Case 580c Circuit Breaker electrical question

[stinky64]

Shoulda caught that, was going by the title.

 

[edgephoto]

The warning bulb supplies 12v to the executor at the alternator. If the bulb is burnt out it can't provide the 12v and the alternator won't charge.

With the key on and engine off the bulb should light up. Once running it should go out. Make sure you don't have a voltage drop going to your alternator.

You should measure all you alternator wiring looking for voltage drops. Even when you said your alternator was working that voltage is way too low. You have something wrong and need to diagnose it.

 

[franklin2]

That diagram shows the old GM style alternator, which my 480c has also. Very simple setup. As the diagram shows, terminal 1 is the feedback for the internal regulator. It monitors the system voltage so the regulator knows how hard to run the alternator. It's just jumped to the output terminal.

Like the other guys said, terminal 2 brings the alternator online from the keyswitch. If that wasn't there, the alternator would run the battery down while it sat there not running. When GM had these in the late 70's and early 80's vehicles, they would put a resistor across the indicator bulb, in case the bulb burnt out the alternator would still get a signal to start charging. Don't know if Case did this or not.

 

[Ed White]

Thanks Tinkerer, you nailed it! removed dash unit , replaced three bulbs and hoorray turn signals , and especially tach and alternator ( $185.00 wasted purchase) working as it should ,14.60 vom. I say wasted because the old alt was probably just that same issue , never would have figure a bulb acts like a fuse , completing the circut, but while runing engine the alt light is stayin lit?? now what?

 

[Ed White]

Also thanks to Edgephoto, for the tips . Burned out bulbs was the culprit, but alt light stays on with engine running?? and fuel guage still not working , where does it connect 1993 case 580SK

 

[Tinkerer]

The light bulb should not be lit up when the alt is charging.
If the bulb doesn't doesn't stop being illuminated and the alt is charging I would guess there is problem with the wiring to it.
The bulb doesn't act as fuse in this situation.

 

[Ed White]

SORRY GUYS, BACK TO SQUARE ONE, DIDN'T KEEP WORKING! ran the hoe for a few minutes and alt light burned out , lost tach and alt only putting out 12.50 again!! No am not computer or cell phone savvy for sending pictures, The back of the dash is a printed circutry schematic ( no wires to the bulbs) they get contacts on the printed circutry that has little copper circles, just plug in and turn 1/4 turn to lock in place. Is alt bulb a specialty one, I just had a regular 12 volt plug in bulb on hand.

 

[Ed White]

SORRY GUYS, BACK TO SQUARE ONE, DIDN'T KEEP WORKING! ran the hoe for a few minutes and alt light burned out , lost tach and alt only putting out 12.50 again!! No am not computer or cell phone savvy for sending pictures, The back of the dash is a printed circutry schematic ( no wires to the bulbs) they get contacts on the printed circutry that has little copper circles, just plug in and turn 1/4 turn to lock in place. Is alt bulb a specialty one, I just had a regular 12 volt plug in bulb on hand.

 

[Ed White]

is the ignition switch faulty? haven't found a wiring issue

 

[franklin2]

If you need to use the hoe for some important job coming up, just take a small alligator clip jumper and jump #2 teminal to the large bat terminal. It should charge. Just make sure you pull this jumper off when you turn the machine off, or it will run the battery down overnight. Just use the jumper again if you need to use the machine again till you get it figured out.

This may also get in your head how it works. 12v on #2 terminal activates the alternator to charge.

 

[Tinkerer]

Umm, Ed said it is charging, but the red bulb continues to stay lit.
It could be dirty or loose battery cables. Especially the ground to the tractor frame.
A hard glaze on the serpentine belt is another possibility.

 

[Ed White]

Good clues and advice. Already cleaned all battery connections( took battery ground off and cleaned) , replaced all bulbs on circuit board , pulled out resistors and cleaned appear to be working ( clicking noises) by-passed tach wire ( W ), lights on dash oil,hydraulic, brakes , water come on with key just before start, but no alternator light. Alternator putting out 12.55 ( VOM) but no gauges work including tach, after starting engine. The alt light stayed on for about 10 minutes, the first time I replaced bulbs 1 Might just try that #2 jumper idea. Doubt that belt is an issue since it did put out 14.60 on the first go around. Going to replace resistors and ignition switch,( just as a desperate trial) , and run a new tach wire next, but have no hope that will do anything. Circuit board doesn't seem to have any burnt issues but not positive that bulbs are getting good contacts, even though they look ok.

 

[edgephoto]

When the alternator was working what was the voltage you measured at the battery terminals? A full fielded alternator can put out around 18v which will burn out bulbs. The bulb does not act as a fuse. It actually provides voltage to the regulator via the filament. If the regulator goes bad it puts a ground on that wire which causes the bulb to light up. As someone mentioned some vehicles actually had a resistor in parallel in case the bulb burnt out.

Let's help you diagnose this problem and not just take wild guesses.

Do you have a a wiring diagram or does someone here have one they can post. Then I can help you with what measurements and tests to make.

 

[Ed White]

The voltage was the same at battery as it was at alt. Is the regulator on the alt ? Found two resistors down deep in dash, or are they regulators. removed them, and a friend thought they were ok, but weren't sure how to test them. Ran a continuity test on tach wire appeared to be ok. all bulbs have been chacked replaced ( 12 of them). turn key on just before start and Hydraulic, AIR , Oil ,trans light up but not alt! brake light came on couple times also. after starting, alt reads 12.55 and battery the same. all wiring and harnesses appear normal no burnt or broken, spade clip wire was a little loose on new alt and tightened it up. Really stumped, . Thanks for hanging in there for me. None of the gauges move after starting, They all worked when first rplaced three bulbs ( except fuel gauge), and like I said it ran for about 10 minutes with all the lights and gauges working , but alt light stayed on during that time, which I knew was not right. after shutting engine off , have never had alt light again even with new bulbs.??? and the alt at that time was reading 14.60

 

[Tinkerer]

Ed; This image is from the service manual. It isn't a very good one.
Do your wire connections match these ??
There is a male/ female plug in the wiring harness. It would be prudent to unplug it and look for corroded and/or burnt wire connections in it.

 

[Tinkerer]

Here is the schematic diagram. Unfortunately it is printed on 6 different pages in the service manual.
If the color codes for the wires are need, I can post them also.

 

[Tinkerer]

 

[Ed White]

Yes, that is same as my 1993 580sk. # 3 has a W for the tach, and cleaned and tightend spade clip. Red/yellow for tach, blue/yellow for #1wire (alt) ?? Thanks for pictures wire colors very helpful. Still not sure where regulator is located

 

[Tinkerer]

The regulator is inside the alternator. They are quite easy to replace and not very expensive.

 

[franklin2]

Umm, Ed said it is charging, but the red bulb continues to stay lit.
It could be dirty or loose battery cables. Especially the ground to the tractor frame.
A hard glaze on the serpentine belt is another possibility.

I don't think it is charging? Post 27? Tell him how to jump the bat voltage to the exciter wire on the alternator just to see if it will charge.