Hitachi Ex120 Problem

storm1n · Feb 25, 2011

Hi 3Doc,

We have a Hitachi EX200-3 machine that is having the same hydraulic problem as everyone has been experiencing on these threads... The PVC computer has been disconnected as well as all the sensors and our mechanic cant put these back together so I think that would explain the hydraulic problems etc. According to him they have operated this machine for months and was working fine with the computers disconnected and the sensors disconnected as well. Is this possible?

I have suggested that the PVC computer and sensors be connected back but we are in need of a manual for the wiring diagram and probably the hydraulic diagram as well as they have dismantled everything now. Thanks to my very brilliant mechanics!

storm1n · Feb 25, 2011

Sorry I cant PM you as I am a probationary member only. My email address is arnold.araza@gmail.com....cheers

Trout Creek · Mar 8, 2011

-3Doc said:
I can supply you with one if you are interested. Just PM me.

Hello, I am new to this forum. Never had a real reason to join until a few days ago when I pulled the trigger on a new to me Hitachi EX120-2. I am sure I will be back on this or other threads. If this offer is good to others I would love a copy of the full service manual. If not, can you tell me what the differences are between the EX120-3 and the -2?

Thanks in advance. I woul PM you but do not have those privliages yet. my email: tom(at)troutcreektreefarm(dot)com

Tom

Sripola · Mar 8, 2011

Sripola said:
Hi Wardiker,

Happy New Year!
Well we found the problem and also a theory on how it happened.
Well basically the PVC is fried. Overvoltage had blown a whole bank of transistors and a couple of resistors. Also noticed that someone had messed aorund with the angle sensor. So our techie adjusted it "manually" by setting it so that the pump doesnt overheat (i couldnt find the correct calibration instructions for it so had to go with our guy's logic).

The guys took the PVC and repaired it (cost about $200), and we tried a donor PVC and found machine worked perfectly. But put the repaired PVC and machine was ok apart from auto throttle not reponding. So the guy's gonna take a second shot at it and hopefully fixes it this time!

So the theory on how this all happened. We found a pressure sensor for the machine travel was inop. So it looks like someone had tried to adjust the angle sensor to fix this (cuz they didnt know the presssure sensor was inop), and made the prob worse. The next dumb move by this mystery mechanic was prob to have put a voltage through to pin out the harness and thus blowing the PVC. Because when we got to it we could see signs that someone had already been there messing around.

SO hope this info helps. But basically, adjusted the angle sensor, fix/new PVC and a pressure sensor and the machine's a good un!

Also our techie told us that there is a bit of kit to bypass all the sensor and make the machine a "manual" although this makes the machine run slower and not very efficient as you can imagine, so if anyone has info on this procedure i am more than interested as i have heard this procedure from quiet a few guys but its almots an urban legend as no one can give me any technical info on this.

Hi guys,

So much for the early celebrations! Our Hitachi EX120-3 has developed the same problem again! We got the electronics "expert" to fix teh PVC and it worked for about 6 hrs before blowing it again.

Not sure what to do now as a few ppl have messed around and teh waters a bit muddied. Any suggestions guys as to what could be causing it? Bad DP sensor? The machine tracks very slowly as well no matter what you do. And after working for a few minutes or any load on the hydraulics it just stalls.

Might replace the PVC and see what happends but the risk is another blown computer and no root cause.

ANy help is appreciated and if someone has the service manual etc that would be great.

Cheers

GCC · Mar 8, 2011

Just throwing it out there but my Hitachi ex300lc-3 did the same thing I placed the prussure release valve on the hydraulics and bam back to work I went best of luck with yours and mine also had a problem sometimes when I turned my machine on it wouldn't rez up at all but had to replace the stupid motor that controls the throttle postion.

rgl726 · Mar 8, 2011

Sripola said:
Hi guys,

So much for the early celebrations! Our Hitachi EX120-3 has developed the same problem again! We got the electronics "expert" to fix teh PVC and it worked for about 6 hrs before blowing it again.

Not sure what to do now as a few ppl have messed around and teh waters a bit muddied. Any suggestions guys as to what could be causing it? Bad DP sensor? The machine tracks very slowly as well no matter what you do. And after working for a few minutes or any load on the hydraulics it just stalls.

Might replace the PVC and see what happends but the risk is another blown computer and no root cause.

ANy help is appreciated and if someone has the service manual etc that would be great.

Cheers

first thing to do is replace and adjust the angle sensor before you go to the PVC.

