Tech Tips

3 Things to Remember

10/14/2015
This month we have 3 small items that are important to remember when troubleshooting your Skyjack Aerial Work Platform.
The Skyjack Tech Tip
3 THINGS TO REMEMBER

This month we have 3 small items that are important to remember when troubleshooting your Skyjack Aerial Work Platform.

1. When testing electrical circuits on Skyjack aerial equipment, please remember that we do not use the machine frame as a ground. The ground circuits on Skyjack models are a dedicated ground circuit with their own wiring and are circuit protected. Any solid white #02 wire or solid white #00 wire is intended as a ground wire. Every valve coil, light, alarm, etc, has a ground wire attached to it that will provide the ground portion of the circuit. When troubleshooting, please check the ground circuit breaker and use the white ground wires when attaching your volt meter leads.
2. When working on any Skyjack scissor lift, the serial number plate is a source of valuable information. In addition to the machine model and serial number, the serial number plate states the main relief and lift relief valve settings, the maximum drive height, and the model year. When testing the machine’s hydraulic pressures, consult the serial number plate for the correct relief valve pressure settings. When testing the machine functions and limit switches, it is valuable to know if the machine is drivable at full height, consult the serial number plate for that information. If the plate is damaged and unreadable or missing, a replacement part is available from Skyjack parts department.
3. When you are troubleshooting a problem on any equipment, it is always best to test ALL functions before trying to determine the exact problem. Look for function/problem commonality. Multiple functions can be affected by the same limit switch or valve and if all the functions related to that specific limit switch or valve are failing; this may pinpoint the source of the problem. By operating ALL functions and checking common points, you can save a lot of troubleshooting time and effort.

When servicing or troubleshooting your Skyjack scissor lift, boomlift, or telehandler, please use the correct manual for the model and serial number of the unit you are working on. If you have any questions or need further assistance, please contact Skyjack Product Support at 1-800-275-9522 or email service@skyjack.com

TECH TIDBIT

In order to make all the latest information available to technician in the field and the shop, we have put all the operating, service, and parts manuals on a portable USB Flash Drive. This allows the technician to access pertinent information without having an internet connection. The flash drive is updated once a month at the Skyjack website skyjack.com/usb-update and any manual additions and corrections are installed. The flash drive is available from Skyjack Parts department and has part number 167847. This can be a valuable tool for technicians particularly in the field where internet access can be difficult.

skyjack.com/tech-tip Skyjack

Deutz 2.9L T4 Fuel Pumps

09/15/2015
The new Deutz 2.9L tier 4 engines utilize a common rail fuel injection system.
The Skyjack Tech Tip
Deutz 2.9L T4 Fuel Pumps

The new Deutz 2.9L tier 4 engines utilize a common rail fuel injection system. Gone are the familiar lift pump and injector pump arrangement. These engines use an electric fuel pump to deliver fuel through the filter to the high pressure fuel pump. The pump is mounted near the fuel tank near the replaceable cartridge fuel filter.

When the machine is powered up, the fuel pump runs to build pressure in the circuit. Once enough pressure is seen by the ECU sensor, it allows the engine to crank. If you encounter a no crank situation, check that the fuel pump is running and that the fuel lines are not pinched or constricted. If the pump is not running, check the CB3 circuit breaker on the base control panel. If the breaker is not tripped, you can check for power at the fuel pump terminals located at the fuel outlet end of the pump. See figure 1.

Notice the terminals are marked with positive and negative symbols. Note: the replacement part will not have darkened symbols. Verify that the power and ground wires are on the correct terminals or the pump will run backward. Test for good voltage (12V) and a good ground. Make sure there is no rusty or loose connections at the terminals or wire ends.

Once these tests have been made, you can determine if the fuel pump needs replacement. If your Deutz engine is still under warranty, please contact your local Deutz service center for replacement. If the engine is out of warranty you can purchase a replacement part from Skyjack parts department.

