Thank you DemianM and Marcb,
Your comments are very helpful as these are concerns that we are currently working on. Very helpful also to know that you and other Forum users know the real value of these Forklift community technical discussions where technical issues are raised, discussed and solutions found and documented; where the resolve can be documented and become searchable, leading to knowledge growth and future innovation. We are proud of our Discussion Forums and are working to bring you some exciting developments to improve the current Forum model and perpetuate its knowledge bank.

We encourage everyone in our Forkliftaction community to raise issues, offer advice, knowledge and opinions and, very importantly on technical matters, document in the discussions how you eventually found a work-around or solved the matter. You would be surprised to see how often the same, or similar problems recur and how often these updates are researched and help other Technicians.
Kind regards,
Forum Administrator

Hey DamianM,

Thanks for your open reply, if I understand it correctly it was a bad soldering on the printcard. Can imaging that it's hard to find and solve.
About your answer regarding people not responding on this forum, you are more than right to mention it, I've noticed it too and it bothers me as well. What can also be mentioned is that if the person who asks the question gets a solution offered (or finds one themselves), they should also be able to answer with what solution they found. so we all can learn from it.....

Marcb

Good afternoon. I want to share this with you. I discovered a malfunction.

As I wrote earlier, all the parts on the board are working properly.
Here's what the problem was:

The steering control contactor is controlled by a constant voltage level on the transistor on the main controller board.
All other contactors are controlled by PWM with a frequency of 1 kHz. A PWM signal of an inconsistent level is supplied to the gate inputs of the field-effect transistors. And you can hear it with your own ears.

The PWM signal is generated by the processor at pin 97.
When the board is powered on, a very short series of pulses is generated at pin 97 of the processor to check the status. If this series is successful, generation at a frequency of 1 kHz is activated. If this fails, the processor continues to generate packets.

Since the hydraulic contactor is activated immediately after power is applied to the main board, error 38 is activated first. Then, when an attempt is made to activate forward or backward movement, movement errors are generated.

Interestingly, the control of the field-effect transistor of the hydraulic contactor and all the other contactors on the board is carried out in different ways. Hydraulic control is based on pulse-width modulation, while control of the other contactors is based on voltage levels.

Thus, the malfunction is related to pin 97 of the processor - it has desoldered! Because of this, the loader would sometimes work and sometimes not, i.e., the contact would sometimes appear and sometimes disappear. Finding this was very difficult. Because nothing is visible on a working board. Furthermore, this is confusing due to the different operating modes of this pin: when it's turned on, the first control pulses are sent, and during continuous operation, a 1 kHz constant PWM signal is already generated.

Now, regarding error 98 - it indicates a lack of communication between the system controller and the multi-controller. During the check, it turned out that the system controller is not generating any pulses at all. The controller started generating a pulse only when I precisely adjusted the potentiometers of the hydraulic control levers! so that they output exactly 2.5 volts. And I restored the shorting resistors on the connectors of the missing levers. After that, the system controller resumed generating pulses, and error 98 disappeared.

This is not described anywhere in the documentation.


I already asked in the post above what the difference is between two identical main boards, but different versions. The difference is that these boards use different data exchange protocols. After connecting another main board, the display stops working and does not recognize any of the boards. At the same time, the forklift works completely normally. Checking with an oscilloscope shows that all pulses are being generated, but no data is being sent to the data bus.

I've noticed that the forums are getting worse every year. People are stopping writing to each other. They're using artificial intelligence. But the AI gets data from the forums - the same data that was written earlier. Soon, the AI will have no information left, and we will stop exchanging experiences because we will stop communicating...

Hey DemianM, never worked on this model bud had in the past worked on Komatsu FB25ex-5 that similar problems on the contactors. The problem came then from a leaking battery voltage to the chassis. You can remove the battery out of the machine and reconnect the battery with the machine.
You can send me a mail.
Marcb

I'll attach a photo of the multicontroller, just in case.

MEIDEN main controller board problem

What's the difference between these boards: N61F20306-3 and N61F20306-1? Both are working, and both have issues. The original N61F20306-1 works and transmits data to the multicontroller, but periodically glitches and the loader stops. The second board, numbered 3, was bought by chance; its origin is unknown. It works reliably. But the multicontroller doesn't display any data from it, nothing at all. There are pulses, I compared it with the old one with an oscilloscope-they're basically the same. If I disconnect the wire, the display immediately shows error 97-no connection to the main controller. But there's no data, and the red LED on board numbered 3 flashes code 87. In the Komatsu documentation, this code refers to the system controller board, and the voltage is 5 volts, which is what this code indicates-normal. Is there a way to get the second board, numbered 3, to communicate with the multicontroller? I'll attach a photo of the multicontroller, just in case.

Hello

I have deciphered the error codes, but it has not become clearer.
E98 - there is no connection between the system controller and the multicontroller.
E38, E07, E10 - the drives of all contactors are faulty, but they are working properly.

The main controller board is fine too, I didn't find any broken parts. And it works for a few minutes, only then these errors come out.

Can you tell me, please, what is the name of the software for this model of forklift? which one can I connect the computer to the main controller to check the settings?

And there is also a small seven-segment indicator on the system controller board. I can't find anywhere what it's for. when I change the main controller board to a perfectly serviceable one, the system controller does not work for long and starts giving an error on this indicator. Does anyone know what these F-letter errors are?