6146 Replacement

[Bill Coleman]

On Aug 29, 2006, at 2:26 PM, Davies, Doug A FOR:EX wrote:

> Well, I've digested all of the replies on this query and I think I'm
> going to try one of the 6146B's in the DX-40.

The DX-40 was designed for the 6146/6146A. I would not use the 6146B  
in it.

> This rig doesn't require
> any neutralization in the true sense of the word so I'm going to  
> give it
> a shot.  If the output continues to drop off, I obviously have other
> problems.

First thing to check is the plate supply voltage under load. It needs  
to stay around 600 volts in order to get the required output. Also  
check the screen supply and resistor. If the resistor has drifted to  
a higher value, it may cause the current to fall off.

Another thing to be wary of is bad metering circuits. The resistors  
in the metering shunt may have changed value over time. The tube  
could be operating normally, but the meter lies.

Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr at arrl.net
Quote: "Not within a thousand years will man ever fly!"
             -- Wilbur Wright, 1901

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