My Craftsman uses two diodes to control alternator output, and the diode that outputs to the lights has gone bad. Figure the other diode for charging can't be far behind. There's also a major backorder all over for those diodes. So, I was wondering if anyone has swapped out the diodes for a solid state voltage regulator. Or, if not, if anyone would know what would be required to do the conversion.
ledzilla
The incandescent lights usually don't use a diode because they can work off of A.C. current just fine, An L.E.D. light has to have D.C. current to work.
Your battery needs D.C. current to accept the charge.
The diodes change A.C. current to D.C. current. On the type charging system you have, it is an 'Un-regulated' system meaning the output of the stator/generator is limited by its size and doesn't need to be regulated so it won't overcharge the battery. It has a limited output to it and is basically controlled by engine speed.
We would need to know what engine you have to know better what type charging system it has. It sounds like it has the 'Dual Circuit' stator on it. 1 part of it is A.C. output that doesn't require a diode, the other part is D.C. output that uses the diode and goes to the battery for charging.
The 'Solid State' type regulator/rectifier unit and that uses a different type of stator on the engine and sometimes a different flywheel because of the magnets inside the flywheel, depending on how many amp output it is designed for. The higher output used bigger magnets than the low output units do.
It depends on the engine you have to see what different types of charging systems were made for it and how you want to re-wire the electrical system to accommodate a higher output charging system, which can be done on most engines and tractors.
If the tractor has an Electric PTO clutch on it, it would usually have the higher amp output charging system with a Solid State type voltage regulator and the higher output charging system with the bigger stator and bigger/stronger magnets built into the flywheel.
Your battery needs D.C. current to accept the charge.
The diodes change A.C. current to D.C. current. On the type charging system you have, it is an 'Un-regulated' system meaning the output of the stator/generator is limited by its size and doesn't need to be regulated so it won't overcharge the battery. It has a limited output to it and is basically controlled by engine speed.
We would need to know what engine you have to know better what type charging system it has. It sounds like it has the 'Dual Circuit' stator on it. 1 part of it is A.C. output that doesn't require a diode, the other part is D.C. output that uses the diode and goes to the battery for charging.
The 'Solid State' type regulator/rectifier unit and that uses a different type of stator on the engine and sometimes a different flywheel because of the magnets inside the flywheel, depending on how many amp output it is designed for. The higher output used bigger magnets than the low output units do.
It depends on the engine you have to see what different types of charging systems were made for it and how you want to re-wire the electrical system to accommodate a higher output charging system, which can be done on most engines and tractors.
If the tractor has an Electric PTO clutch on it, it would usually have the higher amp output charging system with a Solid State type voltage regulator and the higher output charging system with the bigger stator and bigger/stronger magnets built into the flywheel.
If you have the owners manual, or can get one online, you should find the diode(s) that are used. Generally, the in-line diode(built into the plug coming from the engine) can be replaced with a generic diode that handles the output voltage and the amperage passing through.
If you want to combine both AC legs of the charging system, you can feed them to a rectifier/regulator and then feed the DC from there to the battery and the power input to the headlight switch, converting the headlight power to DC(you can use LED bulbs then if desired).
A Kohler Command rectifier regulator can be gotten that should handle the output of the charging system and regulate it to protect the battery. Another one is the John Deer unit. Both have 2 lines for AC input, and one output for B+, and a ground. Simple to connnect, but you have to be correct or can cause damage. Be sure to NOT pass DC to the magneto, as it can be damaged readily by DC voltage.
tom
If you want to combine both AC legs of the charging system, you can feed them to a rectifier/regulator and then feed the DC from there to the battery and the power input to the headlight switch, converting the headlight power to DC(you can use LED bulbs then if desired).
