The Combine Forum banner

Right to repair, fried my CCM3 computer on 7230

4K views 31 replies 13 participants last post by  torriem 
#1 ·
Had a fuse blow the other day that powers some sensors including rotor speed, spreader speed, feeder speed, water in fuel sensor, and a couple other sensors. This happened once before so that indicates damage to wires in the harness, but a new fuse held, so I thought I was okay, at least for a while.I put in a new 10 amp fuse while the key was on (which may have been stupid), and it promptly blew out. I turned everything off and put in another 10 amp fuse and when I turned the key on it did not blow. However when I started the engine, the rotor began to turn. That's very bad. Got a Rotor EtR Current Sense Shorted error. The 12V orange sensor wire was shorted to one of the Rotor EtR solenoid wires. Long story longer, after fixing up the wiring harness and following the diagnostic procedure for the error message I determined that the computer itself was faulty. I even ran two two wires from the underside of the cab back to the Rotor EtR solenoid and still no change. I determined the computer wasn't even sending volts to the solenoid, although the current sense side of the circuit still worked. Service tech came to the same conclusion and we stole a computer out of a combine in their shop and confirmed what we suspected. So I have a replacement CCM computer module on order. @lanwickum said a few years ago he'd only changed just a few computers in his entire career. I guess I must be bad luck. Hopefully with the wiring harness fixed up, and some new wires run, we can avoid this particular problem in the future.

If I had more time I'd probably try to find a computer out of a wrecked combine somewhere.

Now for the right to repair stuff. I cracked open the computer box and sure enough, something on the board had exploded. The remains were too melted to be identifiable but I suspect it was a power transistor of some kind. The area that leaked the magic smoke is not densely populated and despite the board being multi-layered I strongly suspect boding some burned traces and replacing a few components would fix this computer. If Case provided just a schematic, this could be repaired and returned to service quickly. Instead they'll give me a core refund on the burned out computer, which they might fix, or just toss.

By the way I removed all the ribbed plastic sheathing from several feet of harness around the rotor and feeder solenoids. Lots of wire damage. I recommend anyway pre-emptively strip all those sheathings off and just tape it up with cloth or electrical tape. The smaller bundles get damaged the most from what I can see. You can pop off the joints and then the sheathing removes quite easily. this winter I'll go over it more thoroughly.
 

Attachments

See less See more
1
#9 ·
Picture wasn't very clear but there are three big pads under the burned out area if I'm not mistaken. I'm sort of tempted to take one of the other computers apart and see what that component is. But I think I'll let this one go. Maybe if there was no replacement available I might consider doing that. The unit itself is otherwise functioning. It can read voltages from various sensors just fine, and responds on the bus. It's just the 12V output(s?) that is dead.

Dealer let me use a loaner module they took off a combine they've got in the shop for a few days. Hopefully by then either I'll be done or the new module will have arrived.
 
#4 ·
That stinks, literally. Don't the smoke of those things. It needs to stay inside!!

I went through 3 bad PCU on a Ford escape I bought with a bad PCU for cheap. They kept sending me bad ones that were supposed to be rebuilt. Finally had to buy one from a junkyard. It now runs great. Somedays just don't go your way. Hope they had one available to get you going quick.
 
#5 ·
Those look like reverse current protection diodes that blew. It's common on X20 monitors and Deere CCUs....


$0.75 part. I bet it never blew a trace, from the looks of it. just had a short somewhere that overloaded it?


Not having diagrams is my biggest complaint. Especially now that one of the big manufacturers of all these boards disappeared in merger, and all the old stuff got obsoleted (name starts with a "V").
 
#7 ·
What is the nature of the damage to the wires in the loom? Are you thinking the wires are rubbing together from movement of the harness and so grinding off the insulation? I always considered the loom as a means to make tidy wire runs and protect the wires from external damage. Internal damage should not be occurring as the wires themselves should have durable insulation. Though that may be the issue right there.

I assume you are talking split loom/slit loom - that plastic stuff with the ribs running around the outside and a slit down the middle.
 
