tbone95
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Post by tbone95 on Nov 16, 2020 10:36:21 GMT -6
Old school, not DAM, just straight auto header height on a 4420 Deere and 215 Flex head.
Is it really as simple as: if the header is too high, the linkages make the switch contact and energizes the valve to lower the header. If the header is too low, the other switch closes and energizes the valve to raise? Really just like any DC this way or that way configuration?
So, you should be able to trouble shoot with a jumper. Disconnect header, turn on AHHC, jump from power to one other wire, will raise, other wire will lower??? Seems that's all it could do. . .
In use, what do you do while turning on the end rows? Just hold the lever up?
We just got this last year, and only used it on a few acres. Worked sort of OK, not enough to really judge. Had a lot more acres to cover this year with it. It seemed to work better on the first 30 acre field this year than it did the rest of the way. It will raise when it encounters a high spot, but doesn't seem to go back down by itself.
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Post by cptusa on Nov 17, 2020 8:17:01 GMT -6
There has to be something to tell it to go back down I would think, like a potentiometer. Otherwise it will just go up and you would have to manually put it down all the time. I'm sure not familiar with those machine though.
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tbone95
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Post by tbone95 on Nov 18, 2020 9:52:40 GMT -6
Captain, that's what the other switch does. In the sweet spot, neither switch is closed, a bump should activate one switch, a dip should activate the other. Electrically, it seems like any other "reverser" DC arrangement, like a snow plow on a truck, or a spout control on a chopper, or a power window....At least that's what I'm trying to confirm.  The DAM system....I think....has a potentiometer and more wires. This is a "simple 3-wire system. |
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Post by kenmb on Nov 18, 2020 10:30:06 GMT -6
I don't have a clue how it works but given two possibilities - pot or contacts, I would get my ohm meter out and start the basics of understanding any given circuit.
If a potentiometer, it will have full resistance of the pot read across two of the wires, and a variable resistance across the 3rd. If you don't get measurements to confirm this, you either don't have a pot involved or it is defective.
If a contact arrangement with a common wire and then one wire each off a raise and lower contact then again, a guy should be able to figure out which contact is which by operating the mechanism that changes the contacts and look for a change in state from normally open to normally closed. If you don't notice a change of state, you may have a bad switch.
A parts manual is a good starting point to. If you can identify the part # of the mystery component then you can usually find information on it or a picture.
A guy needs to know how to use a multimeter these days so hopefully everyone knows the basics. One thing a lot of guys don't do is make test leads with alligator clips instead of probes. Buy a set of probes, cut the probes off and install smallish alligator clips. I use these 99% of the time. When I need a probe I often put a small screwdriver into the alligator clip jaws or a small wire, paper clip, what ever, and probe.
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tbone95
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Post by tbone95 on Nov 20, 2020 10:50:29 GMT -6
I can most definitely assure that there is no potentiometer. I also know that there are 2 switches, and in fact they are both NEW, I replaced them last year on the advice of a Deere mechanic who stopped by and looked at it (this is a story in and of itself, a bit of the Gong Show variety) but I digress.
I guess my question really comes down to the "dumb question" variety....I mean honestly, what else could 3 wires and 2 switches do except 1)nothing 2)raise until switch breaks 3) lower until switch breaks. Guess just looking for confirmation and confidence.
Sure, there's more to the system than that, there's drop rates and a cutout chain and of course the hydraulics. But electrically, to troubleshoot/isolate the header from the combine and see if the combines side works, I should be able to jump the wires together and raise or lower accordingly. That was my thinking.
Thanks for the replies guys.
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Post by kenmb on Nov 20, 2020 12:42:12 GMT -6
Ok, good to know. Yeah, I can see a set up of 2 switches being used for a raise and lower command. Exactly the same as you could control the header height manually. Push one button and it goes up, push the other and it goes down. And so approach it that way.
