[Hallicrafters] HA-1 issues...

[Roy Morgan]

On Jun 4, 2008, at 1:20 AM, Kenneth G. Gordon wrote:

> I have an ancient Hallicrafters T.O. Keyer, HA-1 which has
> been giving me fits lately.

Congratulations - that's a very nice gadget.

> First of all, I think there is an error in the manual

May well be.. I don't have a keyer or manual handy.  I appreicate your  
calling attention to possible errors.

>  Pins 1, 2, and 3 of V-1 are around 20 to 30 volts low,  but
> that COULD be due to out-of-tolerance resistors, or a gassy
> tube drawing too much current.

Some, not all of,dual triode tubes should be 5965's, or whatever they  
are.  These are "computer-rated" dual triodes much like the 12AU7.   
12AU7's will work fine, but not for as long.  The issue is development  
of "Cathode Interface" during long OFF periods of no cathode current.  
This happens in a computer or keyer when it is in one state and stays  
there.

More likely is drifting of any or all of the high value resistors (are  
they one meg or 10 meg?  I can't remember.) Anyway, measure them and  
be prepared to replace them.  Also, any caps in the timing or flip- 
flop circuits should be ceramics or modern film caps.  Any paper caps  
in those spots are almost certain to be leaky enough to cause trouble.

>  BTW, ALL of the tubes in my HA-1 are labeled
> Hallicrafters, so I think they are original.

See that the 2AU7's and 5965's are in the right spots.

> I suppose it COULD be a failed NE-51, but the bulb sure
> isn't discolored...just dark.

Drifted-high resistors.

  Note: the thing will not run right on it's side.  The relay is  
mercury wetted and so the mercury can run to the wrong spot inside and  
cause trouble.  Upside down may work ok, but  you may need to make up  
an extension cord octal to octal to mount the relay right side up  
while troubleshooting.

However, if you replace all high value resistors and suspect caps, you  
may well find that it runs just fine.

No CW ham's shack should be without one!

(If you are keying lots of current, pay attention to the graph in the  
manual telling about the needed snubber resistor/cap combination,  
advised to be placed AT the relay socket.)

Roy



Roy Morgan
k1lky at earthlink.net
Lovettsville, VA 20180