OPC CB blows. Operator Protection Circuit

[KauaiJohn]

The 5AMP OPC circuit breaker has blown twice.

After replacing it the first time, things worked for several months -- until I noticed that getting out of the driver's seat with the PTO engaged did not shut the B3030 off. I "vowed" to fix that some day.

About a month later, the OPC CB blew again. It took a bit to figure it out again (i.e. sitting on the couch for a few hours letting my lower brain process information) but then 3 minutes to put in a new CB. Tractor started right up and ran for about 5 minutes before the CB blew again.

So, it is pretty clear that the Operator Protection Circuit has a short somewhere. The trick is how to find it.

I have the schematics and ohm meter (and voltage meter), I could use some instruction on the best way to proceed. IOW, do I look at each switch in the OPC first? Should I have the ignition on or off? Where in the long line of OPC parts should I think about starting?

An addition datum point that might be helpful, when I first purchased the tractor (slightly used) a rat decided to live behind the dash. Rats love to eat wires. I've had to rewire the dash a couple of times. Many of those connections are soldered. I got them "mostly right", the few things that didn't work correctly when I was done were of no consequence to me.

I "solved" the problem by ensuring the area behind the dash has a nice chunk of rat poison in it. (FWIW, they did it to my truck too, the dealer couldn't figure out they'd bitten through one of the pollution control wires right away. They're also eating nuts on the VW's battery. So, you can see, I go through a bit of rat poison.)

So, I'm just asking for the best way of trouble shooting this problem. Thanks

 

[Jim L.]

The least risk way is to pull the 5 amp fuse and use the ohmmeter.

Some of the OPC components have dual switches, one 12V hot and the other set grounded.

By pulling components from the harness, you can isolate wire runs and look for grounds that should not be there.

Any relay coils may give a false reading of ground. So I would pull that first. Also if you have an OPC timer, I would pull that so as not to worry about timing issues or powered / not powered.

Make a copy of the schematics and use a highliter to mark the wiring as you go. There are only a half dozen components so it won't take a grand strategy.

If the problem is not found on the first run, then you may have to wiggle components and harnesses on the second to find the fault. Or you may find chewed insulation where the wires are bumping together.

 

[Grouse Feathers]

I can't help with your electrical problem since I have a BX, but I do have a thought about your rat problem. To be effective the rat poison has to attract the rats. Do you really want to attract the rats to the exact place where they do damage?

 

[Jim L.]

Please meet Vito. He handles our rats.

Badge? I don't need no stinkin' badge.

 

[KauaiJohn]

JimL: Thanks. I find my troubleshooting book schematics to be difficult to read at times. I appreciate the input.

WRT attracting the rats "Feathers" has a point, but (so far) they eat the poison before they chew on the wires. Of course, it may have been the same rat and he got terrified one day after I'd been mowing for several hours. Crawled up my pant leg (shorts actually). I was able to grab him and toss him into my neighbor's lot where I though the birds would swoop on him. They didn't but he ran like crazy. He was white by the way.

As far as Jim's suggestion of a biological rat trap, no snakes on Kauai. (well, there is one that is about the size of a worm.) There is a local owl that's pretty good at it. Cats sometimes come by too, but I try to discourage them because of the song birds and the Urkels. (At the expense of having to use a pellet gun on all the Chickens. <sigh>) Just have to make the right trade-offs.

 

[D2Cat]

There was a discussion here about mouse control. Someone was using a ultrasonic chaser from Home Depot.

I have a 300 gal. tote I laid sideways, cut the side metal and plastic, hinged and made into a storage box for pelleted feed for cattle. Mice, rats and any of their relatives love that stuff. It come in a large cubical nylon bag. The mice would eat holes all through it.

I purchased a pack of two of the ultrasonic gizmos. Plugged one in and hung it over the end of the metal frame. I have since fed 3 bags for protein pellets (each bag is around 1200#) and not one hole in the bag. This has been through the winter months.

If you use a battery maintainer, or have other power at your tractor storage area just hang one of these units over the steering wheel. Mice will leave.

http://www.homedepot.com/p/Victor-M...Sonic-Rodent-Repellent-2-Pack-M752S/203190302

 

[Burt]

The 5AMP OPC circuit breaker has blown twice.

After replacing it the first time, things worked for several months -- until I noticed that getting out of the driver's seat with the PTO engaged did not shut the B3030 off. I "vowed" to fix that some day.

About a month later, the OPC CB blew again. It took a bit to figure it out again (i.e. sitting on the couch for a few hours letting my lower brain process information) but then 3 minutes to put in a new CB. Tractor started right up and ran for about 5 minutes before the CB blew again.

So, it is pretty clear that the Operator Protection Circuit has a short somewhere. The trick is how to find it.

I have the schematics and ohm meter (and voltage meter), I could use some instruction on the best way to proceed. IOW, do I look at each switch in the OPC first? Should I have the ignition on or off? Where in the long line of OPC parts should I think about starting?

An addition datum point that might be helpful, when I first purchased the tractor (slightly used) a rat decided to live behind the dash. Rats love to eat wires. I've had to rewire the dash a couple of times. Many of those connections are soldered. I got them "mostly right", the few things that didn't work correctly when I was done were of no consequence to me.

I "solved" the problem by ensuring the area behind the dash has a nice chunk of rat poison in it. (FWIW, they did it to my truck too, the dealer couldn't figure out they'd bitten through one of the pollution control wires right away. They're also eating nuts on the VW's battery. So, you can see, I go through a bit of rat poison.)

So, I'm just asking for the best way of trouble shooting this problem. Thanks

KauaiJohn,

Another possible solution...Get yourself a rat terrier or a cairn terrier. They are excellent "ratters." There are about 10 breeds of dogs that will rid your property of rats.

