Mitsubishi mm30sr

[Graham Hamilton]

hey guys i have a 90s mm30 , most cat 302.5 fit my machine, there is a place in north las Vegas NCW TRACTOR PARTS that can get lots of mitsubishi parts the guy there knows everything about these engines,

Yeh, the Mitsubishi S3L and S4L engines used in the MM30SR and MM40SR are in quite a lot of other makes of excavators and forklifts etc which were imported into Europe and I think the USA, so manuals and spares are readily available for the engines. I've had a new starter motor, alternator, fan belt etc which are easy to find.
However its all the other stuff that is hard to find and as far as I know the excavator manuals were only produced in Japanese.

 

[Stan R]

my mm30 has the k series engines ,used in a lot of tractors,marine ect ect,my k3g needed a complete rebuild,they got me parts from the crank up,is hard to find info on there machine.

 

[antinejtrino]

Hello. I want to help a friend with a mitsubishi mm 30sr excavator. Problem - can't use the boom. Any wiring diagrams will be grateful. If anyone can send - antinejtrino@gmail.com. Thanks! Sorry for google translation.)

 

[Batu]

I wonder if there is a chronic problem with this machine? I was thinking of buying too. However, few people said he had the same problem. This made me wonder ...

 

[T-in-T]

I have an MM55SR2 that had boom operating problems. Suspect the system is the same or similar on all the MM series machines. I have a manual translated from Japanese with troubleshooting procedures and wiring diagram. When anything in the boom operating system malfunctions, the whole system shuts down. The system can be reset by pushing the red reset button under the seat.

First thing to check is the wires connecting the boom potentiometers (one at each joint) to the computer box under the seat. If any of these have weak signals (short, frayed wire, corrosion) the system shuts down. Another problem I have read about is a weak ground on the computer box. The box is under the seat. Some guys have soldered a ground strip from the box to a known good ground or the battery neg post. Though I have never heard of it happening, a proper safety signal to the computer might cause a problem. When the safety arm is up, the machine can be started but the boom-computer will not operate. When the arm is down, computer receives a “safe” signal and boom operates. This is controlled by a switch at the base of the arm sending a signal to three relays located behind the fuse panel. I really do not understand how this all works or how to check it, but suspect that if this circuit were to fail, the computer would think the arm is not in the safe position, and would not work.

My primary problem was a blown potentiometer in one joystick. The manual helped identify this as the problem. Tried getting it fixed here in USA to no avail. Used ones are scarce as hen’s teeth. I sent mine to Tony at IMDynamics in Australia. The voltage of these operating systems possibly varies from one model to the next, because the first time he “fixed it”, he assumed it was a 12 volt system. It wouldn’t work. After taking several voltage readings from the computer and referencing the manual, I determined it to be 5 volt based. Sent it back along with output specifications from the manual and he did a proper repair. When I hooked the repaired joystick up to the system, it still would not work until a reset was done via red button under the seat. It works perfectly now. IMDynamic also builds an analog operating system that will replace the existing computer/digital system.

I hope these thoughts give you some ideas as to where to start your assessment. Knowing any sequence of failed functions that occurred prior to complete shutdown might indicate where your problem lies. For instance my bucket curl function (left to right movement of right joystick) became erratic just before the whole system shut down. The potentiometer controlling that function was the one that failed.

 

[Fordzilla]

Actually the first thing to check is under the seat. There should be a RED button there. Push it to reset your computer. That fails, try holding it down and moving your sticks. IF your sticks work with button down, either continue to chase Potentiometers as T-in-T states above. Or you can redneck it like I did (Posted a step by step on this forum). Cut the wires off the back of the button, and twist them together for good. But then your computer beeps so you might want to take it apart and remove the speaker.

 

[Fordzilla]

I have MM40SR, and had to order a new drive motor for it. It apparently is a 2 speed machine, so I looked under the seat at the foot pedal. Has wires not connected to anything, anyone know which solenoid I need to connect it to to get the dual speed?

 

[antinejtrino]

Thanks for the help. All potentiometers are broken on this excavator. Dummy plugs are installed in their place. The malfunction is wandering. Maybe a day to work, then 2 days does not work. Many electricians have tried to solve this problem. But the result is always negative. I examined the excavator today. The CPU lamp is flashing. When you press the red button, the screen lights up 8.8.8., But does not respond to joysticks. But as soon as the CPU stops flashing, the excavator starts working. I removed the connectors from the control unit - 2 contacts in one connector are burnt (black wires in the bundle). This leads me to believe that the problem is a poor ground connection. Also, traces of repair are visible on the control unit board. I took the board home, wash off the car sealant from it and see what was repaired on it.

 

[T-in-T]

I had the problem of intermittent operation in the past. Boom would not work until I shook the machine vigorously by engaging the tracks forward-reverse-forward-reverse-etc. This was most prevalent after a rain or heavy dew. What was happening was poor signal strength from the boom potentiometer wires. After repairing all the connections in the boom wires (soldering, insulating, etc) it worked good. Also the connections into the control box have been an issue. Sometimes the boom would operate erratically or not at all. I could reach behind the seat and jiggle the controller plugs and solve the problem. Finally used electrical contact cleaner and a brass brush to clean each contact thoroughly and made sure the plugs were seated securely. Problem solved. Since your machine operates occasionally, a bad controller or joystick is not likely the problem. Indicates a bad electrical contact somewhere is interfering with the controller. Also, when the monitoring is flashing are there any readable letters or numbers like PE3 OR PCE4 or SCE and is the buzzer sounding too or is it silent?

