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Offsetting boom problematic?

John C.

Senior Member
Joined
Jun 11, 2007
Messages
12,872
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Northwest
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Machinery & Equipment Appraiser
Here is what I am familiar with. I agree with heymcall in that the problems are all operator and owner caused. I will say that I've never seen one of these machines being sold used where the intermediate boom section was tight.

DSCN1515.JPG
 

Batkom

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Joined
Dec 24, 2017
Messages
202
Location
Idaho
I agree with JohnC. The potentiometers / wiring/ computer - are a mess to deal with. Mine were disabled, I started to go thru and fix the system. Decided instead that I would never take my eyes off the bucket when my hands were on the joysticks.
However I much prefer this style offset boom to the normal mini boom that swings in front of the cab. I use the offset boom rarely, but find it much nicer to use than pivoting the std style mini boom and then rotating the house and looking sideways at where your digging.
There’s a lot of joints to wear out n get loose though!!
 

Batkom

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Joined
Dec 24, 2017
Messages
202
Location
Idaho
Oh and by the way -
On mine some one had run the bucket thru the front window into the door corner post and up near the top of the right corner post on the cab.
So be careful if you end up with one!
Price was right though!! Took some creative body work to push it all back out - those cabs are not made out of car body sheet metal, pretty decent stuff, seemed like 14 gauge.
 

davo727

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Mar 7, 2013
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175
Location
N of Houston Texas
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Aircraft mechanic
Ok guys the style with the vertical pins in the intermediate section are the style I was asking about. I didnt know about the TAK style where the base slid over to the side.
 

245dlc

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Joined
Mar 16, 2010
Messages
1,228
Location
Canada
Occupation
Heavy Equipment Operator
Here is what I am familiar with. I agree with heymcall in that the problems are all operator and owner caused. I will say that I've never seen one of these machines being sold used where the intermediate boom section was tight.

View attachment 192260
I've seen this style of boom often referred to as 'Z' style. I worked for a sewer and water company for a while that used a number of Komatsu PC75's and PC125's for water main renewal work in places like back alley's and on tight city streets. They were alright for this kind of work but the mechanic always had to chase after operators to grease everything as some people don't know how to do that and also make sure they weren't pounding on the old cast iron pipe to break it in to smaller pieces as he had to get a replacement boom piece on one of the machines because he suspected somebody was busting old pipe with it.....just to make it fit better in the scrap bin..... He said he tried welding it and even sent it out but I guess the damage was done and who knows it could of been a manufacturing defect. I don't see as many of these machines for sale in Western Canada anymore since the earthquake in Japan. I would of liked one of the PC75's with a monoboom (regular boom) they were pretty nice machines.
 

Stinger

New Member
Joined
Feb 27, 2019
Messages
3
Location
British Columbia
I didn't have time to fully compose my thoughts on these machines when I had to leave to go to a funeral, "way too many of those these days".

The articulating boom machines in this country, for the most part, came in through the gray market and as such were not exposed to the safety scrutiny associated with use in the USA. The problem with them is that the bucket is totally able to smash into the cab and endanger the operator that isn't cognizant of this fact or is inattentive to operation at inopportune times. The manufacturers saw fit to install a safety system composed of analog potentiometers and digital encoders tied to a programable logic controller to prevent this safety issue from happening. One of the things they did to kind of hide the real reasons for the safety feature was to put a display panel in the cab and use the system to monitor the depth of cut the machine was digging. All this was useful in a trained operator's hands but unfortunately the panels were in a foreign language and there was no printed materials available explaining operation and repair of the systems. As I stated earlier the most common damage to the system is the rods and potentiometer mounted on the stick end of the boom would get damaged and the machine would stop working because the PLC did not know where the boom and stick were in relation to the cab. The only fix available in those times was to tie wire or weld the linkage in a place where the system worked and hope the operator does hurt themselves. The problem with doing that is you have now disabled a necessary safety system which is a willful violation of state and federal regulations and now may carry a felony charge and likely jail time if someone were to get hurt.

I've inspected my share of these machines to the point that I won't have anything to do with them anymore. I only have to glance at the front of the cab looking for a dent that straight lines just above the top of the kick window to know the system is disabled. You tell me you are thinking of buying one and I'll say do what you want, but my recommendation is to steer clear.
I didn't have time to fully compose my thoughts on these machines when I had to leave to go to a funeral, "way too many of those these days".

The articulating boom machines in this country, for the most part, came in through the gray market and as such were not exposed to the safety scrutiny associated with use in the USA. The problem with them is that the bucket is totally able to smash into the cab and endanger the operator that isn't cognizant of this fact or is inattentive to operation at inopportune times. The manufacturers saw fit to install a safety system composed of analog potentiometers and digital encoders tied to a programable logic controller to prevent this safety issue from happening. One of the things they did to kind of hide the real reasons for the safety feature was to put a display panel in the cab and use the system to monitor the depth of cut the machine was digging. All this was useful in a trained operator's hands but unfortunately the panels were in a foreign language and there was no printed materials available explaining operation and repair of the systems. As I stated earlier the most common damage to the system is the rods and potentiometer mounted on the stick end of the boom would get damaged and the machine would stop working because the PLC did not know where the boom and stick were in relation to the cab. The only fix available in those times was to tie wire or weld the linkage in a place where the system worked and hope the operator does hurt themselves. The problem with doing that is you have now disabled a necessary safety system which is a willful violation of state and federal regulations and now may carry a felony charge and likely jail time if someone were to get hurt.

I've inspected my share of these machines to the point that I won't have anything to do with them anymore. I only have to glance at the front of the cab looking for a dent that straight lines just above the top of the kick window to know the system is disabled. You tell me you are thinking of buying one and I'll say do what you want, but my recommendation is to steer clear.
 

Stinger

New Member
Joined
Feb 27, 2019
Messages
3
Location
British Columbia
Hi John C. just wonderin if the potentiometers are shutting down the hydraulics on my pc75uu, i have never had a problem with the articulating boom, but now the hydraulics are shut down. nothing else is affected,(engine wise etc.) any ideas??
 

John C.

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Jun 11, 2007
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Location
Northwest
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Machinery & Equipment Appraiser
If the linkages are bent and have moved outside of the calibrated position the computer will shut down all hydraulic controls. If a wire is cut or shorted it will also shut off your hydraulics.
 

heymccall

Senior Member
Joined
Feb 19, 2007
Messages
5,425
Location
Western Pennsylvania
And, on my Komatsu machines, there is an override toggle switch to allow maneuvering when the system is out of range or broken.

And never is travel affected, or swing, on mine.
 

John C.

Senior Member
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Jun 11, 2007
Messages
12,872
Location
Northwest
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I've not seen that on any of the gray market machines. Where would one look to find that switch?
 

Batkom

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Joined
Dec 24, 2017
Messages
202
Location
Idaho
They hide it under the seat!!
Seriously, it’s there but very inconvenient to get to
Also shows it in my manual
 
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