Sripola · May 13, 2011

Finally fixed the bloddy thing!
Frayed harnesss!!!!! cant believe it was so simple! I dont know exactly where it was shorting because our mechanic didnt really note it, but it was underneath the cab so i think it was one of the in/outs from either PVC or EPC.

Thanks for all the suggestions guys, once i have more details will post it here as i am sure it will help someone!

ss454mb · Jul 22, 2011

Having wiring problem in the pump area, and if you could send me a wiring diagram of pump selnoids, all the wires have been tore out and I have replaced them the best I could, but to have a wiring diagram would be greatly appreciate. I know this is old post, but haven't seen anyother close to what I need.
My email address is ss454mb@live.com. Thanks, Mike Bentley

Andre-1 · Jul 24, 2011

Is it 24Volts that must be sent to the solenoids on the pump of a 490e Excavator? or does it vary . I tested using a multimeter while the machine was running and got variations; 6volt, 8 volts, 13 volts (was the highest) . I know the ground is controlled by the computer (PVC) but when it grounds must the voltage be 24v or does it vary based on the load.
I ohm tested my rpm sensor and got 862 ohms. This machine has blown a pvc before so i suspect a bad harness. Before, it stalled when under load or if any cylinder was fully extended. I changed the DP sensor and adjusted the angle sensor. got better results when i changed the dp sensor,now it wont stall in any mode higher than (I). If i switch the wiring for the solenoids it overheats. While testing it today I noticed the voltage on one was always higher than the other. one shows like 6v,7v, 8v while the other shows 6, 8, 13v . the state it is in now is that it will come to a stop while working and will only move after the levers are released and the moved again, seems like low oil flow. I ran a self diagnosis and it gave code 28 ( pump dischagre pressure sensor) so i purchased it and it will take a while to get here. Any suggestions?

tool_king · Jul 24, 2011

Andre-1 · Jul 24, 2011

tool king those links dont work, it says link not valid

Andre-1 · Jul 24, 2011

tool_king said:
storm1n
Here are the workshop and tech manuals for dash 5 .maybe they will help.
I do not have them for the 200lc-3 but have the for the dash 5 machines here are the links for the manual download these hopefully they will help.

These are the tech manuals .
http://www.4shared.com/document/Btmp...ONTENTS_1.html
http://www.4shared.com/document/WWhl...ENTS_157T.html
http://www.4shared.com/document/m2nd...157T-2-1_.html
http://www.4shared.com/document/sy8j...TS_157T-5.html
http://www.4shared.com/document/W1A0...ERAL_INFO.html

Theses are the work shop manuals
http://www.4shared.com/document/jk11..._157W-1-1.html
http://www.4shared.com/document/aBu8...S_157W-2-.html
http://www.4shared.com/document/VJ1m...ssorieW05.html
http://www.4shared.com/document/0l-m...orieW05_2.html
http://www.4shared.com/document/Kmyk...S_157W-3-.html
http://www.4shared.com/document/ZkAP...ENTS_157W.html
http://www.4shared.com/document/EJG4...157W-4-1_.html

Here is the parts manual for the machine
http://www.4shared.com/document/b1Ls...PARTS_CAT.html
http://www.4shared.com/document/Vr8O..._H_PARTS_.html

If is the Japanense version let me know because the manuals are a little differen for both workshop and tech.
Hopefully these will get the answer you need.Do you have access to the Dr.Ex scan tool or the Hitachi Win Dr. for laptop ? Hop this might help with this .

It's a john deere 490e but most of its components are hitachi made such as the control valve and other things. I dont have Win Dr or Dr. EX scan tool. Please repost the links, those dont work. Thanks

tool_king · Jul 25, 2011

tarzan · Aug 11, 2011

I am interested in Hitachi EX120-3 manuel

tool_king · Aug 11, 2011

tarzan
Which manuals were you looking for the 120-3 operation ,parts or service.

tarzan · Aug 12, 2011

Hitachi EX 120--3

Not sure, I need to know the wiring diagrahm for the # 7 fuse VAL.c/u keep blowing a 1 amp fuse. I have already replaced the computer.

rgl726 · Aug 12, 2011

thats the PVC fuse.

you have a short circuit wiring or short circuit sensors.

check your angle sensor.

if the angle sensor is not set properly or you have an bad angle sensor it will keep blowing the fuse no. 7.

tarzan · Aug 12, 2011

where is this located, the code on the fuse says val.c/u

rgl726 · Aug 12, 2011

it is located on the side of the main pump. its a can shape sensor.

rgl726 · Aug 12, 2011

give me your email address ill send you the component location.

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