[Johnson] Adventurer filter caps

[Don via Johnson]

Also, depending on how precise you want  to be size wise with your 
replacement capacitors, you could contact the  courteous folks at HAYSEED HAMFEST 
COMPANY, and they'll make some up for  you.
 
I have a Knight T-50 transmitter, which  is apparently a clone of the 
Johnson Adventurer.   Since the  transmitter had not been turned on in over 50 
years, I opted to replace the caps  before plugging it in, and the Hayseed 
folks made some up for  me.
 
I have no affiliation with HAYSEED  HAMFEST COMPANY, other than being a 
satisfied customer for RME, Drake  and Knight parts.    Here is a URL for their 
web site, which  provides contact information.
 
http://www.hayseedhamfest.com/    
 
73
 
Don K8MFO
 
 
In a message dated 3/2/2015 2:28:40 P.M. Eastern Standard Time,  
wa6acc at verizon.net writes:

Charles,

A lot of guys use strings of lower voltage  capacitors to replace the
700-Volt units found in these transmitters. In my  Adventurer I've used 
three
33-uf / 350-Volt caps with 270K-Ohm / 1-Watt  equalizing resistors around
them. The 1-Watt rating on the resistors is  necessary because of the
200-Volt+ potential around them. Collins used this  same string in the 
516-F2
S-Line power supply. You need to use the  equalizing resistors because
electrolytic capacitors have capacitance  tolerances of -20% to +100% which
throws the instantaneous voltages across  them all over the place. 

Dennis, WA6ACC

-----Original  Message-----
From: Johnson [mailto:johnson-bounces at mailman.qth.net] On  Behalf Of Charles
Ring
Sent: Sunday, March 1, 2015 8:07 PM
To:  johnson at mailman.qth.net
Subject: [Johnson] Adventurer filter  caps

The original Johnson Adventurer filter caps are two big old axial  8uF 700V.
What is the proper way to replace them? Seems the originals are  really each
two caps in series in one paper enclosure. Two 20uF 400V  directly in series
replacing each one? Equalizing resistors  needed?

--
*Charles Ring  W3NU*
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