[Hallicrafters] Cyclone SR400 questions

[james.liles]

Hi Andrew:
She SR-400 Cyclone consists of six run/engineering change levels A-F.  The A 
through E are Cyclone and the F level is the CycloneII.  The part # suffix 
on the schematic will reveal the engineering level.  FYI, the manual on BAMA 
is the F level or Cyclone II version.  There were a significant number of 
changes from A to F, all of which make significant performance enhancements.

For question 1:  The antenna relay is normally picked/energized for receive 
mode.  It is wired to the 6AQ5A cathode so it will not enable until the 
6AQ5A warms up.  ----- Normal operation

Question 2:  First the meter switch when in receive mode is driven full 
right until V8 the meter bridge warms up then drops slowly back to the left. 
The AGC and meter zero adjustments in the manual are dopy!  Do this ---  
turn the AGC pot full clockwise  --- then set the meter zero adjustment to 
S0 --- then slowly turn the AGC pot counter clockwise until the meter reads 
between S0 and S1 --- you are done but don't do the adjustment until the 
radio has been on for 20 minutes.

Question 3:  The voltages are OK!

Question 4:  That power supply was made for the SR-400 or SR-500 --- the 
SR-500 needs the pot on the power supply and the SR-400 has one on the front 
panel.  I believe the bias for the SR-400 is -125V but check the schematic 
to verify and set the pot on the power supply to the indicated level.

For Jack:  The external VFO HA-20 when used with the SR-2000 or SR-400 A-E 
will be about 6db more sensitive than the internal VFO.  When attached to 
the SR-400 "F" level Cyclone II it will be about 10db better than the 
internal VFO but only in receive mode.  For the SR-400A Cyclone III, the 
internal VFO will be about 6db better than the external.  In all of the 
above cases, the external and internal can be brought very close.  The 
problem is a design oversight within the VFO design.  I am a year and a half 
late in writing a new maintenance and enhancement manual for the SR-2000, 
SR-400, and SR-400A.  I'm in rewrite #3 and am having difficulty writing to 
a broad user group.  If I don't finish soon, I'll begin releasing it in 
sections.  I've redesigned the VFO to correct a number of problems including 
the remote/local VFO parity problem, enhanced dynamic range, birdie 
reduction, and spur correction.  Please don't misunderstand what I say,  I 
have used redesigned and restored the SR-2000, 400, and 400A series for 30 
years and have used the UNALTERED final production level radio's in contest 
environments with mono banders at 110 feet and never detected overload, 
intermod, or other anomalies.  Any re-design that I have done is to make a 
fantastic radio maybe a bit better using in many cases Hallicrafters design 
principals.


Original message:

> Message: 4
> Date: Fri, 11 Jun 2010 23:09:12 +1000
> From: "VK2ACC" <vk2acc at exemail.com.au>
> Subject: [Hallicrafters] Cyclone SR400 questions
> To: <hallicrafters at mailman.qth.net>
> Message-ID: <8F50023C841C4BA88CBFA562D4B900D0 at library>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Hi all,
>
> I recently imported from the US to Australia an SR400 (red logo) + PS500A 
> to restore.
>
> After slowly (over 1 week) bringing up the voltage on a variac I have only 
> replaced the finals (one valve was shorting the grid bias) and the panel 
> lamps so far.
>
> But I'm still a learner so I have some questions for any Cyclone original 
> series owners :
>
> 1) When you turn on your Cyclone, does the antenna relay click over to 
> receive immediately ? I get about about a 15 second delay.
>
> 2) When you turn on with the meter switched to RFO/S what does the needle 
> do ? Mine pegs to the right then drops down after a few seconds. - I think 
> I also have an AGC problem, the S meter is hard to adjust.
>
> 3) What voltages is your PS500A delivering? - I have switched my supply 
> from 110V to 220V and get B++ 830V, B+ 260, Bias -130V, Heaters 12.9V.
>
> 4) The PS500A instructions say to increase the bias control to maximum 
> when you start adjustments, but I have not found any mention of decreasing 
> the power supply bias control to an optimum setting later. Any ideas ?
>
> Cheers
> Andrew
> VK2ACC