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 16 - 30 of 31 results.
Sent, Thank you.

In the meantime I swapped KNOWN GOOD parts with no luck. Tried different LH and RH contactor assemblies, tried "D" contactor (looking at power cable schematic page). tried 4REC B. Swapped all 4 of the little black square blocks, located next to capacitor and behind the board. Nothing, I'm running out of things to try.
  • Posted 25 Jun 2019 07:11
  • Reply by jackson_p
  • Tennessee, United States
Removed answer
  • Posted 25 Jun 2019 06:23
  • Modified 25 Jun 2019 07:43 by poster
  • Reply by Ifixit
  • Pennsylvania, United States
Ah bummer it won't let me upload a picture on here.
Do you have an email where I could send you a picture and maybe you could point me to the 3rec?

  • Posted 25 Jun 2019 05:03
  • Modified 25 Jun 2019 05:09 by poster
  • Reply by jackson_p
  • Tennessee, United States
I don't have a book :(
The price for one via crown is $500 and the shop I work for is too cheap to buy one.. I'm working with the help of the internet, these forums, an almost identical forklift that is running, but slow, and a parts forklift that is the same as the one I'm trying to fix. So you guys are basically my only lifeline.

By rec I think you mean the little black square blocks, 2 terminal. There are 4 of them. They are located in between the board and the EV-100 controller, with capacitor to the left. Or you may be talking about the one with the green and yellow wire going to it. I have already changed the 4 small ones, using ones from the spare parts forklift, so unsure if they are good or not. You are mentioning a pigtail but I'm not seeing a pigtail on these little blocks and such, just single wire terminals for the most part.

A picture may help?
  • Posted 25 Jun 2019 04:57
  • Reply by jackson_p
  • Tennessee, United States
In the book, there is an SCR assembly part breakdown. The 1 rec is the square block in the middle...the 3rec is between the 1rec and capacitor. Remove the 3rec pigtail and motor cable. Plug in battery. Battery volts on RH side of 1rec, EXACTLY half battery volts where you took the 3rec off
  • Posted 25 Jun 2019 04:45
  • Reply by Ifixit
  • Pennsylvania, United States
I tried a different block from the other lift that is up and running. The one with the two larger rectifiers and the rectangle device next to them. I swapped the whole block, still nothing. The block I removed from this one works on the running forklift so I will leave it be.
  • Posted 25 Jun 2019 04:07
  • Reply by jackson_p
  • Tennessee, United States
I have 17v on one, and the other one that is connected to the EV-100 SCR controller I have 0v. The rectangle thing I have 0v and those cables go out and down to the motors.

All fuses on machine are hot 36 or 18v
  • Posted 25 Jun 2019 00:28
  • Reply by jackson_p
  • Tennessee, United States
I think I see what you guys mean by rectifier, it's a round object with a larger hex size with a large gauge bare wire, there are 2 right behind the capacitor and another rectangle looking one.
  • Posted 24 Jun 2019 23:48
  • Modified 24 Jun 2019 23:58 by poster
  • Reply by jackson_p
  • Tennessee, United States
I just tried a different "4REC B" and it did not do anything. I also checked potentiometer voltage at the handle and it is correct
  • Posted 24 Jun 2019 22:58
  • Reply by jackson_p
  • Tennessee, United States
No contactor tips are welded, all are in the open position hanging down, the drive motor contactors are at rest, touching bottoms.
  • Posted 24 Jun 2019 22:34
  • Reply by jackson_p
  • Tennessee, United States
Alright guys good morning: I'm using a weak battery but it's just for testing purposes, which is why these voltages may seem low. But this lift was operating great for a long time, we were hurting so bad for a lift I had to transfer the good battery to the other lift for now. I have a diagram and schematic for the power cables, the ONLY REC i'm seeing is "4REC B" and it's at the very bottom right hand corner of the diagram and the control panel... Please specify what you mean by 1rec, 2rec, 3rec, I also do not see T1 or T2 anywhere. I'm not up to date on forklift lingo either.

1A- key off- 17.66V rear post
34.85 front post
key on- 31.5v (2 small wires going to 1A)

key off at (FA/RA/RB/FB) (left and right drive contactors)

17.7V on BACK MIDDLE POST, on both.

0v at all cables going out to motors from (FA/RA/RB/FB)
31v at all control wires going to FA/RA/RB/FB...

key on D - 0v all posts

key on S - 31v top and bottom large cables
31v top small wire
0v bottom small wire

traction controller:
6 terminal block
1: 3.5v off and 0v fully moved
2: brake sw input battery voltage
3: key sw input battery voltage
4:battery voltage
5:fwd input battery voltage
6:rev input battery voltage

and as already stated,
Height switch input, and both steer switch inputs are correct at controller

thanks for the help
  • Posted 24 Jun 2019 22:31
  • Reply by jackson_p
  • Tennessee, United States
Sounds like the 1rec to me. If none of the contactor tips are welded, remove the motor cable and 3rec pigtail from the LH side of the 1rec. Plug in battery and check voltage on both sides. RH side with cable still attached should be battery volts. The LH side has to be EXACTLY half battery volts. ( 38.6v - 19.3v) etc.
  • Posted 24 Jun 2019 12:37
  • Modified 24 Jun 2019 12:42 by poster
  • Reply by Ifixit
  • Pennsylvania, United States
REC is rectifier. Big diode or transistor if that helps. You have two directional contactors A and B they are the contactors with two contactors in one. RA and FA mean reverse and forward side of A directional contactor the movable tips should be to the bottom of contactor at rest. 1A is high speed contactor were instead of using the SCR to control speed you give full battery voltage to motors.
  • Posted 23 Jun 2019 06:36
  • Reply by popeye
  • Ohio, United States
Popeye, thank you for your reply. It will be this Monday before I am able to see it and work on it again. I do have a wiring diagram and schematic so I will be able to accurately check these voltages that you suggest. I have the page that points out A1, RA, FA, etc.. I've seen "REC" all over this website and nobody points out what this abbreviation is? Please, what is REC? I typically do not work on these types of equipment. Also, which contactor tips are directional? I've looked at all the contactors and none appear to be stuck.
  • Posted 23 Jun 2019 00:39
  • Reply by jackson_p
  • Tennessee, United States
What do you have at the two bolts on top of the 1REC (T2 and A1). The one on the right is A1 and should be battery volts and the other (T2) should be half battery. If T2 is zero check for stuck directional contactor tips if it is battery volts check 1A contactor tips either one of these can also be bad 1REC. If A1 is something other than battery volts check power fuses and control fuses.
  • Posted 22 Jun 2019 22:12
  • Reply by popeye
  • Ohio, United States

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