[Boatanchors] Johnson Ranger R35

[hwhall at compuserve.com]

  Thanks for the comments, all!

I re-read what the Handbooks (plural) had to say earlier this evening. Besides draining off the filter caps when power is turned off, there were two other reasons I saw for pulling all that power down a big bleeder. 

(1) To ensure that a necessary amount of current was drawn from the supply to make the filter choke inductance always met the critical inductance, a condition which keeps a choke-input filter section from acting more like a capacitor-input filter (which lets the output voltage with light loading to float closer to the peak rectifier output voltage than a well designed choke-input filter will do).

(2) The above also contributed to reducing the peak current through the rectifier tube(s) so that more average current could be drawn for a given tube type without exceeding its max current ratings.

Since the pubished modification solid-stated the rectifiers, the advantage of (2) isn't an issue anymore. As long as the other stages (VFO, etc.) & components don't mind the extra max supply output voltage or the (probably larger) swings between key-up and key-down supply voltage, then the supply regulation of (1) becomes no issue. If so, then the removal of hefty bleeder loading isn't obviously an example of a mod that fails to understand the original designer's wisdom.

It's good to learn something new or relearn something every day. :-)
?

 Wayne
WB4OGM
 



-----Original Message-----
From: hwhall <hwhall at compuserve.com>
To: boatanchors <boatanchors at mailman.qth.net>
Sent: Fri, Feb 21, 2014 9:11 pm
Subject: Re: [Boatanchors] Johnson Ranger  R35

 I have a question about removing R35. It's the bleeder resistor on the power  
supply, I see, and I assume that the original designers selected that for a  
particular reason, otherwise they wouldn't be wasting all that energy n heart. I  
assume that it was intended to provide the minimum load on the power supply when  
the transmit key was open, improving the voltage regulation. Are there no  
problems with removing that min load and the increased swing in supply output  
voltage? 
 
  
Wayne 
WB4OGM 
 
 
 
-----Original Message----- 
From: Jbrannig <Jbrannig at verizon.net> 
To: Mr Bill Mellema <n3wm at yahoo.com>; Boat Anchors <boatanchors at mailman.qth.net> 
Sent: Fri, Feb 21, 2014 5:20 am 
Subject: Re: [Boatanchors] Johnson Ranger  R35 
 
  
  
  
Bill,  
Try this site.  I followed Phil's advice on my Ranger restoration and it   
works very well.  
  
http://www.ad5x.com/images/Articles/Ranger%20Mods.pdf  
  
73,  
Jim  
  
-----Original Message-----   
From: Mr Bill Mellema  
Sent: Thursday, February 20, 2014 3:53 PM  
To: Boat Anchors  
Subject: [Boatanchors] Johnson Ranger R35  
  
I have a nice Ranger and need to replace R35 the large cause of heat. I'm   
looking for a simple solution and would appreciate any inputs.  
  
Thanks In Advance..  
  
Bill N3WM  
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