Heathkit FM3A Tuner

audiobliss

First off, I wanna thank opus for being so generous and sending the tuner to me for no cost. That's a stand up guy, if ya ask me.

I can't say as I have an immediate use for it, but I figured that when I finally end up with a tube pre later this year, I'll no longer have a tuner. Though this tuner is mono, I figured it was better than nothing. Plus, it's neat to have an older piece of equipment, and it should at the least be fun to go through and clean up.

It took me a while to figure out what the terminals on the back were, but I finally realized the one on the right (with the two screws) is for the antenna input, while the RCA jacks are for the fixed and variable output (remember, it's mono, so only one RCA jack each). I hooked it up to the front aux input on my receiver just to see if it works. I first used the fixed-level output (the one that says 'Lo'), and I got nothing. So then I moved to the variable-level output (marked 'Hi'), and without an antenna of any kind I managed to pick up two or three channels relatively well. Once I fine tuned it after I found a station, there was no static or noise, provided I didn't walk around the room any.

So, at any rate, I now have a Heathkit FM3A tuner that I've started disassembling to clean it up a bit. Once I realized the guts of the tuner are mounted to a frame and all the gold plates are just added on to dress it up, it came apart pretty easy. I now have the top and the bottom plates off, and I've begun taking the back plate off. And, as no 'project' should be without, I have a problem.

As you can see, both the RCA jacks and antenna input are screwed to the back plate. I took all the screws out, and the back plate would just come straight off if the RCA jack were all I had to worry about, but the antenna input is being a problem. I removed the screws for the antenna input, but as you can (hopefully) see, the brown plate is being a problem. My lack of terminology is probably going to make this hard to follow, but the metal plates that the screws that actually hold the antenna wire down screw into (might hafta read that one a few times! ) appear to be permanently attached (or at the very least installed from the outside) while they are also welded to other things inside the tuner. This is leaving me puzzled, as I can't remove the back panel until I can disconnect the antenna input, and I can't seem to see a way to disconnect it short of cutting the wires, which would necessitate resoldering them. And I've never soldered anything, so I'm a little more than hesitant to do that.

Hopefully your experiences and/or my pictures will serve to clarify all the gaps I've left and confusion I've created with my descriptions.

Any and all advice and suggestions are most welcome!

Picture 'directory':
1) That'd be the front.
2) Those are the 'decorative plates' that I've removed.
3) Here's a close-up of the connections on the back.
4) A close-up of the antenna input.
5) And another angle.
6) Here's a look at the exposed tuner from the top.
7) And from the bottom.

audiobliss

Nevermind. I got the pics to show up.

sda2mike

can you hook up an outboard multiplex unit? that would give you schtereo!:cool:

RuSsMaN

Why do you need to take it apart any further? Clean the outputs with .030 steel wool and wd-40. Pull the tubes (carefully so you remember which socket they go in), clean the tube pins, and clean the sockets (small pipe cleaner / Caig / DeoxiT).

A little wd-40 on the iron, will make it look better - but without getting into the guts, that's all you should need to get your mono FM on.

The tuna he has doesn't have an MPX output.

audiobliss

Why do I need to take it apart any further? I guess to be honest I really don't. However, I really wanna clean it up and get it looking 'new'. There are a lot of little corners and crevices that'll be really hard to clean if I can't take it apart any further. However, if there is no 'easy' way to take off the back panel short of clipping the wires, I guess it will have to stay.

Clean the outputs with steel wool? It'd be a lot easier to get to the outputs if I could take the back plate off. Not too much of them is exposed.

How can I clean all the dust build-up on the tubes without removing the lettering? Will a damp paper towel take off the lettering?

What is a small pipe cleaner?

And, lastly, where can I buy some Caig/Deoxit?

Thanks! Very much appreciated!

opus

Wow that was fast. Glad it got there in one piece. Hope that makes up a little for yesterday.

People helping people. What a great thing:)

audiobliss

opus wrote:

Hope that makes up a little for yesterday.

Haha, I guess so. I must admit I've never been so excited to listen to the radio! lol

RuSsMaN

Go to the local grocery, dental hygiene section - 'Oral B' sells these plastic 'flossers', with very small pipe-cleanerish ends, works great for 9-pin sockets.

Rat Shack will have a white can of 'contact cleaner', that would probably be easiest if you don't have a electronic parts depot around.

audiobliss

Ok, thanks! I googled for deoxit and found their website, so I did a distributor search, and there are none in NC! So I'll just pick up that contact cleaner from Radio Shack.

Thanks!