Hello guys,
I'm looking at a '93 Hitachi EX200-2 excavator. It's got a blown computer and is currently in limp mode... I've seen videos of it operating and it looks like a great machine other than the computer issue. Does anybody know how much a replacement computer would cost? I've found some in China for cheap but am very sceptical of them... If anybody has any experience with one I'd love to hear from you. I'm pretty mechanically inclined but when it comes to the electrical I'm not all that useful.
Cheers!

 

If... "IF" you can by pass the limp mode and make it run manually, it would be a good machine. Otherwise, it could get quite pricey coming up with the required parts.

I did a quick fix on a Volvo early this year, that had a massive electrical fire. The fire was in the battery box, and melted the entire main harness into the coolest looking glob of copper you have ever seen. In turn, this fried the main controller, along with a whole lot of other minor circuits.

I was able to make it run with key start, manual shutdown system. It only had 85% power availability compared to fully operational, but it got them going until we can get the new parts. Which happen to be about < > that far away, give or take.

Good luck with it if you buy it. But be sure to check out every possible problem before throwing a controller at it.

 

Thanks for the reply Pind. They actually have a Manual throttle on it, it runs very nicely from the video the guy sent me. Only problem is that the pumps are destroked and it's not moving at full speed or power. If I do get it I will go through it very thouroughly before I order a new controller!

 

Just looking at the machine you are talking about, the photos are not the greatest, but for the price, if the undercarriage is decent, and the pins aren't slopped out, it will be hard to go wrong.

You would be able, with a little electrical knowledge, to rig up a system to allow the control servos to have full travel, without the use of a compete system controller. DON'T ask me how I know this.

Good find

 

Thanks Pind, I won't ask you how you know this but I might end up asking you how to DO this... My electrical knowledge isn't that great but I do get by... I maintain helicopters for a living and quite often there are electrical issues to sort out so I do consider myself somewhat competent in that department... I've got a friend going to look at it for me tomorrow as I'm away for work. If he gives a positive report I'm sending the guy the money on Monday!
Cheers!

 

Well she's mine now! I just need to find some time to diagnose and fix the problem now.

 

Good to hear.

I am currently at war with auxilliary hydraulic systems on a ZX200, 2010 model machine, that was not set up properly from the dealer for its intended job.

I am several days into installing new piping, flow combiners, and associated controls. Hope to be done by the weekend.

Give me a complete rundown of what the machine isn't doing, and I'll do what I can for a diagnosis.

 

Hello gents,
I've tore into it this morning and found the R1 resistor in the computer is fried, no voltage comes out the other end, it's resistance is infinite, it's got a crack across the top and is obviously burnt inside. Does anybody know the ohms and watts of this thing? I'm going to desolder it here now and see if I can't find some numbers on it.
Thanks.

 

I was gonna suggest checking it for #'s.

The ex200 was a pretty decent machine. My old boss had one from the early 90's.

 

I'd run this by the good folks on www.heavyequipmentforums.com

 

I guess I should let everyone know how this story turned out.

After playing around trying to get the computer fixed I learned that the resistor that was popped was a 10 ohm 4 watt resistor. I took it to a local TV repair shop and they stuck in a new resistor. Then I started investigating why it failed in the first place, and it sure didn't take long to figure out why. The wiring harness was a total and complete mess, somebody had gone in there and spliced wires together all over the machine, but the way they did it... They simply cut the wires, stripped them, twisted the stripped ends together, wrapped a wrap or 2 of electrical tape around them and called it a job well done. They did this everywhere. In the cab, under the engine, you name it, if it was a wire it had been spliced in this fashion. Of course, engine oil dissolves the glue on the tape so some forward thinking individual covered these joints with silicone in the engine room then wrapped the whole works in paper towel. Now it turns out Silicone dissolves just as well as the glue on the electrical tape. So under the engine we now had a whole cluster of bare wires touching each other and the frame of the machine creating all kinds of neat shorts and such, all wrapped in a nice oil soaked paper towel to help speed up the glue dissolving process and to ensure a constant imersion in oil. I'm actually pretty amazed the whole thing didn't catch fire at some point.

