Old Symphonic Record Player

[spartadrive_in]

Just doing some looking in here to make this maybe work. Was wondering if you could tell me what this is?(see pic) Some sort of inductor? Seems like it had something around it, since its crusting off. Should I replace it? and if so, what is it???

[Enzo]

That is a resistor. A wirewound power resistor, the kind that these days would be rectangular and made of cement. Can you read that number printed on it?

Yes it ought to be replaced.

However, your little record player amp has what we call a hot chassis - there is no power transformer. The mains are directly rectified to make the B+. And the tube heaters are high voltage and wired in series. I bet those two tubes are a 35W4 and a 50C5. How did I do? In the recrod player the hot chassis is no big deal, but as a guitar amp - if that is where you are headed - you really ought to add an isolation transformer.

35 and 50 only add up to 85 volts. A lot of the time there would be a couple more 12v tubes. But in any case, the excess voltage left from the 120v mains has to be dissipated in a resistor. The resistor is in series with those heaters and the whole mess is across the mains.

ANd I belive that is what you are looking at.

[spartadrive_in]

Wow you got it dead on Enzo. Those are the correct tubes. I did not know that the first 2 numbers on them meant the voltage (35, 50).

So then a large cement power resistor is the way to go to dissipate that excess heat? Only thing I can read of that thing is 77 (in the pic).

I am not going to make it into a guitar amp or anything. I just want it to work. To play records.

Anything else? All info is helpful as I hate to blow those tubes. I just bought new ones since one had a crack in it.

[Mars Amp Repair]

Also must have been right before the selenium rectifier was put into use...if you've ever experienced one burning up...you'll never forget how that smell...glen

[spartadrive_in]

Originally Posted by Mars Amp Repair

Also must have been right before the selenium rectifier was put into use...if you've ever experienced one burning up...you'll never forget how that smell...glen

So when do you think this player was produced?

[Enzo]

Indeed, NOTHING in my humble existence smellls like a burnt selenium rectifier. A sort of burnt rotten cabbage sort of stink. You will never forget it once smelled.

So measure the resistor now. What does it read?

Looking at the photo again, your 77 - actually more like 077 right? - looks to me more like upside down 220. And that could be 220 ohms or something like 1220 ohms or 2220 ohms or whatever. I am not in the shop with my tube book, but the current through the two tubes will be the same, so we have to make up the rest of the voltage with a resistor conducting that current. Basic ohms law arithmetic exercise.

WE got about 35v to drop at whatever current a 35W4 or 50C 5 draws. Look that up and plug in the number. then calculate the wattage and double it for the resistor rating. Well, double it or even triple it.

[Enzo]

1950s, maybe very early 1960s.

Give us the numnbers on the controls and on the transformer.

[spartadrive_in]

Think you can make sense of it using this schematic that is pasted inside?

[spartadrive_in]

Originally Posted by Enzo

1950s, maybe very early 1960s.

Give us the numnbers on the controls and on the transformer.

Transformer reads TR-109 798 727
That is the little one in the amp. or is that the driver transformer?

[Mars Amp Repair]

As an aside, I had the exact turntable in an Admiral console at one time as a kid, tho it most likely is some form of a VM for that era...I'd guess also late 50's early 60's.
Can't help you on the value of the dropping resistor, tho...looks like Enzo is hot on the path...my guess would be in the 220 ohm range...I just remember as a kid getting burned by them
It looks like you can see the windings on the exposed portion of the resistor...possibly you could try to chip off & measure what's left & get an idea from that ie; in the hundreds or thousands range...glen

[spartadrive_in]

Originally Posted by Mars Amp Repair

As an aside, I had the exact turntable in an Admiral console at one time as a kid, tho it most likely is some form of a VM for that era...I'd guess also late 50's early 60's.
Can't help you on the value of the dropping resistor, tho...looks like Enzo is hot on the path...my guess would be in the 220 ohm range...I just remember as a kid getting burned by them
It looks like you can see the windings on the exposed portion of the resistor...possibly you could try to chip off & measure what's left & get an idea from that ie; in the hundreds or thousands range...glen

What is a VM?

I was chasing around the schemn last night and my guess is also 220. I measured it (in circuit) and it was giving me a reading of about 180ish.Hopefully I did that right. Do you know what the wattage rating for that would be? I'm assuming it is the 220 OHM 5W resistor near the bottom middle.
Another question is what does that symbol mean next to that 220 resisitor. The little 4-3-4-3 sawtooth with the tube names on top? This is where that wire wound resistor is.( After following the circuit). Is that the symbol for it?


