Quote:
Originally Posted by Tony F
I've got a 17" predicta tube (17DAP4 2.68 volt). I checked it with my B&K 466 tester. It pegs the meter on step #6. Just after step #5 where you set the G1 voltage to 45 volts. This is where you gradually increase the pointer by two small divisons, it started to increase 1 divison then pegged the meter. Then when I proceed to step #7 Read Emissions (tests strong) it is like an extra light bulb going off inside the neck of the tube (besides the heater glow). Is this the famous heater to cathode short, for a predicta tube ? What are the chances that a Beltron will repair this tube ? or is it toast. Thanks guys..
Tony
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As a fellow B&K466 user I can tell you...Your tube is shot. When you adjust the cutoff and it wants to be 'all or nothing' instead of allowing 2 division adjustment and the neck and or gun elements glow(presumably purple) it means the tube has too much gas contaminating its vacuum to function...It probably has a VERY VERY slow leak somewhere.
Last 2 CRTs that tested that way on my 466 when connected to a working chassis arced internally between the HV connector/internal dag and the electron gun (much to the distress of the flyback), did not produce screen light and the entire neck lit up purple.
Sorry for the bad news. If your 466 still has its manual I believe it explains the connection between cutoff behavior and gas.