[Hallicrafters] HA-1 TO keyer with modern SS rigs

[Roy Morgan]

On Feb 28, 2009, at 4:48 PM, Tom NØJMY wrote:

> ... the topic of TO keyer's was on one of the
> lists here within the few last weeks,

I may have missed that, but the T/O keyer is one of my favorite topics.

> ... the possibility of using one
> with a modern-day SS transceiver.
>
> Can someone supply me with a brief synopsis?

Just plug it in and go for it.

The T/O keyer uses a mercury relay to key the transmitter it is used  
with. There *may* be a suppressor network installed inside the keyer  
to reduce arcing and wear on the relay, but most of them that I've  
seen do not have any.  The reason is that most transmitters do not  
have at the key jack enough voltage or current to need the suppressor  
network.  (Details of the network and what to use are in the manual.   
The manual is on BAMA, see link below.)

The keyer uses a paddle of your choice to make it work.. That paddle  
will have somewhat high voltages on it, I think.  Likely not on the  
order of 150 volts as some boatanchor transmitters do, but not 6 volts  
as the rice box may have. (My notes seem to indicate that it's on the  
order of 12 volts...)

The keyers relay will be switching the key jack line on the rice box,  
which is likely to have very moderate voltage at very low currents  
present.  There is no need to worry about hurting the keyer or using  
any suppressor components.

Notes on the T/O keyer:

- there are some high value resistors in it that are likely to have  
drifted even higher due to age.  Replace them.

- Some caps in the thing may be leaky also due to age.. Replace them.   
My notes contain this: "Apparently the balance of all circuits that  
have like components in the TO keyer is critical.  So, if a tube has  
one .001 disc that is bad, replace them both.  Knowing this, the  
trouble shooting becomes trivial."

Also I find this report of things to fix:
"Hi all.
I have had a long problem with my HA-1 TO keyer's speed changing.
I replaced C1,C2 .02 mf  "tiny chief capacitors, and they were leaky.
Also resistors R2,R7  5.6 meg ohm with 2% precesion resistors.
The speed is now stable and easer to adjust. The keyer also developed
another problem of sending unwanted extra dits by itself???  I found the
problem was in the dial light. The outside tube was not making good
contact to the solder lug. I soldered the back of the tube to the solder
lug and removed the gremlins. Most of those i work on cw say the ha-1
has the best sound and is the easiest to copy of any keyer.
73 wa8ylz"

- certain of the dual triode tubes are supposed to be 5963's (I think  
that's the right number).  These are "computer rated" dual triodes  
very similar to the 12AU7, and will last longer with no trouble if you  
have them.. Normal 12AU7's are likely to work just fine, though.

- The mercury relay will only operate reliably in the UPRIGHT  
position.  If you are trouble shooting the unit upside down, use an  
extension cable and mount the relay upright.  The thing may key and  
the lights behave properly even if the relay is not in position.  The  
side tone may not work right because that is controlled by one of the  
contacts in the relay (if I remember right.)

-Only some of the similarly shaped mercury relays we may find are the  
right ones.  The T/O keyer uses the HG 1002. This has a coil  
resistance of about 4000 ohms and operates on about 10 ma in the plate  
of a 12AU7 in this keyer.  Certain of the also-found Western Electric  
relays of the same size/shape likely will work, but I do not know what  
the numbers are.  I'm still searching for data on the WE relays.  My  
notes show a fellow who has tested the following relays in the keyer  
with success:
Clare HGP 1002
Clare HG  1002
P and B  JM1 119 11  (Potter and Brumfield)

In 2005, I wrote the list this set of suggested things to do.   
(There'd been a report of the OB2 going into oscillation from time to  
time.)

"1) Get a new 0B2 and check the dropping resistor that feeds B+ to  
it.  If there are 12AU7's at V1, V2, and V3, replace them. Use 5963's  
if you have them.

2) Replace all, repeat all, paper caps (I don't remember which are  
paper and which might be ceramic..):
   C12, 13 across the VR tubes 0.02uF
   C1, 2 mulitvibrator  0.02
   C3, 4, 5   0.001

3) Replace all high value resistors - these are almost certainly  
drifted high or open.
  R1, 6, 17, 19  - 2.2 meg
  R2, 7 - 5.6 meg

Measure the 470K and 680K resistors to check for excessive drift,  
replace as needed.

4) Replace the filter caps: 20uF 250 volt

5) Make sure R 32, 10 ohms and R30 2200 ohms, 5W are not changed in  
value

6) Replace the two rectifiers with 29 cent 1N4007's

7) I suggest a three wire grounded line cord for safety, and add a  
fuse under the chassis - half amp should be fine, or quarter amp if it  
does not blow.

Notes:

1) The mercury relay will/may not operate correctly if on it's  
side..it must be more or less upright to avoid the mercury shorting  
things inside.  An octal extender cable will do for testing if you  
need to put the keyer upside down.  The T/O keyer uses the Potter and  
Brumfield HG 1002 mercury relay or equivalent. This has a coil  
resistance of about 4000 ohms and operates on about 10 ma in the plate  
of a 12AU7 in this keyer.  Other relays of similar coil resistance  
will work fine.

2) The manual is on BAMA:
  <ftp://bama.sbc.edu/downloads//hallicra/ha1>

3) The 5963's specified are "computer rated" tubes comparable to the  
12AU7.  The 12AU7's will work fine buy may not have full life. The  
"computer rated" business means in part that they were made for long  
on/off times without developing "cathode interface" - a degradation in  
the cathode material that appears as if a resistance is in series with  
the cathode.

4) If there's no sound from the speaker and there's no "control plug"  
present, jumper pins 6 and 7 on the rear apron socket.  These pins  
feed audio to the speaker from the normally closed contacts on the  
earphone jack. The "Control Outlet" is normally used to hook to the  
keyed transmitter, so a plug with audio jumper is normally present.   
Some plumbers soldered wires into the circuit at the relay socket.

5) The manual tells of using a snubber circuit at the relay socket to  
prevent harm to the relay, but this is not needed with transmitters  
that have low power in the keyed line. Most Johnson transmitters and  
rice boxes do not need any snubber circuit.

6) The Origin of the "Model HA-1 T.O. Keyer" was an article by W9TO  
with follow-on updates in a ham magazine. "

  (I do  not seem to have the reference to that article, or the  
article itself.. if anyone has that info or scan of the article, I'd  
be very glad to get it.)

Roy


Roy Morgan
k1lky at earthlink.net
529 Cobb St.
Groton NY, 13073