Komatsu pc50 control panel - can they be repaired?

[Scaper]

I have a Komatsu pc 50 and the control panel has stopped working. The machine starts and runs fine without it but the fuel gauge, hour meter, lights and high speed functions do not work because of this.

I was wondering if anyone knows if these control panels can be sent out somewhere to be repaired since the dealer wants $1000 for a new one.

Any help would be greatly appreciated.

 

[Green40]

Are you sure your instrument panel is bad ? Do quick check with a an ohm meter and see if your wiring harness is providing any input to the panel gauges. Fuses good and panel securely plugged in and connection is clean?

 

[Scaper]

Yeah, we took the panel out, checked that the connections were clean and properly attached. This is a module that has all the gauges contained in it, with one plug/harness feed into it. I didn't have an ohm meter, but did use a test light to see if the panel was getting power which it was. This was about two months ago, and at that time the panel would work at times and not at other times with no rhyme or reason as to why. It was doing this when we had it out (as well as when it was installed), if you turned the key on, one time it would work, the next time it might or might not work, and so on. Now, it hasn't worked any in a month or better.

 

[Green40]

Could it possibly the ignition switch? I know they have several leads going to them. When starting the machine, the "warning" buzzer beeps, does this go on and off intermittently also?

If your having a intermittent failure with the gauges maybe its somehow related to the ignition switch which might be responsible for a portion of the buzzer/ panel circuit?

I had a similar issue before, exactly as you described with intermittent failure and after leaving the machine outside in the rain it started to work again. I think the switch go wet inside and made the needed contact ??? Not sure if that helps but keep at it.I will ask another source there thoughts and see what I find.

 

[Scaper]

The "warning" buzzer would only function when the control panel functioned (I believe it's located inside the control panel). I used the test light on the back of the ignition switch when I had it apart, did not observe any difference on what was functioning there when the panel worked and when it did not work. This is what makes me think the control panel itself is bad, but I'm certainly willing to hear anyone's ideas.

 

[John C.]

If it works once in awhile then you most likely have a wiring problem going too or from the panel. I've also seen problems on ground connections on all Komatsu excavators. They are mounted on biscuits so the cab has to be grounded to the machine frame with a wire.

You didn't mention what Dash series your machine is.

Also, I had heard someone could repair the panels years ago but never was able to confirm that. From where I sit now it was probably just wishful thinking.

Good Luck!

 

[Green40]

The buzzer on the machine I mentioned was under the operators seat.

 

[Scaper]

If it works once in awhile then you most likely have a wiring problem going too or from the panel. I've also seen problems on ground connections on all Komatsu excavators. They are mounted on biscuits so the cab has to be grounded to the machine frame with a wire.

You didn't mention what Dash series your machine is.

Also, I had heard someone could repair the panels years ago but never was able to confirm that. From where I sit now it was probably just wishful thinking.

Good Luck!

Well, the thing is, I could not find any change in what wire leads to the panel had power when the panel was working and when the panel wasn't working, which makes me suspect the panel itself is bad - but I'm open to any suggestions anyone has.

As far as the ground connections, the machine starts fine and the power leads to the panel were getting power equally when the panel functioned and when it did not. I would think if I had a bad ground, I would be having problems with these other things as well (based on my experience with ground issues I've had with other machines and trucks), but then again, bad grounds do all kinds of quirky things, so any thoughts you might have would be helpful.

The machine says on it PC50MR with no dashes, the owners manual says PC50MR-2

 

[Scaper]

The buzzer on the machine I mentioned was under the operators seat.

I'm not exactly sure where the buzzer is located, but it seems to be controlled though the control panel, it only works when the panel is functioning.

 

[Green40]

I agree about grounds doing strange things.
You wouldn't lose much by cleaning all ground wires you can find and as mentioned running a separate ground for the cab to the machine frame.
At least you could rule that out.
Cab or open machine? Do you have a schematic of how the buzzer circuit works?

 

[Scaper]

No cab, open machine.

I don't have a schematic for it unfortunately.

 

[Green40]

See if your dealer is willing to print one out for you. Mine did for FREE! It helped me alot.

 

[Green40]

Any luck getting your panel issues resolved ?

 

[Scaper]

No, I haven't had much time to try do do anything with it in the last couple of weeks with the holidays and been snowing here, so I've been busy. Rather cold out right now as well, next week looks warmer, will probably get back on it then.

 

[MrKomatsu]

it is very rare to have a monitor panel go out....there are to many elec. safety devices in the system to protect it..
years ago when Komatsu first came out with the dash '6" series there was a rash of panels being sold... due to bypassing
and such things....there was a time when we in fact opened up them and bought the nessecay componets at Radio shack...
but that was just pure luck....properly trouble shoot your elec. system....there are so many people here on this forum that i do
believe that together we can fix it.....good luck

 

[Scaper]

Whatever suggestions you have to trouble shoot the system would be much appreciated. I will look over the grounds as best as I can next week when it warms up here some - I don't do my best diagnostic work when it's below freezing and windy.

 

[Scaper]

UPDATE - I took a through look at this machine today. The warning buzzer is located under the control panel but seems that it is controlled though the control panel. When I probed with my test light, I noticed one contact in the plug that leads into the control panel would cause the warning buzzer to sound. Thinking it might indeed be a bad ground I decided to add a supplemental ground wire to this lead to see if the control panel would then work. The panel was still dead and the warning buzzer would not turn off after the machine was started like it did normally before the panel stopped working, so it would seem the buzzer and possibly the panel are controled though the ground.

 

[JGS Parts]

Well another thing though if it dose turn out to be the panel i do not recommend buying a whole new unit it will be big $$$$ just buy the boards for the inside of it if you need a hand in finding some let me know can point you in the right direction.

 

[Scaper]

Well another thing though if it dose turn out to be the panel i do not recommend buying a whole new unit it will be big $$$$ just buy the boards for the inside of it if you need a hand in finding some let me know can point you in the right direction.

Sure, I would be interested in getting a new board(s) for it. Any help you can provide would be greatly appreciated.

 

[welsford]

Scraper did u figure it out? I have the same problem with my pc50.