UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post

DMcMahon · 28th Mar 2020, 9:59 am

Thank you Refugee for your suggestion. I do not have a spare valve base socket which without would make the above awkward to do I believe.

I have thoroughly checked all the valve connections, including pushing and prodding with an insulated stick and cannot get any reaction. Also pulling/pushing/trying to twist the valve itself does nothing.

So I think there is no problem with connections either the wires or the valve base itself.

It is only when I lightly tap the valve glass envelope that I can easily induce the noise.

There is a second EL 42 fitted for the bias oscillator, I have been thinking of trying that valve in the output position but somewhat reluctant currently in case it gets damaged by the very large voltage signals that are generated in the fault condition.

I will have a fresh look later this morning.

28th Mar 2020, 9:59 am	#44
DMcMahon Dekatron Join Date: Apr 2019 Location: Worthing, West Sussex, UK. Posts: 6,600	Re: Grundig TK 5 Restoration Thank you Refugee for your suggestion. I do not have a spare valve base socket which without would make the above awkward to do I believe. I have thoroughly checked all the valve connections, including pushing and prodding with an insulated stick and cannot get any reaction. Also pulling/pushing/trying to twist the valve itself does nothing. So I think there is no problem with connections either the wires or the valve base itself. It is only when I lightly tap the valve glass envelope that I can easily induce the noise. There is a second EL 42 fitted for the bias oscillator, I have been thinking of trying that valve in the output position but somewhat reluctant currently in case it gets damaged by the very large voltage signals that are generated in the fault condition. I will have a fresh look later this morning.