Crown RC3020-30:
-48 Code , Loss of fwd/rev travel

I have a Crown RC3020-30 forklift that is losing its forward and reverse. Most of the time I can unplug the battery and plug it back in and it will work, or sometimes I have to wiggle the battery connection for it to kick in. The lift function and everything else works all of the time just as it should, i'm only losing the travel. With my handset I am getting a code of -48.
I have changed out the 1 REC, 3 REC pigtail, Capacitor, FWD/REV switches and contactors, potentiometer, plugging contactor at the very bottom, high speed contactor and even the lift contactor. I also changed out the card with another forklift. I have also bypassed the deadman switch and the brake switch to eliminate that as an issue.
When it runs, it runs great but if you stop to grab something or talk to someone for just a couple minutes, it is like it loses all power to go forward or reverse but it can still lift.
The battery is only a couple of months old but I changed out their housing connections as well to verify that wasn't it. I am completely lost at this point, I have looked at every wire I can think of for a short but have yet to find anything. Like I said, if I unplug the battery, and then slowly plug it back in sometimes moving it up and down, it will all of a sudden work but it doesn't take long to lose it again.
  • Posted 2 Sep 2021 22:45
  • Modified 2 Sep 2021 23:11 by poster
  • Discussion started by tg0486
  • Missouri, United States
Showing items 16 - 26 of 26 results.
when it faults
do the contactors attempt to engage
or is it a case of step on pedals and immediately 48 comes up,
or as mentioned a pmt trip, (which feels like someone just bumped into you)
if you can get it to come good without cycling keyswitch or unplugging battery, that elliminates PMT trip, as that is the process to reset a PMT trip
suppressors on the contactors depended on the year of the machine
does turning the steering, whilst running on blocks make it worse or not, steer position switches have been known to trip the cards, but will need power cycled to reset
have you disconnected and tested the large capacitor on the ev100 panel
  • Posted 4 Sep 2021 07:52
  • Modified 4 Sep 2021 07:57 by poster
  • Reply by crownie
  • Victoria, Australia
The contractors don't come with them from crown. They may be diodes or resistors. I believe you can SEE that a resistor should exist on the wiring schematic. Often people forget to order them or move them from original contractors. Crown parts departments pretty much can never find them for me and I'll point at their computer. Search "crown contactor 112327" on ebay right now and I think there is a used contactor with what I am talking about still attached. Not the ones you want though.
  • Posted 4 Sep 2021 07:03
  • Reply by Jones
  • Texas, United States
I took readings for the 6 terminals on top of the card in "fail" mode and this is the readings I was getting...

1-3 is the top three left to right
4-6 is the bottom three left to right

1- Neutral - 3.7V Fwd - 0V Rev - 0V
2. Neutral - 36V Fwd - 36V Rev - 36V
3. Neutral - 36V Fwd - 36V Rev - 36V
4. Neutral - 36V Fwd - 36V Rev - 36V
5. Neutral - 0V Fwd - 36V Rev - 0V
6. Neutral - 0V Fwd - 0V Rev - 36V

I did add some dielectric gel to the connectors in the contactor panel but it still didn't go forward or reverse until I kept trying and it finally clicked in.

As far as the contactors having a resistor bride, i'm unsure what you mean by this. The contactors I do know are brand new from Crown, i just installed them a couple weeks ago when this first became an issue.
  • Posted 4 Sep 2021 05:23
  • Reply by tg0486
  • Missouri, United States
Do the contractors have the resitor bridge on them? I had a crown reach doing something similar and someone had put the wrong resistors on the contractors.
  • Posted 4 Sep 2021 04:48
  • Reply by Jones
  • Texas, United States
Take readings at the control card terminals while it is fail mode. Should be 6 terminals on top of card. That will tell you a lot. You can also use an LX handset. Try putting Nygel on those harness plugs for floorboard and brake switches. I think you are having a wiring/connector problem and not a rec problem.
  • Posted 3 Sep 2021 23:31
  • Reply by 1CrownTech
  • Washington, United States
1crowntechnician@gmail.com
This one is not doing a PMT, it is simply just stopping. It literally feels like it just loses all power for the forward and reverse. It happens more often when I have it running, turn the key off and let it sit over break or something, go back to run again and it won't move. That's when I can sometimes unplug the battery and plug it back in to get it to move, or if that doesn't work sometimes just continually trying it will all of a sudden start going.
I did look at the harness I believe you are referring to a couple days ago, I unplugged it and blew it out some and when I hooked it back up it started to work, longer than normal but then when i let it set turned off for roughly 10 minutes it was back to not working.
  • Posted 3 Sep 2021 21:13
  • Reply by tg0486
  • Missouri, United States
A PMT feels like a bang or shudder when it stops. It's important to know if it is doing a PMT or just simply stopping. If it just stops I would take a look at the harness that goes from the floorboard and brake switches to the card. It should just connect to another connector behind the contractor access panel. Sometimes codes will throw you off. In my 13 short years as a tech I have learned to simply look at what the truck is doing or not doing. Know what circuit and components come in to play and start from there. I have learned the hard way of just concentrating on error codes. You can sometimes get led astray if your main issue s causing a secondary event code. But in this SRC truck you must know if it's doing a PMT or not to know which direction to go. Hope this helps.
  • Posted 3 Sep 2021 06:36
  • Reply by 1CrownTech
  • Washington, United States
1crowntechnician@gmail.com
It just stops working. I have it jacked up and if I unplug the battery and plug it back in, sometimes it will kick in to drive and sometimes it doesnt. When it does kick in though most of the time it stays running and everything works perfect but sometimes even just running it, it will kick out. As mentioned also, the lift has yet to fail, it is only my forward and reverse but i have thrown several parts to it with no luck yet.

The -48 code in the book shows that it could be a bad 3 REC or bad fwd/rev contactors and they are all brand new parts from Crown so it eliminated that possibility.
  • Posted 3 Sep 2021 05:55
  • Modified 3 Sep 2021 05:56 by poster
  • Reply by tg0486
  • Missouri, United States
When it stops working does it do a PMT, or just stop working?
  • Posted 3 Sep 2021 05:24
  • Reply by 1CrownTech
  • Washington, United States
1crowntechnician@gmail.com
I have changed out all of those parts with new and had no change except I haven't changed out the 5 REC, so I will give that a shot as well.

The FWD and REV contactors are brand new, the 3 Rec is brand new, and I tried a new snubber on all four with no change. Hopefully the 5 Rec will be my issue.

Thanks for the help.
  • Posted 3 Sep 2021 04:26
  • Reply by tg0486
  • Missouri, United States
1. Check Forward and Reverse Contactor and contact tips
2. 3 Rec circuit, Check for short circuit
3. 3 Rac Snubber, 23 Rec
4. 5 Rec
  • Posted 3 Sep 2021 03:25
  • Reply by Ramdeo
  • Netherlands Antilles
Ram
ramkhudan@gmail.com

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