I have been helping the father-in-law with his EX120-2 (serial 12N-35444)as we have some real issues with. the machine would run untill it was hot and then any work on the hydraulics would be like this one in this tread, lots of black smoke with the hydraulics loading it up something shocking. We have had issues with the Hydraulic computer dying as well as the odd fuse blowing. To cut the story short, the computer had a resistor burned out (R1, 10 ohm 4W) This was replaced and all the push button modes came back to life and I think we had to replace Fuse 6, Sw.Box. All seemed ok, but when we had a big job and the maching had to work hard for 30-45 minutes, then the fault returned.
I had monitored the heat on the resistor when we started and it was ok, but it had failed again. We have since put another resistor in and I cant seem to find anything else faulty on the computer (I am an electronic tech by trade) and done a search of the whole machine for wire shorts etc and did finally find one on the wires to the quick hitch solenoid, the insulation had rubbed through and may have been randomly shorting the 24V outs. That may explain the fuse failures. We then (after reading the posts here) measured all the coil (solenoids) resistances, all (SA, SB etc)were around 23 ohms on the digital meter, however SI measured 60 ohms, (I dont have the manual to show what each one controls, but the wiring loom was labeled) but this is a slightly different device in appearence, is this normal? It seemed stable, so I concluded that it may be ok and felt that since the computer pulled to ground to turn it on, it would be unlikely to cook the resistor in the computer which is on the 24V rail.... Again to cut the story short, we restarted digging and were working it hard for some time, a trench in mud rock 8' deep 40' long 4' wide before the hydraulics stopped again, with the computer down with R1 overheated....
Without a detailed circuit diagram, I'm a little lost for ideas now....
Has anyone had issues with the computer blowing after working the machine to it gets hot? We were quoted around $3K for another computer, so it isnt a easy thing to replace when it's likely to blow from something external to it.
Suggestions anyone? Are circuits available anywhere?
I had monitored the heat on the resistor when we started and it was ok, but it had failed again. We have since put another resistor in and I cant seem to find anything else faulty on the computer (I am an electronic tech by trade) and done a search of the whole machine for wire shorts etc and did finally find one on the wires to the quick hitch solenoid, the insulation had rubbed through and may have been randomly shorting the 24V outs. That may explain the fuse failures. We then (after reading the posts here) measured all the coil (solenoids) resistances, all (SA, SB etc)were around 23 ohms on the digital meter, however SI measured 60 ohms, (I dont have the manual to show what each one controls, but the wiring loom was labeled) but this is a slightly different device in appearence, is this normal? It seemed stable, so I concluded that it may be ok and felt that since the computer pulled to ground to turn it on, it would be unlikely to cook the resistor in the computer which is on the 24V rail.... Again to cut the story short, we restarted digging and were working it hard for some time, a trench in mud rock 8' deep 40' long 4' wide before the hydraulics stopped again, with the computer down with R1 overheated....
Without a detailed circuit diagram, I'm a little lost for ideas now....
Has anyone had issues with the computer blowing after working the machine to it gets hot? We were quoted around $3K for another computer, so it isnt a easy thing to replace when it's likely to blow from something external to it.
Suggestions anyone? Are circuits available anywhere?
