Tesla list wrote: >Original poster: FutureT@xxxxxxx >In a message dated 5/17/06 6:25:11 PM Eastern Daylight Time, >tesla@xxxxxxxxxx writes: >Hi Bert, >I tried the debarnacling an 833A tube. It turns out the manufacturer >put a spark gap in the tube, and it kept sparking at that area. I got >nowhere with the process. I didn't persue it or try other types of tubes. >John Hi John, That's very interesting! Do you happen to remember the manufacturer of the tube? I wonder if this might be an "undocumented feature" (from a specific manufacturer?) to otherwise prevent inter-element arcing damage during operation. Bert
Hi Bert, I don't remember the brand name. I seem to remember that the mfr. riveted a little stud to a part of the plate assembly near the top where it exits the glass. This stud is close to another metal part of the tube and it arcs there. It doesn't look exactly like a spark gap but it behaved like one. I agree that the feature is probably to prevent inter-element arcing damage. I just now checked a few other 833A tubes and they don't have the feature, or it's not as pronounced. It seems they might allow some metal parts to get close enough here and there to permit arcing. In some cases the system might look less like an actual spark gap. I don't know. I should have checked out other tubes at the time to compare but I didn't. John