Hello all, I replied to FH130 thread,as that seemed to be the same problem that I'm having. I'm having issues with the shut-down, as well as issues with charging. It would seem that this is indicating a bad alternator. I thought I'd elaborate on my specific symptoms: My batteries are not getting a charge. I put the battery charger on, and they charge up to about 26v, and there is no change when I fire up the machine. About 15 starts down the road, the batteries are not able to start the engine. I have to disconnect the battery, when I shut the machine off, as the charge light, and warning buzzer activate when I turn the key off. I checked the exciter voltage to the alternator, and there is 24v (nominal), when I turn the key on. The exciter wire is in parallel with the battery shut-off solenoid, which was staying engaged, until I disconnect the battery. When I turn on the key, regardless of starting the motor, or not, and then off, the charge light, and warning buzzer would activate. When I turned the key on, and off, with the exciter plug disengaged from the alternator, the light and buzzer did not activate. All that said, I'm thinking it's a bad alternator, and the circuit is being maintained through the battery shut-off solenoid, activating the warning. I'm going to have the alternator checked out (bench test), to be sure, but since both the necessity of putting the battery charger on to maintain charge, and the above symptoms, I'm leaning toward the alternator being bad. I'll update if that's not the cause.
Hi Grandpascott. This same subject has been covered in about three other threads in as many weeks. On a normal alternator it is excited to start externally by the wiring but these Hitachi machines have an internally excitation circuit which is energized when the battery relay applies power to the main output terminal of the alternator. So when you turn the key on there should be no power at the small wire on the alternator. It appears there after the engine starts and the alternator gets up and away charging. If there is power there when the key is on will cause all your symptoms. If you pull the wire of and check it there is power there the diodes have blown in your alt. By the way 26V on your charger is low so your battery's are probably not fully charged . Even if it is a multi stage charger and goes to float i would expect to see around 27.6V Cheers
HI 007, Alternator is on order, so hopefully that fixes issue. I'll update. Thanks!
Okay, so I got a rebuilt Wilson alternator. It has the same case, terminals, but on my original Hitachi alternator there is a wire coming out of the back with a bullet connector. This wire is not present on the rebuild. I checked the schematic, and it looks like it goes to one of the terminals on the Starter Protection Controller. I'm wondering if this is a necessary component? I do have 2 of these machines, so I could check the other one, except that I bypassed the SPC, as it was about $300, so not sure if I would get a proper read on the issue. That said, my other machine doesn't have any trouble with the charging system, and I'm not sure if the SPC is at all active. Clarification on the bypass: I ran a Bobcat starter button (spring loaded push button) to the 2 relay leads on the SPC. All other wires are still connected.
Picture of the back of the two alternators showing the terminals would help if you can.
Here are pic's. The red on the new alternator was from my sharpie, for reference. The hole to the left of the "T" spade receptacle (bottom of alternator, in picture) is where the wire with the bullet connector comes out of the old alternator.
Looks like every model is slightly different which is insane. I would be interested in seeing your diagram and also what wires and terminals you are using. From the diagram i have the wire with the bullet went to the battery terminal that was energized with ignition not straight to battery. On the the other side of that wire inside the alternator my circuit shows a resister which is used to excite the alternator. There should have been two wires in the plug both together connecting to the bottom terminal of the tee with the top of the tee terminals not used. Those two wires should have gone to the safety relay, load dump relay and instrument cluster. So what have you got?.
I am referencing this one, which I got with the machine, from the previous owner, which he got from Nortrax (local dealer).
well it gets interesting now because you diagram is very basic. Heres hoping your new alt is suitable. Do you have a warning light as i cannot see one on your diagram. You need to ask the person you got the new alt from to tell you which terminal in the tee plug is what. I would assume the top of the tee would be on your diagram as ig (ignition Pos) but some new alternators would call that Sense Terminal. An bottom of tee would be going to starter relay.(Lon your diagram) But need to be sure!! if you pull your old alt apart and have a look see and maybe a pick showing internals i can tell you probably whats happening, What ever is easiest really.
If you choose to take pic of old alt try to show where the tee terminals go internally in you pic.
So I just dl'd a service manual from Tradebit, on referral from "excavator" and took a couple of screen shots of electrical. Good referral, BTW. On the "Start Circuit", I'm pretty sure that "L to alternator" is the wire I'm missing. Note references deenergizing after start.
Here's a note on terminal L
007, you mentioned disassembling alternator, and looking inside. I did remove 4 long screws from outside of the case, but it didn't want to pull apart. Do I need to remove pulley, and then case halves can split, over shaft? I've always just R + R'd starters, alternators, etc., so not familiar with process. I got this alternator from Napa, as it was $169 vs. the $750 I paid for OEM from previously mentioned Nortrax (and that was about 15 years ago), when engine heater circuit relay failed, and constant energizing took out that alternator (actually $2800 for that repair, as they had just taken on Hitachi - they were a John Deere dealer, and they charged me for their learning). I am comfortable with doing my own repairs, but some direction is always helpful.
