Magnavox Micromatic Turntable Question

This is my first post on these forums but I've been reading them for a while. I've recently acquired a 1963 Magnavox HiFi console as a project to sort of get my feet wet in the hobby. It's a beautiful cabinet, everythng works beautifully and is intact except for the turntable.

There are a few issues with the turntable:

First off it doesn't turn. I've opened it up and looked at it and the motor runs and the rubber wheel that touches the motor shaft and the metal turntable body does turn the table when manually pushed against the shaft. It appears as though the spring has lost some of it's oomf and can't hold it against turntable anymore. Are worn out springs a common problem in old turntables? The other option is that maybe a few of the joints it moves have lost their lubrication, but upon testing them they appeared to move with no resistance and be pretty smooth. If it is the spring worn out, any idea where I can get a new spring?

Second issue, the automatic record player and tone arm motor control doesn't work. Upon investigation, I've noticed it's a similar problem to the one I'm having with the table not turning, it again appears that a spring has lost it's spring. When you turn it on it pushes a lever out of it's resting place which gets pulled down by a spring to the active place (somewhat rube-goldbergish). I can manually push it down and the whole operation goes on as planned but it's getting past that startup step where the whole thing gets stalled. Again, worn out springs... are they a normal issue?

Third, the entire turntable unit appears to be charged... when it's on I get shocked (not badly, just a tingle). I'm guessing this isn't normal but I'm failing to find any stray wires touching the body. Any ideas? or do I just look harder

Finally, not quite an issue with the turntable more with the whole stereo, there appears to be some intermittent static coming from the left channel. The static does not appear to be correlated with any action I do with the player and it appears while playing a record or listening to the radio. If I turn the unit off then back on quickly it relieves the static for a time. As per some of the posts on this forum I think it's related to some bad contacts or wiring so I'm going to start with cleaning all the contacts that are for the left channel and see what happens. What would you recommend to best clean the contacts? Also if anyone has any further insight as to what the problem might be feel free to chime in.

Well that turned out to be a long first post, but I wanted to be sure the issues were thoroughly explained. Hope to get some answers!

[blue_lateral]

For the tingle, the chassis of the amp or maybe the tuner must be hot. Look for a capacitor connected from the power to the chassis. Look where the power comes in, on both the amp and the chassis. This cap (or caps) is (are) probably electrically leaky. If you find one or two, replace with "y" rated safety caps. if you find one connected across the line, replace that with an "x" rated cap.

There will likely be a few other paper caps in there that will need changing, too.

Regarding the turntable, I would bet on the wheel itself being dried out and not sticky anymore. I think this a more common failure than a spring.

The micromatic is a well-built unit, but it's tracking weight is fairly high by today's standards. Possibly consider plugging a modern turnatble and a phono stage into the Magnavox's phono inputs.

Oh, and welcome to AK!

John

[Eric H]

Hello and welcome to AK!

The springs are probably OK, they aren't very strong to begin with, the most common problem with all old changers is the lube dries out and the drive tires get hard.

The Micromatic uses two tires, one drives the table and the other runs the tone arm, this allows consistent change speed regardless of what speed record you are playing.

There was a guy rebuilding the wheels, don't know if he's still doing it since it's been 2 years since I did mine.

Ed Crockett, his E-mail is: phonoed at aol dot com <(remove the spaces and insert the @ and dots)

I'll take a look for the hot wires when I get home, for the record I don't believe the tuner or the amp are charged I'm pretty sure it's just the turntable.

I really want to use the original turntable because cosmetically it's in great shape and it would just be awesome to have this perfect piece of equipment.

As for the wheels being worn out, I accept that for the drive wheel. It doesn't seem too rigid but after some tinkering I got it to make contact with the turntable side and was listening to it slip away. Like I said though, I can push the lever in that the spring should be pulling in and the thing plays just fine.

As far as the tone arm wheel being worn out, it's not that... the problem lies in the actuation, I'll try giving all the joints a good lubrication.

Anyone know a good lubricant to use?

Likewise, anyone know the best way to clean the contacts? I was thinking sand paper or using tuner cleaner or both but I figure I could learn from your experiences.

Thanks for the responses so far.

