In my L4B amplifier, the tubes burn nicely for a short time, then one of the tubes' filaments go out. I removed the tubes and switched them. Same tube goes out after abit. Took that tube out again, checked filament to filament pins, "zero" on the Simpson 260. Also checked for a filament to grid short, (tapping tube didn't change reading) and that reading was "infinity". So the tube is OK, until it heats up. The solder blob on the pin bottoms are OK.
I think the filaments are getting HOT while I'm transmitting, and possibly a 'fracture' in the filament somewhere, getting hot, expands, then when I'm in the 'listening' mode long enough, the fracture presents itself as an OPEN in the filament line. Comments welcome. 73, Gerald, KB7QQ --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.574 / Virus Database: 364 - Release Date: 1/29/04 ---------------------------------------------------------------------- Submissions: [EMAIL PROTECTED] Subscribe: [EMAIL PROTECTED] - subscribe drakelist in body Unsubscribe: [EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost: [EMAIL PROTECTED] - help in body of message Brought to you courtesy of TLCHost.net http://www.tlchost.net/ ----------------------------------------------------------------------