That would mean, if I push a button and nothing happens, then the basics are either the switch contacts, the wires from switch going elsewhere, or the device that receives the signal from the button. Power would need to be present also.
I am guessing those switches feed into some kind of control box. For me, the easy stuff is to prove out all things I can outside of the black box. Either I found my problem outside of it or I have a pretty good reason to suspect the black box is the problem so I either replace it or get more technical help.
Now getting to your point on end rows, this is where a black box comes into play. Something needs to remove command from the auto header height switches and give it to the operators manual controls in the cab. Can't have header calling for a lower while operator is calling for raise so there needs to be some kind of hardware to sort that out. There is a whole world of speculation open if a black box is involved.
Electrical drawings are a good starting point and mandatory to move from wild speculation to thoughts that are specific.
How are the switches under the header operated? I imagine a paddle that moves one direction and toggles a switch to raise, the paddle moves the opposite direction to hit switch to lower header. Probably uses gravity or spring to make sure paddle hits the lower switch. If header is up there needs to be a constant bias to lowering. You will be able to manually operate whatever linkage is involved on the header and make sure both switches get operated. This rules out sticking mechanicals and moves into electrical testing.
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tbone95
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Post by tbone95 on Nov 25, 2020 11:15:43 GMT -6
The switches are located on the RH end of the header. Under the platform are, if I recall correctly, a total of 6 "floating linkages" that come out to the cutter bar and back to a common rod. The rod comes out of the end of the header where the switches are, and there's a cam on the end of it that actuates the switches depending on how the linkages twist the rod. Clear as mud? It's actually pretty straight forward but maybe hard to say. As the cutter bar flexes, these floaters connect to that rod, if any area of the cutter bar rises up too much, the linkage twist the bar and in turn actuates the raise switch. If the whole bar relaxes down, the bar gets twisted the other way and actuates the "Lower Switch".
As for black boxes....I really don't think so? I have to dig some more. I'm "pretty sure" all the switches do is control a solenoid valve bank with live hydraulic pressure plumbed to it. At the end row, I'm not sure. Either the manual lever is valved such that it takes precedence, or maybe you're supposed to shut the toggle switch off when you turn. That seems kind of silly, but that's the only control in the cab there is, a toggle switch for the AHHC, and a manual hydraulic lever.
Anyway, thank you for the discussion. I'll giver 'er hell one of these days. Might be a moot point as the clutch on the old girl is buggered.
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Post by Albertabuck on Nov 25, 2020 13:35:01 GMT -6
I looked several days ago but I got no info on this system, I have the manuals for the 100 series combines but not the 20s. As someone had suggested I never did look at it in a parts diagram. Sounds like a simple enough system. I am wondering is it possible you have an issue with the solenoid valve perhaps? For example on my Macdon swather, especially when its cold in the fall, it becomes very difficult to just bump the table up a little bit without it either doing nothing or going too far. Its not that the spool is hanging up in the magnetic coil, I think part of it is the switch itself, as it does it even when the oil is warm. The reel curcuit does not do it. Nor does it do it in the summer when I got the hay table on. Must be some books that cover this set up, your dealer should be able to at least let you look at the book and even photocopy the wiring schematic for the system.
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Post by kenmb on Nov 25, 2020 17:21:26 GMT -6
What you describe there about the linkages is what I was envisioning so on the right track.
I was thinking that the system could be setup with interlocking electrical contacts on relays rather than some kind of black box doing some logic functions. It would be similar in ultimate function. However the hydraulic solenoid arrangement I can see working in that same regard. A solenoid rack and block could be designed with passages to give one circuit priority over another so I would think you are on the right track. There are other possibilities, but I would say whatever thinking I had using electrical controls could be substituted with hydraulic system design.
AB is probably getting close then. Could be a solenoid sticking a bit. Or electrical connection. Get back to same troubleshooting steps of proving out the wiring from the header to the solenoid arrangement and after that, how you prove out that hydraulic block is a bit of a challenge for me.
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