[blue_lateral]

Well If it's just the turntable thats hot, follow its power wires and see what you find. There may be a capacitor up there. I'll bet, though that the turnatble, tuner and amp are grounded together. If thats true, the leakage could be coming from any of the three. It could even be the motor, but I'll bet its a capacitor.

The favorite thing for cleaning contacts around here is Caig Deoxit. I'd stay away from sandpaper at least for now.

I dont know what an appropriate lubricant would be.

Good luck!

John

[Eric H]

Antique Electronic Supply has something called "Phonolube" "Light bodied grease made of polymerized oil specially developed for the lubrication of small geared mechanisms. Retains its viscosity over a wide range of temperatures"

I prefer light oil for the motor and idler wheel shafts. I have some of this but I bought it locally: http://cgi.ebay.com/Pen-Type-Clock-O...QQcmdZViewItem

My 55 Maggie will shock me if I lift the tone arm and come in contact with the cartridge connectors!

Thanks for the lubricant suggestions.

But it's not just coming into contact with some wires. It's the top of the tone arm, the body of the phono, the spindle, I mean the whole thing is hot Been doin some other work today probalby won't get a chance to find out what the problem is until this weekend. I'll keep you all posted.

Ok got a second to look at it tonight and I was wrong, the amp and tuner and everything is hot so I'm starting to investigate the capacitors.

So I took a look and looked at the amplifier and saw the capacitors... and then realized I had no idea how to check if a capacitor was "leaky" or if it needed replacement or what the entire statement about x and y and line meant at all. I have little knowledge of electronics but am quick to learn. If you know of any sites, tutorials, books that will point me in the right direction let me know. Likewise, if I'm in over my head let me know too (in which case what do I do? call a radio repair guy?

Also, yes the idle wheel is hard... I discovered this as I went to clean it and let it slip off the edge of the radio while I was doing something and watched chunks break off. At this point can a rebuild work? Should I buy a whole new wheel? Should I just buy a micromatic turntable off ebay and call it a day?

Thanks in advance for all the help.

[Celt]

I'd try to find a replacement idler wheel first. Another TT from E-Bay probably won't be in any better condition.

That's what I figured... now the best place to find said part would be... ? And how much would a reconstruction of the other wheel be if I went that route?

[blue_lateral]

Line capacitors or "line filters" are capacitors connected to the power line. Disregarding all the other capacitors that might be bad in there, a line filter is the most likely thing to be causing the chassis to be hot. In the old days, they just used regular capacitors for this. X and Y capacitors are modern units that are purpose-built to be line filters. This is important because they are still connected to the power cord even if the unit is switched off.

There is a good page on them here:
http://www.justradios.com/safetytips.html

Any old line filters should be replaced even if they are not bad. X and Y caps probably wont fail in this kind of service, and if they do, they probably wont catch fire.

In your case i'll bet there is a capacitor in one of the chassis connected from the power cord to the chassis, and it is bad.

John

I'll need a schematic to replace all these correct? Where do most of you get yours?

[wa2ise]

You don't necessarily need the schematic to replace wax paper caps. Helps, but not critical. But you should replace one cap at a time. That is, remove an old cap, and immediately install the new cap of the same ratings +-10% with the same or higher voltage rating. Before you forget where the old cap connected to. I just snip out the old cap with some of the old wire lead still attached to the locations it connected to. You could just "J hook" the old wire lead to the new cap's lead and solder it. Just keep the physical location of the new cap the same as the old one. And try to make the J hook connections reasonably straight, and not likely to touch something else and short out. Don't try to remove all of the old wire lead from tube sockets or terminals. Those are rather fragile and tend to break under the stress of trying to remove leads.

Ceramic caps (the ones that look like discs) don't usually go bad, so you don't normally need to change them.

The caps connecting the chassis to the powerline are not essential, worst that happens without them is that you might pick up some noise or hum on some AM radio stations. SO you could just remove them and wait for the X or Y replacements to arrive later. Just keep notes where they went.

[Nick_the_'Nole]

The tingle on the TT isn't coming from the amp. There's a little .01mf ceramic disc capacitor under the platter that crosses from hot to chassis, and it gave out on mine and gave the same effect. I think it was a little under-rated or something, I replaced it with a .02 630v I had around and it solved the problem.