[MrFixr55]

Hi Phil, 

Sorry for joining this thread late.  Hopefully I am adding to the conversation.  

First off, Welcome to the Phorum!  You have some very talented people helping you.
Secondly, I think that this will be a great sounding radio!  This is a nice radio, ca 1933-1934 with a triode push pull output.  I am guessing that the output is 5Watts or so if it is Clas A or 10 watts if Class AB2.  Considering that there is a 6F6 Driver, I am thinking AB 2.  The radio has a separate oscillator and mixer and covers from broadcast to 22MHz in 4 bands.

Thirdly, re the electrolytics, this is a rather complex situation.  I believe that, based on how it was mounted, the Tobe branded cap (we usually refer to capacitors and condensers as "caps" as shorthand) was a replacement, and likely not done correctly.  In addition, the blue 2 section cap by the wirewound resistor, 90, is also a replacement, put in parallel with one section of Cap 73.   Just cut this out.  Looking at your pics, in Post 7 and the last 2 pics, the opening in the lower right hand corner housed 2 electrolytic caps, #91 and #98.  #98 is a single 8uF cap.  Cap #91 was a dual cap of 10 and 12 uF with a common negative connected to the can of the cap.  The can of both of these caps were insulated from the chassis The connections must be made correctly.  This bears discussion. 

Attached below is a copy of one of your pictures.  The red circle shows the original location of Cap # 91.  Please note that the red circle is not indicating the speaker jack, it is locating the area above the speaker jack.  Cap # 98 would have been next to it.  The blue circle is Cap # 73.  This cap is an electrolytic cap, not an oil cap and it should be replaced.
   

The attachment below is the pictorial of the chassis from the service documentation.  As above, the red circle denotes Cap #91, the blue circle encompasses Cap # 73
   
Looking at the schematic, it is important to note that Ground is not the most negative point in the power supply.  The center tap of the HV secondary of the power transformer is the most negative point.  This is very common with radios from the 1930s.  Chassis ground was considered B- and C+.  The HV secondary center tap was considered "C-", the grid bias source for the power amp tubes. However, this is a matter of semantics; the radio is really cathode biased as opposed to fixed bias.  Since the chassis has been modified (the mounting tab for the clamps for Caps 91 and 98 were hacked off) replace these 2 caps with 3 separate caps.

Attached below is a copy of the section of the schematic which contains Caps 98, 91 and 73.  The 2 caps comprising Cap #91 are circled in red.  The 4 caps comprising Cap # 73 are circled in blue.    OOPS-  The 2 caps that comprise Cap #91 are circled in blue.  The 4 caps that comrrise Cap # 73 are in red.  (I am nothing if not consistently inconsistent.) Hopefully, this makes the next instructions more simple:
     
 
Cap 98 is straight forward.  Use a 10 uF cap, connected per the schematic.   The positive (+) terminal of this cap connects to the junction of the 80 Rectifier filament and the input of the filter choke, #96.  The negative (-) terminal of this cap connects to the center tap of the HV secondary of the power transformer. 

Cap 91 is a little more complex.  Use 2 separate caps.  For the 1st cap, use a 10 or 12 uF cap and connect the positive (+) terminal connects to the junction of the output of the filter choke #96, the speaker field connection and several resistors.   The negative (-) terminal of this cap also connects to the HV secondary center tap of the power transformer.   Finally, for the second section of Cap #91, Use a 10 uF cap.  Connect the positive (+) lead of this cap to Chassis ground and the negative (-) lead to the center tap of the HV secondary of the power transformer.

Finally, there is another 4 section cap, # 73 on the Schematic and on the Pictorial.  The easiest way of handling this cap is to remove the connections form the original cap and install 2 solder type terminal posts to handle 3 separate caps of 1.0uF and one cap of 2.0uF.  If these are electrolytic, use 450V caps.  If mylar then use 630V caps.  Do not attach the replacement caps directly across the terminals of the original caps.  This is called bridging and is a poor practice.  The original electrolytic may be open but it could also short, arc, etc., all of this being bad.  Some restorers like to "stuff" the original cap (cut the cap open, remove the original contents and install new caps within the original can).  This is not easily done but is aesthetically pleasing.  This can be done with Cap #73 because it exists on your chassis.  To "stuff" Caps 91 and 98, you need something to stuff and the hardware to mount the stuffed caps, and you need to add metal to the chassis.

[Phil27]

Thanks Rod. Hope you don’t mind the constant posts. I’m getting to a messed up area of the chassis now. Still working on the bakelite blocks. 

This is a photo where someone made quite a few alterations. I’m missing bakelite block #22 but I can figure out what he did there. He has installed a terminal strip and put part #23, a 1K resistor and a .05 cap on it. Photo enclosed.

The bakelite block with the red arrow is part #75, a .05 cap is supposed to go from lugs 1-3. Mine is attached to lugs 2-3 with nothing attached to lug 1. That doesn’t appear to be correct, should the new cap I install go from lugs 1-3?

I can account for all the resistors in the photo with the exception of the 56K one. It’s not on the parts list and all resistors are accounted for. Any thoughts. Just cut it out?

