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Big-Dirty 47-1230 Electronics Restoration - Printable Version

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Big-Dirty 47-1230 Electronics Restoration - MRohrb - 10-04-2018

Hello all,

I finally got around to working on my 47-1230 and I think its safe to say that I may have bitten off  more than I can chew.

First off, I have recapped the chassis and checked the connections to the best of my knowledge. Everything went well on the recap process but man is it a painstakingly slow process  Icon_thumbdown  

After the recap and a little cleanup I decided to try and plug it in to see if it works at all.
I plugged in the speaker because I read it will damage the chassis if it is turned on without the speaker plugged in.
I turned it on and the two front lights came on and the tubes started slowly glowing, then the speaker started to hum.


With that being said, no sound except a hum was heard on any of the AM, FM, etc....  Actually FM is almost silent.
I really need help on where to start with the troubleshooting process. I have started with the "Section 1 - Troubleshooting" section of the philco papers that I have. But where from here??  
These are the values I got with an input voltage of 122Vac
 EtoC : 217 VDC
 DtoC : 162 VDC
 BtoC : -12.16 VDC
 Resistor 100 I have 20 Kohms
 Resistor 101 I have 138 Ohms

I know these values are a little off and one of my questions is how do I test the 5Y3GT tube?

https://www.dropbox.com/s/2pn126nyoqdp1lk/Photo%20Oct%2004%2C%204%2029%2032%20PM.png?raw=1

RE: Big-Dirty 47-1230 Electronics Restoration - Radioroslyn - 10-04-2018

Check ur pm box.

RE: Big-Dirty 47-1230 Electronics Restoration - morzh - 10-04-2018

Have you verified the tubes?

RE: Big-Dirty 47-1230 Electronics Restoration - MRohrb - 10-04-2018

Morzh,
Not sure how to test the tubes, I’m a late 80’s baby so the tube thing is new to me.
Any info is appreciated.

RE: Big-Dirty 47-1230 Electronics Restoration - morzh - 10-04-2018

Well.....to test tubes you need a tube tester Icon_smile or a working rafio using the same tubes. Or a reputable source who will sell you guaranteed working tubes.
If this is one off for you, the latter will do. Or find someone who is in this hobby and has the tester.

RE: Big-Dirty 47-1230 Electronics Restoration - Radioroslyn - 10-04-2018

>I know these values are a little off 

A couple of thoughts. Could have a replacement power transformer that is a bit lower in output voltage, weak 5Y3, or something is loading the power supply down. In any event the hv voltage are still are within 10% of where they should and that's good enough to do some troubleshooting.

I wouldn't condemn any of the tubes so far as for the most part a weak tube will still work short of the heater being burned out.

GL

RE: Big-Dirty 47-1230 Electronics Restoration - MRohrb - 10-08-2018

So a quick update.
I was looking at the schematics and checking connections/voltages again with the radio on and noticed when I touched PIN number 6 on the 7R7 tube,or moved the wire (green) coming off the pin, the humming in my speaker totally stopped. No sound at all. When I let go the sound came back. The green wire coming off pin 6 goes to the trimmer between 7R7 and 6BA6.

Any reason for this?

I’m also still in the process of finding someone locally to test my tubes.

RE: Big-Dirty 47-1230 Electronics Restoration - morzh - 10-08-2018

>>>....or moved the wire (green) coming off the pin

Moving in what way? holding it by fingers ?

What happens if you move the same wire by touching it with, say, a pen?

The effect could be due to simply applying capacitance between the GND and that pin, that is the grid (you serve as the capacitance).

RE: Big-Dirty 47-1230 Electronics Restoration - MRohrb - 10-09-2018

Moving the wire using fingers, pen, or my small needle nose all have same result.

RE: Big-Dirty 47-1230 Electronics Restoration - MRohrb - 10-09-2018

I also just realized that cap 206 was not in my radio when I got it and is still not installed. 
It is listed as a Condenser: 100mmf r-f bypass. 

Try to put a link for a picture, let me know if it works. 

https://www.dropbox.com/s/h9uz9s74t59o0ty/Photo%20Oct%2004%2C%204%2029%2028%20PM.jpg?dl=0

RE: Big-Dirty 47-1230 Electronics Restoration - LarryFS - 10-09-2018

I sent you a PM about a way to get your tubes tested if you aren't finding anyone locally who can do it.

Larry

RE: Big-Dirty 47-1230 Electronics Restoration - MRohrb - 10-13-2018

Another question I have is.. If the push button portion of the radio is bad will that make the rest of the functions not work? 

I guess what I'm getting at is that if I have a working record player and plug it in, would it work or does everything have to work together? 
Again I'm a rookie and still not sure how these things work. Still quite a learning curve.

RE: Big-Dirty 47-1230 Electronics Restoration - morzh - 10-13-2018

The record playing mode is switched on by the left button so, yes, the buttons have to work, at least t some degree.
There's a YouTube video of your radio and the changer operation. Look for it by name.