THANKS A MILLION!

[Mars Amp Repair]

Hello,
yes, the resistor you found on the schematic is the series dropping resistor for the filiaments, so there is your answer 220 ohms @ 5watts.

The slanted lines with the 4-3, 4-3 is the schematic symbol for the tube filiaments. the 4-3 are the pin numbers on the tube for the filiament..they've just broken the filiament circuit away from the tube symbols for simplicity...glen

[spartadrive_in]

So then does that mean that pins 4 and 3 need to be connected?
And just to make sure, when counting pins, it is in a clockwise motion correct?

As for the resisitor I need. Is it's modern equalavent those cement block ones we see in modern amps today? Or at least in that 70s peavey I was working on last month.

[Mars Amp Repair]

No,
Pin 3 & 4 are connected by virtue of the tubes being plugged in their respective sockets.

Just cut the existing resistor out, leaving some lead length to bend over & solder your new resistor to. It's easier than trying to get the old resistor leads off of the terminal strips. Also if you're not very experienced, you can easily break off the end of a terminal strip thereby causing much more work for yourself.

The newer style cement resistors you speak of should be an exact replacement...they might not dissipate their heat as well having less surface space, but five watts is 5 watts.

glen

[spartadrive_in]

Ok that's good to know. I will go out tomorrow and find that resistor and put it in. Anything else I should look out for? I don't want to blow out those tubes.

Finding a second opinion here:
On the schem it has a tube placement diagram. It shows that the 35W4 is in the middle next to the filter. EXCEPT I've been following the circuit around to the socket pins and it appears that the 50C5 is in the middle. So those two tubes should be switched in that diagram. Could I be wrong? Why would they print out the diagram like that??? Maybe I'm wrong??

thanks.

[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]

Originally Posted by 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.

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]

Originally Posted by Mars Amp Repair

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]

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.

[spartadrive_in]

Originally Posted by Enzo

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

Yes I know. That's what I said. But wondering if anyone was familiar with the mechanics of the arm.

[Enzo]

There are 8,000,000 mechanical turntable designs. They are all very similar, but each one is unique. very hard to tell you what is binding. A cam follower may have left its track, a mechanical link may have come off, some foreign object could be in the works. And a common problem with old turntables is they won't turn. The lube gets hard and binds it up so you can barely rotate teh thing using force. Have to take it apart, clean off the old lube and put a nice light coating of grease/oil on the works. If the table won't tirn, then the linkages that it drives won't move either.

[Mars Amp Repair]

Originally Posted by Enzo

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

OH MY!! ;- ]

Yeah, either the tone arm shaft has dried up grease on it or the mechanism that engages during record cycling is not disengaging during normal play. does the mech cycle properly..ie; lift the arm off the rest, drop the records, move onto the record? This is basically an old version of the VM (Voice of Music) turntable.

Believe it or not I have an old portable Philco 'record player' in the shop now. I'll take a quick look at the mech & see if I can come up with anything for you...it's been mannnny years since I messed with one of those....g

[spartadrive_in]

Originally Posted by Enzo

There are 8,000,000 mechanical turntable designs. They are all very similar, but each one is unique. very hard to tell you what is binding. A cam follower may have left its track, a mechanical link may have come off, some foreign object could be in the works. And a common problem with old turntables is they won't turn. The lube gets hard and binds it up so you can barely rotate teh thing using force. Have to take it apart, clean off the old lube and put a nice light coating of grease/oil on the works. If the table won't tirn, then the linkages that it drives won't move either.

NO the table DOES turn. Everything does it isjust that I can not pull the arm inwards. Like something is "locked".

The record loads and the needle comes into position it just doesn't gradually glide along.

[spartadrive_in]

Originally Posted by Mars Amp Repair

OH MY!! ;- ]

Yeah, either the tone arm shaft has dried up grease on it or the mechanism that engages during record cycling is not disengaging during normal play. does the mech cycle properly..ie; lift the arm off the rest, drop the records, move onto the record? This is basically an old version of the VM (Voice of Music) turntable.

Believe it or not I have an old portable Philco 'record player' in the shop now. I'll take a quick look at the mech & see if I can come up with anything for you...it's been mannnny years since I messed with one of those....g

Yes the record DOES drop and the arm comes into place. It just does not gradually glide during play. When I switch it to REJECT it does what it should. Turntable stops and arm goes to "home".

Thank you. Let me know when you do.