I had a FL-2100B and did the bias mod that RF Parts recommended. It
worked fine with the Svetlana tubes after that.
Before the mod, right after I put the tubes in, I keyed the amp with no
drive and it pegged out the meter and ruined 1 tube. RF Parts replaced
it for free and sent me the modification. 73
Tom W7WHY
On 11/7/2014 11:24 AM, Dave wrote:
The service bulletin was in the bias system for the FL-2100B. Improper
bias triggered instability. There were not RF related changes.The FL-200Z
has a different bias system but I don't remember if it fixed the problem.
The problem does not exist in the 30L1 or the SB-200 .All the details are on
the Web. I Svetlana's plate dissipation rating is 160 watts, just like the
572B. Yes, the plates are smaller but they are also thicker and are made of
graphite like the original T160 (original nomenclature for what became the
572B. I have a set of original ceramic base 572B in my 30L1 and they have
worked perfectly for over 5 years of daily use and the amplifier is stable
on all bands. I wish I had bought a spare set back when they were current
production.
Dave
W7VM
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|