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Old 19th Oct 2017, 7:32 pm   #1
Gi4CZW Cliff
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Default How to open 15W HF dummy load?

My 50 Ohm 15 Watt dummy load is inter. diss. Noticed small movement on the PL259 centre pin. So before I bin it, is there a way to open it, to do a repair ? Thanks Cliff.
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Old 19th Oct 2017, 8:17 pm   #2
Boater Sam
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Default Re: How to open 15W hf bummy load.

Why not just superglue the center pin into the insulator? Seems a shame to bin it if it still works.
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Old 20th Oct 2017, 8:24 am   #3
davidw
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Default Re: How to open 15W HF dummy load?

I'd try resoldering the centre pin using a large iron and fresh solder.
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Old 20th Oct 2017, 9:25 am   #4
Herald1360
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Default Re: How to open 15W HF dummy load?

If resoldering doesn't do it, I reckon judiciously applied brute force is called for.
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Old 20th Oct 2017, 1:17 pm   #5
merlinmaxwell
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Default Re: How to open 15W HF dummy load?

Yes, open it up using percussive methods (hammer) and see just how bad it is made and do a better job yourself.
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Old 20th Oct 2017, 2:14 pm   #6
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Default Re: How to open 15W HF dummy load?

However, if you get a good dummy load or power attenuator - something with decent HF-VHF performance surplus from either commercial or military use, then open it at your peril. Many of these contain Beryllium Oxide whose dust can be fatal if inhaled.

Cheapies made for amateur radio are may well be safe, but risks have to be judged before taken.

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Old 20th Oct 2017, 2:26 pm   #7
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Default Re: How to open 15W HF dummy load?

Correct! I was thinking of that substance as it is certainly used on the higher wattage loads.
Though mine was marked as Do Not Open.
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Old 20th Oct 2017, 4:31 pm   #8
merlinmaxwell
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Default Re: How to open 15W HF dummy load?

Quote:
Though mine was marked as Do Not Open.
In case you find out!
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Old 20th Oct 2017, 5:15 pm   #9
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Default Re: How to open 15W HF dummy load?

I certainly had no intention I add of opening my dummy load as I knew that stuff is lethal and used also in power transistors.
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Old 20th Oct 2017, 6:02 pm   #10
Gi4CZW Cliff
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Default Re: How to open 15W HF dummy load?

As I went to remove the existing solder on the centre pin, a length of wire fell out with it. This was just the right length to go from tip of pin to edge of heat sink, so I assume the dis' was down in there. Efforts, including lump hammer, and grip wrench distinctly unsuccessful. No warning signs and I've bumped into Beryllium before so thank you all for the input. Cliff.
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