I picked up a used 21" Compaq P110 monitor (Sony Trinitron tube) and the brightness was too dim even at the highest manual setting. So I took off the case to adjust the brightness pot and I can't seem to find it anywhere? The screws to adjust are labled with abbreviations such as HDK and XBV but none of them seem to increase the brightness. Anyone have an idea which one I have to adjust? Thanks!