[bridkarl]

Duh, I’m a dummy. I finally found a picture that makes this all clear. There was a dual cap - common ground. Connecting a ground to each end of the candleohm will never work - facepalm.

Common ground of 12 and 16 mfd to 15 ohm end of candleohm
Positives to appropriate terminal strip locations
8mfd cap negative to 146 ohm candleohm 
Positive to pin8 of 5y3

[RodB]

Now you're on track! I was just writing a response and noticed you figured it out. You have to be very careful with wiring this section. On the schematic there are several wires coming off the candohm running to the grid circuits of other tubes. These are negative bias voltages that control the current flow through those tubes. The candohm sets up the voltages. When you grounded both ends of the candohm these voltages were gone. Note that when you tell us you've wired in a part it helps to use the schematic designated number to make it easier for us to follow along.

[bridkarl]

I’ll be sure to add the part numbers. I add a picture of the terminal strip. I’ve since cleaned this up, but it might be helpful for someone doing this. This is how I am understanding this based on what people here said and an afternoon working on this.

I’m reading this as part 27 - 8 mfd positive- going to 5 on the terminal strip and 27a - 16 mfd positive going to 4.

The tab 2 on the terminal strip is the red wire going to the 2nd IF transformer. That’s one side of resistor number 28 with the positive side of 27 on the other side.

The negative common ground goes to the 15 ohm end of the candleohm. Right side of the candleohm.

 Part 62 - the 12 mfd cap has the negative to the 
146 ohm end of the candleohm with the positive to the pin 8 of the 5Y3. This negative will be on the left side of the candleohm with the chassis front away from you.
Pin 8 is the same as pin 4 on the original 84 tube.

The picture is some other Philco like a 41-280 I found but it seems the same layout. Obviously more to do - I need to put some heatshrink tape on some of the wires. Once my new parts come I can check out my understanding of this and see if it actually works.

[MrFixr55]

Hi Bridkarl, 

Thanks for the pictures, they are helpful.  On first view, if the 16 uF cap appears to be soldered to pin 8 of the 5Y3.  If this is the case, then the 2 caps may be swapped.  This is not horrible, it is just not per the schematic.  Make the following checks:

• Verify resistance of the Candohm.
  
• Verify that the side that reads 15 Ohm is grounded and the side that reads 146 Ohm is connected to the center tap of the HV secondary.
  
• With the speaker connected, verify resistance approximately 1100 Ohm between the +Terminal of the 16 uF cap and  the 12 uF cap.
  
  

I modified the schematic for you to reflect a 5Y3.  Refer to the pic attached below:
   
Note that only the 5Y3 heater and HV windings are shown. The heater winding for the other tubes are not shown

Note the red numbers for the following instructions:

1. 1. This connection is the junction of the 5Y3 filament at Pin 8, the input to the field coil and the + terminal of the 12uf cap, (#62 on the schematic).
      
   2. This connection is the junction of the - terminal of the 12uF cap (#62), the center tap of the HV secondary winding of the power transformer (This is the winding that feeds the plates of the 5Y3), the 146 Ohm end of the Candohm and Line J. (Line J connects this most negative point of the power supply to the grid bias resistors of the two 41 output tubes.
      
   3. This connection is the junction of the + terminal of the 16uF cap (#27A) and the B+, Lines E, F to the rest of the radio, feeding the audio output transformer, the 41 screen grid, the 3700 Ohm resistor to the other 41 screen grid, the IF input and output transformer primaries, the plate load resistor for the 1st AF amp, and a voltage divider consisting of resistors #28 and 26.
      
   4. This connection is the junction of the - terminal of the 16uF cap (#27A), the 15 Ohm end of the Candohm and chassis ground.
      
   5. See the next diagram.  
      
      
        This is + terminal of the 8uF cap (#27) and the junctions of resistors #28 and 26. This point provides the B+ to the       mixer tube and the screen voltage for the IF tube, and, through the other leg of resistor #26, the 40VDC to the
        oscillator plate.  The - terminal of the 8uF cap is connected to chassis ground.
   
   Voltage between points 1 and 2 should be about 260VDC.  Voltage between 3 and 4 should be about 180VDC.
   
   Hope this helps!
   

[bridkarl]

Thanks. This not only clears up where to place the parts, but is a clear explanation of what's happening in the circuit. I don't see the "next diagram" you mention but I can figure out this. I'll assume chassis ground means I can just solder the ground lead of the 8mfd cap to the chassis. Previously I think there was a 20mfd cap there that had the ground connected to the candleohm ??? Not sure why. The radio seems to work well with good volume so I suspect the candleohm is OK. I have the instructions somewhere for rebuilding this. It involves sourcing some resistors I don't happen to have on hand right now.

I think, if you are ok with this, when I get this done I may make a youtube video that explains this and shows what goes where with your diagram. I suspect that this 5Y3 substitution may be common. The good news in this is I also have a 41-255 with the original 84 tube in it - so this should work the same for that.

[MrFixr55]

Hi Bridkarl,

Sorry, I have been running behind you.  I put the statement "see next diagram", saved it, then created the 2nd diagram.  You may have viewed it in the interim.  Look at the post again; it should be there.  Please note that my numbering does not correspond to your numbering of a terminal strip.

Does it still hum?

Sure, feel free to use the diagram.  Please credit Philco Phorum, modified by MrFixr55 in your video if you use the diagrams.  They are my cutouts, mod and markup of the Philco diagram. 

The one interesting thing is the 12uF (#62) cap in the set that still has the 84 is that the + and - leads are reversed.  Considering the blue ends of that cap, I wonder if it was restuffed and they put the paper tube on in the wrong direction.  If polarity is actually reversed, it will go off like a firecracker!  I speak from experience.

Given the expense and scarcity of power transformers, I think that if you can't find an 84, you can use a 6X5.  This is a somewhat more available tube, as it was used in some HiFis as well as car radios.  See diagram below, from RadioMuseum:
[attachment=28959]  There is a 9 pin version (I have to find the number) that will also work, as it was the rectifier used in 1950s HiFi and many German radios.

[bridkarl]

I’m confused now. Isn’t 2 and 4 having the negative on both ends of the candle ohm grounding that per RodB’s comment. I thought that originally this has a 16mfd and an 8mfd dual cap with a common negative which went to 4

[MrFixr55]

Hi Bridkarl, 

Remember that the numbers on my diagram do not coincide with the numbers that you assigned to the terminal strip. Point 4 at my diagram is chassis ground and 1 end of the Candohm.  Point 2 is the other end of the Candohm, and ties to the center tap of the B+ supply transformer.  The - terminal of the 12uF cap (#62) ties to this point. However, this is not chassis ground. The 12uF cap is separate from the 8/16 Ohm dual cap. Point 2 on my diagram is the most negative point of the supply and is more negative than chassis ground. This is a style for developing grid bias that went out of style in the postwar years.  If you are familiar with radios from the late 40s and 50s, this usually throws a curve.  There is about an 18-20volt drop across the 2 ends of the Candohm

Cap # 27 and 27A is the 8 / 16 uF cap.  The 16uF cap + terminal goes to point 3 on my diagram.  The 8uf cap + terminal goes to the junction between Resistors #26 and 28.  You can either ground the - lead of the 8uF cap at any convenient ground point on the chassis or ground at the grounded end of the Candohm (point 4 on my diagram) along with the - terminal of the 16uF cap.



Hope that helps.

[bridkarl]

That clears up my confusion. Admittedly I’ve only done one other radio - Sparton 617 - that was old enough to use this candleohm setup. In that case it was just swapping out the caps so I didn’t think much about what was happening.
The oldest radio I have actually is an RME-69. I actually own two - I saved one from a Miami Florida landfill. And I also have the speaker plus the preselector. At some point I’m going to get that finished and setup with my 1939 Hallicrafters HT-5 transmitter. Picked that up a few years ago - never seen another anywhere.
My retirement project will be a 1930s AM phone station.

Thanks so much.

[MrFixr55]

Hi Bridkarl.

For only your 2nd radio, you are doing well! Kep it up, and you will become an expert.

I retired February of this year after a 45 year career in the Clinical Laboratory and as a Field Engineer for a major manufacturer of automated clinical laboratory instrumentation, automation and informatics.
My retirement projects are:
-Complete the restoration and display of over 75 radios from 1921 to present, some from childhood scrounging, some from a moderately bad eBay addiction.
-Complete the restoration of my grandmother's DuMont RA112 TV, my Mom In Law's 1964 RCA CTC24 (last of the "roundies" (Round CRTs))
-Service and restore an Admiral 20A12 and RCA S721 10" B/W TVs
-Restore a 1964 Lincoln Continental 4 door convertible.
Remodel our house, possibly adding a 16X24 extension.

And the hardest part:
Maintain sufficient physical, mental, financial and marital health to complete the above projects.

[bridkarl]

I think you misunderstand. I meant this is only my second repair of a radio using a candleohm resistor setup.

I’m listing this so people realize I’m not new to all this. I’ve been doing this off and on since the 70s when I was a General class license holder and had a commercial license at age 10. Not a bragging thing - just to show I do know what I’m doing. 
I’ve repaired lots of different radios by now for my collection - from brands everyone knows -Collins, Heathkit, Hallicrafters to some really strange stuff like a Babcock DX-mitter mobile transmitter with the mobile power supply,  Eico 723 transmitter,  a Heathkit ca-1 Conalrad receiver, and even a Meissner signal shifter. Plus a National vhf 1-10A. Not to mention all the McMurdo Silver test equipment.
I’ve never seen another DX-mitter ever - it was in a barn in Kansas. 

I have the majority of this fixed and working. My plan is to work through the rest so when I retire I just quit repairing and have a vintage radio room where I just sit and listen all day

An old picture of the workroom - it’s like a Where’s Waldo of antique radios - that’s one corner of my shop. I have about 25 linear feet of shelves in my storage with the rest - mostly repaired and boxed up- NC300, RME69, Hallicrafters. I even have a Johnson Viking CDC - never been able to fix that one yet. As far as I know there are not any others left.

[MrFixr55]

OOPS!!  Very sorry, Bridkarl!!  Thought you were new.  My fault, my apologies.  Impressive radio shack! 

My "office" is only 8X10, so there is stuff stored in the basemsnt and the garage. House is only 1000 Sq Ft. $400.000 (current worth) does not go very far on Long Island (I am about 45 - 50 mi from the Empire State Building in Manhattan. Having a commercial license at the age of 10 is more than a little bit impressive.

I figured that I would make a big dent in my various projects upon retirement, but just as stuff will suck up your room, favors and needs of family and friends, and illness will suck up time.

[bridkarl]

It’s perfectly OK. I probably don’t sound like I know much so that’s understandable. 

 This is the other side which is the operating position. I have a 20 by 20 storeroom with shelves with either storage items or things waiting for repair. I’m in the process of boxing lots of it in anticipation of a retirement move in a few years. 

  Most of this I bought as junk/not working. 

For two or three years I aggressively bought stuff. I have now more than enough for my retirement projects. plus the pandemic - what else could I do locked in my house for two years?

[MrFixr55]

That's even more impressive! I take it that that is the 41-250 or 255 sitting on the bench?

I never learned Morse Code. That was the biggest think keeping me from being a HAM. Now that they removed the code, maybe when things settle down. A woman in my prayer groop, a lawyer, one day decided to be a ham, started reading up, learned enough electronics, and within a few weeks, got her Tech, then General, then extra class licenses. She is egging me on. We likely need to get new blood into this. HAMS can do so much in an emergency.

[bridkarl]

I have the 41-250 on the bench waiting for my new parts. The 41-255 is sitting in front of the Collins receiver. It has the original 84 tube in it. The cap repair on that should be the same as for the 41-250. I also need to do the bakelite cap block. I just bought a 200 watt heat gun so that should melt through that tarry stuff.

Well the emergency stuff is nice. If you go that route check about what they want before you buy gear. That is all fairly structured with standards. That don't just want someone showing up with their Icom 7300 after the tornado asking to help. That's a whole specific set of things I've never gotten into.

The ham license is fairly easy now. I'd find a local ham club - they have classes. There's plenty of free apps and books online you can study from. Nowadays they publish the questions -- so much easier than in the 1970s. You had to know your stuff and go take the test in a federal building with FCC examiners.