Discussion:
Jump starts

I have an electric Yale forklift from 1977, it jumps 2 feet when I hit the throttle and then nothing. Earlier it has been working fine, but for some while now it have been comming and going. Now it is jumping each time. Forward and reverse works fine and also the forks. What I can say is that earlier on low speed it has been quite weak and there have been a change in weather from -5C to -15C. So I thought it could be something with the bateries, but they are fully charged and shall be in good condition. I am in desperate need of help, the forklift need to be in working condition within next week.

I have made this video to descrive the issue:
http://www.youtube.com/watch?v=Gc1Qp-MTcyQ&feature=youtu.be
  • Posted 26 Jan 2013 08:27
  • By anders_m
  • joined 26 Jan'13 - 4 messages
  • Vestfold, Norway
Showing items 1 - 8 of 8 results.
Anders M,
Glad to see you got a good result.

Regards Titus
  • Posted 29 Jan 2013 05:54
  • By Titus
  • joined 6 Jul'10 - 185 messages
  • North Yorkshire, United Kingdom
Now I have cleaned the pedal assy and it now seems to work fine and it also has extra power :) but knock knock on hard wood! Thanks for all help
  • Posted 29 Jan 2013 04:00
  • By anders_m
  • joined 26 Jan'13 - 4 messages
  • Vestfold, Norway
Ok I will chek out the accelerator pedal assembly and see if I can find the problem there.
  • Posted 28 Jan 2013 19:20
  • By anders_m
  • joined 26 Jan'13 - 4 messages
  • Vestfold, Norway
well you may have answered your own questions

"Every time the forklift have not been used in a while it has this jump start problem, but after 5-15 kicks on the throttle-pedal it is working normal."

sounds to me like something in the accelerator pedal assy? or there abouts? high speed switch sticking? loose connection?
I'd check that out
  • Posted 28 Jan 2013 14:30
  • By Jplayer
  • joined 12 Apr'07 - 407 messages
  • North Carolina, United States
John Player Jr
_________________
LiftOne, LLC
Charlotte, NC
Email: jplayer@liftone.net
Model: Yale 1977, BELT30-77
Serial: UK-058

It is four cards, I took every one out and looked for damage, but nothing to see.

Every time the forklift have not been used in a while it has this jump start problem, but after 5-15 kicks on the throttle-pedal it is working normal. So for me it seems like something need to get hot before it is working normal. And when it is working it dosen't suddenly start to fail, then it is ok until I live it for a while and the same thing over again. No differns if I unplug battery or not. For a little while a thought it had something to do with the ignition key, but it dosen't seem to be a connection there since it works after i while without touching the ignition key.

I can take pictures if that's needed.

Here is the link again:
http://www.youtube.com/watch?v=Gc1Qp-MTcyQ
  • Posted 28 Jan 2013 05:12
  • By anders_m
  • joined 26 Jan'13 - 4 messages
  • Vestfold, Norway
anders_M,
first things first
can you give us a full model and serial number?
also if you can see the control panel and the logic card, can you tell us what it is?

many things can cause the truck to jump like this but we need more info to help determine what it might be.
  • Posted 27 Jan 2013 13:59
  • Modified 27 Jan 2013 14:00 by poster
  • By Jplayer
  • joined 12 Apr'07 - 407 messages
  • North Carolina, United States
John Player Jr
_________________
LiftOne, LLC
Charlotte, NC
Email: jplayer@liftone.net
Anders M,

This is due to the electronic system fail safe. System being activated, when the direction contact pulls in to drive the truck If the system detects a fault it blows the contact out and the truck appears to leap, there may be a short on the wiring or the logic unit may have failed a board component may be failing possibly one of the three thyristors has failed or one of the flywheel or braking diodes has.
The system on this truck is known as the mark v second system,
If you take the lid of the logic unit you will see that the unit comprises of a base board with four other boards plugged into it also several relay assy all these can be removed carefully to be examined for burnt out circuits,
Check the shorting contractor make sure it's not stuck in as this would also cause this problem.

Regards and good luck Titus
  • Posted 27 Jan 2013 01:32
  • By Titus
  • joined 6 Jul'10 - 185 messages
  • North Yorkshire, United Kingdom
Anders M,

This is due to the electronic system fail safe. System being activated, when the direction contact pulls in to drive the truck If the system detects a fault it blows the contact out and the truck appears to leap, there may be a short on the wiring or the logic unit may have failed a board component may be failing possibly one of the three thyristors has failed or one of the flywheel or braking diodes has.
The system on this truck is known as the mark v second system,
If you take the lid of the logic unit you will see that the unit comprises of a base board with four other boards plugged into it also several relay assy all these can be removed carefully to be examined for burnt out circuits,
Check the shorting contractor make sure it's not stuck in as this would also cause this problem.

Regards and good luck Titus
  • Posted 27 Jan 2013 01:31
  • By Titus
  • joined 6 Jul'10 - 185 messages
  • North Yorkshire, United Kingdom

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