In lightspeed go to Catalog > products and make sure there are no filters. Click on "Export List..." and choose CSV Format. Once that has downloaded come back to this page and click "Choose File" and select the file you just downloaded. Do not check "Insert Missing SKU's" unless a new product is being added to the display screens. Once that is done go to the TV's click back and reload the pages, or wait 5 minutes and they will do so automatically
id,handle,sku,composite_name,composite_sku,composite_quantity,name,description,product_category,variant_option_one_name,variant_option_one_value,variant_option_two_name,variant_option_two_value,variant_option_three_name,variant_option_three_value,tags,active_online,weight,weight_unit,length,width,height,dimensions_unit,supply_price,retail_price,loyalty_value,loyalty_value_default,account_code,account_code_purchase,brand_name,supplier_name,supplier_code,active,track_inventory,outlet_tax_Nature_Center,inventory_Nature_Center,reorder_point_Nature_Center,restock_level_Nature_Center
Only sku and retail_price are required. Optional fields, if present, populate new rows when “Insert missing SKUs” is checked.