Never had to tweak that one Sam. There is a preset near the meter
driver circuit, (An6552, Q51, on the R.F. board.) That may be the one.
There is a 'pot' to set the FSD of the meter on Tx (for SWR forward
reading, obviously you set it to full scale, then set the swr switch to
reverse.) It is not that this control has been set too far up?? (Its on
the back of the unit, under the antenna socket, marked 'fwd set'?)
Best of luck, mate, I have got a few bits of cct diagrams if you are
really stuck, and may help....
Fred