Ryobi RY48110 Operating instructions

Ryobi RY48110/11/12 Riding Tractor

Electrical Components Troubleshooting and Testing

(Lead-Acid Battery Version)

J.Davis 9-4-2018

Table of Contents
•WARNING
•Mower Overview
•A Word about Brushless Motors
•Using this Manual
•DMM and Other Tools
•Block Diagram and Control Flow
•Troubleshooting: General
•Troubleshooting: Detailed
•Component Locations
•Main Battery Connection
•Testing Main Fuse
•Testing Battery Voltage
•Separating Connectors
•Control Panel
•Testing PTO Switch
•Testing RMO Switch
•Testing F-N-R Switch
•Testing Cruise Switch
•Testing Fuel Gage / Hour Meter
•Testing Key Switch
•Testing USB Port
•Testing Headlight Switch
•Testing Headlight Assembly
•Testing Accelerator (angular transducer) 2
•Testing Brake Switch
•Testing Beeper
•Testing Seat Switch
•Testing Master Blade Motor Controller
•Testing Slave Blade Motor Controller
•Remove / Replace Drive Motor Controller
•Testing Drive Motor Controller
•Testing Master and Slave Motors
•Testing Drive Motor
•Testing Drive Motor Hall Sensors
•Testing 48V-12V Converter and fuse 
•Replacing the 48V-12V Converter
•Testing Relay 
•Testing Relay Diode
•Testing Charge port and interlock
•Testing the Battery Charger
•Testing the Temperature Sensor
•Charger Error Codes
•Wire Harness 
•Pre and Post-Repair Checklist
•Electronic Tips for the Mechanical Small Engine Tech
•Electronics Terms, Symbols and Tools
•Using the Digital Multi-Meter (DMM)

THIS MATERIAL INTENDED ONLY FOR TECHNICIANS TRAINED IN ELECTRICITY.

Technicians should wear personal protective equipment, such as rubber

gloves and safety glasses

Dangerous voltages /currents are present. Exercise caution at all times

This manual assumes knowledge of basic electrical equipment such as DMM (Digital Multi Meter)

to measure voltage, current, resistance, continuity, and diodes.

< Table of Contents

Mower Overview

The Ryobi riding tractor is completely electrical,

consisting of 3 brushless Motors and controllers

for each motor:

•A brushless electric motors/controllers for each

of the 2 blades

•1 brushless motor/controller to propel the

mower. This Drive motor controller also contains

the “brains” that responds to various inputs such

as the accelerator, seat switch, cruise control, etc.

< Table of Contents

A word about Brushless Motors

Brushless motors operate quite differently than brushed

motors, which you may be used to (i.e. a starter motor)

With a brushed motor, you can quickly check them by

applying voltage to the two terminals.

Brushless motors can be recognized by 3terminals.

These 3 terminals require a controller to operate them

and to “fire” these 3 phases in a precise fashion similar to

spark plugs firing a 3 cylinder gas motor. Applying a

voltage directly to these phases may cause damage.

< Table of Contents

Using this Document

•Anything in blue 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

•A block diagram shows the general flow to visualize how the mower is

connected and a chart shows general symptoms/solutions for repairs.

•Electronics tips , Terminology and using a Digital Multi-Meter (DMM) are

included for the technician familiar only with gas machines.

< Table of Contents

Block Diagram And Control Flow
Batteries
Main
Fuse
Charge 
Port/lockout/ 
battery temp
48V to 12V 
(DC to DC)
converter Relay
Fuel
gage
Drive 
Controller
Control Panel
Brake 
Switch
Beep
Seat 
switch
Fuse
Master 
Blade 
Control
Slave 
Blade 
Control
Motor Motor
Motor
Head
Lights
PTO
RMO
FNR
Cruz
Light
Gage
USB
Key 
Switch
Accelerator
Note: A detailed wire harness diagram is 
located later in this document
USB
Hall Sensors
Important: Master and slave have
A communication link. If one blade
Motor or controller fails, BOTH will
Shut down
< Table of Contents 
48V

Troubleshooting: General

•Follow the block diagram on the previous page

•Test the easiest components first

•Mower should be fully charged (if possible)

•Before disassembly:

–Attempt to charge mower (note any error LED indications)

–Check for voltage at charge port

–Check if USB indicator and headlights work (this tests DC

converter)

•Remove instrument panel cover

–Test key switch

–Check all other connections while panel is removed.

< Table of Contents

Troubleshooting: Detailed
Use the block diagram as a guide
1. Verify the battery charger is functional by plugging it into the charge port on the back of the mower and let it charge.
2. If necessary, further test the charger and charge port. Replace as needed. Charge port, Interlock, and temp sensor should be replaced together. 
3. Test the key switch by operating it, making sure it has a solid “click” when turned on or off.   Replace if necessary
4. Test and replace main relay and diode as necessary. (Note: when you turn the mower on, you should hear the relay click)
5. If necessary, check the main fuse. If it is blown, check the system for signs of a short circuit before replacing the main fuse
6. If the fuel gage has power, but not display or malfunctions, replace the fuel gage
7. If ONLY the fuel gage works when the key is turned on, test/replace the 48-to-12V DC converter and 5A fuse as necessary
Note: this fuse is a common part available at any automotive store
8. If the mower will not drive:
a. Make sure the seat switch is functional and activated
b. Test the F-N-R switch. Replace if necessary
c. Test the accelerator transducer. Replace if necessary
d. Test the brake switch. Replace if necessary
e. If the mower still will not drive, test the Drive Motor controller. Replace if necessary
9. Test the blade operation by pulling up on the PTO switch
a. Make sure the seat switch is functional and activated
b. Test the master and slave motors. Replace as a pair if found bad
c. Test the master and slave controllers. Replace as a pair if found bad
d. If the mower blades still will not operate, replace the Drive motor controller (same as step 8e above)
10. If the mower works except for the headlights, test the headlight switch and headlights. Replace as necessary
a
9
< Table of Contents 