I repair now of the same as yours forklift ( i have 3 wheel forklift ).
pay attention to the steering switches (possibly one constantly closed), when turning in one of the sides one wheel rotates slower. very old device but at first glance there is not anything to break down.
now I have a problem with the signal generator board, after replacing the chip forklift traveling at very high speeds (I installed an analog now waiting for the original chip from Japan.)
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