Astrosonic Recapping

[Motorola minion]

Here is a great eye-opener for anyone considering buying a solid state Magnavox Astrosonic. Every single black nichicon-branded capacitor tests bad on my PEAK 70 ESR tester, yet both chassis somewhat play. I do not believe these solid state equipment caps reform like some higher-voltage electrolytics do.

I restored a TOTL tuner/preamp and amplifier chassis for a 1966 Imperial, using even fewer caps than lower priced sets, with good results. The best part was, it was for my cousin as a present so, I did not need to sell it to compensate the efforts.

Having done "a few" early 60s Astros in all price ranges, it is a sure bet to have a working like new receiver BUT only after you replace ALL of those black (or light blue) electrolytics, 1 to 1000 mfd, and all 50 volts. Usually it is best to test the multi-section can out-of-circuit.

This begs an existential question: " Is a little unit like this worth the same or more effort as an expensive model ?"

No doubt a large TOTL unit is worth some effort, but isn't it harder to re-home due to size and weight?

I prefer tube models for low-power small consoles but early to mid-60s solid state, while overestimated in most power ratings, have a cool factor tag along as part of that dubious power rating upsell.

AstroSonic R204 series.jpg (122.08 KiB) Viewed 5754 times

AstroSonic all bad caps 2.jpg (133.26 KiB) Viewed 5754 times

2ST647.jpg (108.97 KiB) Viewed 5754 times

[hermitcrab]

Yes... those black caps are always bad , but on the bright side, those chassis are some of the easiest to work on...components not squished together, makes for easy replacement. it is nice to be able to pull the chassis out and work on it out of the cabinet and still power it up to test it...

[Motorola minion]

The easy access is very helpful yes. These are really not much worse than a Zenith or RCA solid state, except the fact these have many more caps you must change before you're done.

[Firedome]

Yeeesh.. doesn't make me hopeful for my late uncle's '71/72 R231 Maggie SS receiver... not one I'll try to attempt I guess.

[Motorola minion]

Your caps may not be as bad as the early astrosonics. R222 and R231 are such chassis, an improvement in parts selection must have occurred at some point. The later W800 series changers were an improvement as well.

Later Mags don't need much recap but cabinets began to use plastic like Zenith did with TV cabinets in the 70s.

I only needed a few caps to make a 1967 Magnavox R214 (20w) keep plugging away as my shop console, though the volume control is shot, its receiver is dependable.

[Firedome]

I recall this one being used on my uncle's workbench as recently as about 6 or 7 years ago so there may yet be hope, being used not too long ago may have helped it. Now I wish I could find an original faceplate + knobs. Finding another R231 console with a trashed cabinet might be the only alternative.

[19&41]

I still have to do my '64. I got a vacuum solder extraction station to do it. I'll start on it when I retire.

[hermitcrab]

I bought a vacuum solder sucker and love it... parts literally fall out unless the leads are long ...

[19&41]

I've used one at work for the last 35 years. They're a handy tool for discrete circuits.

[William]

I found solder sucking tape and I like that. I have a manual solder sucker that I paid good money for and it only works half the time. It is always plugging up on me and the hard to get the solder out of it. Has anyone beside me tried the solder tape?

Bill

[19&41]

I use the tape for high volume removal on the older hardwired circuits. With the manual suckers, I use super lube gel in them. the grease holds much of the extracted solder in place and it doesn't fall into the nozzle as easily. it doesn't build up so much on the rod that extends through the nozzle. With a bit of non chlorinated brake cleaner, cleanups are easier.

[William]

Thanks, Rex, I will try that.

Bill

[hermitcrab]

Solder sucking Tape?.... are we talking about solder braid?

[William]

Probably, it is braided and kind of a copper color. I like it, and have good luck using it.

Bill

[19&41]

Solder braid, tape, wick, pretty much the same thing.

[hermitcrab]

I never had luck using the desoldering braid , I use it like they do on the web and it never seems to remove it very good , but it could be user error....

[William]

Sometimes it can be fussy, but most of the time it work well for me. I set my soldering iron to maximum, apply the tape a few inches in from the end of the tape. Then I apply the heat and as the solder starts to wick on the solder tape I slowly pull the tape towards the end of the tape. I hope that made sense? If there is a lot of solder, it might take a couple of applications to get it all off.

Bill

[19&41]

I always use liquid flux when soldering and when the wick is slow to take up the solder, a drop or two on it will get it working well.

[Motorola minion]

Solder "wick" is my choice to do PC boards. William has the right plan to use it well, pulling in fresh wick as it gets saturated.

I use the 40 watt iron and a flat side of a chisel tip. Putting the wick over the largest area of contact you need to de-solder, then put the iron's tip on braid to heat it first, before the heat flows into and melts the connection itself. Pulling out 1/4" increments works like a charm as you fill the braid with solder.

The suckers have not been helpful, clogging up. I may invest in such a dedicated vacuum unit.

[19&41]

One other help with my manual suckers is a modification I use. using a good file, I rebate the nozzle tip to a smaller diameter, usually about 6 mm,I make the rebate about 1/4 inch from tip to shoulder. On Ebay I found a source for silicone rubber vacuum hose in 4mm inside diameter. I cut a bit long enough to push onto the nozzle tip with a little less than 1/4 inch extending beyond the nozzle tip. This gives the sucker "lips" to conform to and draw more solder off the knotted hardwire connections our old radios have. They do well with printed circuits also, surrounding the solder point and drawing them clean. I won't use a manual sucker without it.