John Deere x748 problem solved "help my x748 is driving me crazy"

[chiefswood]

Finally solved the dilemma with my x748 that was totally dead in the ignition area.
Had to replace the whole dash panel as a ceramic capacitor on the main board had totally cooked and burned out.
These come as a sealed unit and have to replace the whole panel.
Probably could solder in a new capacitor if I can find out the rating on it as the rest of the board looks perfect. This would be a good winter day project and then just keep it on hand as a spare part.
The stinker in this case was the new ignition switch that I had put in when it first died. The new switch was faulty and finally put the old switch back in we were in business. This was a real stinker as you assume it to be ok and yet the all the testing and continuity tests didn't make sense.
I guess the lesson learned here is don't assume anything especially that all new parts are 100%.
Any way the x748 is running like a top again and the grass is under control.
Many thanks to all of you that helped with the diagnosis as you put some good logical thinking into the problem !

Chiefswood

 

[beenthere]

The new switch being faulty caused your capacitor to cook? Seems if true, there is evidence that John Deere owes you the new main board.

Can you fill us in on how the ignition switch cooked the main board?

Puzzled why the trouble went away when you put the old ignition switch back in.

 

[chiefswood]

Hello,
Early on in the diagnosis of the problem I put in a new ignition switch thinking that perhaps it was faulty. Eventually after testing everything possible I took the dash panel out and cut the seal and opened it and found the burned capacitor. Purchased a new dash panel and installed it thinking my problem was solved however the whole ignition was still dead. At this point I went back over everything again and could not find the problem as all wires checked out ok. The next door neighbour was over and we went over things and he asked me if I had changed any other parts and I said yes I had put in a new ignition switch just after the tractor would not respond. He suggested trying the old switch again so I just disconnected the new one and plugged in the old switch and left it hanging on the wires , turned the switch and everything lite up and ran like normal. I tested the new switch and the ground was no good.
so everthing is normal now as cut grass for 7 hrs yesterday and all is well.

 

[Kyle_in_Tex]

Hello,
Early on in the diagnosis of the problem I put in a new ignition switch thinking that perhaps it was faulty. Eventually after testing everything possible I took the dash panel out and cut the seal and opened it and found the burned capacitor. Purchased a new dash panel and installed it thinking my problem was solved however the whole ignition was still dead. At this point I went back over everything again and could not find the problem as all wires checked out ok. The next door neighbour was over and we went over things and he asked me if I had changed any other parts and I said yes I had put in a new ignition switch just after the tractor would not respond. He suggested trying the old switch again so I just disconnected the new one and plugged in the old switch and left it hanging on the wires , turned the switch and everything lite up and ran like normal. I tested the new switch and the ground was no good.
so everthing is normal now as cut grass for 7 hrs yesterday and all is well.

Sounds frustrating. Glad you got her running. This might help others in the future.