I have just begun restoring a Model 38-620. The power transformer has obviously over heated in the past: wax leaking out of the transformer and splattered around the local area. All windings ohm out correctly.

Is this transformer safe for future use? In any case I intend to add an in-line 3/4 Amp fuse.

Thank you

Don

Hello, 
I have recapped the radio. 
1st time powering it up the speaker does thump-thump-thump when I place my finger on the grid cap of 6K7G the thump goes away and the radio is silent.

The other problem is there is no power going to the pilot lamp which is connected to the 6A8G. I have checked all the resistances for the transformer and they are all within spec. 

Not sure what to look for on these 2 problems.

Ralph

Hi everyone,

First of all I'm completely new into this world, but I feel really excited about it.

My grandmother gave me this Phonorama before passing away. I have been researching and it's a Philco Phonorama B1756 from 1954. I'm from Chile and, according to her and my mom, there were only two imported when my grandfather bought it.

The wood is absolutely beautiful, and according to what I have researched, it was top of the line back then. When I was I kid I remember we turned it on once and it worked, but now the chord is in bad condition, so I must to replace it. I want to take the challenge and make this beauty sing again, but have zero knowledge of electronics. Where should I start? Does anyone have a pdf version of the service manual?

Any further information about it would be much appreciated.

           

Hi, I'm new to the forum. I'm in my early 60's. First and foremost, I have VERY basic radio skills and tend to be more automotive/mechanical. I had my Grandparents Philco F-1902-121 Hi-Fi (they bought it new) gone through locally by a very sharp young man. Tubes checked, replaced some transistors, capacitors, and cleaned pots. It all works. I had'nt heard it in 40+ years but I am sure that the unit used to have bass that would literally rattle the windows. Am I imagining this? It is not capable of that now and at higher volume and bass levels it make the sound quite distorted/fuzzy/muddy. He repairs many very old radios, but I don't think he is aware of this ones potential as he isn't real familiar with them. He thought it might be that the 2 larger tubes (T-6L6GB-PSV) were not "matched" so 2 new "matched" tubes were installed. It may have helped some but it is still way off the mark sound wise on records and radio both. I will say he did check the 15" speaker for damage and said there was none. Could the speaker still be lacking in some way? I could divert the 15" speaker wires to a boxed speaker for testing if needed. The treble is handled by an electro static amphitheater which sounds pretty good. I will add that Grandpa did replace a socket for one of the aforementioned tubes and the remaining one you have to wiggle the tube to make it glow intermittently. Even if they are glowing could there be high resistance in either of those sockets causing an issue? I am capable of soldering new ones in if needed. Also there is a slight hum to it. I'm not sure if that is normal but I could add a grounded power plug (ground the 2 chassis's) if that might help. Again, I don't think I am imagining how rich it used to sound and am looking for suggestions on how to get it back up to snuff. Thanks! Dave.

Found in the wild today.  Three generations in the same house for over 100 years. This was put up in the attic decades ago.  Philco model 70

Tried something for the first time.  Heard about using GOJO hand cleaner then Howard’s but never have tried it.  One of the guys on a restoration page thought this would be a good candidate so I gave it a go.  Not finished yet but wow does it work. See new pictures below

I think the answer is no, but is there any way to test capacitors without unsoldering them?  I can check with an ohmmeter for continuity I guess as a basic test.

I have a radio with what looks like a good set of Sprague caps. I plan to just leave them alone until I have an identified problem.  I need to replace these obviously physically bad electrolytic caps.

I have noticed that in several of my Philco radios, that some of the wax paper capacitors are marked with the number "7" inside a circle.

Not every paper cap in a radio is marked this way.

Any idea what this means?   I didn't see any mention to this in the service documents.

Hey everyone,

I need some help please with a signal generator usage issue.  I am learning and practicing signal-injection and getting to know this new Siglent signal generator. I have made progress using it and I can inject a signal at the top of the volume control and get a tone out on the speaker.  In that case my test cables are set with the ground clipped to the metal chassis of the unit under test.  And the positive probe is clipped to a .22 mf electrolytic cap, then the other end of the cap lead I touch to the volume control.  That works fine.

But if I try to inject into the grid of the IF amp, as soon as I touch the tip of the cap to the tube grid pin, I trip the GFCI outlet that my entire bench set up is connected to.  I have also tried connecting the negative black lead to B- and as soon as I touch the lead to B- the GFCI trips again.  

I am using an isolation transformer for the unit under test.  

I get that the signal generator has a 50 ohm resistance to ground, so I am guessing as soon as the GFCI outlet senses current flow on the ground it is tripping my bench.  But I feel like I am just making a rookie mistake in how I am using the signal generator.  Do I need to isolate the ground also with a capacitor?  

And is there a more elegant way to do this than using a capacitor?  How are you all making the connections?  Is there some BNC device that can connect between the signal generator and probe set to more easily do the isolation of the DC voltage?

If this is a rookie mistake, feel free to give it to me, I have thick skin.   I am just trying to learn how to use the signal generator more effectively.  Also trying not to blow out a channel on this new piece of gear.  My goal is to use signal injection methods of troubleshooting (whereas I have only used signal tracing with a scope up to now), and to use the signal generator for calibration/adjustment once I am more familiar with it.

And just to complete the picture, the unit under test is a 46-350.  The unit works and powers on and I have can tune stations and play them on the speaker.  There is some 60hz ripple/hum because I haven't replaced all the caps yet.  But this is my test unit that I often use to try out new test equipment since I know it works and I can use it for troubleshooting.  

What am I doing wrong?

Thanks,
George

Hello Everyone,
Well I wanted to share this short video of A prop car made for the tucker movie that my friend helped build for the movie .

Sincerely Richard

https://www.youtube.com/shorts/yF_Vq-eQlKg

Does anyone know where I can get a copy of the parts layout for a 38-620T?
I have the schematic and parts list but no layout.

Thank you
Don