If you have any questions regarding the fuel pump or any Skyjack product, please contact Skyjack Product Support at 1-800-275-9522 or email service@skyjack.com

TECH TIDBIT
Technical training is an integral part of keeping your fleet operating safely and efficiently. Less down time means more production and profit from your Skyjack equipment. Skyjack offers technical training for the equipment we manufacture at your location. For more information, contact your regional service representative or call Skyjack Product Support at 1-800-275-9522 and ask for Rich Soltas. A well trained service staff is part of a safe and profitable service department.
skyjack.com/tech-tip Skyjack

OCM/SCM TEST BASICS

08/26/2015
The OCM/SCM has a two line LCD display and a membrane keypad that allows the technician to access the programming without the need for a separate plug-in calibrator.
The Skyjack Tech Tip
OCM/SCM TEST BASICS

All the latest Skyjack boomlift models utilize a function control module called the OCM – On-board Control Module, or the newer version; the SCM – Skyjack Control Module which are located in the platform control console. The OCM/SCM has a two line LCD display and a membrane keypad that allows the technician to access the programming without the need for a separate plug-in calibrator. Once the programming is accessed, the technician can monitor function status and make adjustments to function speeds similar to adjusting the trim potentiometers on a joystick circuit card.

When troubleshooting a ‘no functions at platform controls’ problem, there are a few tests that need to be done initially to help determine the problem. With the machine powered up, the key switch in platform position, and both the base and platform emergency stop buttons pulled out, please check the following items.

  • Using a voltmeter, check wire 04 for 12 volts at the start or horn switch. Wire 4 (or 4A if generator equipped) supplies power to the foot switch.
  • With foot switch depressed, test wire 08A out of foot switch to the OCM/SCM.
  • Then test wire 08B from the OCM to relay 08BCR.
  • Test wire 08 at 08BCR for power when the relay is activated.
  • Once these steps are completed and you have power at the correct terminals, you can test the OCM/SCM output for the function or functions you are having a problem with. Activate a function and observe the display – it should show which function is being operated and the percentage value it is currently supplying to the function valve.

By checking the above first, the technician can determine if the OCM/SCM is getting power into it and then putting power out to the switches. This enables the technician to quickly and accurately diagnose a ‘no platform function’ problem.

For more information regarding the OCM/SCM operation and input and output voltages, please consult the service manual for the serial number of the machine you are working on. If you have any questions regarding a Skyjack product, please call Skyjack Product Support at 1-800-275-9522 or email service@skyjack.com

TECH TIDBIT
With the increased use of electronic circuits, the voltages that each circuit requires are more precise than a simpler wire/relay circuit. As a result, a good ground circuit is essential for correct operation. When testing for correct voltages make certain that the ground circuit is good.
skyjack.com/tech-tip Skyjack

FIBERGLIDE BUSHINGS

07/14/2015
Skyjack uses Fiberglide bushings, which are self-lubricating and maintenance-free.

Skyjack aerial work platforms utilize bushings at major pivot points such as the scissor stack end and center pins, steer kingpins and most boom pivot points. We use Fiberglide bushings, which are self-lubricating and maintenance-free. The bushing consists of a thin-wall steel backing with a woven PTFE bearing material bonded to it as seen in Figure 1. The bushings are designed to run dry with no additional lubrication required for the entire life of the bushing.

The best method to maintain the bushings and pins is to thoroughly pressure wash the pivot area and then blow the bushings and pins dry with compressed air. Do not add lubricants since this can flush the self-lubricating particles from the bearing and/or attract and retain dirt – both leading to reduced bearing life.  Bushings and/or pins should be inspected and may need to be replaced if there are signs of damage, rust, wear or noise at the pin connection.

When replacing these bushings, they are usually easy to remove from the mounting boss since they are a thin-wall design that is open along one side and will collapse with little effort. When installing a new bushing, it is recommended to use a step mandrel tool that is the same O.D. as the I.D. of the bushing, to prevent the bushing sustaining damage when installed. The step of the tool applies the force to the bushing as it is installed in the boss as in Figure 2.

