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

agardiner · 16th Nov 2020, 2:53 pm

Hi,

So I have a valve emission tester, which I am familiar with using, and indeed I have made up an adapter from an octal base to crocodile clips for older valves that don't plug straight in. Over time you get a 'feel' for valves which are not listed in the book for it, as to whether the emission is OK or not.

Back to the valves above; I have just completed restoring a Philips set which has the valve line up of 2x UCH21, UBL21 and UY21. The UY21 was indicating short circuit on my tester, but I ended up having to replace all 4 valves.

The question I have, is what am I missing in understanding these particular valves, as I cannot get any emission at all on my tester. None. And this was with new, old stock valves. Can anyone shed light on this anomaly for me?

Many thanks,

Adrian.

16th Nov 2020, 2:53 pm	#1
agardiner Octode Join Date: Sep 2020 Location: Thetford, Norfolk, UK. Posts: 1,744	UCH21 / UBL21 / UY21 Valve help please Hi, So I have a valve emission tester, which I am familiar with using, and indeed I have made up an adapter from an octal base to crocodile clips for older valves that don't plug straight in. Over time you get a 'feel' for valves which are not listed in the book for it, as to whether the emission is OK or not. Back to the valves above; I have just completed restoring a Philips set which has the valve line up of 2x UCH21, UBL21 and UY21. The UY21 was indicating short circuit on my tester, but I ended up having to replace all 4 valves. The question I have, is what am I missing in understanding these particular valves, as I cannot get any emission at all on my tester. None. And this was with new, old stock valves. Can anyone shed light on this anomaly for me? Many thanks, Adrian.