It copuld have been lightning, but also a severe mismatch or antenna system fault at high power can cause some crazy nasty voltages and currents.
73
-Jim
NU0C
On Fri, 2 Apr 2021 16:37:10 -0700
"Patrick P" <sbus1313@...> wrote:
So what smokes these things anyway? Lightning? Or is it a problem in the design to be resistive at high potentials? I don¡¯t see any soot, which you¡¯d expect from a lightning strike. But it was hot enough to shatter the ceramic and melt the contacts. A little puzzled on this one.
Patrick
NG7I
On Apr 2, 2021, at 16:09, VE7PS <ve7ps@...> wrote:
? Patrick:
A while back Paul Kraemer, K0UYA, posted some pics that I believe are posted on this group that shows a repair job he did on that switch using a 5 position, 5 or 6 pole switch from Russia that is still available on E-bay for (I believe) $18. You mount it backwards as I recall so the front of the switch is mounted on the rear, after removing all but two of the wafers. That leaves you plenty of shaft to connect to the rest of the shaft going to the front panel control. You will have to make up an offset shaft coupling to connect the two shafts and retain the correct indication.
I have an MN-2000 here that is in need of that same repair.
If it is not there in the files or pics section, get back to me as I have them saved too.
73
Peter
VE7PS
On 2021-04-02 3:36 p.m., Patrick P wrote:
Here are some pics (if this will work from my phone)....
Patrick
NG7I
<image.jpg>
<image.jpg>
On Apr 2, 2021, at 14:46, Patrick P via groups.io <sbus1313@...> wrote:
?Gentlemen,
I got an MN-2000 tuner off eBay last month and finally had time to test it. The knob in the upper left ( Alternate / Match 1 / Match 2 / Direct 1 / Direct 2 ) was seized so upon further inspection it appears this unit was hit by lightning. Does anyone have an extra rotary switch for this tuner? It's frozen in Match 1 and the rotary contacts were vaporized / welded together. I would really like to keep this old soldier online if possible.
Regards and 73's
Patrick
NG7I
Jim Shorney