hifi engine

in need of onkyo tx-sr503 service manual

can anyone pls provide me a copy of service/repair manual for onkyo tx-sr503? Im having trouble recently my a/v receiver (tx-sr503). it can not store the "advace setup settings" anymore...every time i will unplug the unit the previously set settings will be gone...its so annoying configuring the unit every time i want to use it... i have compared the unit characteristics to some of my friends for which had bought the same model with mine and all of them did not experience my situation... :cry: