Yamaha 643 intonation issue - edited.

[ttf_Goddardo]

Edit - I am returning this instrument, so the main purpose of it is gone, but I would still quite like to know for the future:

1) Could a lack of compression in a trombone slide cause one partial to end up being very out of tune?
2) Would there be other side effects to poor compression, or would you only pick up one or two indicators at a time?
3) If someone needed/wanted to replace a Yamaha/Conn trombone slide as a whole, how would they go about it?

The basic gist of the previous text was that a bought trombone played fine apart from being very flat in the partial with first position  . A decent repairer thought that it could be caused by a compression issue in the slide. Using a brand new instrument to isolate the bell/slide appeared to show that the slide was an issue (although it was fine when bodged together with a medium bore bell).

[ttf_Goddardo]

Edit - I am returning this instrument, so the main purpose of it is gone, but I would still quite like to know for the future:

1) Could a lack of compression in a trombone slide cause one partial to end up being very out of tune?
2) Would there be other side effects to poor compression, or would you only pick up one or two indicators at a time?
3) If someone needed/wanted to replace a Yamaha/Conn trombone slide as a whole, how would they go about it?

The basic gist of the previous text was that a bought trombone played fine apart from being very flat in the partial with first position  . A decent repairer thought that it could be caused by a compression issue in the slide. Using a brand new instrument to isolate the bell/slide appeared to show that the slide was an issue (although it was fine when bodged together with a medium bore bell).