Magnavox Astro Sonic stereo

[chrisw71]

I recently acquired a Magnavox Astro Sonic AM/FM/Phono stereo set, looks like a 1969 model. I am trying to remove the AM/FM radio chassis in order to clean the scratchy pots. It looks like it slides out along some rails but I can't seem to find the screws that hold it in. Is there a trick to getting
the radio chassis to slide out easily? Any tips would be appreciated.

Chris

[RetroHacker]

Most of the time, the chassis will be secured with four bolts that go through the board that it's mounted to and into the chassis, and the chassis comes out through the bottom, leaving the faceplate mounted into the console. You have to remove all the knobs first. They made lots and lots of Astro-Sonic sets, and yours could be different though, but typically the tuner/amplifier chassis is mounted to a flat board on the "bottom" of the chassis, even though it's probably sideways in the cabinet. Make note of wires before you unhook anything, and there typically isn't enough slack on the wire to let you get the chassis too far out without disconnecting anything, so unhook first, then unbolt.

-Ian

[Randy Bassham]

The screws that hold the chassis in are under the bezel, to get to them remove the knobs and look around the shafts. Some of the shafts that have inverted pal nuts, Magnavox made a tool that slipped over the shaft and went into the nut to remove them, without the tool it can be tricky, but can be done.
The tool goes down into the nut instead of around it, in a pinch I've been able to get them off with a pair of duckbill pliers. When you get the pal nuts off then you can lift the bezel off, now look at both ends of the chassis on the same side as the knobs to the right of the dial, in the corners you should find two screws with 5/16 inch heads. Remove these screws and the chassis will lift out. If your set has controls on the left of the dial there maybe pal nuts there also that will have to be removed. As you are removing the chassis be careful that you don't catch the speaker selector switch they are easily broken.

[RetroHacker]

Originally Posted by Randy Bassham

The screws that hold the chassis in are under the bezel, to get to them remove the knobs and look around the shafts. Some of the shafts that have inverted pal nuts, Magnavox made a tool that slipped over the shaft and went into the nut to remove them, without the tool it can be tricky, but can be done.

Hadn't seen that setup before - I didn't know Magnavox was that sneaky. You learn something new every day .

-Ian

[chrisw71]

Thanks for the help guys. This Magnavox has the inverted PAL nuts, and I was looking at them few days ago, thinking a special tool would be needed to remove them- so that's the trick. I'll try carefully using the pliers. I suppose one could replace them with regular nuts afterward. I'll watch out for the speaker selector switch as well.

[Randy Bassham]

A trick to try is to get a nut that will fit down into the pal nut, then enough of that nut will stick up above the pal nut that you should be able to get on it with a deep well socket. You may have to drill out the nut so that it will go over the threads on the control. I bought a set of tools from Magnavox when I was working for the dealer in the 70's. The set was made by xcelite and included two different pal nut wrenches and the little forked tool that was used to take the tuner assemblies out of the console TV's. Ocasionally the Magnavox Handi-Tool shows up on ebay, it has a 1/4 and 5/16 inch nut driver, the pal nut wrench and the fork for the TV tuner assemblies.

If you're going to try the pliers, you put them inside the pal nut and open them up to make contact with the nut while turning them.

[chrisw71]

OK Randy I did a search on Ebay and I think I found the handy tool. It looks like the tool you described, 4 tools in a + configuration. I bought it for $12 including shipping (hopefully its the right one!). The funny thing is, a week's worth of use has caused most of the static to go away from the controls so a cleaning might not be necessary. I'm thinking that maybe the electrolytics should be changed out (in the power supply at least?). It runs without any detectable hum for now though. I also like the tape player input/output ports they provided, my MP3 player is plugged in and works well through it.

[saltwater]

i plugged my ipod into the tape inputs, and its not made for that, the ipod didnt put out enough juice for the equalization to be right. also whats the deal with the 6 extra speakers that can be hooked to it?

Where Can I Pick Up A Pal Nut Set.

[saltwater]

Originally Posted by JACKIEJ

Where Can I Pick Up A Pal Nut Set.

Try fastenal?

[mhardy6647]

for the benefit of the original poster...
there's a pretty nice "Magnavoxfriends" group at Yahoo (in case you didn't know).

[fuqueue]

I'm in the same situation as chrisw71. I picked up a (late '70s?) Astro-Sonic and this thing is pretty sweet, but the scratchy pots are the first on my list of things to fix up.

I also want to see about replacing what looks like the crossover, the speaker wires go from the amp, to the component, then to the speakers (theres two 'components', one for each speaker). From a wiring diagram I found nicely taped inside the console, it looks like some kind of RLC circuit, with a resistor, inductor, and capacitor all in parallel. I had problems with the left speaker cutting in and out, but wiggling the wires on this thing seemed to help, for now. I'm gonna replace 'em, Any ideas guys?

Third on my list of things to do are to replace some of the old capacitors/transistors, or maybe even build a new amplifier from scratch, though that is probably a lengthy project. Does anyone have a service manual, or wiring diagrams, or something that could be useful??

[fuqueue]

Great news! I finally managed to get the dam thing open. Those inverted palnuts are really tricky, but luckily I only had to remove them from 2 of the six control knobs. Heres the trick: Find a nut that will slip into the palnut(I just eyeballed it), and then I drilled through it while the bench vice was holding it. Basically, I had to drill out as much of it as you can without having the nut fall apart. Guess and check, redrill, get it so it slides all the way down the bezel. Next problem: I had some trouble getting it to slip all the way into the inverted palnut. Turns out the threads continue a little ways up from the valley of the palnut. Solution: bigger drillbit, but I only drilled about half the way up the nut for this one, so its kind of like a counterbore/countersink.

With the drilled-out nut properly seated in the palnut, its really easy to get it out with the needle-nose pliers.