24-05-2017, 10:55 AM
External heater supply?
A good idea and in fact I have a huge heater transformer that was removed from a 1953 Pilot TV87.
Actually, the EHT voltage in the 1804 is surprisingly low, only 3.5KV. Of course that doesn't make it any safer. After the Emiscope 3/4 CRT became obsolete EMI service supplied the TA10. This tube requires a higher final anode voltage so a special EHT booster was supplied. This device rectified the flyback pulse present at the anode of the KT44 line output valve and added the resultant voltage to the existing mains derived EHT.
Geordie McBoyne.
A good idea and in fact I have a huge heater transformer that was removed from a 1953 Pilot TV87.
Actually, the EHT voltage in the 1804 is surprisingly low, only 3.5KV. Of course that doesn't make it any safer. After the Emiscope 3/4 CRT became obsolete EMI service supplied the TA10. This tube requires a higher final anode voltage so a special EHT booster was supplied. This device rectified the flyback pulse present at the anode of the KT44 line output valve and added the resultant voltage to the existing mains derived EHT.
Geordie McBoyne.
