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Diabolical Artificer · 15th Jan 2018, 7:24 am

Treat the CRT as a big valve, it has a heater, anode, cathode, and grids just like an EL84 or ECC83 so no EHT is stored.

Most analogue scopes have positive and negative rails in relation to ground. Most of the rails are measurable with a 1000v DC DMM apart from the cathode ( over -1000v DC ish ) the anode is usually about + 700 - 900v , again ish. The CRT heater winding is usually center tapped and referenced to some high negative voltage, usually the cathode.

But as your scope uses tranny's and not valves and you know the CRT is ok, you can leave the scary rails be. All you have to be aware of is caps holding charge, which you know about.

Andy.

15th Jan 2018, 7:24 am	#16
Diabolical Artificer Dekatron Join Date: Jul 2009 Location: Sleaford, Lincs. UK. Posts: 7,662	Re: New member and a Telequipment D54 Treat the CRT as a big valve, it has a heater, anode, cathode, and grids just like an EL84 or ECC83 so no EHT is stored. Most analogue scopes have positive and negative rails in relation to ground. Most of the rails are measurable with a 1000v DC DMM apart from the cathode ( over -1000v DC ish ) the anode is usually about + 700 - 900v , again ish. The CRT heater winding is usually center tapped and referenced to some high negative voltage, usually the cathode. But as your scope uses tranny's and not valves and you know the CRT is ok, you can leave the scary rails be. All you have to be aware of is caps holding charge, which you know about. Andy. __________________ Curiosity hasn't killed this cat...so far.