I have an elka elkatone700...i've

Question

i have an elka elkatone700...i've been trying to find some information on this amp but everything is pretty much in german or sites that are now non-existant...the problem is i can't get the horn thing at the top to work, i wouldn't mind having a root around inside myself and trying to fix it but any technical info relating to it would be very useful...is there anywhere i can get any info at all?