Not being one to give up, Spitzair goes and spends several days fixing all the splices and shortcuts with proper heat shrink style butt connectors. I replaced all kinds of wires, fixed all the obvious problem spots and generally did what I thought would have been a pretty decent job. Then I was ready to test everything to see if my healing hands had actually done any good. But now the batteries were totally dead. Odd, as they started the machine great when I drove it in the shop a week or so before. I put them on the charger and came back the next day. They just barely managed to start the machine, but it did start none the less. Thinking the charging system must be on the fritz I put my meter across the battery terminals. Holy cow, 36 volts! At idle!

Now it was obvious why them batteries were cooked. I needed the machine to load a few loads of gravel before I could fix it and it proved to me that the rest of the machine was actually in very good condition. The whole time I was using the machine (in limp mode which was VERY slow) the batteries were getting a good bit more than the regular 28 or 29 volts they should have and were being boiled alive. So I hopped in my 2007 Ram 3500 6.7 4X4 Mega Cab dually and headed to Napa for a new alternator and 2 new batteries... Once I had them in I nervously tested the system again. Now we got a nice 28.5 volts at all but the slowest engine speeds.

Then it came time to test the computer. I plugged it in, hoping to see some sign of life on it's LED. But alas I got nothing. The only thing I got was a cloud of smoke from the new resistor that was put in . I shut everything off before the resistor blew up again and started looking for a possible cause as I thought that I did a really nice job on the wiring. After several hours of cursing and scratching my head I disconnected everything and ran power to just the computer by itself and lo and behold more smoke came out of it. This convinced me that the computer was totally fried. I ordered a new one and had to go back to work.

3 months later I had a few weeks off, came home and went straight to work on it. I double checked everything and then stuffed the new computer in there. Turned the key on and voila, the little LED on the new computer blinked away happily. Now I was all proud of myself for having fixed all the wires and having the computer blinking away not blowing up. I took the pumps out of limp mode and started 'er up. It started hard and the engine laboured right away, black smoke coming out of the exhaust. Obviously something's not fixed yet. I noticed the light for the fast warmup mode was on, so I pressed the button to disable it, thinking somehow that was loading the engine to warm things up faster. I heard a buzzing sound when I pressed the button. What the??? I pressed it again, same buzzing sound. Somehow this button had gotten connected to the window washer fluid pump. Cursing again, I crawled behind the seat and pulled out the washer fluid pump relay. Thinking this was the problem I fired it back up. It started easy, no black smoke and everything suddenly worked perfect. It was load sensing, all the movements were smooth and precise, the speed was up, and I was starting to smile like it was christmas.

But Santa didn't stay. In fact he left less than 2 minutes later and the pumps went to full stroke once again, the engine smoked and stalled as soon as I tried to activate a funciton. I rooted around in the wiring, trying all kinds of things but nothing worked. Being the glass half full kinda guy I realized that at least all the sensors must be working and that the computer works too. I then bit the bullet and ordered an entirely new wiring harness. It showed up 3 days later and the fun began. I put it back into limp mode, drove it in the shop and tore all the old wiring out and put the new harness in. It went a lot smoother than I thought but my hands looked like I got into a fight with a cat.

Once I had all the wiring in, I left it in limp mode and pulled it back out of the shop. Right away though I could tell that it was working because the travel speed changed when I pressed the speed button, something that never worked before. Once clear of the shop door I took it out of limp mode and gave it another go. I'm happy to report that my smile made a comeback as did all the functionality of the machine. It worked flawlessly, just like it should. There were some alder trees that were begging for attention so I walked the machine over to them and plucked them all out one by one, giving the machine a light workout. It didn't skip a beat and my smile kept getting bigger!

The machine has since been on a demolition job where it got great reviews from the guy running it. It's had about 30 or 40 hours put on it since and it's been running and operating great. It turned out to be a great purchase and even with the repairs I've had to do it still was a great buy. The undercarriage is in really good shape, most of the pins are good and tight and the engine purrs like a kitten. I'm really glad I bought this machine and very happy with the way it turned out. The guys over at www.heavyequipmentforums.com have been very helpful. Now I just wish I could get some time off of work to go play with it myself.

Sorry for the long post and for waiting this long to update it... I'll try to dig out some pictures of the wiring and such...