Figure 2

When ordering replacement bushings and pins, please use the parts manual for the serial number of the machine you are servicing to get the correct parts and quantities. If you have any questions regarding your Skyjack product, please call Skyjack Product Support at 1-800-275-9522 or email to service@skyjack.com

TECH TIDBIT

The new Deutz Tier 4 2.9 Liter diesel engines are now being shipped in Skyjack boomlifts. The engines feature improved exhaust emissions that meet EPA standards and use engine computer controls. Please refer to the information in the Deutz engine manuals supplied with each machine and the recommended service intervals and procedures in the Skyjack and Deutz service manuals.

A.C. Power Cord Wire Colors

07/06/2015
The U.S./CA follow the NEC standardized colors. The U.K./Australia wiring uses the IEC standardized colors.
The Skyjack Tech Tip
A.C. Power Cord Wire Colors
When working with the A.C. power cords for the power to platform and the battery charger replacement cords, the wire colors for U.S./CA (North America) power cords may differ from U.K./Australia wire colors. The U.S./CA follow the NEC standardized colors. The U.K./Australia wiring uses the IEC standardized colors. The table below shows the corresponding colors for the NEC and IEC wire identification.
NEC Wire Color Description IEC Wire Color
Black Single Phase Line (hot/live) Brown
White Neutral Blue
Green Protective Earth (Ground) Green-Yellow
To help technicians identify the wiring colors, we have added the wiring color code identification and cross-reference to the service manuals. A label is also being installed on the power to platform cable showing the wire colors and how they correspond (see Figure 1). As you can see, the decal depicts the NEC wire colors and their corresponding IEC wire colors.
Figure 1
When troubleshooting or repairing your Skyjack product, please consult the correct operating, service or parts manual for the serial number of the unit you are working on. If you have any questions regarding wiring, or any questions at all regarding your Skyjack Product, please contact Skyjack Product Support at 1-800-275-9522 or email service@skyjack.com.
TECH TIDBIT
When contacting our Service Technicians, please have your pertinent information ready. Your name, company name, branch location or branch number, and the machine model and serial number. Please test ALL the functions from both the platform and base controls. This information will help our techs help you troubleshoot problems quickly and accurately.
SERVICE REMINDER
JULY 11 — 15, 2015

During this week, the Technical Support Staff will be involved in our Annual Training Seminar. For more information, please visit our website.
skyjack.com/tech-tip Skyjack

SKYTOOL1 - Pin Extractor Tool

05/31/2015
The Skyjack SJ12 and SJ16 model vertical mast lifts share many characteristics of the SJIII scissor lifts.

The Skyjack SJ12 and SJ16 model vertical mast lifts share many characteristics of the SJIII Compact and Conventional scissor lifts. One feature is the ability to remove the platform control box from the machine. This allows the operator to prevent unauthorized use of the machine or allows a technician to swap in a different control box if the control box becomes damaged or for troubleshooting. The connector contacts use a male and female pin and socket arrangement.

As with any connector, contamination or damage can result in electrical issues. Always check for dirt, rust, or bent and loose contacts. With this particular connector, the wires are directly crimped to the contacts and then inserted into the block in the connector housing. Ensure that the contacts are secure in the block when inspecting the connector. If the male connector is mated to the female side without indexing properly, or forced into connecting, the contacts can be damaged.

If the contacts need replacing, a special tool is needed to remove the pin/socket. Skyjack parts department has the tool available as part number ‘SKYTOOL1’. It is a pen shaped tool that allows contact removal without damaging the block. The tool is slid over the contact from the mating side until it stops. Push a little harder and the contact will unlock and push in to the wire side.

For more specific information regarding the SJ12/16 Mast Lifts, please refer to the correct service or parts manual for the serial number of the unit you are servicing. If you have any questions regarding your Skyjack Aerial Work Platform or Telehandler, please contact Skyjack Product Support at 1-800-275-9522 or email service@skyjack.com.

TECH TIDBIT

When servicing the wear pads on a boomlift, remember that an important part of what he wear pads do is to center the inner boom section in the outer section. Adjust the wear pads so that there is the manufacturer’s specified clearance between the pad and the boom and that the inner boom is centered in the opening of the outer boom section. The wear pad adjustment helps the platform to remain stable as the operator moves from side-to-side in the platform.

