[Top] [All Lists]

[AMPS] SB-1000 mods?

To: <>
Subject: [AMPS] SB-1000 mods?
From: Mike" < (Mike)
Date: Fri, 7 Sep 2001 18:43:10 -0700
Hi Tom,

Is there any reason that a glitch resistor is preferred over a fuse in the anode
lead. I opened up my L-7 power supply last night and found that someone
had replaced the 0.82 ohm glitch resistor with a fuse (I was planning to replace
the 0.82 ohm resistor with a 50 ohm 50 watt power resistor as per the
recommendation on G3SEK's website).


Mike, W4EF..........

----- Original Message ----- 
From: "Tom Rauch" <>
To: "Vic Rosenthal" <>; "Ian White, G3SEK" 
<>; "Phil Clements" <>
Cc: <>
Sent: Friday, September 07, 2001 5:11 PM
Subject: Re: [AMPS] SB-1000 mods?

>  work, but thousands are in use. I have always added
> > Rich's grid fuse resistor scheme when repairing SB-1000's.
> > No tube failures to date that I know of.
> You'd be far better off to use a HV glitch resistor, and leave the grid 
> grounded. Resistors in grid leads are bad news unless there is 
> good reason to add them, because they let the grid rise to anode 
> voltage if there is a fault.
> If the grid rises to anode voltage, the grid naturally no longer 
> shields the filament from the HV surge. That means the filament is 
> many times more likely to rise to B+ rail.
> Better to simply put a proper surge resistor in the HV lead, and let 
> the arc pull the anode low through a series resistance!!!
> 73, Tom W8JI
> --
> FAQ on WWW:     
> Submissions:    
> Administrative requests:
> Problems:       

FAQ on WWW:     
Administrative requests:

<Prev in Thread] Current Thread [Next in Thread>