Meanwhile, I agree with the attraction of the poison. Do you really want the rats going there?

Burt

 

[Daren Todd]

KauaiJohn,

Another possible solution...Get yourself a rat terrier or a cairn terrier. They are excellent "ratters." There are about 10 breeds of dogs that will rid your property of rats.

Meanwhile, I agree with the attraction of the poison. Do you really want the rats going there?

Burt

My miniature dachshund is better then any cat we've owned as far as a mouser when we bought our house it had sat vacant for two years. The critters had moved in with a vengence. Pest service got rid of the bugs, and spiders. But my wife and I fought with the mice for around 6 months. It was really hot out so I left the dachshund inside while I went to town. Came home and found a soggy mouse in the middle of the carpet. later that day I ran back to town and found another one on the carpet

We use the ultrasonic mouse chasers now, to keep them from getting inside the walls. It's been a year since we put them in and no mice. Picked up a couple extra and put one on the back sunroom and one in the garage near where the bird seed is kept.

 

[KauaiJohn]

You guys are getting way off topic. :^>

I will vouch for those ultrasonic mouse chasers. We moved into a brand new house and the mice moved in with us. Picked up a 3 pack of those ultra-sonic transmitters. The mice that had already moved in found "safe areas" which were laden with traps, so they didn't last long. New mice don't move in.

Now, who wants to wave the magic wand to fix my tractor?

 

[Daren Todd]

Check the quick disconnects and relays in the wiring harness for water and corrosion. Trace the wires and check for pinch points as well. Near linkages, pedals, seat track. Also if it goes near the engine and transmission where temps can get really hot.

Another option is to start disconnecting any quick connects at the closest point to the key switch and work your way to the opc. Checking the fuse as you go. It will give you an idea as far as which direction the short is in. And if there is a rubber boot on the wiring harness to protect the back of the connectors, it wouldn't be a bad idea to roll the rubber back and check the back side of the connectors.

 

[KauaiJohn]

Thanks Darren:
I've started down that path. I was hoping the problem was in one of the PTO switches so that I could get the tractor up to the barn and out of the rain while I looked further. Unfortunately, even with the PTO off, as soon as the switch was turned on the fuse blew.

That does tell me something though. Probably mostly that I have to go to NAPA for more fuses.

 

[Daren Todd]

Yup, but it will probably be a head slapper when you find it those pesky little shorts usually are. I had one on mine, where the wires looked perfect. But part of the wiring harness melted down where it came in contact with the engine block. Didn't find it till I started removing the wiring harness to rewire the circuit

 

[KauaiJohn]

Thanks Darren, that's a hint worth its weight in gold to me.

 

[Grouse Feathers]

A volt meter is usually invaluable for this type of problem. We have a lawnmower at the gun club that had random starting problems. The guys would go out there and jump on the seat, engage and disengage the mower deck and slam the brakes on and off. Once in awhile it would start. They asked me to take a look so I walked out there with my voltmeter and returned in 5 minutes with it fixed. There was a glass fuse in the circuit that looked good until I checked the voltage. I pulled the fuse and one of the metal ends fell off. I guess the wire in the fuse made contact part of the time. The point is you often can't see the problem, but a voltmeter never lies.

 

[Bulldog]

Put a 30amp fuse in, it'll show your problem spot. Of course it might involve a small fire by doing it that way.

JUST KIDDING of course!!!

 

[North Idaho Wolfman]

For situations where there is intermittent and sporadic fuses blowing, I like installing a circuit breaker in place of the fuse (they come in the same sizes as most fuses).
That way when the event happens you can possibly correct what cause the event to happen and the circuit breaker will reset and continue working.

 

[BAP]

Another thing to try, would be to go threw the safety switches, one by one, and use a jumper wire to bypass them. While you have the switch bypassed, run it for a while and see if the fuse still blows. If one of the switches is bad, you should find it by using this method. Of course, only bypass them temporarily for safety.

 

[Tooljunkie]

I use a power probe, circuit tracer and a circuit breaker. Also my power probe circuit tracer shows open, power or ground. When circuit changes from open to closed it changes tone.

These wiring problems can take time,by isolating each circuit systematically you shoul be able to locate the issue. Because its the fuse blowing, i would start from fuse panel and follow it to the end.

 

[KauaiJohn]

OK, I've removed the OPC controller, it is not attached anywhere.
I took off the dash, found some new rat chews on those wires and repaired them.
I checked 4 of the safety switches. (not as thoroughly as the shop manual suggest though)

I didn't want to go through the hassle of taking out the
seat to get at independent PTO switch (I will be doing that tomorrow)
I followed all the wiring harnesses, haven't found a problem.

So, thought I'd try a test. Put in a new fuse, without replacing any of the stuff I've taken out. Turned on the key, fuse blew immediately.

I've stared and stared at the wiring diagram. The only thing it can be is the independent PTO lever.

I do wish that seat wasn't so hard to take off.

Anyone have a different idea? See any holes in my reasoning?

thanks

 

[KauaiJohn]

Taking off the seat was as painful as I remembered it to be.

I have a bad Independent PTO safety switch.

It wasn't even installed finger tight, so maybe its a good thing this happened

It isn't at all clear though how a bad switch causes the fuse to blow. After all when the switch is closed, there is no resistance.

I put in a fuse with the safety switch disconnected. it did not blow. So I'm assuming the problem is on that circuit only.

I tried other continuity tests from the Fuse box trough the Independent PTO circuit. They look OK to me. I could not find anything physically checking the wiring harness. My probes of the circuit only returned expected results.

So, for me the question remains. How does a bad switch blow the fuse? I can understand how a bad switch might leave the engine running with the PTO engaged when I got off the seat. But the blown fuse???

thanks