[Amps] 3-500Zs inverted

[Pete Smith N4ZR]

I need to trouble-shoot my QSK system, which is built into my SB-220.  
Will it do any harm to apply filament and plate voltages, but no drive,  
to the 3-500Zs in the inverted position for a few minutes at a time?

-- 
73, Pete N4ZR
Check out the Reverse Beacon Network at
http://reversebeacon.net,
blog at reversebeacon.blogspot.com.
For spots, please go to your favorite
ARC V6 or VE7CC DX cluster node.