[Boatanchors] type 83 mercury vapor tube
k4oah at mindspring.com
Thu Mar 7 10:20:15 EST 2013
Gee that sounds more like screen or grid voltage failure to me. The tube is set up with some
specific conditions of Plate, Screen and Grid voltages, and the meter reads Cathode current. The
Grid voltage applied is AC. Too MUCH current is not a result of insufficient Plate voltage.
I'm wondering ifthe circuit may be oscillating?? I know the later TV-7D/U test sets had ferrite
beads on all the socket leads to prevent oscillation with the higher gain tubes, like the ones that
are giving you trouble??
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
and TR-4/C Service Supplement CDs
Joseph Trombino, Jr wrote:
> Many thanks for the info Garey.
> The problem I'm having with the Hickok 752 is when testing transmitting tubes like the 12BY7, 6146 and 6JB6.
> Under test the GM meter pins to the right...this doesn't happen using receiving tubes i.e., 12AT7 6AU6, etc.
> I believe the 83 tube provides plate voltage for tubes under test and the 5Y3 provides screen voltage.
> Can't figure out why this is happening....will check the 83 for blue glow when I put another tube under test.
> 73, Joe W2KJ
>> Joe -
>> Your tube is probably just fine. The blue glow only appears when current is being drawn. In the Hickok no current is drawn until you 'push a button' as part of a tube test.
>> The glow is also directly affected by the amount of current passed, so try testing a power tube with the case off, I bet you see the blue glow!
>> 73, Garey - K4OAH
>> Glen Allen, VA
>> Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
>> and TR-4/C Service Supplement CDs
>> Joseph Trombino, Jr wrote:
>>>> I just opened up my Hickcock 752 tube tester and turned the lights off in the shack to observe the 83 mercury vapor after a several minute warm-up period.
>>>> I saw NO blue haze that is typical of mercury vapor tubes.
>>>> I am fairly sure this indicates a bad tube....but ask if any of y'all have seen the same thing in a GOOD type 83 tube.....that is NO blue haze but the tube is still good.
>>>> If the tube is bad I wonder if anyone has a spare to sell...I've seen prices upwards of $50 from on-line vendors.
>>>> Also interested if any one has successfully used a solid state replacement for the 83 tube in the Hickcock line of tube testers??
>>>> Many thanks for you comments/observations.
>>>> 73, Joe W2KJ
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