MZ Charly scooter controller box fried

[stockjock]

I have a MZ Charly scooter, which is a full-sized, seated scooter as shown in the link. It was made by the German motorcycle company of the same name out of quality components. For those unfamiliar, it looks a bit like ET.

Looks like the controller box is history. Motor seems to work fine. Fuses check out okay. The #6 LED corresponds to a battery or controller box error and the batteries are new.

Having a tough time finding one. I've seen a few on German Ebay, but they aren't cheap and are 240v rather than the 110v I need. Even though MZ went bankrupt, another group took them over and I think they have the part for about $306 USD, plus $31 USD shipping to the UK (they don't ship to the USA), and I'd have to have a friend forward it to me, which I'm guessing is maybe $60. So roughly $400 USD all-in. That's a lot of money to put into an old scooter.

I know that other companies make controller boxes that are not OEM, but they require external chargers, rewiring, new throttle, new plugs and so on. I'd much rather have an OEM plug and play solution.

If anyone knows someone who has one of these boxes and would let it go cheap, let me know. I'd also be open to someone who can repair the controller box. So far, I haven't found anyone in the Southern California area. TIA.

 

[Clintw]

Hi. I'm also trying to fix an original OEM controller from a Charly scooter. I just got the #10 security torx bit yesterday that's required to remove the circuit board from the enclosure. I have the board out but I'm just starting to troubleshoot. So far I don't see any obvious faults with the motor control. There are 2 faults I see so far in the battery charging circuit. There's a blown fuse for the AC input and a partially melted choke, just downstream of the AC input. I have looked for a schematic for the controller board but I haven't been able to find one. If anyone has any resources regarding the operation of the controller I would appreciate it if you could share them with us. I found a manual with a schematic that shows the connections of the scooter wiring but the controller is just shown as a black box. I'm hoping to be able to repair, rather than replace the original controller.
The controller I have is immediately blowing the 35 amp fuse when the key switch is turned on. One thing I see that seems odd is that the positive input from the battery is directly connected to the main heat sink and the aluminum enclosure. Looking at the board it seems that this controller is intentionally designed with a positive ground. Has anyone encountered this?
First I'll see if I can fix the controller I have. Then maybe I can help others. These look like well made controllers. All the components are through hole so they should be easy to repair.
Any help will be appreciated.