Tachometer Quit working JD 4400 tractor
- Thread starter ohiogar
- Start date
zSince I really do not know what I am looking for would you be so kind as to give me a link to an amazon signal generator for sale
regards gary
rScotty
Super Member
- Joined
- Apr 21, 2001
- Messages
- 8,261
- Location
- Rural mountains - Colorado
- Tractor
- Kubota M59, JD530, JD310SG. Restoring Yanmar YM165D
You can test the alternator connection with most any basic Volt/ohmmeter that has a setting for frequency.Both of my hand-held Fluke VOMs will not only tell if there is a signal - and all about it - but will also tell you the frequency.
That will give you the specifications of the signal that would need to be generated and will also confirm that the alternator is generating a signal.
I'd do that before investing in a signal generator.
You may already have a signal generator built right into the alternator - or somewhere else on the tractor.
Either you have a signal and the tach is fine, or you don't have a signal and no tach will ever work. Whatever the case, it makes sense to check if the tractor is putting out a signal to the gauge before buying a piece of test equipment to generate one of our own.
If you could attach a high resolution photo of the cable ends and the place on the tach where the cable attaches we might know a little more.
rScotty
That will give you the specifications of the signal that would need to be generated and will also confirm that the alternator is generating a signal.
I'd do that before investing in a signal generator.
You may already have a signal generator built right into the alternator - or somewhere else on the tractor.
Either you have a signal and the tach is fine, or you don't have a signal and no tach will ever work. Whatever the case, it makes sense to check if the tractor is putting out a signal to the gauge before buying a piece of test equipment to generate one of our own.
If you could attach a high resolution photo of the cable ends and the place on the tach where the cable attaches we might know a little more.
rScotty
Last edited:
rScotty
Super Member
- Joined
- Apr 21, 2001
- Messages
- 8,261
- Location
- Rural mountains - Colorado
- Tractor
- Kubota M59, JD530, JD310SG. Restoring Yanmar YM165D
I'm sure he is right. But does he even know that your alternator is one that has a special connector out for a pulse to run the tachometer? Did he look for that?
You might want to ask him that because maybe I'm just wrong - or more likely just way out of date. After all, it's been more than a few decades since I had my shop. But I've tested a lot of alternators, and I would usually usually just test them for output. I don't believe I have ever looked for some sort of special tach output from the AC side of the output coils. Generally I just look for charge voltage, voltage regulation & rectification, and at total amps. If they pass that, I called them good to go.
rScotty
Really Good Thought Scotty
He is an older guy that pretty much has his
guy fix stuff anymore but he tested this himself and I am sure I told him the tach runs off of the alternator and he said it was fine.
Us Old Folks Ha ha
He is an older guy that pretty much has his
guy fix stuff anymore but he tested this himself and I am sure I told him the tach runs off of the alternator and he said it was fine.
Us Old Folks Ha ha
Century3040
New member
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- Oct 29, 2021
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- 7
- Tractor
- Century 3040
Would that affect the fuel gage, hour meter, and the temperature gage as well as the tachometer? Those 4 items are not working on my tractor, I was thinking a microprocessor in the dash???
Well the 1999's did not have a computer so no microprocesser.
I was told the tach and hour meter on mine both run off of the alternator pulse. BUT my hour meter works while the tach does not.
4000's deere fuel guages go bad a lot. ususlly the tank sender.
On cars the temp sending unit in the block is usually the culprit.Cannot help with newer machines.
Good Wrenching
I was told the tach and hour meter on mine both run off of the alternator pulse. BUT my hour meter works while the tach does not.
4000's deere fuel guages go bad a lot. ususlly the tank sender.
On cars the temp sending unit in the block is usually the culprit.Cannot help with newer machines.
Good Wrenching
DieselBound
Elite Member
IF alternator is ruled out (and it IS the driver of the tach) then that leaves:
1. Wiring - would have to check output at tach side connection point of wire/harness;
2. Tach - you said new dash; does this also mean new tach? (unproven equipment- possible DOA).
1. Wiring - would have to check output at tach side connection point of wire/harness;
2. Tach - you said new dash; does this also mean new tach? (unproven equipment- possible DOA).
Well i have checked the continuity of the alt wire.
I am leaning toward the pulse thingy in the alternator. When it gets cold
i will head back in to have it checked
I suppose the new instrument cluster could be faulty but all other functions seem to work fine.
I am leaning toward the pulse thingy in the alternator. When it gets cold
i will head back in to have it checked
I suppose the new instrument cluster could be faulty but all other functions seem to work fine.