Another Maggie

Are you guys tired of seeing another new guy with another late 60's Astro-Sonic?
Well too bad - I just got one too. And its my first record player (I'm 32) My wife is 26 and I just got her the Dirty Dancing soundtrack on vinyl and she is quite happy with my new hobby as you will see in the pics below I have a cool wife that enjoys the same furniture I do.
I will include a couple of pictures below.

Of course there is an issue with my new console.
Changer works great!
There is no sound however coming from the right side speaker.
I switched the phono inputs and still only the LEFT side works - so its in the amp I guess?
I know I know... I have read all the threads about take it to a tech - but no more than I have in this thing I will most likely mess with it myself.
Anyhow, I plan to change out some capacitors and maybe some resistors once I figure out the lopsided issue.
I can include more pictures if anyone wants me to but I figure they are all about the same...

Enjoy!

I think my wife likes the 80 more than I do!?!?!






Sorry it rotated on me... Stupid iphone..

Hmm my pictures were cut off on one side - Sorry

Probably those expensive and hard to get output transistors are blown from chassis deterioration.
Could be anything.

Well, it looks like you have one of those Barcelona Astro-Sonic 40s from around 1966 with a W621 record changer, and I have two of them...well, one was a parts unit with a reel-to-reel tape deck, but the other one plays just fine. I think I paid $28 bucks for it and keep it in bedroom #4.

Before ripping into caps/resistors/transistors etc., please be aware that the control pots will most likely need a good cleaning. Something out there like Deoxit, etc., tuner cleaner of some sort.

I have several units long overdue for that cleaning. Stepping the bass or treble up cuts out one channel until I rock those controls back and forth. Even turning up the volume will cut out one channel, or even switching from phono to Aux or radio. And, don't forget the external speaker switch.

A dead channel doesn't always mean shot output transistors. I'm no professional here, but have been at it for a long time. For the longest time, I though I had a dead channel until I rocked those controls back and forth and found otherwise. On another unit, I found a cold solder joint by taking a toothpick/chopstick and pressing on different areas of the circuit board and using the continuity feature on my multi-meter.

Cleaning all the pots first may resolve that channel issue, and then move forward to have everthing else properly serviced. Be sure to check all your wiring from the chassis to the speakers and crossover network. Some idiot could have been in there tinkering and didn't bother to put speaker wires and things back in their original state.

I bought one console where some nitwit strapped one speaker to the other because of a dead channel and didn't bother to fix it. The thing didn't sound right, so I pulled out some old 60's LP's where the separation was "hard panned" left or right, drums on the right, bass on the left.

Anyhoo, you have a nice unit with 15" woofers and 4x10 exponential horns. If you think that sounds great, wait until you encounter an Astro-Sonic 100 or Imperial Astro-Sonic 100 with four horns. --BB

Bobby Basham
Tucson, Arizona

P.S.: This may have the R204 Chassis, Sams Photofact Set 841 Folder 6, dated October, 1966, and the featured model on the schematic is the "Madrid Astro-Sonic 40".

Thanks Bobby Basham for the excellent information.
I have not had much time yet to look around at the insides of this one very much (aside from a few minutes during my lunch hour yesterday)
I am going to familiarize myself better with what it is suppose to look like and see if I can find something simple.
Other than that its just a matter of getting time to really dive in and see what I can find.

Thanks for the replies fellas.
Greg

I dono--you have me totally comfuzzed---???
First you say "--no sound-right side--", then you say "switched inputs--still only--right side WORKS" ???
I'll let yo Maggie guys sort this one--You know I am going to suggest "pro help"-- Ron Rich

Ron Rich wrote:I dono--you have me totally comfuzzed---???
First you say "--no sound-right side--", then you say "switched inputs--still only--right side WORKS" ???
I'll let yo Maggie guys sort this one--You know I am going to suggest "pro help"-- Ron Rich

Oops - fixed it - LEFT SIDE only works

OK--dould be "the amp". Also could be ANYTHING, past the amp--still the same advice--do not power-up, in that condition--- Ron Rich

Maybe a process of elimination. If the phono only plays through one channel, but the radio and aux inputs play through both, then narrow it down to the turntable with a faulty cartridge and/or wires. --BB

Bobby Basham
Tucson, Arizona

Even after solving the issues I mentioned above, the chassis should be serviced. Recapping is not a cure-all for all issues. There are many other semiconductors in the mix and, in some cases, voltages as bias (where applicable) need to be checked. There may be a small, separate circuit board that has several pairs of driver (?) transistors. I've had one of them fail during a storm, but it was good timing since that transistor was kinda crusty looking, and I guess the power surge pushed it over the edge.

I don't know the proper names of the components, but I know how to test them. I'm my own worst enemy and a true procrastinator in getting all my units up to par. I'm taking two weeks off starting next week and hope to get this house in order and much needed TLC for my Maggies. --BB

Bobby Basham
Tucson, Arizona

Interesting post Bobby.
I am just going to start out with caps and resistors.
I'm excited to get a chance to dive into the manual.
I think for the short term I will temp mount a receiver that I have laying around into my magnavox cabinet.

I will be posting for help with testing transistors.

Aldrich, before doing anything with "capacitors and resistors" you need a set of schematics. Do you have them?

Here is a top shot of the receiver in my 1965 set which appears identical on the face to yours:

http://www.fileconvoy.com/dfl.php?id=g5 ... f1f07d5ab8

Ignore the small board on the right of the chassis, that is the speaker crossover and whoever photographed this set just placed it there for convenience.

If the chassis inside looks the same chances are good that you can use the schematics that I can upload.

While transistor sets do not have the high voltages of tube amps, the transistor is --much-- more delicate electrically then a tube - so casually "probing around" is out. You need to know what you are doing and have a decent meter for troubleshooting.

There is a good chance that a capacitor replacement will get things running and frankly, even if one channel is working, there is little chance that the entire receiver is running anywhere near it's best with aged capacitors. The values are pretty standard and easily available.

As for mounting another receiver in there, bear in mind that the speakers in these sets were designed for the available wattage and frequency response of the original receiver/amp.

The old amps were around 10 watts/channel. In connecting a modern receiver with substantially higher power output you do risk blowing the speakers out.

Another consideration is that the record changer has a ceramic pickup. These have much higher output and also require a higher input impedance than the "Phono" input on a typical receiver which will likely be designed for a magnetic pickup. Connecting a ceramic to this type of input will normally result in a lot of distortion.

The best approach is to rebuild the original unit (or have it done) and then consider any further modifications after things are working.

Rob/NYC

Thanks for the input Rob.
I am waiting for the schematics before i start in on this one.
I do have a good meter or 3 (fluke 189) and access to a scope if i need it.
While i havent worked on these units before i have done simple troubleshooting and have enough training to know how to not cause damage while taking measurements.

Sure if i use a modern receiver to power these speakers AND abuse it they wont last long.

Greg has the schematics, and wow, he has some Fluke meters and access to a scope! I'm jealous, because those meters are high quality and aren't cheap by any means. You go, Greg! --BB

Bobby Basham
Tucson, Arizona