A Kohler Command rectifier regulator can be gotten that should handle the output of the charging system and regulate it to protect the battery. Another one is the John Deer unit. Both have 2 lines for AC input, and one output for B+, and a ground. Simple to connnect, but you have to be correct or can cause damage. Be sure to NOT pass DC to the magneto, as it can be damaged readily by DC voltage.
tom
The tractor is model # 917.255970 with engine 422707-1243-01. And it does have an electric PTO clutch. This wouldn't be so much of an issue if it weren't for the fact that the diodes are on massive backorder everywhere and absurdly expensive.
But, I've included a shot of the tractor's wiring diagram showing that part of the circuit.
![Image]()
But, I've included a shot of the tractor's wiring diagram showing that part of the circuit.
To be honest, I've been wanting to install different lights powered off of the battery, using the original circuit to instead power a relay. I wanted to put a LED flood lamp on the front and a couple red LED markers on the back. This tractor is mostly going to be used as a winter driveway plow and I want to make sure when running after dark that I can see and be seen given that I'm on a main road. Just was never really certain if the charging system could handle the LED flood or not.
If you have the electric PTO it should have the higher output, say 10-15 Amps unless someone changed something. The numbers will help us to look it up, thanks.
With the higher output you should be able to wire in the light you want to put on it right from your key switch or battery.
With the higher output you should be able to wire in the light you want to put on it right from your key switch or battery.
The motor should have the dual circuit alternator
| Alternator | 592831 |
| Type | Dual Circuit |
| Testing RPM | 3600 |
| AC Volts | 14vac |
| DC Amps | 3adc, 5adc thru reg |
If he has the Tri-Circuit stator #691065 he will need the harness #691955 that has the 2 diodes in it.
#691955 Harness should be available from a Briggs and Stratton dealer.
Hopefully that will be of help to get the harness, then he won't have to try and find the diodes to repair it. The harness comes with the diodes installed.
I would think with an electric PTO clutch, it should have a stronger output for the clutch than the 5 amps, those are usually a 10amp output but not always.
If he's going to use an LED light, they don't use much power so a lower output stator will work.
Some of those systems use a small regulator, there are 2 different ones, one a 9 amp, the other a 16 amp.
The harness #691955 is around $60 in price.
#691955 Harness should be available from a Briggs and Stratton dealer.
Hopefully that will be of help to get the harness, then he won't have to try and find the diodes to repair it. The harness comes with the diodes installed.
I would think with an electric PTO clutch, it should have a stronger output for the clutch than the 5 amps, those are usually a 10amp output but not always.
If he's going to use an LED light, they don't use much power so a lower output stator will work.
Some of those systems use a small regulator, there are 2 different ones, one a 9 amp, the other a 16 amp.
The harness #691955 is around $60 in price.
That's not the standard connection for a Tri-circuit alternator connection, that would use a single round wire connector to the harness that has 2 wires with diodes coming out of it.
Somebody made up that harness with the rectangle connector.
The dual circuit alternator uses the rectangle connector like the black one shown, and is a white connector coming out from the engine.
I don't like the way they 'Jumped' a wire in between both wires of the output after the diodes, that could possibly damage the stator and a regulator if there is one, plus not regulate the voltage properly if there is no regulator.
Somebody made up that harness with the rectangle connector.
The dual circuit alternator uses the rectangle connector like the black one shown, and is a white connector coming out from the engine.
I don't like the way they 'Jumped' a wire in between both wires of the output after the diodes, that could possibly damage the stator and a regulator if there is one, plus not regulate the voltage properly if there is no regulator.
Ok, so, based off of the factory wiring diagram, the red and orange wires that run together into that connector are correct, with red being the charging circuit and orange being the lighting circuit. From things I've seen, the diodes are not original, and factory definitely would not have used such spade connectors, especially not without any heat shrink protection.
I attached a photo of the harness mentioned. Which wire should be connected to which section of the circuit? My first thought is that the red wire with the round white connector would connect to the AC circuit coming from the engine, given that it should connect right up to the existing round connector.