No pulley stays on you just need to use a couple of screw drivers to gently separate in two half's. The stator which has all the wires goes with the end plate not the pulley side. You have to be gentle and rock from side to side as sometimes the brushes will get caught on the slip rings and you can break them. If you carn't get it apart with out forcing it you can undue all the screws on the end plate and batt pos terminal and then the stator diode heatsink brushbox regulator, basically all of the guts will come out of the end plate and you can lift the brushes with a small screw driver. ok well the first diagram is nothing like these new ones which are the same as i have. So the bullet wire is the N connection going to starter safety relay ant the tee plug is L and R connections which we will figure out. I assume your ex was expecting to use all three wires?
Yes, they were all connected at time of removal. The wire with bullet seems to have something to do with the load dump, which I understand to buffer "slamming off the power", for anything using voltage when shutting down. Of course I went out last night after dinner to R + R alternator, and it was 7:15 pm when I came in and looked up Wilson's #, only to find out that their tech support is 7 to 7. I might give the old alternator a try, regarding splitting the cases. The new one is 25 years younger, so will probably come apart easier.
I have my version of what the load dump does but would be interested what the manual says if it tells you. I can guide you through altering the new alt to add third wire or i think we can fudge the wiring to achieve almost same thing what ever is easiest. is late here now so i will look in tomorrow cheers
As I noted in previous comment, regarding bypassing Starter Protection Controller, I'm OK with fudging, if it's easier, or less expensive. I am the only operator, so a switched wire, or some such, would be just fine. Rest easy, and I'll look forward to hearing from you, tomorrow. Cheers!
i have looked at some Hitachi alternator circuit diagrams and they all vary as they seem to have evolved as time go by. But as best i can see on your new alternator the top of the tee in the plug should have ignition on it and the two other wires joined together on the bottom terminal, and they should be one to the starter relay and load dump relay. Is that the way it is currently wired? I assume it is still not charging? Do you have a multi meter?
I've been out working, so thanks for getting back to this. I haven't installed the replacement alternator yet, so no answer to the charging question. The "T" plug only has 2 wires to it, one hot, and the other goes to ground, it looks like. The wire that is still on the old alternator (picture) comes from inside the case, and to the Starter Protection Controller. A note in the manual said that the Load Dump Relay gets a prompt from the wire in question and buffers the electronics from instant shutoff, or some such. I'm willing to take the cases apart and remove the wire from the old, and attach it to the new (I'll be able to see where the connection is being made), but as I said yesterday I wasn't sure about the process of getting inside the unit(s)
not sure what you mean by one hot and the other ground? please explain. That should not be the function of those terminals In my opinion the whole Hitachi wiring is a bit of a joke. The function of the start relay is to prevent someone trying to start the engine if it is already running and also stop the starter if the motor starts. Durr there are billions of vehicles out there without this relay and the operators seem to have got the hang of when not to crank the engine and when to stop cranking. So if you left that wire off the start relay would not function and it would be like every older car you jump into. Don't get me started on the lunacy of the ignition key operated isolation relay which has forced the addition of this load damp relay. The only vehicles which come to mind with similar isolation is fuel transport trucks with half a million liters of fuel behind them. Due Hitachi excavators burst into flames regularly? Maybe it was a mining requirement somewhere they wanted to comply with.
I agree, that they have made things more difficult than necessary. The machine has been good to me over the years (so much so, that I bought another one, just in case). Electrical, though has been the shortfall! I've decided to leave it to the pros, and send to old alternator (and maybe $100 USD) to the local rebuilder, and I did get a hold of Wilson and with the help of one of their tech supporters, found what appears to be the correct alternator (little bit different case, but proper bracketing), with the bulleted pigtail coming out of the back. For the sake of this issue, I will check the voltage on the bullet (and update), when I'm getting the new, good, alternator in. I'm assuming voltage will be present, as it's the female side of bullet coming out of the alternator. Thanks for your time, and sharing of expertise! Cheers!
I forgot to clarify, one of the terminals is marked with +, the other a -. I think the - goes through the battery cutout relay, and then is grounded on the back side of that.
Yes correct, a positive voltage with respect to ground will appear on the bullet and will be maybe 1 to 2 volts less that the output +B terminal but only when running. Like wise on the - terminal voltage will will be a few volts with the ignition on and then go to about the same as B+ terminal when the alt starts. The + terminal probably needs ignition positive there to start the alternator. Good Luck