[Test-Equipment] GR1617A Standard Capacitor is Shorted

[Barry]

I discovered last night that the "standard" capacitor in my GR1617A bridge is shorted.  This was a 50uF, 1/4%, 800V capacitor.

Anyone have any ideas how this can be replaced?  It would be ideal to find a parts donor but I'm guessing that's not going to be easy.

I wonder if this same capacitor was used in other models.  If so, perhaps a donor might be easier to find; otherwise, I'm faced with trying to figure out how to replace it with modern components.

The original capacitor is in a rather large, tall "cube" and there's plenty of room to build out a replacement but I'm just not sure how I can compose a capacitor with those same characteristics.

Thanks,
Barry - N4BUQ