An Astron RS-35A power supply is my latest acquisition. Saw it on ebay for a pretty decent price, and after a few days of watching it, I thought I’d put a bid on it fully expecting someone to come in at the last minute and snipe me.
Well, that didn’t happen so now I have a big beast of a linear power supply that puts out 13.7V and peak current of 35A (“25A continuous”) for less than half of what one costs new. My original plan was to use it for what ever radio I ended up buying, but we’ll be putting Connie’s radio and its power supply into the office/ham shack so this one will probably sit out on the workbench and supply power to my other projects, maybe a second radio if we end up getting one.
Except for a dinged up corner and a broken foot (probably during transport) it’s physically in good shape. After plugging the unit in, flipping the power switch brings the beast to life with an intimidating but satisfying “chunk” from the transformer and the hum of electricity.
The power terminals are these bare exposed bolts with nuts to hold any wires on. I don’t really like the thought of exposed power terminals, so I think I’ll look into replacing them with some Anderson power poles.
With a pair of needle nose pliers and some very gentle pressure, I was able to bend the plates of the variable capacitor back to where I thought they should be. Both plates are parallel to each other now and don’t hit each other when rotated.
Now I just need to put everything back together, add power and test it out.
Spent some time going over the innards of the MFJ-207 antenna analyzer I picked up and doing some research to figure out what kind of rotary switch I’ll need to replace the existing messed up one with. I think I’ve found the correct replacement switch (a Lorlin CK1025 rotary switch).
Everything else inside looks in decent shape as far as I can tell. I haven’t tried to test all the individual components yet. No leaky/bulgy capacitors or burn marks and all the soldered connections seem solid. Aside from the rotary switch I’m not seeing anything else wrong with it.
Now to go over the MFJ-208. I don’t know if I’ll be able to find a variable plate capacitor to replace the existing one, but I might be able to fix it up so that it works the way it should.
While browsing radios on ebay, I came across a couple of MFJ antenna analyzers: an MFJ-207 and MFJ-208.
They were both being sold as “For parts” and the person selling them wasn’t able to test them. From the description and the pictures that were posted, my expectations weren’t very high. The price was pretty low, and I figured if they worked I’d have a couple of antenna analyzers for pretty cheap and if they didn’t, I’d have an interesting project on my hands that I could learn something from.
They arrived in the mail today and I had a quick look inside both of them. Off the bat the 207 is going to need a new band selector dial. It looks like it’s supposed to be a one of those multi-position switch knobs, but if it was it isn’t anymore. On the 208 it looks like a new variable plate capacitor is in order. I’m no expert but I’m pretty sure the plates aren’t supposed to touch when the knob is turned. I’ve also never seen a variable plate capacitor with just two plates (one moving, one stationary).
I’ll have to spend more time and go over them more closely, but if these two things are all that’s wrong with the two analyzers, then this should be a pretty easy refurb project for me (provided I can find the parts). Fortunately the manuals for both of them are available on the MFJ website, and the 207 manual even has a schematic in it.