{Collins} Re: KWS-1 injects HV noise into my KWS-1



Ed,

The tick-tick-tick sound is either coming from a momentary arc in 
your high voltage supply, or from an arc in one of your final 
amplifier tubes. In either case, the electrical discharge is creating 
noise that's getting into your 75A4.

Here's what I'd do to isolate the problem:
1. Separate the KWS-1 from it's power supply by a couple of feet and 
listen carefully to see which unit is producing the tick. Most 
likely, it's coming from the power supply. If it's coming from the 
transmitter unit, then try disconnecting the plate caps from the 
4cx250bs. Be suspicious of the HV feedthrough capacitor into the 
final amplifier compartment. Make sure it's clean.

2. Unplug the KWS-1, and then unscrew the HV cable from the high 
voltage power supply. Then power on the HV and see if the ticking 
stops. If it does, then make sure something isn't loose in the HV 
connector, and that it's been tightened properly.

3.  Unplug the KWS-1 and remove the rectifier tubes. Clean the tube 
sockets and pins carefully of any accumulated dust or grime. Ditto 
for all the HV cabling.  Make sure the nets on top of the filter caps 
are tight, and ditto for the screws on the plate transformer. Check 
that metal shield partitions have adequate clearance from any high 
voltages. One common failure is the insulation in the filter choke. 
Let's hope that that isn't the problem.

4. If you've had no luck so far, then you'll have to do some more 
serious detective work. Disconnect the filter caps and fire up the HV 
supply. If the ticking disappears, then your problem is probably in 
one of the caps. If you have spare rectifier tubes, then try 
replacing them to see if the ticking goes away.

73,

Jim Garland W8ZR





At 07:04 PM 1/11/2006, you wrote:
>Greetings All,
>
>With the kind help of NI6Q I have finally gotten the Gold Dust Twins on
>the  air. I do have one lingering problem. HV noise from the KWS-1 is
>getting into the 75A-4.
>It is heard as a tick tick tick noise that sounds like the stopwatch on
>60 Minutes, accompanied by some general hash. It's not too terrible but
>it is annoying.
>Turning off the Plate Supply kills the noise.
>
>I have tried strapping the chassis together, no diminishing of the noise
>results.
>Being on the second floor the rig is grounded by the AC outlet only.
>The HV line is a piece of coax.
>The line from the antenna relay is also new 50 ohm coax.
>
>Anyone running this pair that has heard this before?
>
>Ed Simeone K6EGS
>
>Sponsored by the Collins Collectors Association http://www.collinsradio.org
>Nets: Tues: 3.805 Mc-2000 Central / Thur: 3.875 Mc-2000 Central
>Fri: 3.895 Mc-2000 Pacific / Sun: 14.263 Mc-2000 UTC
>1st Wed (of the month) AM Net 3.880 Mc-2000 local (ET, CT, MT, PT)
>Sun AM Net: 29.050 Mc-1200 Central

Sponsored by the Collins Collectors Association http://www.collinsradio.org
Nets: Tues: 3.805 Mc-2000 Central / Thur: 3.875 Mc-2000 Central
Fri: 3.895 Mc-2000 Pacific / Sun: 14.263 Mc-2000 UTC
1st Wed (of the month) AM Net 3.880 Mc-2000 local (ET, CT, MT, PT)
Sun AM Net: 29.050 Mc-1200 Central






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