[bikelectro]

Despite all the criticism i would urge you not to give up! I have never heard bad reports or any reliability problems with these except:
The controls are poorly supported and they can break with rough handling.
The insulators on the O/P transistors can cause crackling if they break down.
I had mine in use with not too efficient large speakers and played loud and it has never given trouble! This is a cracker sounding amp.
I’ll try to put the diagram i have on here, this is for early models like mine from early ‘80’s ( model was launched in about ‘82 , mine is ‘84 )
In the top corner it states ; “C25 is essential if original Philips Q6 & Q7 are not used”. I was wrong about the BD139, these are the O/P darlingtons, so do check this out! I remember now what happened, i was checking things and had accidentally left the cap disconnected and it blew O/P’s on switch on.