hello
I need help for KOMATSU FB25H-1E year:1995???

there is always:F41 on dash display???
I check all wiring and power component (SCR&capacitor)
it means leakage of negative battery to frame!

really when i remove power steering and pump cable,the leakage decrease to 12V (between positif batery and frame) but even this solution the dash display fault F41(unsafe case).in the past i repaired this forklift and the truck move even with this fault F41,now,the fail safe circuit open direction contactors with arkin.
I don't found F33 fault that appear in the display?
I Change all necessary thristors (main SCR1,SCR2,SCR3)but i don't change commutation capacitor (i check the commutation capacitor,its ok).there is option potentimeter in serial with thermal switch,i check his value i found 5ko (in the drawing it writen 10ko!!)
also i give 80Volts in the illumination wire of dash display and it illuminate few second and return black.can be damged
can anybody help me
BEST REGARDS.