P.D.I. PRE-DELIVERY INSPECTIONS

05/21/2015
It is recommended that all aerial work platforms be inspected prior to being sold, leased, or rented.

It is recommended that all aerial work platforms be inspected prior to being sold, leased, or rented. Completing the Pre-delivery Inspection, or PDI ensures that the machine has been tested and inspected for proper and safe operation prior to being put into service, and that the unit has no worn or missing parts and is not damaged. Skyjack furnishes forms to assist in the completion the PDI inspection. These forms are available in the Forms Library. There is a form for the vertical mast/electric powered scissors and engine powered scissor lifts, as well as for the telescoping and articulating boomlifts. These PDI inspection sheets help you comply with the inspection requirements.

When a new unit is being put into service for the initial rental or sale, use of the Pre-delivery Inspection is very important. It documents completion of the final inspection before the unit is put into service for the first time. The Pre-delivery Inspection also serves as the owner’s verification of the condition of the machine at the start of the warranty period. Skyjack uses the date of the PDI as the warranty start date. Any problems identified are reported on the inspection sheet and can be corrected, under warranty, before the unit is put into service.

If you have any questions or need technical assistance with your Skyjack product, please contact Skyjack Product Support at 1-800-275-9522 or email service@skyjack.com

TECH TIDBIT

With the use of new engine designs and hydraulic system components in our equipment, please check the correct service manual for the serial number of the machine you are servicing for the correct oil and fluid specifications. There may be different motor oils, hydraulic fluids, and coolants that the engine and hydraulic manufacturers recommend for these new components.

BOOM JOYSTICK CONTROLLERS

03/27/2015
The joystick controllers used on the Skyjack telescoping (40/45 T & 61/66 T) and the articulating (46/51 AJ & 63 AJ) boom lift models all operate similarly. Whether it is a single or dual function joystick, testing and troubleshooting steps are the same.

The joystick controllers used on the Skyjack telescoping (40/45 T & 61/66 T) and the articulating (46/51 AJ & 63 AJ) boom lift models all operate similarly. Whether it is a single or dual function joystick, testing and troubleshooting steps are the same.

When the joystick is powered, it shows a neutral signal to the On-board Control Module or OCM. This neutral signal is between 4.2 and 4.8 volts. As the joystick is moved in any direction, this signal changes by either rising toward 8.5 volts maximum, or dropping to .5 volts minimum. This change in signal tells the OCM which direction you are asking the function to move – the volts drop or rise, and how fast you want the function to move – how much rise or drop in voltage occurs.

Reading this on a voltmeter would show the neutral signal sitting at 4.2/4.8 volts. As the joystick is moved forward, and the voltage rises to 4.9, the valve will start to move the function and as the voltage continues to rise toward the 8.5 volt maximum, the function speed will increase. When the boom is to be lowered, the volt reading would start again at the neutral signal of 4.2/4.8 volts. As the joystick is moved backward, and the voltage drops to 4.1, the valve will start to move the function and as the voltage continues to drop toward the .5 volt minimum, the function speed will increase.

Troubleshooting the joystick is simple. Connect your voltmeter to the power and ground wires at the joystick. Power up the control box and you should read your system voltage. If no voltage is seen, repair the ground or power circuit to the joystick. With good power and ground to the joystick established, move the meter positive lead to the signal wire to the OCM. Power up the controls and check that the OCM is powered and shows FUNCTIONS OFF. The signal wire should read 4.2 to 4.8 VDC. If not, check the OCM and if OK, replace the joystick. If OK, operate the joystick and watch the signal raise or lower as the handle is moved. If no signal change is seen replace the joystick. If the signal changes as it should, the joystick is working.

The correct service manual for the model and serial number of the machine you are servicing has complete joystick controller and OCM information and voltage references for troubleshooting. These manuals are available here. You can also contact Skyjack Product Support at 1-800-275-9522 or email service@skyjack.com if you have any questions regarding this or any Skyjack product.

