Crown 45RRTT:
No FWD or REV Movement - Lots of Troubleshooting Inside!

Hello!

We've had this machine for a while. It finally stopped moving.

I'm not sure if this is relevant BUT In the past, we've had problems with the high speed engaging, especially under load and especially in reverse with a load. We learned to deal with it because none of the forklift 'experts' in our area could figure out the issue.

So, here is what I've done:
I removed the side panel and the top panel to access the controller, contactors, and control wiring/switches.

I found the FWD/REV contactors pull in just fine. I'm not too sure which contactor is the 1A but I am willing to bet that the control of that contactor has something to do with this... but I've learned to not jump to conclusions.

I have a schematic of the EV-1 (oh, yeah, the controller I have is the EV-1) but not everything is clearly defined. I am going to assume that the "TRACTION ARM" motor is the one that drives the truck forward and backward. It looks like the FWD & REV contactors are interlocked in several ways (yay redundancy!). So, the positive feed for the motor goes through A1 contactor, then either the F or R contactor depending on the selection at the stick, and then to the motor. The negative side of the motor goes to a sensor which isn't telling me much but it looks like a shunt in the schematics (no clue where this is on the truck), then it connects to Batt neg.

So, to me, if the F & R contactors can engage and if I can assume just for a minute that the inline "sensor" on the negative side of the motor is okay, the only other thing to get in the way of engaging the motor is the 1A contactor.

1A appears to be quite the security guard in this machine. Load, overheating, acceleration... everything can cause this thing not to engage... but I'm not sure where to begin. I see there are a few experts on here and I am hoping you are still around to give me a hand.

Thanks in advance! I can't wait to poke at this more!
  • Posted 18 Jan 2025 06:36
  • Discussion started by Joshman
  • British Columbia, Canada
Thanks for your help!
Showing items 1 - 15 of 41 results.
Also if you do have to replace one or both
Look at the base of each diode there will be a diagram of which way it blocks be sure to replace the way they came out some are blocking toward the base and some block toward the lead please do not get them crossed ! If , so when you go to plug in hot battery there could be a fireworks show !
  • Posted 8 Feb 2025 11:07
  • Reply by John_Bradley
  • Texas, United States
Jb69
Yes , the snubbers should charge snd discharge like a cap if you put your meter on continuity
You should get results as in last post if open both ways or closed both ways they are not checking out as good
  • Posted 8 Feb 2025 10:55
  • Reply by John_Bradley
  • Texas, United States
Jb69
That's what I mean. The diodes are not acting correctly.
For one, it's blocked both ways (megohms and megohms)
For the other, it's also blocked both ways (megohms and open lead)
... unless I am checking them wrong.

The main capacitor checks out fine but I used my multimeter capacitance setting. The snubbers act the same way? I use capacitance setting?
  • Posted 8 Feb 2025 10:33
  • Reply by Joshman
  • British Columbia, Canada
Thanks for your help!
When you check 3and 4 you will have continuity in one direction ie positive lead on base neg on lead then when you change and put neg on base and positive on lead you will have a slight bleed on newer diodes should not have complete continuity the number 4 rec is the plugging diode if it goes bad it affects plugging when traveling in forward or reverse and change directions it allows the unit to slow down before it goes into direction you also should check your filters they are square blocks with two screws you test them like a capacitor which you need to test as well
  • Posted 8 Feb 2025 10:20
  • Reply by John_Bradley
  • Texas, United States
Jb69
Sorry for the delay... life happened.

So, I was able to test 1REC with a bulb and power supply and it works fine as far as I can tell (switches on and stays on with a momentary positive voltage to the gate).


3 & 4 REC are questionable. Maybe you can tell me. Here's what I did:

* I removed the flexible ends of both and isolated them.

* I left both REC 3 & 4 mounted to the plate. It seems to be common between the two.

* I clipped one end of my digital multimeter on the flexible end and put my other probe on the base plate they are mounted to.

* On the diode closest to REC1, I read 5 Megohms one way and 1 Megohm when I switch the leads.

* On the diode closest to the edge of the SCR panel, I read 1.5 Megohms one way and O/L when I switch the leads.


I still have to check 5REC and 2REC but those diode readings might be telling.

What do you think?
  • Posted 8 Feb 2025 06:23
  • Reply by Joshman
  • British Columbia, Canada
Thanks for your help!
As far as recs gating on you either need a handyman or you can make a tester with a flashlight and some wire and alligator clips
As far as pot wire if you get no change check
The wiring to and from pot I will look and see if I have info on making a tester you should get 3-4 volts and then drop as you press accelerator if you type in how to make an scr
tester with flashlight it will show how also show how to use as far as the shunt it should read ohms
  • Posted 28 Jan 2025 09:45
  • Modified 28 Jan 2025 09:50 by poster
  • Reply by John_Bradley
  • Texas, United States
Jb69
Sorry to bug you but can you have a look at my results and let me know if you have any feedback please?

