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Heatercathodeshort · 26th Jan 2019, 12:23 pm

The Marconi 707 I am working on at the moment has an intermittent grid/cathode short and a large ion burn. The emission is 100%. It does settle down after about 5 minutes.
Tapping the tube neck can cure/cause the fault to occur.

I'm stuck with a difficult choice. Leave it alone or attempt to dislodge the short with a charged electrolytic. I am going to leave it alone. The second picture shows the screen under bright bench lighting. John.

26th Jan 2019, 12:23 pm	#185
Heatercathodeshort Dekatron Join Date: Jun 2005 Location: Warnham, West Sussex. 10 miles south of DORKING. Posts: 9,147	Re: HMV 905 Project The Marconi 707 I am working on at the moment has an intermittent grid/cathode short and a large ion burn. The emission is 100%. It does settle down after about 5 minutes. Tapping the tube neck can cure/cause the fault to occur. I'm stuck with a difficult choice. Leave it alone or attempt to dislodge the short with a charged electrolytic. I am going to leave it alone. The second picture shows the screen under bright bench lighting. John. Attached Thumbnails