#8 ·
Yes the plastic split loom stuff is the problem. It's not the wires rubbing together that's the problem. It's actually abrasion of the plastic ribs of the split loom sheathing against the wires. I'll post a picture later today. I expect all CNH combines to have this sort of damage in their looms after some years. I think it's likely to break wires before you'll see a short. I was just unlucky to have that 12V power wire short with one of the rotor EtR clutch solenoid wires.

I'm sure it would have cost CNH more money but braided looms would not have this abrasion problem.
 
#12 ·
I don't doubt you are right Torriem about the loom wearing on the wires. Visual damage can only be caused by so many things. But that doesn't bode well for the quality of the wire. I would never of suspected it is possible for a loom, whose job is to protect the wire from abrasion, is the item that is doing the abraison. Those loom sleeves aren't that bad. So what it means is the wire itself is that bad. Wire is made for many different applications and naturally durability of the insulation is the thing that changes. Copper wire is copper wire, what is put on it is what determines how it functions long term. If wire loom is rubbing off the insulation it tells me Case really made a big oops to use a wire whose insulation can be so easily worn off.
When shopping for automotive (or any kind of wire really) there are many different options. And they get more expensive but durability for mobile equipment does rank up there pretty high as a factor to consider rather than just $$. Xlpe insulation is noticeably tougher than pvc, you can tell right away when you strip it. Xple is usually the dull colored/pastel insulation, if it is glossy in color it is usually best to avoid that wire for use where durability matters.

This link touches a bit on the different insulation classes for auto wire. I am going to bet the wiring you have isn't of a very durable insulation design.

 
#13 · (Edited)
Torriem I have a few old ccm’s laying around I don’t know where they came from they have been in the shop longer than I have. If you travel south of the boarder I would probably let one go if you wanted to tear into it. The sensors for the drills is a huge problem, there are no fan speed or meter speed sensors available anymore. The fan speed likely would not be that hard to get another sensor to work on. The meter speed I’m more worried about because of the shape it needs to fit. If anyone knows any substitutes off hand let’s hear it.
 
#14 ·
The problem with the Case wiring harnesses is they had the bright idea to zip tie the loom to the steel hydraulic lines. Nylon seems to always win so after 1000-1500 hrs of vibration the wires are cut by the loom and shorting together. I can’t remember what coming they went to cloth loom but it was either the 30 series or 40 series that helped a ton.
 
#16 ·
Hard to believe KenMB but the flagship wiring is famously notorious for internal rubbing in the plastic sheath.
This pic is down on the front axle on top off the gearbox. There’s no harmonic vibrations here like the PTO gearcase hyd lines. The gearbox usually has a pile of chaff, dust and grain on it so there’s no better cushion than that. Yet they still rub themselves to death. Puzzling
 

Attachments

#20 ·
Using wire loom like that is not made for vibration what so ever. Case should have their head examined or any other manufacture for that matter that uses wire loom like this in anything with vibration The cloth stuff has always been trouble free for me for decades on old Gleaners. The wiring Gleaners had yrs ago was superior. I can't say anything about the S series because I have never owned one but this shows what to look for when considering a combine. You just don't usually consider a wire harness giving trouble. These days fire it out the door for cheap as possible and sell for the most you can is the new normal. With everything electronic the future of how wiring is done on a machine will determine it's life expectancy. That board is likely made in China for $2. You won't buy it for that though lol. My Polaris Ranger had all the wires from the cab run through a clamp behind the cab with that loom. 18,000 km it looked just like your wires.
 
#21 ·
Good pictures Phantom. Never have I seen a loom damage wire insulationand so it has never been one of the troubleshooting possibilities to be looked into. Would always look for physical damage on outside of a harness and then suspect the damage went deeper than the loom.

I suspect in Phantoms picture what you are seeing is heat damaging the insulation. The wire is warm and pressure from the loom ribs is concentrating the heat and melting the insulation. Those rib imprints look like the insulation melted and was displaced vs been worn away. I can't see a wire vibrating in such a way to rub off the insulation in those precise spots.

That split loom has been used for decades. Yesterday threw out a coil connection from a mid 70s Ford. That's the one piece coil cap with the two coil wires molded in and you slide it onto the coil. It has split loom over the wires coming off that connection. No one ever said "yup, that vehicle is 10 years old and has split loom laying on top of the engine - we need to rewire your vehicle". Never happened in history so I don't see the split loom being the issue.