Thanks!
  • Posted 28 Jan 2025 09:17
  • Reply by Joshman
  • British Columbia, Canada
Thanks for your help!
Okay, here's what I found. Let me know what you think. It's strange.
Tests have been done with key on only (unless otherwise instructed)

Check volts at SCR positive. Should be battery volts. If not, check power fuse:
Yes, full battery voltage.

Check volts at T2. Should be zero:
Yes, ZERO.

Check volts at R5. Should be 3-4 at creep reducing to 0.2 or less at top speed:
No! 4.8V no matter the accelerator pot position!

If R5 remains about 4 volts, check accelerator:
I checked the pot resistance at R4-R5 and it swings from 4 ohms FWD to 6K NEUTRAL to 4 ohms REV.

Check volts at R7. Should be 2-2.5 when Key switch closed:
I get 1.7V

When F or R contactor is closed and accelerator depressed, should increase to about 6.2 volts:
No change (still 1.7V)

If remains near 2 volts, check volts at lC (grey wire or 2 REC anode):
I get 8.38V

If more than 0.125 BV, check if 2 REC will gate on:
Not sure how to do that

If less than 0.125 BV, check if 1 REC will gate on:
Not sure how to do that

Check current sensor green lead to card input pin 13:
Check for what? It's there and has continuity.

Check 23 FIL for shorted resistor:
No short. 8 ohms, I believe.
  • Posted 25 Jan 2025 06:41
  • Modified 25 Jan 2025 08:08 by poster
  • Reply by Joshman
  • British Columbia, Canada
Thanks for your help!
No sir , you try to operate machine and get symptom then diagnose.if you get on lift put in direction and contact closed but no scr sound
The you diagnose contacts close no movement no scr sound etc honestly ,I'm leaning toward drive motor issue ,but as you run diagnosis
You will find the problem it's better to run diagnosis than to go with a gut feeling
  • Posted 24 Jan 2025 11:44
  • Reply by John_Bradley
  • Texas, United States
Jb69
Thanks again! So, in these troubleshooting steps, should I be creating the situation during the test? For example, "Contact Closes, No SCR Hum" is the symptom. Should I be key on, foot on the brake and pushing forward on the accelerator while doing these tests? If so, I may need more hands.
  • Posted 24 Jan 2025 10:32
  • Reply by Joshman
  • British Columbia, Canada
Thanks for your help!
That is #1 rec
  • Posted 24 Jan 2025 08:09
  • Reply by John_Bradley
  • Texas, United States
Jb69
Thank you.
The first step says Check volts at SCR positive. Is that talking about the card or a power terminal on the unit under the card or?
  • Posted 24 Jan 2025 04:59
  • Reply by Joshman
  • British Columbia, Canada
Thanks for your help!
Yes , there is a section that says contacts close no scr and no movement TB refers to terminal board snd number o terminal board ie TBR 4
Right side of card terminal 4 or R4
  • Posted 24 Jan 2025 03:24
  • Reply by John_Bradley
  • Texas, United States
Jb69
I have that manual but some of the tests are quite non-descript to the point of convolution.

Here are some examples:
L4: "When used ignores open switch between L4 & L5" Pardon me??
L5: "Must be high after L3 & L7 are at battery volts for over 0.5 seconds and while L9 & L10 are low to complete SRO logic" Whoever wrote this must have been high after L3 & L7 are at battery voltage.
R2: "1A thermal holdoff control jumper to R4 to disable 1A thermal holdoff." Is that saying to put a jumper from R4 to R2 or... what?
R3: "5-10milliamps" from where to where? I assume R3 to the wire that I disconnect and connect to the ammeter? Or maybe to R4 because of note 1? I just don't know.
R4: "read from TBR4 to Neg." What is TBR4? I could assume it means R4 to Neg without disconnecting any wires but I don't want to assume.
R10. Not plugging mode vs plugging mode. How do I get it into plugging mode to see if I get the 8 volts?

Are there any particular tests in this manual that would address the FWD/REV movement issue I am having? This is a LOT of info with quite a bit of assumption that the reader has experience in testing these things. I'm very lucky and I count my stars that I have some equipment to test with and that someone like you is here to help... but this is stating to melt my mind.

In case I haven't said it before, thank you for your help so far. I really do appreciate it.
  • Posted 24 Jan 2025 03:16
  • Reply by Joshman
  • British Columbia, Canada
Thanks for your help!
Could not do it if you go to shopfsipbiz
Click on technical info the ev1 manual is on there it gives values for input and output on card and how to test
  • Posted 24 Jan 2025 02:26
  • Reply by John_Bradley
  • Texas, United States
Jb69

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