Grundig Super Colour TV Serie F 3016 - lack of...

Question

My old Grundig Super Colour 16" ? TV Serie F 3016 has stopped responding to commands sent by the remote control.  I have tried 2 remote controls (both originals) with new batteries but to no avail, even after stripping and cleaning their internal keyboard contacts which makes me suspect the TV itself.  The TV is normally used every other day but this lack of response occurred following a weeks holiday when it wasn't used.  Tell me if there is a battery within this TV set which will require replacement to solve this problem before I extract it from its housing in our wardrobe top cupboard and delve into its innards.  If it is not a battery problem what else is it likely to be also is a circuit diagram or service manual still available?  The set works OK otherwise using its own control panel to change channels and its on/off switch to turn it on and off.  I am an old electronics engineer hence understand circuitry but just need help / data for this repair. Thanks in advance.  Chris Walton e:[e-mail] Tel:[phone] working hours, or 0116-239-2160 evenings/weekends.