[R-390] V509 runs hot

[Robert Young]

I'd like to thank everyone for their help, the radio ran fine all night with the new 5814A subbed in for V509, no volume changes. Now to check the caps and resistors around that stage,

Bob Young
KB1OKL
> 
> Message: 2
> Date: Fri, 25 Feb 2011 00:14:51 -0500
> From: k2cby <k2cby at optonline.net>
> Subject: [R-390] V509 runs hot
> To: R-390 Mailman <R-390 at Mailman.qth.net>
> Message-ID: <EE98F48B61EC40619E4532DFF521D96C at milesdesk>
> Content-Type: text/plain; charset=us-ascii
> 
> The only thing that will make a triode run hot is excessive grid voltage.
> 
> There are three suspects:
> 
>             The most likely is a short or leak in the capacitor leading to
> the grid from the plate of the prior stage causing the plate voltage to
> drive the grid of the following stage positive.
> 
>             The less likely (but possible) is a short in the capacitor that
> bypasses the cathode resistor, causing the tube to become zero-biased.
> 
>             The least likely is a plate resistor or a cathode resistor that
> has vastly decreased in value (although the plate resistor may well have
> changed value due to excessive current). 
> 
>  
> 
> Miles B. Anderson, K2CBY
> 16 Round Pond Lane
> Sag Harbor, NY 11963
> Tel.: (631) 725-4400
> 
> Fax.: (631) 725-2223
> e-mail: k2cby at optonline.net 
> 
> 
> **************