Zoom on Toshiba ST-20 Projector

[TechSupp]

How can I adjust the image size on a Toshiba ST-20 projector (the one on a boom arm). Cant find anything on the projector or on the projector menu, so I presume its by means of position on the boom. The image is slightly too large for the board. Found how to adjust the tilt or the vertical position just not the image size.

[Educare_AV]

Not done one for a while, but is it the style with the pitched boom arm?

[TechSupp]

Found out what it was, it just slides along the boom arm, could not get any adjustment at first as the original installers had just coiled up any spare audio/video cable inside the boom/projector mount, thus jamming it up. Pulled all that out and hey presto, can slide the projector to zoom it in :-)