Old Symphonic Record Player

[Enzo]

If it were me, I'd get a 10w cement resistor.

The 50C5 definitely belongs in the center, the 35W4 goes on the end.

Right in the center of the photo, that large yellow cylider with wax oozing out the end, that and its similar friends likely need replacing.

Interesting tone control.

[Mars Amp Repair]

agreed, since you have all kinds of room in there...might as well put something in that won't get so hot.
I wouldn't worry so much about burning out those tubes....they are very resilient..the most common 'failure' of tubes is when you set them on a non-level surface & gravity takes over from there ;-]
As for tone ckt..I guess you couldn't get much simpler. Merely shunt the highs to ground at the plate.
Also I guess I never realized a crystal cartridge had enough juice to directly drive a 50C5! Must be a couple of volts anyway.
As a kid of about 8 for some unknow reason, I decided to try to ground my 3 tube record player...I proudly connected a wire from the chassis to a hot water pipe above my head in my basement & plugged it in...
Years later when I was about 30, I visited that house I grew up in & observed the pipe still had the divits in it from the 'experiment'. That was my first lesson of a 'hot' chassis. Looking back I still don't understand how I survived so many similar types of experiments!! glen

[spartadrive_in]

If it were me, I'd get a 10w cement resistor.

The 50C5 definitely belongs in the center, the 35W4 goes on the end.

Right in the center of the photo, that large yellow cylider with wax oozing out the end, that and its similar friends likely need replacing.

Interesting tone control.

I was also thinking what that waxy stuff was. In the schem I have determined that it might be the 05/400watt cap and the .01/200 cap. Although on the actual cap itself is has different values written on it. Do you think they might have been replaced by someone using a different value?

thanks again enzo

[Enzo]

I only see two such caps in the schematic - .05uf at 400 and .01uf at 200. The larger one looks like the .05. What is in there now? A .047 is the same as a .05. The values are not critical, and may have been changed during production. Higher voltage caps wouldn't matter, but I doubt the factory wasted extra cents on higher voltage parts.

Those are what we call paper caps, and they are wax impregnated. The wax seeps out over time. They get leaky. Replace them with modern film caps. That is a low voltage circuit, nothing will be over 170v tops, so 400v or 600v caps will be fine. More likely to find .01 at 400 or even 600 in my shop than 200v ones anyway. They don't cost much. They will be called film or mylar or polysomething.

In the old days, your hands took on a wax coating working under electronics chassis by the end of the day.

The tone ckt shunts the highs to B+, whose low impedance becomes ground for them. Struck me as novel.

[Mars Amp Repair]

Yep...agreed on the tone ckt. Also, you generally don't expect to find b+ levels on a tone control. Could catch ya by surprize.

BTW as a kid, as probably did you, I used to have a box of those bees wax caps I cut out of junk I couldn't fix (which was just about everything at that point!) & after ferriting through it you'd have a heck of a time getting that stuff off.

Between that & burning selenium rects, I wonder how we ever survived ;-] g

[spartadrive_in]

What's all this about the tone circuit you guys are talking about? How do you know that it goes to B+ and what is special about this?

[Enzo]

Only thing special about it is I don't recall seeing this particular arrangement before. No reason for it not to work, and as a record player, no reason to change it.

This is an extremely simple cicuit, everything has to suround just the one signal tube.

At that output tube, there is that 50k pot with the .01 cap in series and they are across the output transformer primary there at the 50C5. THAT is a tone control. One end goes to the plate of the powerr tube, and the other goes to the B+ end of the power transformer primary. SO the tone control circuit is connected from B+ to the tube plate.

No big deal, just a couple old timers here babbling about a tiny detail.

[spartadrive_in]

I bought some caps to replace the leaky wax ones. They are a lot smaller but they are the same values.
Does size matter? Is it that we are now more advanced that the same thing can fit in a smaller package? These new ones are both rated for 630V and were about 80 cents a piece.

[Paul P]

As a kid of about 8 for some unknow reason, I decided to try to ground my 3 tube record player...I proudly connected a wire from the chassis to a hot water pipe above my head in my basement & plugged it in...
Looking back I still don't understand how I survived so many similar types of experiments!! glen

Reminds me of one of my experiments at about the same age. I'd heard you
could recharge batteries so I taped a wire to each end of a D cell and stuck
them in the wall socket in my room. Not sure what the battery would have
done with 120v across it but I was using thin enameled wire and it going
"poof" and blackening the wall was enough to discourage me from further
attempts.

Paul P

[Enzo]

I bought some caps to replace the leaky wax ones. They are a lot smaller but they are the same values.
Does size matter?

No, it is how you use them...



har har




Material science and stuff has advanced some in the last 50 years. Caps ARE a lot smaller these days. Was a time when a 25uf 50v cap for the power tube cathode was a chassis mount can cap. Now the thing would sit on your thumbnail.

In the old days a .047uf 600v cap might have been 2 inches long with four inch wires at each end. AMp makers counted on that, so parts could reach a long way between tube sockets or wherever. Now the same part is a half inch long with 1.5 inch wires and sometimes won't reach. So we wind up either rerouting the part or clipping the old part off leaving its wire leads and splice the new part onto them.

For example, a cap running from pin 6 of a 12AX7 to pin 2 of the same tube would have run around the outside of the socket or even run to a terminal strip and a wire returns. Nowdays you can just perch the cap across the socket itself.

[spartadrive_in]

Ok great so these little guys will work perfectly then? I'll just splice.

[spartadrive_in]

It Works!

I replaced the leaky wax caps with newer ones and the old resistor with new cement ones. I could not find a 220 ohm so I just put 2 110 ohms in series. Looks good? Works good.

NEW PROBLEM!
The amplifier works now but the needle arm does not move inward. So it only plays one line and repeats itself.
"She's too cute to be a minute over seventeen... She's to cute to be a minute over seventeen... She's ...and so on and so on."

Looking at the mechanics below I'm trying to make sense of it. Any idea what could be causing this?

[52 Bill]

Thats called "skipping". I could be a mis-balanced turntable, a bad/worn needle in the cartridge, a bad record, a too light tone arm, a sticky tone arm, etc., etc.

If you move the arm to another section of the record, does it still do this?
Have you inspected the needle? Are you using the correct side of the cartridge?
Does the tone arm move side to side freely? Can you feel any resistance or binding as you move it through the full arc of motion?
Are the turntable suspension springs all in place and free moving?
If you add weight to the tone arm by placing a penny on top of the tone arm above the cartridge, does it stop skipping?

Hope this helps.

[spartadrive_in]

Yes I forgot to mention that the arm will not move freely at all. I can not get it to move inward so it's only been able to reach to the far outside of a 33.
I can move it out to it;s dock but not inwards towards the center.

The nedle is original (to best of my knowledge). It is the kind in which you rotate for 45s and flip the other way for 33s. The 45 side is missing the small needle.

[Enzo]

Well, it is a mechanical problem, and has nothing to do with resistors or caps or transformers.