Crown RC3000:
No forward or reverse after short repaired in wiring

Ser #1A222551


This forklift was operating great for a long time before this issue arose. machine has been used and abused in a heavy equip. repair shop. rear wheels are kidney killers and machine was bouncing around all over the place before failure...

It started blowing fuse F6 immediately upon plugging in battery. I found and repaired a short in the wiring, it was a twisted set of wires going to a 5 terminal block next to the hydraulic filter inside left rear pillar of machine. wires from the block then go to a small alarm right beside it. The FU6 is no longer blowing.

But now lift has no FWD or REV. When moving handle forward or rear there is no clicking, sounds, nothing changes. ALL other controls on machine work. The switch under the front plate where you stand is jumped. At the card (EV100?), I checked the inputs coming from the two steer limit switches and they seem to be correct. There is a 3rd switch with the other two steer limit switches i do not remember which one it is but the input for it is also correct. I checked the 6 pins at the card, all voltages seem to be correct here. Accel input, changes from 5v to 0v when moved. voltages are correct for brake switch, key switch, fwd and rev switches. I have 18v going to the forward and reverse contactors on the middle posts, and 36v at all the control wires going to both contactors. I have 36v at the 4 terminals for the forward and reverse switches right under the handle. We have another RC3000 in the shop with its own problems, and another that we use for parts. I'm not sure what half of this stuff is without a manual or experience with these things. But I've tried a different handle from the parts forklift, swapped as an assembly, wiring, and 3 wire potentiometer? I've tried several different cards, (EV100?).. I've tried several different boards (the one that has 9 terminals on one side and 11 on the other.. I've tried a different SCR controller, the little diodes that surround it, tried a different capacitor... and a few other things im forgetting and I'm getting nowhere. What are some more tests I can do and what are the proper way to check them? I have surfed around a little on just the general Crown repair forums, do you really need to remove the larger amp fuses to properly check them? I have continuity across all fuses, small and large, what is correct way to test potentiometer? or micro switches for handle?
  • Posted 18 Jun 2019 05:35
  • Modified 22 Jun 2019 14:11 by poster
  • Discussion started by jackson_p
  • Tennessee, United States
Showing items 1 - 15 of 31 results.
Unfortunately, Jackson has my spare book. Those books are very expensive...and they have been out of print for a long time. Google "Crown repair manual for sale", you might get lucky
  • Posted 12 Nov 2019 20:55
  • Reply by Ifixit
  • Pennsylvania, United States
Hey Ifixit,

I'm working on a used RC3020, problem is at least tangentially similar to this one, but I'm having trouble identifying components to communicate with people and know what voltage I should be expecting.

I suspect the fuse going to the traction motor contactors should be transmitting half bat volt, or full bat volt, and not 3.6, which I thought at first might be an artifact of some erroneously high resistance somewhere and a 5v control circuit when I first saw the voltage, but I'm gathering this is not correct from reading Jacksons posts.