My money is on poor insulation. And yes, split loom is highlighting the issue. Replacing the loom will alleviate it to some extent. Problem is, if the insulation is melting down due to heat then you still have the issue of wire to wire contact with in the new loom.

Hydraulic lines run hot so more heat transfered to loom and then to the wire insulation.

Can't say there is an easy fix. I just wouldn't go around looking at all my +20 year old equipment with split loom all over it and think I need to trade it off right away. I think the problem stems from the type of wire insulation Case is using here.
 
#22 ·
Looking again I see the copper in those wires is ground down too. So the ribs on the loom are chewing up the wires also and is not just a heat issue. Insulation of the wire should be more durable than the plastic loom wrapped around it. But not in those pictures.
 
#23 ·
Correct. It's abrasion from vibration, not heat. You're correct, though, that if the insulation of the wires was of higher quality this abrasion would probably take much longer. Rubber insulation instead of PVC would likely last longer but be much more expensive.

I'm going to take some of the looms apart this winter around the PTO gearcase and the engine and inspect them. Could buy some rolls of fabric loom tape and tape them up.

It would have cost them more but it's clear to me CNH should have used the woven style of looms instead of the split plastic.
 
#25 ·
Torriem; I believe you’re still running a 7230 and 7240 machine? I’m assuming you’re seeing this damage in the older, higher houred 7230? Does the 7240 use same loom and routing? I had a few different flagships and it seemed every newer model the wiring was routed a bit better (but still using the loom causing your issue). We always had trouble with the nylon zip tie that hold the loom rubbing through a hydro line and making a mess but many hours were spent off season going over these spots and wrapping small pieces of swather canvas on the hydro lines and knock on wood haven’t had a blown line since. We’re around the 13-1400 separator hour mark on our 2014 7230’s and feel they have lots of life left in them mechanically but all the wire chaffing like yours has is quite concerning.
 
#26 ·
Geeze I blew those pictures up phantom posted and the loom is worn through as well.
Some vibration there. Surprising considering it looks to be bolted to the top of the transmission.
Heat shrunk on loom cover has its issues as well but generally not to this extent.
The down fall of the heat shrunk cover it seems to somehow buckle the individual wires and sometimes you get the smallest kink and you have a break the wire will go open intermittent or permanent.
 
#27 ·
Yes this was on the older 7230. The wiring on that combine is virtually unchanged from the 8010 as far as the looms and routing goes. On the 7240 they made some changes around the PTO gearbox. I haven't looked closely but I know at least the problematic zip ties near the feeder CVT are changed. They still use the ribbed split loom material though.

I found wires with wear marks on them not near any zip ties and just hanging in air. This was a small 2-wire loom. So just small movements over time can still cause problems. I think the bigger looms have tighter bundles and probably wear mostly from the tie downs. We shall see.
 
#31 ·
[КУОТЕ="торрием, пост: 3457911, члан: 6034"]
Да, пластични раздвојени разбој је проблем. Проблем није у томе што се жице трљају. То је заправо абразија пластичних ребара оплате подељеног разбоја о жице. Поставићу слику касније данас. Очекујем да ће сви ЦНХ комбинати имати овакву штету у својим разбојима након неколико година. Мислим да ће вероватно покидати жице пре него што видите кратки спој. Само нисам имао среће што сам имао кратку жицу за напајање од 12 В са једном од жица соленоида квачила ЕтР ротора.

Сигуран сам да би то коштало ЦНХ више новца, али плетени разбоји не би имали овај проблем са хабањем.
[/КУОТЕ]
Могуће је одвојити напајање свих сензора у посебну линију?!🤔
 
#32 ·
Могуће је одвојити напајање свих сензора у посебну линију?!🤔
Sure. Just have to run some new wires from the fuse to the sensors (orange wire). There are about 6 sensors that get fed off the line that gave me problems. I lost my fuse box card so I don't know exactly what Case calls this fuse. It was a 10A fuse. Feeds rotor speed sensor, feeder speed sensor, rotor cvt motor speed sensor, spreader speed sensor, fuel in water sensor, and maybe one other one i've forgotten.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top