[AMRadio] Johnson 500 Schematic

[Dave Harmon]

Hi Craig....thanks for the answer.
The original manual I have with the correct s/n on the warrantee card has
2/57 on the left bottom of most pages.
The tube lineup shows a 4-250 in the tube lineup.
The BAMA manual has 2/58 on some pages...probably the updated pages....and
the tube lineup shows a 4-400.
So....I DO believe there were at least 2 manuals.
Note on the schematic says "rev 4 5/12/58"

I think I have figured out the wiring and resistor changes on the keyer so
I'll make the changes and see what happens.

Thanks again.
73 

If anyone else has any info at all I would appreciate it!


Dave Harmon
K6XYZ[at]sbcglobal[dot]net
Sperry, Ok.


-----Original Message-----
From: Craig Heaton [mailto:hamfish at efn.org] 
Sent: Wednesday, March 20, 2013 7:28 AM
To: 'Dave Harmon'; 'am'
Subject: RE: [AMRadio] Johnson 500 Schematic

Dave,

Two things: One, I don't think there was an early Junkston "500" which used
a 4-250A. Their production years were 1957-1962? (going from memory here).
By 1957 Johnson had switched to 4-400A's in the Desk KW. Sort of apples to
oranges. 

Like you I'd have to see a 500 schematic showing a 4-250A.

Two: When a "500" followed me home and upon inspecting the entire rig wire
by wire, part by part; the keyer circuit was not as per the BAMA schematic.
I then restored the 500 as per the BAMA schematic, keyer works!

Best Regards,
WD8KDG
Craig
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-----Original Message-----
From: amradio-bounces at mailman.qth.net
[mailto:amradio-bounces at mailman.qth.net] On Behalf Of Dave Harmon
Sent: Tuesday, March 19, 2013 7:33 PM
To: 'am'
Subject: [AMRadio] Johnson 500 Schematic
Importance: High

Recently I acquired a Junkston 500 and it works great....except the keyer is
not adjustable.
The rig can be keyed ok but the adjustment pot has no effect.
Yes...the pot is good.
The keyer does not conform to the schematic I have.
Apparently I have an early model but a later schematic.
Can anyone help me out with the early schametic?
All I need is a .jpg of the keyer area......or a location to dwnld the early
schematic.
I think the early schematic will show a 4-250....

Dave Harmon
K6XYZ[at]sbcglobal[dot]net
Sperry, Ok.



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