Hi Peter,
IF you use ohms law to figure the current thru the resistors, you'll
see that one tube is drawing about 28 ma., and the other is drawing 43
ma. They'll probably be in about the same ratio under higher load.
Checking this is one way, when the resistances are equal, to determine
if one tube is getting weak.
You should replace both resistors with new ones rated at 1w or more.
73,
Al, W8UT
www.boatanchors.org
www.hammarlund.info
"There is nothing -- absolutely nothing -- half so much
worth doing as simply messing about in boats"
Ratty, to Mole
On 9/18/2012 2:08 PM, Peter Ravn wrote:
The two cathode resistors in the finals in the TX4B should be 15 ohms
each, but R32 is 30 ohms and R33 16 ohms with the finals unplugged, so
R32 is definitely bad. The difference in voltages on the cathodes of the
two finals is, however, minimal. The voltage across R32 is 0.85 and 0.7
across the R33.
What are the causes and consequences of the differences in the cathode
resistors?
Thanks.
OZ8CTH
Peter
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