UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Probs. with Blaupunkt Bremen 'W' Car radio

'LIVEWIRE?' · 13th Mar 2009, 12:55 pm

THis mid/late 1960s Car radio - a 'simple' MW/LW receiver, typical of it's time, is very unstable - as soon as the volume is advanced more than about 25% above minimum, the radio oscillates. The circuit is quite conventional for the time, using AF126 & AF139 transistors(2 of each) in the RF/IF Stages, and 2 x AC153(AC128), plus 2 x AD148 in a transformer coupled Amp. It is built on 3 boards, connected together via pluggable leads, and is switchable for both 6 & 12v, and -Ve/+Ve earth, using slide out reversible tabs for this purpose(Yes I've checked for dry joints, bad connections, etc, but cannot find the cause of this problem!)

Can anyone help, please?
NB I don't have a manual for this model(request out on the 'Info. & service data wanted' section).

13th Mar 2009, 12:55 pm	#1
'LIVEWIRE?' Rest in Peace Join Date: Mar 2006 Location: N.W. Oxfordshire(Chipping Norton) Posts: 7,306	Probs. with Blaupunkt Bremen 'W' Car radio THis mid/late 1960s Car radio - a 'simple' MW/LW receiver, typical of it's time, is very unstable - as soon as the volume is advanced more than about 25% above minimum, the radio oscillates. The circuit is quite conventional for the time, using AF126 & AF139 transistors(2 of each) in the RF/IF Stages, and 2 x AC153(AC128), plus 2 x AD148 in a transformer coupled Amp. It is built on 3 boards, connected together via pluggable leads, and is switchable for both 6 & 12v, and -Ve/+Ve earth, using slide out reversible tabs for this purpose(Yes I've checked for dry joints, bad connections, etc, but cannot find the cause of this problem!) Can anyone help, please? NB I don't have a manual for this model(request out on the 'Info. & service data wanted' section).