EX120-2 and Dr Ex Software

[jefftchase]

Hi,

I have been tinkering with a ex-120-2 for a year now. It was leaky and uncared for. I been fixing the leaks, but shortly after buying last year the hydraulics went out (it was real jerky and would stall when I would steer hard right before it all went out). Anyways I replaced the dp sensor, angle sensor, filters, center joint seals (leaky), and swing reduction seals (leaky). Still need to do oil cooler and stick cylinder. I check the solenoids on the top of the pump too, seem to be working. If the machine was cold it would allow me to move the boom and swing for a minute or two, but after it warmed up it would barely move. And now when I drop the safetly lever the machine total stalls out. My ecm and pvc are blinking red. I checked all the fuses.

Anyway I order cable off ebay and it came with dr zx with a palm pilot emulator for a pc, but it will not connect to the machine. Does someone have dr ex pc version they can share or any other tips so I can read the machine.

I got the machine to limp along by taking the plate of the bottom of the pump and flipping it and putting it back in, so I think the pump is ok.

I am at the point were i either by pass the electrical systems (rather not) or start replacing wiring I guess.

All I want to do is dig a pond,
Jeff

 

[mg2361]

Welcome to HEF Jefftchase!

Despite the vintage of those machines they are quite complicated. It is extremely difficult to walk experienced technicians through testing one of these machines let alone an owner who wants to try to fix it himself. With that being said:

I replaced the dp sensor, angle sensor

When the angle sensor was replaced was it adjusted correctly? Was the little spring on the end replaced. Did you get a DP sensor that was adjustable (old style, new are not adjustable)? If so was it adjusted correctly. Either one of these adjustments being out by a few 10ths of a volt can throw the operation of that machine way off.

Did you use genuine Hitachi parts? If not then it is a crap shoot on whether they will work or not.

Did you short the two right side (looking into the plug) diagnostic connector terminals and watch for blink codes?

How did you check the solenoids on top of the pumps? Just checking voltage won't do. They are pulse width operated. They have 24 Volts to them all the time and the PVC controls their ground. Were they physically swapped to see if the operation changes?

If any fuse higher than 1 amp has ever been placed into the F7 spot then your PVC is smoked.

And yes, wiring has been an issue with Hitachi excavators as well.