48V Yamaha Controller Issue (relay not triggering)

mluvara

I have a 48V 1998 Yamaha G19 cart that appears to have an issue with the stock motor controller. I've poured through the threads here, the schematics and it appears the controller is not closing the ground to the solenoid. When I purchased the cart, someone had mounted the tow/run switch where it was accessible and placed a switch on the pedal to close the solenoid as a bypass. Even then, the cart wouldn't always start and one would have to cycle the controller with the tow/run switch. I replaced the relay and the batteries appear to be healthy.

Before I remove/repair/replace the controller, I'll do another pass through all the wiring to ensure I haven't missed anything. Any other thoughts on how to debug? Seems like a fairly common issue from what I can tell.

Also, if anyone has had this issue, have they ever opened up and repaired the motor controller unit? It appears there is a rubber seal of sorts on each end that I have yet to start to pry off and would be interested in any tips on disassembling it. I'm an EE by trade, so this isn't an area I'm afraid to tackle.

Thanks!

BGW

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cgtech

Entire board is potted in some rubber stuff, can't see anything other than a cap sticking out.

mluvara

So, given I've narrowed my issue down to the controller as suspect, my curiosity got the better part of me and I disassembled the controller today. There is a rubber end cap on each end of the unit that can be pried off, followed by a rubber/silicone potting material on each end to seal the unit. The top can be removed as it interlocks to the lower section and has some silicone applied to seal it off. Slipping an xacto between the bond line of the case and the potting material, I separated the two part aluminum case from the lower section.

Inside, there are two boards. One is full of mosfets/capacitors and is the power section (what drives the motor) and the other appears to be a logic/controller section. The mosfet section uses the lower part of the case as a heat sink. I haven't found any physically compromised (blown up) components, but did notice the processor was not fully seated in its receptacle. Not sure if this could be related to my issue, but I'll likely put it back together and see if it functions normally.

Given I may need a new controller, I'm looking at other 48V replacement units. I see that some will work with the stock controller and increase the top speed a few mph. Any suggestions on your favorite controller to look at?

Thanks!

Attached Images

	controller1.jpg (193.4 KB, 0 views)
	controller2.jpg (183.5 KB, 0 views)
	controller3.jpg (186.2 KB, 0 views)

cgtech

Xct-48400 will do wonders, more power and 24 mph speeds with stock tires & gears. If you don't want to upgrade all your cables & solenoid, get the Xct-48300 model. Similar power as stock, still get 24 mph.

slurrr

What did you end up doing?

I am in the same situation. Seems like a fun project to try and fix but an aftermarket controller would be cool too.

I was also thinking of supplying the negative through other means, not sure if this would cause issues tho...