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sexton_mallard · 11th Mar 2018, 11:24 pm

I have been extremely fortunate to obtain a NOS LOPT, more about this later. Upon returning to this telly, I decided to try the NOS valves I obtained recently. I now realise a PY81 was fitted in place of a PY83. A NOS PY83 has been fitted. In addition, the new PL81 appears to have a different electrode structure (see pic). A quick image google pf PL81s seems to show some variation in electrode design. To be honest, the valve markings have all but disappeared and that valve might be something else! The envelope appears to be slightly different in height.

Replacing the valves unsurprisingly did not make a difference. I will next remove the old LOPT and treat the new one to a 'warm up' by slowly passing a current through it to minimise any chance of any moisture absorption.

11th Mar 2018, 11:24 pm	#63
sexton_mallard Heptode Join Date: Sep 2013 Location: Ellesmere, Shropshire, UK & Co. Cork, Ireland. Posts: 501	Re: Kolster Brandes RV 10 (Crown) I have been extremely fortunate to obtain a NOS LOPT, more about this later. Upon returning to this telly, I decided to try the NOS valves I obtained recently. I now realise a PY81 was fitted in place of a PY83. A NOS PY83 has been fitted. In addition, the new PL81 appears to have a different electrode structure (see pic). A quick image google pf PL81s seems to show some variation in electrode design. To be honest, the valve markings have all but disappeared and that valve might be something else! The envelope appears to be slightly different in height. Replacing the valves unsurprisingly did not make a difference. I will next remove the old LOPT and treat the new one to a 'warm up' by slowly passing a current through it to minimise any chance of any moisture absorption. Attached Thumbnails __________________ Dom Less snakes...more ladders!