So long story, my grandfather in his 80's decided he wanted to be able to move dirt with something other than a shovel and wheel barrow and bought a used EC35 for him it worked well. He might of used it once every 6 months for a couple hours. He passed away this summer and I've ended up with the Volvo. I've used it a few times and its done OK. Yesterday I fired it up and drove it about 25-30 ft and started digging a small hole and the hydraulic boom lost all power, tracks and blade work fine. I've read a few things on here and a couple other places that are stating that its a fairly common problem and generally the computer/display is the culprit. However at $3000 to replace is undoable for me. One gentlemen pondered if it would be possible to bypass the computer and install manual switches to engage the hydraulic systems and add gauges to monitor the engine functions? I have done zero trouble shooting at this point and that's next on my list but I really prefer manual controls/readouts to computer displays.
Did just the boom loose power? How are the arm, bucket and swing? Do you have function with no power or no function at all?
Sorry to hear about your Grandpa, the guy liked his toys it seems. Well, hmmm, how about a reboot, disconnect the batteries for an hour? so the hand controls don't work but the blade/tracks are on the floor? Is it possible that its part of some safety lock, seatbelt or such that's failed and thinks its unsafe? Could be a bad wire or broken ground some place that's got you all wedged up. Are there any warning indicators? does the display seem to work okay? usually computers are all or nothing?