Thanks, I very much appreciate all your help and welcome any advice from any other member that wishes to contribute.

[Phil27]

Mr Fixr55

Sorry but I just saw your reply and will check my work. It takes me forever to figure out how to explain what I mean in a post so I hadn’t noticed your post.

Appreciate the advice!

[Phil27]

The resistor I was referring too.

[MrFixr55]

Hi Phil,

Don't worry, no need to apologize. It takes me forever to do a post and then go back after interruptions caused by life, and then update after I note my mistakes. Please do feel free to read that post only when you are ready to do the electrolytics. I posted now, not to dump more stuff on you for you to worry about, but to make sure that I documented what I thought was important.

What you may be seeing is new resistors being put in parallel with old resistors whose values have changed. the original resistors of the 1930s, sometimes referred to as "dogbone" resistors are very much prone to increasing in value. this radio was likely 10 years old by the middle of WWII. Unlike modern electronics which rarely require service and are unfortunately discarded as unrepairable, these sets represented a major investment by the owner. By the time that they are 8-15 years old, they would have required service. During WWII, from 1942 till 1946, there was no new consumer electronics, and even tubes and repair parts were scarce. Therefore, putting another resister in parallel to bring the errant resistor back into spec was common. then by the time that new electronics was available or the radio broke enough times, it found itself at the curb or in a landfill where preteen or early teen boys, and occasionally girls) like me picked them up as their first electronic projects, usually resulting in such butchery as you are noting in your set.

The best way of dealing with this is replacing the dogbone resistors and even the 1940-s- 1970s style resistors with new metal film resistors. Signal resistors can be 1/2 w. But any resistors in "voltage dividers should be of higher wattage.

Regarding the bakelite blocks, there are 2 ways of handling them. Either scooping out the contents and replacing them with modern caps. This can be done without disconnecting the external connections; see Morzh's post in the Library under Techniques. A link is attached here:

https://philcoradio.com/library/index.ph...soldering/

The other way is to just pass a drill through the rivets to cut the wires connecting the internal components to the external terminals. Thie is quick but dirty, and Morzh's technique is rather quick, and results in a clean, factory-like result.

Any paper caps, "black beauty" or "bumble bee" caps or ceramic coated tubular caps should be replaced as they leak or short. You likely do not have many of these. It appears that the dark brown caps that are clustered in one area are likely mylar. If installed correctly, they can remain. As stated before, by many experts in many posts, any electrolytic must go if not recently replaced. It is likely that all electrolytics are either original (Cap # 73) or are replacements (the Tobe cap and the blue electrolytic by R90). These must go!

Good luck, keep asking, please never worry about asking us to clarify our posts. Keep plugging and you will be rewarded with a nice, historically important radio. Just think that the owner was listening to shortwave to find out what was happing in their ancestorial country, praying while listening to Vatican Radio or feeling anxious, listening to news of a world descending to war. Remember, radio, especially shortwave was the internet of the 1930s and 1940s

[MrFixr55]

Hi Phil,

Looking at the pic posted re bakelite block #75 in Post35, look carefully at the middle taqb and ensure that in fact, there is no wire soldered to it. The connections made to the 3rd "blank terminal (no connection internal to the block) is a standoff meant just for the purpose of acting as a terminal for eternal connections instead of the connection just hanging in the air. Comparing most Philcos to most non-Philcos, the non-Philcos use multi-terminal strips for interconnections with most resistors or capacitors hanging between these terminal strips and a tube socket or from one strip to another. Philco made extensive use of these blocks, probably as a shortcut to ease of assembly. Remember, this is the depression, and in the 1920s, you could buy a Model T cheaper than some radios. Radio prices had to drop precipitously for manufacturers to sell radios. RCA Radiolas went from $150 for the Radiola 60 to $72 for the R-7a "Suprette", a much better radio with twin Push Pull pentodes and 5 Watt output, variable mU tetrodes and an 8" electrodynamic speaker built into the set as opposed to the Radiola 60 with all triodes, 0.7W output and speaker at additional cost (about $35 for the 103 magnetic speaker or more than $100 for the 106 electrodynamic in a large cabinet. the Philco Model 20, a seminal radio sold for $49.95 (without tubes. 2 years later, the 80 Jr, a 4 tube superhet sold for $18.05 with tubes. Some of this was due to better mass production techniques, some reduction was due just to belt tightening and gettiing what the market would bear which was a lot more in the 1920s than the 1930s.

[Phil27]

MrFixr55

Thanks for your help. I have a couple of questions that will hopefully help me understand how things work. 

The two resistors, a 70K and a 56K, both start at a common lug on the terminal strip but then go to different terminals on the Bakelite block. I think these are the two that you were referring too as in parallel. Does it make a difference that they both don’t end at a common terminal. 

When I checked on the Philco site about block #22.  3615-BL was discontinued and replaced with 3615-OSG which has one .05 cap going to wiring lugs 1-3.  I still don’t know if it makes a difference that my block is connected 2-3. As far as the middle tab on that block I’m enclosing a better pic that shows nothing is connected to it.  What makes it more confusing is that it appears that something at one time was connected there. 

I am learning a lot just on this radio alone     and please don’t take offence to my questions.