开云体育

Update:

I finished making the repairs to the Band Switch.? New pictures are in the /g/DRAKE-RADIO/album?id=301171 album.

The fingers on the switch I bought were mounted in two sections and the switch needed them all in one contiguous section.? I removed one of the sections and re-mounted it using #80 brass screws and stainless-steel nuts with Loctite to make sure those nuts did not work themselves loose.? Since the fingers all need to be be connected together, I soldered a heavy-gauge piece of copper wire to both sections.? I also needed to remove one switch finger as there were 11 and the switch only uses 10 of them.

The switch I bought also did not have the connection points rotated such that they faced each other in pairs like the original switch was configured.? I opted to remove the flat straps from the capacitors and substituted a heavy gauge solid copper wire in a VEE shape that connects two solder points to each capacitor (see pictures).? That seems to work well enough.

Getting the "fingers" of the coil reattached was a bit painful.? I formed loops of solid copper wire to accept each finger and connect it to two of the solder points on the switch.? That was quite tedious due to the limited space but I got it done.

I reassembled the internals and, for fun (since I didn't have a transmitter on the workbench) I connected it to my R390 receiver.? I was quite surprised at what a difference that makes matching my 20M inverted VEE in my attic to 80M at the receiver.? In my 50+ years as a ham, I've never owned a separate tuner like this and was impressed at the sharpness the tuning provides in that scenario.? I intend to drag out the TR-4 and my dummy load and see what that looks like.? Of course, since it's a 50-ohm dummy load, the tuner won't have much to do but I thought I'd see what it does there before moving on to using the attic antenna with it.? I don't have anything to test it with legal-limit power so I'll have to trust that it will properly handle that much power the way I reconnected the switch.

I really, really like this new "toy"!

Thanks
Barry - N4BUQ

> Pictures of the switch/cap/coil assembly are here:
>
> /g/DRAKE-RADIO/album?id=301171
>
> Barry - N4BUQ
>
>> I have removed the switch assembly from the tuner and have a question.? If I'm
>> not mistaken, the original switch had 10 fingers, each one contacting 2
>> contacts at any of the 5 positions.? Is that correct?? Based on what I can
>> surmise, that's likely correct but thought I'd check first.
>>
>> Thanks,
>> Barry - N4BUQ
>>
>>> I have an MN-2000 that somewhere in its long history, suffered a somewhat
>>> catastrophic event that vaporized one set of the rotating fingers on the band
>>> switch, damaged two of the contact points on the steatite wafer, and cracked
>>> the wafer.
>>>
>>> I found this switch which has potential:
>>>
>>>
>>>
>>> The contacts are much like the one in the tuner; however, the rotating part is
>>> different.? The band switch in the MN-2000 isn't a traditional rotary switch in
>>> that it doesn't make use of a wiper and, instead, the rotating fingers are like
>>> a rotary shorting bar (for lack of a better way to describe it).? Presumably if
>>> you've ever looked at one of these, you know what I'm talking about.
>>>
>>> Does anyone have any pointers on how I might go about replacing/repairing this?
>>> The tuner is is in otherwise exceptionally great condition so I'd like to
>>> repair it and use it.
>>>
>>> Thanks,
>>> Barry - N4BUQ
>>
>>
>>