UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Quiescent Current of a Yacht Boy 300 Radio

'LIVEWIRE?' · 23rd May 2019, 10:53 pm

I've now found the circuit diagran on http://radiomuseum.org, and have been listening to the Yacht Boy, which, to me, compared with my similar Brandt RS 902, sounds a little distorted, especially on FM Music Stations. Given that the audio amplifier in the YB has failed at least twice before, and, on the second occasion I replaced T12,13, 14, & 15, but on this occasion only T14, perhaps I should check for other faults &/or check and adjust R 80 in the Vbe multiplier circuit, the only adjustment provided, but no indication of Iq is given anywhere in the manual. (N.B. in post #1 I mistakenly referred to T14 as T4. As this is the Vbe Multiplier, then IMHO, the adjustment should be carried out, since the replacement transistor will have different gain to the original

23rd May 2019, 10:53 pm	#5
'LIVEWIRE?' Rest in Peace Join Date: Mar 2006 Location: N.W. Oxfordshire(Chipping Norton) Posts: 7,306	Re: Quiescent Current of a Yacht Boy 300 Radio I've now found the circuit diagran on http://radiomuseum.org, and have been listening to the Yacht Boy, which, to me, compared with my similar Brandt RS 902, sounds a little distorted, especially on FM Music Stations. Given that the audio amplifier in the YB has failed at least twice before, and, on the second occasion I replaced T12,13, 14, & 15, but on this occasion only T14, perhaps I should check for other faults &/or check and adjust R 80 in the Vbe multiplier circuit, the only adjustment provided, but no indication of Iq is given anywhere in the manual. (N.B. in post #1 I mistakenly referred to T14 as T4. As this is the Vbe Multiplier, then IMHO, the adjustment should be carried out, since the replacement transistor will have different gain to the original Last edited by 'LIVEWIRE?'; 23rd May 2019 at 10:58 pm.