TECH TIDBIT

Make sure to keep all your indicator lights and LEDs in working order. They inform the operator to safe and unsafe conditions, engine distress, and can also help when troubleshooting a problem. They can indicate function operation or tell a technician if power is present without opening a panel or control box saving time and work. Checking all the indicator lights and LEDs should be a regular part of your maintenance and safety checklist.

FIRST THING TO CHECK

02/19/2015
When troubleshooting Skyjack electric scissor lifts, it is useful to be aware of two manually operated valves that can cause operation issues and which may be overlooked.

When troubleshooting Skyjack electric scissor lifts, it is useful to be aware of two manually operated valves that can cause operation issues and which may be overlooked. These should be the first items checked when experiencing the symptoms described below.

Symptom: The platform lifts slowly and seems to have a heavy load on the platform. The pump motor strains as if the batteries are low on charge.

First thing to check: Take a look at the lift cylinder holding valves. These are the valves that are opened when using the emergency platform lowering. There is a red knob that protrudes from the center of the valve stem. Make sure the valve is closed - the red knob is pushed in and turned clockwise approximately one-quarter turn and stays in that position when you release it. If the valve is not closed it restricts oil flow into the cylinder slowing the function speed.

Symptom: The unit will not drive. The pump runs but no motion occurs and the pump motor sounds like it is running with no load at all. The brake cylinders may or may not retract.

First thing to check: The freewheel valve. Located on the end of the frame where the drive wheels are located, it is a black knob valve that is closed when turned fully clockwise. It should be closed for normal drive operation. If the valve is open, the drive oil is routed through it and back to tank.

When troubleshooting or repairing your Skyjack product, please consult the correct operating, service or parts manual for the serial number of the unit you are working on. If you have any questions regarding any of your Skyjack products, please contact Skyjack Product Support at 1-800-275-9522 or email service@skyjack.com

TECH TIDBIT

Do you own a Skyjack USB drive?

USB driveIf so, please download the latest program that will ensure your USB drive
stays current and up-to-date. Our website offers simple step-by-step instructions
for you to follow.

DIODES

01/19/2015
Diodes are used extensively in the electrical circuits of every Skyjack aerial work platform and telehandler.

Diodes are used extensively in the electrical circuits of every Skyjack aerial work platform and telehandler. We use them primarily to separate common circuits from each other. For example, the SJIII electric powered scissor lifts use diodes to allow multiple circuits to power the pump motor solenoid but each separate function valve will remain unpowered; only the specific function valve that is asked for will be powered. The diode acts like an electrical check valve allowing power to flow through it in one direction only.

The diodes we use have a round body with a lead extending from each end. One lead is the cathode the other is the anode. Figure 1 shows a diode schematic symbol and diode.  

Figure 1Any power coming into the anode will flow through the diode. Any power at the cathode side will be blocked from passing through the diode.

The silver band on the diode body marks the cathode or blocking side of the diode.

This is critical when installing a new diode. The direction of the silver stripe must be placed correctly in the circuit for the diode to perform its function.

The best way to test a diode is with voltage. The diode check feature on most multimeters will not accurately test these diodes. To check the diode, use a battery and your multimeter; attach the black (ground) meter lead to the battery negative post. Connect the red (positive) meter lead to the cathode side of the diode and touch the anode lead to the battery positive post. You should read the battery voltage on the meter. Then flip the diode around - connect the red meter lead to the anode side of the diode and there should be no voltage reading on the meter when you touch the cathode to the battery positive post. This is the most accurate method to test a diode on your Skyjack equipment.

When replacing a diode, please use the correct part number or diode specification that was originally used. For more information about diodes or if you have any questions regarding your Skyjack product, please contact Skyjack Product Support at 1-800-275-9522 or email service@skyjack.com

TECH TIDBIT

When using a manual to perform service, troubleshooting, or ordering a part for your Skyjack scissorlift, boomlift, or telehandler, please use the correct manual that corresponds to the serial number of the unit you are servicing. Having the correct information for your machine is critical when performing diagnostic testing, making adjustments, or ordering the correct replacement parts. Manuals are available digitally at our website, www.skyjack.com or a hard copy may be purchased from our parts department.

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