Pye Q6 noisy output stage - UK Vintage Radio Repair and Restoration Discussion Forum

tin0gauge · 23rd Feb 2017, 6:32 pm

The radio has white noise after the volume control and a faint signal coming through, I disconnected C27 coupling between V4 and V5 but the noise remains. I disconnected the collector of V5 and the noise goes away. I have disconnected the decoupling electrolytic C28 on the emitter of V5 but the noise remains. So is it likely to be V5 ? it is a flat Pye ? transistor and I think an OC81D will be a replacement? Any ideas gentlemen.

Herald1360 · 23rd Feb 2017, 7:02 pm

Sounds plausible. Try another PNP Ge and see. Just about anything would do......

Ed_Dinning · 24th Feb 2017, 6:42 am

Hi, some of there Pye sets were prone to noisy resistors. Try tapping them with a screwdriver to see if the noise comes over the speaker.

Ed

tin0gauge · 25th Feb 2017, 4:11 pm

Thank you gentlemen I changed V5 to an OC81D and the noise went but it was quiet and these Q6's usually perform very well, but C27 the coupling capacitor to the base of V5 had gone O/C and changing that means it now really belts it out. Case closed

23rd Feb 2017, 6:32 pm	#1
tin0gauge Tetrode Join Date: Oct 2013 Location: Guildford, Surrey, UK. Posts: 82	Pye Q6 noisy output stage The radio has white noise after the volume control and a faint signal coming through, I disconnected C27 coupling between V4 and V5 but the noise remains. I disconnected the collector of V5 and the noise goes away. I have disconnected the decoupling electrolytic C28 on the emitter of V5 but the noise remains. So is it likely to be V5 ? it is a flat Pye ? transistor and I think an OC81D will be a replacement? Any ideas gentlemen.

23rd Feb 2017, 7:02 pm	#2
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,536	Re: Pye Q6 noisy output stage Sounds plausible. Try another PNP Ge and see. Just about anything would do...... __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

24th Feb 2017, 6:42 am	#3
Ed_Dinning Dekatron Join Date: Jan 2004 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 8,195	Re: Pye Q6 noisy output stage Hi, some of there Pye sets were prone to noisy resistors. Try tapping them with a screwdriver to see if the noise comes over the speaker. Ed

25th Feb 2017, 4:11 pm	#4
tin0gauge Tetrode Join Date: Oct 2013 Location: Guildford, Surrey, UK. Posts: 82	Re: Pye Q6 noisy output stage Thank you gentlemen I changed V5 to an OC81D and the noise went but it was quiet and these Q6's usually perform very well, but C27 the coupling capacitor to the base of V5 had gone O/C and changing that means it now really belts it out. Case closed