The bias board is put in there for convenience IIRC. So that TP7, 8, & 9 are joined together with that board so that it can easily be removed for bias adjustments . SO, provided there are no mods to the chassis as you claim, then there is no reason they cannot be linked with anything you have laying around that will fit into those clamps if it didn't come with one.
eg. small piece of steel, aluminum, or copper wire.
If it doesn't have that board in there (or any conductor for that matter); then there will be no output until there is.
Hope that is your only problem, and hope that was it.