![Image]()
I attached a photo of the harness mentioned. Which wire should be connected to which section of the circuit? My first thought is that the red wire with the round white connector would connect to the AC circuit coming from the engine, given that it should connect right up to the existing round connector.
The red wire goes to the battery, the white wire goes to the lighting circuit in that pair that comes out from the heat shrink.
The single red wire that comes out the end before the diodes goes to the engine, which should be a black wire if it has the Tri-circuit stator/alternator.
If it is a Tri-circuit there should be just 1 wire coming out of it.
If it is a Dual circuit there would be 2 wires coming out of the stator going into a rectangle terminal coupler with 1 red wire with built in diode that goes to the battery, the black wire without the diode goes to the lighting circuit.
Looking at your picture, it appears there is a white connector terminal coming out of the engine, That is usually from a Dual circuit stator/alternator that should have a black wire and a red wire coming from the engine.
If that's what it has coming out of the engine then there is a different harness that connects to it than the one I listed with the part number earlier. I listed the Tri-circuit harness number, but that engine is supposed to have the Dual circuit stator.
If it has the dual circuit and the diode is good in the wiring coming out of the engine, then you just run the red wire that is rectified with the diode into D.C. to your battery or ignition switch that would send it to your battery depending on how the key switch is wired, the black wire would then wire in to your lighting circuit wiring. It would be A.C. current for the lights. The Dual circuit has the white plastic rectangle shaped connector coming out of the engine with the red and black wires.
An LED light needs D.C. current to light properly. If you feed it with A.C. it will flicker like a strobe light.
It's hard to tell if you have it wired correctly because the wires are of a different color that the factory wires. You can tell someone replaced a lot of wiring on it and your diagram doesn't show all the wire colors.
The orange might be right if it is on the engine side of the harness being used as a jumper to the other diode connection but the single wire coming from the engine if that's where it is coming from should be black in color for a Tri-circuit system with a round green connector.
If the jumper is on the tractor harness side of the diodes and not the engine side it is hooked up wrong.
You can tell someone did some re0wiring on it and hope they did it right or they could burn out the stator and a voltage regulator if one is used on that tractor.
If you use the harness you have in the picture, the red with round connector goes to the engine, the other red goes to the battery and the white goes to your lights, but disconnect the diodes that are in your tractor and don't replace/use them because the harness you have pictured already has the diodes in it.
It's kind of hard to tell in your picture of where the wires originate or go to but the diode picture is good to see how it was re wired and connector changed, wire colors may have been changed also, but it might be routed correctly..
The single red wire that comes out the end before the diodes goes to the engine, which should be a black wire if it has the Tri-circuit stator/alternator.
If it is a Tri-circuit there should be just 1 wire coming out of it.
If it is a Dual circuit there would be 2 wires coming out of the stator going into a rectangle terminal coupler with 1 red wire with built in diode that goes to the battery, the black wire without the diode goes to the lighting circuit.
Looking at your picture, it appears there is a white connector terminal coming out of the engine, That is usually from a Dual circuit stator/alternator that should have a black wire and a red wire coming from the engine.
If that's what it has coming out of the engine then there is a different harness that connects to it than the one I listed with the part number earlier. I listed the Tri-circuit harness number, but that engine is supposed to have the Dual circuit stator.
If it has the dual circuit and the diode is good in the wiring coming out of the engine, then you just run the red wire that is rectified with the diode into D.C. to your battery or ignition switch that would send it to your battery depending on how the key switch is wired, the black wire would then wire in to your lighting circuit wiring. It would be A.C. current for the lights. The Dual circuit has the white plastic rectangle shaped connector coming out of the engine with the red and black wires.
An LED light needs D.C. current to light properly. If you feed it with A.C. it will flicker like a strobe light.
It's hard to tell if you have it wired correctly because the wires are of a different color that the factory wires. You can tell someone replaced a lot of wiring on it and your diagram doesn't show all the wire colors.
The orange might be right if it is on the engine side of the harness being used as a jumper to the other diode connection but the single wire coming from the engine if that's where it is coming from should be black in color for a Tri-circuit system with a round green connector.
