Hello jim.thom@...,
Thanks Jim, very helpful, work has sidetracked me for a while but I
will post back as to what i find but I don't think my Hi-Pot tester
goes over 8kV
Best regards,
Chris 2E0ILY mailto:chris@...
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jttnh> If the tube is rated fo 3.5 kv, it should hipot a lot
jttnh> more than double that. When driven to max out, the RF
jttnh> voltage in the PI / PI-L will back feed via the plate block
jttnh> cap...and superimpose itself onto the tube's B+ DC
jttnh> voltage. Typ the total voltage will be a little bit less
jttnh> than double the key down loaded B+ value.
jttnh> Any good 3-500Z will hi pot test to 12-16 kv. A
jttnh> 3CX-3000A7 will easily hi pot test to 20 kv. The
jttnh> 3x10/15/20 all hi pot test easily to 30 kv.
jttnh> Once tube is warmed up for 20 mins......with NO B+ applied,
jttnh> then check for shorts etc. That's when u can get cathode to
jttnh> heater shorts or cathode to grid shorts. Buddy with the
jttnh> YC-156 amp went through 12 tubes.... just to get 3 good
jttnh> ones. The 9 bad ones all developed shorts..... but only
jttnh> after the heater was on for 5-10 mins.
jttnh> If u dont see any shorts after 20 mins... ( test one tube
jttnh> at a time).... then do the hi pot test on each individual
jttnh> tube... removed from socket, on the bench.
jttnh> Let us know what they hi pot to. Typ hi pot test is run up to aprx 5-10 microamps.
jttnh> Jim VE7RF
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