Discussion:
Clark TM12 troubleshooting

Hi, i'm new in here.
I just bought an Clark TM12 forklift. This is my first forklift, so i need a users manual, service manual, and maybe a wirediagram (Having some troubles)

Well, the forklift drives well, except, It can't raise the forks, and the steering don't work either.

I dit find the contactors/relays? that starts the steeringunit, and the hydraulicunit.
If i give the coil power directly from a powersource, the respective device start. ie. the steeringmotor, or the hydraulic unit to lift and tilt the forks.
As an "emergency-repair" to use the forklift, i coupled a relay to the switch sitting near the levers to raise/lower/tilt, and it works great.
The steeringunit is started by a switch, coupled to a relay. So everything is working, just not the correct way.


It will be nice to find the failure, so everything works like the factory had in mind. So i have a bounch of questions
Why is there 4 switches to the steering? And what are they starting/stopping? I see two of the switches, triggers another relay (Not the one that starts the motor)
There is a box labeled Pulsomatic Mk. X, i don't know if that is a sort of controller?

What can i do to locate the failure? Bad connections, broken controller?

Thanks in advance. (And sorry, English ins't my native language)
  • Posted 21 Dec 2008 19:34
  • Discussion started by Carsten_S
  • Århus, Denmark
Showing items 1 - 13 of 13 results.
Did you ever get this fixed? I have a problem too!
  • Posted 4 Feb 2014 09:27
  • Reply by pineddy
  • Nevada, United States
Fix it like it's your own equipment!
I have a fault with my pulsomatic controller! Anyone with a circuit diagram or wiring diagram? Any help or advise would be appreciated.
  • Posted 11 Sep 2013 18:17
  • Reply by Ernie
  • Manchester, United Kingdom
I repaired one TM12 with problem in pulsomatic controller electronic. It would been much easier with schematic diagram to find the two faulty transistors
  • Posted 19 May 2012 21:37
  • Reply by Laukke
  • RAUMA, Finland
the four switch are for the weels when i go left and the steer weel is om position 30 degray the left motor go turn backwards and when i go to right same the right motor go turn backwards

Its 3 wheel when this is not working you have no power when the steer wiel is compleet turn to left ore right and for smooth drive left en right direction. and you can make circel drive

John
  • Posted 7 Jan 2012 18:46
  • Reply by johngen
  • NB, Netherlands
Email harlekein@hotmaildotcom and djdotdj@kpnmaildotnl
Look always to SN. number
And to Gef....... very importend there are different drawings
with littel small box below sometimes 3 ore 2 ore pompcontroller
There many type

Give the Serial number Complete with Gef number 7000 - 7001 - 4800 5400 etc etc several type

regards

John.
  • Posted 7 Jan 2012 18:40
  • Reply by johngen
  • NB, Netherlands
Email harlekein@hotmaildotcom and djdotdj@kpnmaildotnl
Hi, send me an email at: carstenks (at) gmail dot com, and i'll send you the wiring diagram.
  • Posted 7 Jan 2012 17:47
  • Reply by Carsten_S
  • Århus, Denmark
the wiring-diagram would be a great help
  • Posted 7 Jan 2012 15:36
  • Reply by jason_r
  • Oklahoma, United States
Sorry, i just have the wiring-diagram.
  • Posted 7 Jan 2012 00:41
  • Reply by Carsten_S
  • Århus, Denmark
did you ever find a parts, service, user manual for a clark TM 12.
Really could use a copy, any help would be greatly appriciated
thanks
  • Posted 6 Jan 2012 06:48
  • Reply by jason_r
  • Oklahoma, United States
Hello, could someone send me the circuit diagram of this Clark?
Thanks!
  • Posted 17 Mar 2009 05:11
  • Reply by diego_c
  • Buenos Aires, Argentina
The Controller allows the triggered input through the plastic logic card to sellect your direction contactors, and also allows the system to trigger the thyristors within the aluminium block which in turn allows your motors to turn and drive the truck, if there is a fault condition the system has a fail safe circuit in the card which will trip out the contactors to prevent any serious damage or injury. Traction control is in reference to the pulsomatic system.

As for the switches on the steer hub, not sure but sounds like your truck is probably twin drive with 2 motors, and the switches probably drop out one of the motors when in one lock and vice versa. I know the system but am not familiar with the actual truck sorry.
  • Posted 26 Dec 2008 02:39
  • Reply by elektrodrive
  • West Midlands, United Kingdom
Thank you for your answer, Elektrodrive.

Yes, the controller is as you said an alloyblock, and a plasticbox. What is the controller exactly doing? - I've got a wirediagram by email, and the circuit looks quite simple.
As far as I can se from the diagram, the coils are negative-triggered/fed with a positive constantly.

Btw. in the diagram, tractioncontrol is mentioned - Is this like in a car? Mine is spinning the wheels easily, so i guess this is broken.

What is the idea with 4 switches on the steering hub? 2 of them seems to activate a contator (Not the same as starts the hyd-pump), when the wheel is fully turned.
  • Posted 25 Dec 2008 12:22
  • Reply by Carsten_S
  • Århus, Denmark
Hi there

I dont know much about the truck itself, but I can tell you a bit about the pulsomatic. Its a cableform control unit which controls the drive system. If i understand its a pulsomatic mark 10 system then it will be a power unit made up of 2 black aluminium blocks clamped together. Some of these have a small module which has a row of spade terminal connectors normally coloured yellow, blue,red, white and green i think.
The other unit looks similar but has a logic card enclosed in a black plastic box known as the 17191 logic card.
From what i understand for these controllers, the power steer and pump do not work through pulsomatic controller, rather the contactor is supplied with a direct feed either pos or neg and the other feed to the contactor coil is switched through switches.

For example if the power steer contactor coil is fed with a direct positive, then perhaps either through the park brake switch or seat switch they feed a negative supply to the contactor coil.
Similar with pump contactor if its fed directly with a positive then the hydraulic lever switches the negative supply.

The problem is possibly a lost feed either directly to the contactor coils or from the switching side. I would guess the direct common feed to the contactor coil has been lost. If someone can provide a diagram it should be simple to follow.
  • Posted 22 Dec 2008 04:16
  • Modified 22 Dec 2008 04:18 by poster
  • Reply by elektrodrive
  • West Midlands, United Kingdom

Post your Reply

Forkliftaction.com accepts no responsibility for forum content and requires forum participants to adhere to the rules. Click here for more information.

Having trouble using the Discussion Forums? Contact us for help.

PREMIUM business

Noblelift
Global leader and manufacturer of high quality electric, lithium-ion, and IC material handling equipment.
Latest job alerts …
FT-Myers/Naples area, United States
Kortrijk, Belgium
East Peoria, IL, United States
St. Louis, MO, United States
Fact of the week
Architect Gustave Eiffel originally submitted his design for the Eiffel Tower to Barcelona but the city rejected it for aesthetic reasons. As we know, he had more success in Paris, however, his plan was far from popular at the time.
Honeywell announces collaboration Charlotte, NC, United States
Upcoming industry events …
June 24-27, 2025 - Lima, Peru
August 1-3, 2025 - Coimbatore, India
September 16-18, 2025 - Dar Es Salaam, Tanzania
Upcoming in the editorial calendar