Edit: two short runs later and the gears stripped! DOh. Might have been because I added grease when I reassembled the servo....
My PowerHD lw20 servo stalled on full lock when I powered up the car.
When dismantled I found the legs of the potentiometer corroded and one had snapped.
Now I know this is a budget servo, but I hate throwing things out so I went searching for a replacement pot.
Found one that looked very similar:
Futaba Y-l39668, Pot VR TR133-15
Example here: https://www.gravesrc.com/futaba-vr-tr133-15-pot.html
Not readily available in the UK it seems, but found one on eBay, the packet looked about 20 years old. Not exactly cheap (£6) for a simple pot, but decided to risk it....
Happily, it fitted perfectly and was easy to solder the wires on. The servo is now up and running again in my Axial Wraith.