If the jumper is on the tractor harness side of the diodes and not the engine side it is hooked up wrong.
You can tell someone did some re0wiring on it and hope they did it right or they could burn out the stator and a voltage regulator if one is used on that tractor.
If you use the harness you have in the picture, the red with round connector goes to the engine, the other red goes to the battery and the white goes to your lights, but disconnect the diodes that are in your tractor and don't replace/use them because the harness you have pictured already has the diodes in it.
It's kind of hard to tell in your picture of where the wires originate or go to but the diode picture is good to see how it was re wired and connector changed, wire colors may have been changed also, but it might be routed correctly..
There's a red wire leading to that orange jumper, on the other side of the round connector. You can actually see it in the photo. In terms of making the repair, I had no intention of leaving the old diodes in there. I can tell from the photo of the new harness that it has the diodes. The heat shrink doesn't really hide them. =P
But yeah, I'd just remove the bad "harness", disconnecting with the connectors at each end, chop off the spade connectors from the orange and red wires, and then splice in the new harness. Thank you for pointing out which wire on the new harness goes where. I'm not a noob when it comes to wiring. I've done plenty of automotive electrical work over the years. So I'll get this all patched up nicely knowing what should be where now.
But yeah, I'd just remove the bad "harness", disconnecting with the connectors at each end, chop off the spade connectors from the orange and red wires, and then splice in the new harness. Thank you for pointing out which wire on the new harness goes where. I'm not a noob when it comes to wiring. I've done plenty of automotive electrical work over the years. So I'll get this all patched up nicely knowing what should be where now.
That should work for you then, good. It's kind of hard to tell a bit from the picture, but good luck with it and let us know how it works for you.
Why not just get some 10 amp 1000PIV RATED silcon diodes on-line dirt cheap? They will operate cooler. Very unusual for the light ckt diode to fail. Probably and pinched wire or a bulb filament shorted)
Silcon diodes do not just fail often, unless they are overloaded (too much current per their rating which produces heat and they short or burn open.
10 pack at less than $10
The PIV Peak Inverse Voltage can be lower, like 100 volts but the 1000PIV rating is just a more normal thing.
Fuse the circuits with a 5 to 10 amp inline fuse in each diode leg.
Silcon diodes do not just fail often, unless they are overloaded (too much current per their rating which produces heat and they short or burn open.
10 pack at less than $10
The PIV Peak Inverse Voltage can be lower, like 100 volts but the 1000PIV rating is just a more normal thing.
Fuse the circuits with a 5 to 10 amp inline fuse in each diode leg.
I already tested out the circuit with no power on the lights side of the diode, and I confirmed no damage to the wiring for the lights which work just fine when powered straight from the battery. So, there's no short in the wiring, no damage to the circuit, and the diodes aren't exposed to any excessive heat since they're on the opposite side of the battery from the engine. What's there doesn't seem to even be original, so who knows what quality those diodes are. Besides, the replacement harness should be arriving today anyway. Should be quick and easy to get wired into place.
It could have a bad wire right where it is crimped into the terminal or a broken wire internally somewhere in the harness. It will take time to try and trace it throughout the whole harness.
It took a while, but I finally patched in the new harness. I can't believe how busy things got, this just wasn't a big enough priority. I still have more waiting to do, though, because now there's a fuel delivery issue, so I can't get it started right now. I know how to solve it, so that's a plus, but it's going to take a couple days before I can go get what I need. So, crossing my fingers that all goes well once it's put back together.
![Image]()
I'd get rid of that mess and just get a regulator. Easy install, low priced. Hundreds on Ebay for 10 or 12 dollars. Three wire hook up and you'll have the positive power for LEDs.
This is what I installed on my B&S opposed twin:
I think it previously had the lower 3A stator with diodes.
![Image]()
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I think it previously had the lower 3A stator with diodes.
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