Argonaut 505

[KA9MOT]

Nice rig! I hope you get it working.

[W3WN]

I would redesign the PA and look at using an MRF device or its equivalent. Have a look at an NTE236 for starters, or a 2SC1969.

Well, if it gets that far... but first things first.

[K7SGJ]

I would redesign the PA and look at using an MRF device or its equivalent. Have a look at an NTE236 for starters, or a 2SC1969.

I like the MRF458 for HF amps. They are very stable and easily matched. No coupling or feedback issues. Just a good solid performer. My wife closed out all the RF transistors they had down there. I got them for their cost at the time they bought them. Somewhere in the 80s. Bless her heart. There were a lot of MRF245 80w @ 136-176Mhz. And a bunch of low power, med pwr, hi pwr from below 2Mhz up past 500Mhz and some in the micro wave region. Already fixed and sold a bunch of radios, but I have many more to go.

[W3WN]

I like the MRF458 for HF amps. They are very stable and easily matched. No coupling or feedback issues. Just a good solid performer. My wife closed out all the RF transistors they had down there. I got them for their cost at the time they bought them. Somewhere in the 80s. Bless her heart. There were a lot of MRF245 80w @ 136-176Mhz. And a bunch of low power, med pwr, hi pwr from below 2Mhz up past 500Mhz and some in the micro wave region. Already fixed and sold a bunch of radios, but I have many more to go.

Well, IF I get to the point that I have to revamp or redesign the PA, I will be talking to you and Fred. I'd probably want to boost the output from 5 W to 10 W or so too... but first things first.

That receiver has to be brought back to life, or the rest of the rig is a moot point.

[K7SGJ]

You could always put a 5 tube ac/dc Silvertone ahead of it.

[W3WN]

You could always put a 5 tube ac/dc Silvertone ahead of it.

Hah! :twisted:

An All American 5, naturally!

Besides, I still have my OTHER project rig... the Swan 3Drifty, er, 350 station. That would do as well.

[K7SGJ]

Hah! :twisted:

An All American 5, naturally!

Besides, I still have my OTHER project rig... the Swan 3Drifty, er, 350 station. That would do as well.

Maybe you can get it to drift close enough to merge. Then you would probably end up with a Swargonaut 3505, eh?

[W3WN]

Boy, has it been almost 6 months already?

Came across a ham on the Ten-Tec reflector with time on his hands, test equipment, and looking for projects to work on. He offered to take a look at the Argonaut, so it's in his hands right now.

Keep your fingers crossed! (NO, not THOSE fingers!!)

And I've sent him the links you gave me Fred, since at least one (Alltronics) appears to have the appropriate transistors in stock for the audio board.

It doesn't look like I got around to posting this before, but I heard back from John Henry at Ten-Tec. The audio power out transistors (2N4105 & 2N4106) appear to be shot. They didn't bother troubleshooting beyond that... TT no longer has those transistors in stock (well, the rig is around 35 -40 years old!!), so they stopped there, they don't believe in running the charges up. But first things first.

And as I said before, if the finals are shot, which would be a redesign, going from 2-3 W out to about 5 to 10 would make some sense. We'll see.

[K7SGJ]

Do keep us posted. I for one am curious. Oh....wait.. that's on Mars.....oh well, keep us in the loop.

[W3WN]

I've heard back from Wade.

The new transistors arrived yesterday. Along with new grease for the PTO -- the old had hardened, a common issue. The PTO is now mechanically functioning again. He removed the old transistors, removed them from their heat sinks, and got the new ones installed.

In the process of the removal, he accidentally drilled himself in the finger... seems that because of the short lead lengths, he had to drill out the heat sinks... so the rig has drawn first blood.

Should know more later today or tonight.