 WIRING HARNESS Confidential & Proprietary – Property of Techtronic Power Equipment – DO NOT COPY or DISCLOSE...

  • Page 53: Pre And Post-Repair Checklist

    PRE AND POST REPAIR CHECKLIST Jack rear tires approximately 2” off the ground and support securely with jack stands. Sit on mower. Turn main power key to “ON”. The Fuel Gauge/Hour meter should light up. Put FNR switch in FORWARD position. Put accelerator at full speed and hold.
  • Page 54 ZTR BEEP DIAGNOSTIC CODES BEEP # DESCRIPTION CHECK: IF NOT SOLVED… IF NOT SOLVED… IF NOT SOLVED… Angle sensor not at Replace control lever Turn key off, return both levers to open, turn key on Replace charger board Check angle sensor connections neutral assembly Return both levers to open and try operate again...
  • Page 55 ELECTRONIC TIPS FOR THE SMALL ENGINE TECHNICAN A service person who has spent many years working on gas mowers may feel uneasy when working on the new generation of electric mower. If this sounds like you, fear not, you’re not alone. This section is for you.

  • Page 56: Electronics Terms, Symbols And Tools

    ELECTRONIC TERMS, SYMBOLS, AND TOOLS Voltage is potential Energy noted by the symbol “V”. For the scope of this document, we are only concerned With DC voltage. So be sure when setting the DMM to Measure voltage it is set to DC. Resistance is opposition to the flow of current.
  • Page 57 USING THE DMM TO MEASURE VOLTS Before touching the probes of a DMM to Anything, be sure it is set to the correct setting To measure DC voltage: 1. first set the DMM to measure voltage, ensuring DC (NOT AC) setting DMM shows 12.55V DC battery voltage 2.
  • Page 58 USING THE DMM TO MEASURE RESISTANCE Before touching the probes of a DMM to anything, be sure it is set to the correct setting. Power must be OFF when measuring resistance To measure DC voltage: 1. First, set the DMM to measure resistance 2.

This manual is also suitable for:

Ry48ztr100Ry48140

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