How does a guy go about getting a repair manual for an old hunk like this? I also have a 30rctt or something, the older model of this counterbalance tall mast truck, and I'd be interested in getting a book for that too if they are significantly different in their wiring and control. Where do I look?
  • Posted 12 Nov 2019 18:01
  • Reply by Pastoral
  • Washington, United States
Email me your address, I'll get a book to you
  • Posted 27 Jun 2019 02:32
  • Reply by Ifixit
  • Pennsylvania, United States
Just for others potentially reading this in the future. The problem was in fact the reverse switch, mounted right under the multi-function handle. To verify this was the problem, I installed the switch on a different forklift that was working. When I installed it, I lost forward and reverse. good luck.
  • Posted 27 Jun 2019 01:25
  • Reply by jackson_p
  • Tennessee, United States
I put a different reverse switch on it, machine is working fine now. I guess it was the problem the whole time, I don't know for sure. Since I swapped many components. But I did have 36v at fwd and rev switches at TB11 when I first started. I guess if you have voltage at these terminals it doesn't mean the switches are good. Anyways thanks for all your help guys. Now I just have to replace the rear wheels and machine should be ready for service again. which is a job because I just did them on our other lift.
  • Posted 26 Jun 2019 23:34
  • Reply by jackson_p
  • Tennessee, United States
Ifixit, please check your email again. I said there were two pins that were "Backed out" not Blacked out. It was on the 6 plug connector from the card, for the fwd and rev control and 1A and D outputs. Nevertheless, they are fine, I just shoved them forward to make sure they are making FULL contact. They are. ALL PINS, male, female, and connectors on the card are good.
  • Posted 26 Jun 2019 21:46
  • Reply by jackson_p
  • Tennessee, United States
Popeye, no the contactors are not pulling in. They pulled in once or twice yesterday. Then back with same problem (original problem), sorry I should have been more specific. Contactors are still not pulling in.
  • Posted 26 Jun 2019 21:36
  • Reply by jackson_p
  • Tennessee, United States
Popeye....I had him check the pins in the control card connectors, said there were a couple black ones... he didn't specify which ones though, or which connector.
  • Posted 26 Jun 2019 11:25
  • Reply by Ifixit
  • Pennsylvania, United States
So contactors now pull in but no hum from EV-100 card and no travel? Try turning steering from one side to the other so that you are only trying to power one motor or the other. If it still will not travel you might have a bad EV-100 card.
  • Posted 26 Jun 2019 11:16
  • Reply by popeye
  • Ohio, United States
I've been working on this forklift for 2 weeks now and I finally just got the forward and reverse contactors to close for the first time since it's been out of service. many attempts. I could not move because I have the brake pedal off, so I can't release the brakes, I also have the battery next to the machine, not inside of it.

But, back with some problem. No forward or reverse. Whatever it is it must be a bad ground, bad connection or weak component. I just have no idea what or where I've tried everthing and I have been crawling around all over this thing for weeks.
  • Posted 26 Jun 2019 06:26
  • Reply by jackson_p
  • Tennessee, United States
Does anyone know of anything else to try? I'm trying to check all the wiring to make sure it is correct, I can compare some things to the old parts lift because it is the exact same but some parts have been robbed from it leaving the wires hanging. I'm confident the contactor board is correct. I'm pretty sure TB601 is correct but unsure about TB602 wiring. Of course if I had the right diagram it would help. I think for the most part it is correct because I've been careful when replacing parts and swapping wires over. If anyone has any other ideas I would be glad to try them. Thanks guys.
  • Posted 26 Jun 2019 04:28
  • Reply by jackson_p
  • Tennessee, United States
I tried a known good rec1 , still nothing. I now have 37 on right side and 19 on left side. By the way the voltage may have gone up from the first test because I'am charging the battery with a small charger while doing repairs.
  • Posted 26 Jun 2019 00:23
  • Reply by jackson_p
  • Tennessee, United States
Ok Ifixit

I have 35.20v on right side of 1rec and 18.02 on left side, where I removed the 3rec cable.

It's not exactly half so I guess I need to try a 1rec. I tried one from our parts forklift which is the one I just tested. It also did nothing. I will try one from the our other lift that is working.
  • Posted 25 Jun 2019 22:21
  • Modified 25 Jun 2019 22:37 by poster
  • Reply by jackson_p
  • Tennessee, United States
Popeye sorry bud, it's probably because i'm working without a manual, the only thing I have is the "power cable" schematic and a few diagrams. On the "power cables" page, there is a "4REC B" on the bottom right of the page. It is physically mounted on the bottom right corner of the contactor panel (inside where you stand). It was the only rec I was seeing but now that Ifixit has helped me locate the other ones I see exactly where you guys are talking about. The RECs are all located next to the capacitor.
  • Posted 25 Jun 2019 22:14
  • Reply by jackson_p
  • Tennessee, United States
You have completely lost me now. You say you swapped out 4B but do not see 4A or 3 recs. They look exactly like 4b and they are on SCR panel up on top. You say you have 17 volts at the bolt on the 1rec where the 3rec and another cable are(T2) and 0volts at the A1 connection right beside it which means the power fuse is blown or cables are not hooked up correctly to it or on contactor panel. Start with that and go from there.
  • Posted 25 Jun 2019 09:46
  • Reply by popeye
  • Ohio, United States

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