Bill, beside a little study on the workings of a radio the next most important thing is to have proper repair documentation. Before I start on a Philco I ALWAYS go to the attached link to get a full set of clear documentation including schematics that are clear enough to actually read and related service information. The best service provided for this stuff and extremely reasonably priced. Don't start without this stuff!
Best Jerry http://www.philcorepairbench.com/
Plus some pics of me trying to take the dial apart and a pic of what it looks like now taken apart and clean up with goop.
If you can't use water on the dial how to you clean it off, just use goop on there too? Wow that RCA 1930 online course is crazy, and I quote. "The study of the electron theory as applied to the vacuum tube is comparatively easy if the student will concentrate, otherwise it is a difficult study and only results in a state of confusion."
On the underside some parts/wires look wet or something like something melted on it... not sure... bought a book or two on radio restoration but not sure I'll be able to follow everything with out a bit more review of the basics so I'm just gonna press forward on the cabinet.
If what you want is a well playing radio, just replace the capacitors. Use an ohm meter to check the resistors as you go; if they are far off in value change them as you go too. You can get a good parts list with layout of the parts to help identifying them properly as mentioned earlier. Then you won't have to learn anything right away. You can do that as your time permits. We can always help too. I've done two of those and I am finishing a third now, so I can help with questions.
Someone replaced the filter caps already so you need to be sure they did it right when you replace them, otherwise it looks original, which is easier to restore. You will also have to rebuild the lamp sockets but Ron has a nice write up on those.
Doing it this way won't take as long and you won't loose interest or be overwhelmed.
So I started messing around with the radio last night and wondered if you guys can point me in the right direction. Keep in mind I have no idea what I am doing and so far I have only understood about 30% of what you honyacks are saying.
I bought a used variac, tube continuity tester and made a dim bulb tester. I plugged the variac into the wall, the dim bulb tester into the variac and the radio into the dim bulb tester. I figured this way I could slowly up the voltage and still see what was going on with the current. There were no sparks, smoke, burning, or other bad signs so I took it to 100% voltage. When the radio is powered up the dim bulb tester burns brightly at first and then slowly dims back down like it is supposed to…. But it doesn’t seem to dim back down as much as I have seen in videos online. It went down to about 20-30% of the amount when it first turned on? I used a 60W bulb? Not sure if this is okay but I figured at least it shouldn’t have a bad short or it would have stayed bright right? After that I just plugged into the variac directly and powered up and left on for a little bit and most of the tubes started to glow very dim, but no sound at all or any other signs of life.
So next I took all the tubes out noted what was supposed to be in that spot, what actually was in that spot, and tested them with the continuity tester. Table of the results is attached and at this link: https://www.flickr.com/photos/58236519@N00/16698888316/
A little detective work and you can see that it appears that someone put two sets of tubes in the wrong place. The Rectifier and AVC tubes appear to be switched as well as the Push/Pull and one of the discriminators. All the rest appear to be the correct tubes or substitutes in the right places. Would this have caused some damage elsewhere in the radio? I am thinking about putting them all back in the right position tonight and seeing what happens? From the continuity tester the Driver tube didn’t light the indicator light at all, the Rectifier and AVC light up the indicator light but very very dimly, and one of the discriminator tubes is separated from its base and nearly falling off, but indicator lights tests okay, but I don’t trust it and think I should probably get a new one? Wondering if I should put the tubes back all in correct position and see what happens, or just order 4 new tubes (Driver, Rectifier, Discriminator, and AVC)?
Also, after all of the tubes were taken out I tried the dim bulb tester again and when turned on the light did not come on at all? Is that what it is supposed to do?
next time you get itchy to power something up, considering your own "Keep in mind I have no idea what I am doing and so far I have only understood about 30% of what you honyacks are saying." admission, it will benefit you to ask if you even should.
i don't know if you have read other threads on restoration, or any general comments, at all, but if you did, you'd probably noticed that
1. Powering up, with or without dim bulb, variac or what not, a chassis that has not been thoroughly inspected is a bad idea. Really bad idea.
My opinion: people who power a chassis like that, and there are those who do it, without due inspection, are simply impatient and want to impress others by writing a post containing words "variac", "dim light tester" and such.
Do not do that. Does not do anyone good, no one gets impressed and you are the one who stand to incur potential losses.
It is quite possible that some tubes that otherwise might be just fine got killed due to being powered in wrong sockets.
2. Even when you inspect the chassis and the bulbs are in their proper sockets, what good does it do to power it? Nothing.
Remove bulbs, mark the places, TEST all tubes, and not for continuity (good continuity, I hope you are talking about the filaments, only gives you maybe 1/4 of the chance of the tube tested being good. There could be shorts, there could be no emission or the lack thereof, etc). You need to TEST the tubes, at leas using emission tester AND for shorts too.
3. test the power transformer first. With all tubes removed test the filament and high voltages.
