Looks like Philips Prestige was popular Model. I also have this model. Was the first entertainment electronic product when we shifted to Kalyan from our native place. Strong emotional attachment to it. However my radio stopped working long time back. There was burst noise (Capacitor blown I think). But as of now I dont have zeal to open and repair.
I have schematic / service manual for 15RB505/00Z model No. It is in PDF format. Can not attach large files in the forum. See if following link works.