Marshall DSL401 filaments

[52 Bill]

...so could I use the old BR102 or should I get another new one with longer "legs" to mount it a bit higher above the board?

Either way. You haven't said if your friend's amp really has the same problem or not.

If the original one is still working, but just needs to be re-soldered, do as Enzo suggests and clean up the leads and the board and resolder it in place.

If it needs to be replaced because it is open, shorted, burnt, cracked, whatever, then replace it with a new bridge or with 4 discrete diodes. If you need to replace it, you can either free-air mount it or heatsink it if you wish.

[Enzo]

They come mounted flush, but if I replace one, I like to leave them up off the board a little ways. That lets the legs act like little heat sinks, and it will be easier to remove in the future.