Magnavox AstroSonic repair help

I recently bought a mid-60s AstroSonic on Craigslist, had been looking for a long time. The phono works decently well, but does seem a little slow or low pitched. The AM radio picks up a few stations, the FM picks up none. The sound overall is a little muddy, and seems to be balanced around 80/20 to the right side speakers.

If I understand correctly, the set needs to be recapped and perhaps some other adjustments made.

I'm primarily looking for a tech in the Washington DC area who works on these, as I'd like to get it back in shape. If anyone knows someone in this area, I'd very much appreciate a referral. If not, are there some simple steps I can take to improve the sound and function beyond cleaning the stylus (already done)?

Thank you very much for any help.

Is the "balance" (if on the front panel) control centered? - this control varies the volume level between the speakers.
Is the imbalance only while using the phono? - or on all sources?
Speaker selector switch might be dirty due to age - rotating it though its positions might give a clue.
Is the built-in FM antenna connected to the two screws labeled on the rear?
If all this produces no change, it's time for a long overdue overhaul.

Unfortunately, proper servicing of the record changer is not for amateurs and really needs a thorough overhaul after decades of neglect.

Thanks for the reply. I emailed you separately, in case you're wondering if it's the same person.

There's no balance control knob on this set, at least not that I'm able to locate. I've taken the back off and disconnected all the speaker connections I could find, cleaned the contacts, and reseated them with no difference I could detect.

I think you're right, definitely time for a tune-up, but I need a local person to do so...the search for which, thus far, has been unfruitful.

Currently I don't know anyone local to you that performs such work.
People like me seem to be scarce, which is partly the reason I've been so backed up with requests.

"kedhegard' that machine is probably very similar to my 1965 model. The entire chassis is behind the faceplate. There is a balance control on the chassis -but that is not your problem here. If the balance is off in all modes, not just phono or radio, then you have aged capacitors in the unit.

I had a similar problem on ours after it had not been used for a period of over a decade. The caps that go bad are likely on the tone-amp board, but realistically, all of the electrolytic caps should be replaced at this point.

There is nothing exotic in these old sets , you can find suitable replacements at Radio Shack or online outlets.

If you have some experience with soldering or are willing to take some time to read up on simple electronic repair methods, you can accomplish this yourself.

Otherwise look online for antique radio clubs and collectors and don't forget Ham Radio operator clubs in your area.

I do have the Sams schematic for my unit here, if you are interested in doing this yourself, I'll find-scan-upload it for you and others with units from that era.

As for the "muddy sound" understand that these units as-built had a certain tonal characteristic that today would be considered dull, back them the emphasis on bass was, for this market, considered desirable.

Rob/NYC

Hey Rob, that would be great if you could send me those schematics. I would definitely be up for trying to recap it myself. I've done a fair amount of soldering before, and from reading/watching as much as I can on the subject, it looks like something I could handle. If not, I can at least get a fix on what type of capacitors will be needed before passing the job onto a pro. Can you PM me? I'll send my email.

Ok, here are the schematics and pics of the 1965 unit I have.

http://www.fileswap.com/dl/2mMDUJ4Xto/ schematic -1

http://www.fileswap.com/dl/PP4EybDQsc/ " 2

http://www.fileswap.com/dl/0qqr3C7rba/ " 3 There is deliberate overlap but you can trim if it is printed out.

http://www.fileswap.com/dl/smUyDBucC2/ Cover shot

http://www.fileswap.com/dl/5eRbemctES/ Chassis 1

http://www.fileswap.com/dl/xHzCNuWpVm/ " 2

http://www.fileswap.com/dl/xfCf92DDqf/ " 3

http://www.fileswap.com/dl/yBRLZDagX7/ Alignment. This is better left alone if you don't have the necessary equipment. However the AM section can be easily touched up by carefully tuning a weak station and slightly touching up the IF's starting with the first one while watching the tuning meter. Use ONLY plastic hex tools designed for this purpose and don't force the slugs as this might break the coil loose and kill the IF tran.

Rob/NYC

I didn't include the parts list since what you will be replacing are mostly capacitors and all are marked.

The FM may be inoperative because it needs an external antenna.

If one channel is missing from only the phonograph, the mica blades on the muting switch may have failed. I cut up some plastic guitar picks to repair mine (in 1972).

The balance control is a screwdriver adjustment on the power amp module.