Schindler inverter board blowing 5A fuse anyone seen this

[hydroliftexpert1022]

We're currently working on modernizing a couple of older Schindler controllers, but we've run into a bit of an issue. One of the inverter boards keeps blowing its 5A control fuse as soon as we power it on. We've disconnected everything to try to pinpoint the problem, but the fuse still blows right away.

We've ordered a replacement board, but then another car in the same bank started doing the exact same thing. I'm not sure if it's just a coincidence or if there's something upstream causing these issues.

Has anyone experienced this with Schindler inverters? Is there a common component or failure point we should look into? These boards have been running smoothly for years until now.

I'd really appreciate any advice or insights!

 

[Dress-Defender2523]

Looks like this could be something upstream like a shared power supply issue or even a grounding fault affecting both cars. Have you checked for shorts on the DC bus or any signs of capacitor failure on the boards?