 

[T-in-T]

Also---This machine records errors in the monitor. If you simultaneously push the red button under the seat, the button left of the numbers on the monitor and the top button of the three vertically stacked buttons on the right edge of the monitor , the LED should display "S-E 4" or "S-E 5". Then press + or - to get S-E5 showing. Then press the middle button of the three stacked buttons and error codes should start flashing up one every two seconds. Record these and post on the forum and I'll look them up in the manual for you. Maybe this will help.

 

[antinejtrino]

I’ll only get to the excavator tomorrow. I'm sure the problem lies somewhere in poor contact. It remains to find where. ) If someone has an electrical diagram, please see where the 2 black wires are laid in connector 101 of the control unit.
When the ignition is turned on, the inscription S.L.E appears. What does it mean?

 

[T-in-T]

Cannot find a SLE error. Maybe you have a bad LED on monitor and it should be SCE. SCE is code for communication error between connector 39 at monitor and connector 101 at controller. The manual is somewhat confusing. It shows a diagram that wire 11 of connector 39 leads to wire 7 of connector 101 and that wire 12 of connector 39 leads to wire 8 of connector 101. This is followed by a diagram that says " Check item-- Conn. 39-3 leads to 101-7? and 39-4 leads to 101-8?" If no = harness failure - rework or replace. If yes = controller failure - replace controller." Wires are numbered left to right as viewed from the wire entry end of the plug. The wiring diagram shows wires 39-3 and 39-4 going to the boom potentiometers and 39-11 and 39-12 going to plug 101 at controller. If wires 101-7 or 101-8 are the ones that are burned, they are probably malfunctioning.

 

[antinejtrino]

T-in-T, thanks for the help. You are right, the monitor is not fully functional. I'll check the harness. Could an SCE error be causing the boom to malfunction?

 

[antinejtrino]

Hello. Today I dealt with the excavator. I cleaned the contacts on the control unit - the SCE error is now not displayed. But the CPU lamp still blinks. I have read the errors. "S-E 5" - 52.53.54.66. "S-E 4" - 52.53.54. If anyone has a wiring diagram and error codes, a divider please. I will deal with the problem quickly, the excavator will work, a friend will dig the foundation for me and I will start building a garage.)))

 

[T-in-T]

Glad to hear your communication problem is fixed. But the error codes indicate a bigger problem--JOYSTICKS!. Codes 52,53,54 indicate the voltage output of the joysticks when centered is not within specifications, 52 is for front-back function of left hand stick is below 2.3 volts, 53 is for left-right function of left stick is below 2.3 volts, and 54 is for front-back function of right stick is below 2.3 volts. Diagnosis guide says "If one of any channel is out of center, all channels stop. Wait until joystick comes back to center. Operable only if all channels are set in center." When my left-right function of right stick went out, error codes for both sticks were present- so the issue is identifying which component of which stick is actually malfunctioning. Code 66 is for microswitch of front-back left stick. Diagnosis guide says "If microswitch is on more than 1 second with joystick centered, troubled channel stops. If microswitch is OFF with joystick is ON, troubled channel stops." With errors 52-54 you should be getting a blinking monitor and buzzer; with error 66 you should be getting a constant ON monitor and buzzer. I'll now try to lead you through testing for errors 52-54. Remove seat so you can access the controller while connected. Remove controller cover and look for test points labeled TPG=ground, TP1-TP4= joystick outputs. You will also find TP5-TP8-- those are for the Differential transformers on the valve bank- not relevant yet. TP1 measures output of front-back function of right stick; TP2 for Left-right of right stick; TP3 for front-back of left stick; and TP4 left-right of left stick. With the switch on and the safety lever locked, measure the out puts of each test point. With sticks centered each TP should measure 2.35-2.65 volts. TP1 should measure 0.35-0.65 volts with right stick full front and 4.35-4.65 at full rear. TP2 should measure 0.35-0.65 volts with right stick full left and 4.35-4.65 at full right. TP3 should measure 0.35-0.65 volts with right stick full rear and 4.35-4.65 at full front. TP4 should measure 0.35-0.65 volts with right stick full right and 4.35-4.65 at full left. If measurements happen to be within range, but for reverse positions of stick, it is because the translator of my manual got stick positions wrong, not a bad component. While you are inside the controller, see if the connection leads of plug 182 are numbered. If they are, continuity between leads 8 and 10 test for the left stick front-back microswitch error 66. Centered = no contact; front or back= contact. If not labeled, pull 182 off and facing contact point end with lock mechanism up, lead 8 will be fourth contact from right of bottom row of contacts and contact 10 should be third point from right on top row.

 

[antinejtrino]

Thanks. I found parts of the repair manual and error codes on the internet yesterday. I am currently translating it into Russian. That's what I don't understand. Do the joysticks return to neutral by themselves? My excavator has a very large play in the joysticks.

 

[antinejtrino]

Today I will translate the repair manual. Tomorrow I will go to repair the excavator again. I will check the TP1-TP4 control points. What is the working principle of joysticks? Are there potentiometers inside?

 

[antinejtrino]

To diagnose correctly, I need to understand how joysticks work. There are microswitches and potentiometers inside the joysticks, right? When I move the joystick forward, a microswitch is triggered, which informs the control unit about this, right? After that, the potentiometers come into operation, according to the voltage drop on which the control unit understands how hard the lever is pressed, right?

 

[T-in-T]

Right. When the joystick is not being deflected by operator, it should return to a fairly stable center position. I cannot remember exactly, but seem to recall that springs or other mechanical devise inside the joystick return it to neutral. When moved from neutral a microswitch activates and then potentiometers send varying voltage signals to controller based on joysticks' degree of deflection. I am not versed in electronics and do not understand much about how these components operate. But whoever repairs the components needs to know that it is a 5 volt system.

 

[antinejtrino]

Excellent. Almost the entire puzzle is assembled in my head.))) Now I understand how everything works. Tomorrow I'll disassemble the joysticks and see what's inside.