Replacing diodes in rectifier

[Wes]

Would it necessarily be bad to replace only one string of diodes in, say, an old Fender that has the dual string
of diodes for a rectifier?

I'm looking at a '64 Showman AB763 that has only one side of the rectifier replaced. You know- three in a row....

For the cost it seems that just replacing them all would have been ideal, but is there really any operational problem that
could be encountered replacing only one side?

http://schems.com/manu/fender/showman_ab763_schem.pdf

Thanks for your input.

[pdf64]

There's no immediate operational problem with only replacing failed parts, however, my view is that it is poor practice, as all the diodes may have been subject to the conditions that killed the one side.
The surviving ones may be walking wounded and liable to fail sooner rather than later.
The collateral damage from such failures could be high, eg PT, so replacing all helps to mitigate that.
Pete

[Wes]

It just looks like whoever did the work didn't want to remove the board to access the other side of the rectifier.

I think I'll just change them. It is an original PT from '64 so......

[52 Bill]

I think I'll just change them. It is an original PT from '64 so......

Replace all 6 if you are going to do it.

It's hard to say why somebody did something in the past. You can usually remove all of the diodes without removing the board, so I would think that it was done just as a matter of economy.

If this repair was done last week, they all should have been replaced. If this repair was done 40 years ago, who's to say.