4. Recap. And do not power before you do. You can power with bad resistors, but not with bad caps.
And....ask, ask, ask questions. You have accepted the fact you do not know much right now, so better safe than sorry, ask questions, there will be no lack of help here, but do not get bold.
And remember - the voltages in this radio can kill you in a jiffy and more experienced people than you and me get zapped and, yes, killed sometimes.
Be diligent, patient, do not rush, this is your first experience, make it a learning one, you will have your braggibg rights later when it sings.
best of luck.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
To answer your question on the dim bulb test with tubes out, yes, the bulb should not show any appreciable glow. The power transformer is under no load. You passed that test and that was actually a "safe" one to try (all tubes out).
As for your question on speakers, the large one is a full range speaker and the only "active" speaker in the radio. Notice the three small ones have no wires going to them. These are referred to as acoustic clarifiers and provide dampening of cabinet vibrations. It is some type of acoustic magic that Philco came up with.
Jerry
A friend in need is a pest! Bill Slee ca 1970.
(This post was last modified: 03-05-2015, 02:08 PM by jerryhawthorne.)
So I bought several books and am trying to follow one called Antique Radio Repair by Alfred Corbin, since it seems to be the most thorough from a troubleshooting stand point and ease of understanding. But on here and every other forum there seems to be two ways of going about this, 1) just slowly test every individual thing, replacing a bunch of tubes and capacitors slowly working your way replacing most things or 2) get it running and follow sort of standard troubleshooting to get it running correctly. The book I am reading said in big bold letters, Do Not Replace All the Capacitors. But elsewhere I hear, first thing to do is replace all the capacitors. Very confusing. I tried to buy a complete tube tester on ebay but after it got to $80 that was out of my budget, since I have no idea if I will do this again and I don't think I paid that much for the whole radio, so I got a cheaper one for $15.
How do you do number 3, test the power transformer?
Thanks Jerry for the info on the speakers, I was able to figure that out from a video and also saw how a guy replaced the rubber damper straps that go on the back, mine are still there but the seem to be melted and drooping so I don't know if they work properly? Are they absolutely necessary to have a working radio?
Just from looking at the pics I don't think you have the 5X4 plugged into the proper socket. Should be plugged into the top of the power transformer(that big square black thing w/the tube socket on the top).
Terry
About replacing the capacitors. You do replace ALL the paper caps and electrolytic caps but you don't have to normally replace the mica capacitors unless you find a bad one. So both statements are true. You don't replace every single capacitor just the paper and electrolytic ones.
To start off you can use an ohm meter to measure between the different wires on the transformer to see if the resistance is correct. The schematic should show you what the ohms should be between which wires from the transformer.
It is nice to check the "iron" first. The power transformer can be checked easily by unplugging the radio first and pulling the rectifier off the top of the power transformer.
1. With your meter attached one lead to each of the A/C plug and set for a low resistance scale, turn on the radio. On should show low resistance, off should show open. You have checked the primary of the transformer
2. Place one meter probe in one of the small pins of the rectifier socket on the top of the power transformer and connect the other to ground. Measure the resistance. Do the same for the other small pin to ground. They should read about the same. You have checked the HV winding of the transformer!
3. Place your probes on the two large pins, one on each. Should measure low resistance. You have checked the 5V heater winding on the transformer!
You may need to wiggle the probes to get a good reading.
As for cap replacement and yes it is necessary many people handle it differently. I would say first the e-caps and check the radio for performance, voltages and response on your dim bulb. Then a few wax caps at a time and a recheck. If you are careful and move slowly to assure you don't mess up the wiring, go ahead and do all of them. Everyone works differently.
Good luck and keep in touch with the Phorum for answering questions along the journey.
Yes Terry you are correct, the pictures are where the tubes where when I got it and the 5x tube was not installed in the right place. I reinstalled all of the tubes in the correct locations and did another dim bulb test tonight and this time it burned brightly and never dimmed. I also did with with all the tubes out except the rectifier plugged in and this also burned brightly never dimming, so I took everything out. Even before I turned anything on the rectifier tube never passed the tube continuity checker so it is probably dead. Unplugged all of the tubes and put them in a box (except the one that I accidentally broke when I knocked it on some metal) so I just worked on vacuuming and cleaning the chassis.
Jerry couple of questions on 1. above. When you say meter, I have a digital volt ohm meter that they sell at every hardware store, will that one work, I believe it is Cen-tech 7 function?
If that is one of those little red jobs that uses a 9v battery. Two things it will read a bit higher on the voltage ranges (it's digital) and the ohms scale only goes up to a meg or so.
Terry
Terry is correct on your meter. The nice thing about them is if you have the settings wrong and blow the meter, they are cheap to replace! Your test with all the tubes out except the rectifier is not a safe test. The indication of a bright light is indicative of bad e-caps in the power supply. Don't try that test again until you have at least replaced the e-caps. Also check the rectifier for shorts.
Jerry
