[Yaesu] FT2100B help needed

[Dr. Gerald N. Johnson]

221K would mean 220 pf.

You can make some very rudimentary tube tests with your ohmmeter. You 
can check for filament continuity, and interelectrode shorts. Especially 
grid to filament and even grid to plate, though a test at 9 volts may 
not necessarily tell you much about operation at a peak voltage over 4 KV.

It is possible with three power supplies and your Fluke to test for tube 
gas. You apply +45 to the control grid and -45 to the plate with respect 
the the filament. You meter the control grid current as you bring up the 
filament to limit the grid current to its current rating. That's 
electron current. Then you check the plate current which in a perfect 
tube will be zero to less than 1 millionth the grid current. The plate 
current is positive ions caused by the electrons hitting gas atoms or 
molecules in the tube. A lot of plate current, say 1/1000th the grid 
current in this test means a very gassy tube. It may improve 
significantly by applying filament power alone for a day or a week.

I've seen FL2100B manuals I think.

Bama has FL2100Z. bama.edebris.com/manuals/yaesu/fl2100z/ as does KO4BB.

mods.dk has the FL2100B manuals for download. You have to sign up and 
can download one each 4 days. Pick the most complete for your first 
download. mods.dk/manual.php?brand=yaesu

73, Jerry, K0CQ

On 11/27/2012 7:20 PM, Rick Gouge wrote:
> Hello to the group. I just pick up a FT2100B amp and it is broken. The amp was very dusty with dustbunnies and all. I found a resistor and a square looking cap at the base of a 572B tube blowen in half. I do not have a manual for this amp . Does anybody have any idea what might have caused this? Bad tuning practice? Tube gone bad?Andbody have the parts i need from a junker? The 330 resistor i have. Its the square cap with 221k written on it that i need. I do not have a tube tester to check the 572bs. Is there a way to check the tube with my fluke ohm meter? Rick VE7RiK
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