My Grandpa's Old Radio: It's time I got her going

[bcmatt]

He passed away back in '99. This Rogers Majestic "Deforest Ritz" (the 9r1092) was in my Aunt's basement for just over a decade.

Front.jpg

Back.jpg

Apparently she said it was working fine last time she tried it... but knew I was into tube amps and would appreciate it, so I've had it sitting in my living room for the last 10 years. The power cord was completely disintegrated, so I was not about to plug it in until I had a chance to give the thing a proper fix-up. I knew it would need new caps at least.
I found the schematic today and took a peak inside.

rogers_14-106_chassis_9r1092_sm.pdf

I got to say, electronic components sure do look a lot more alien when they are about 85 years old. Some of these things look so unfamiliar.

Inside CHassis.jpg

I guess I ought to replace all these wax covered capacitors... and I maybe I should re-stuff the cap cans or something. Even though it's my radio, I don't want to do anything too non-kosher when updating this. I don't feel like I need to cut the jackets off the wax caps or anything... but I'm not totally against it if it seems offensive to see a bunch of orange drops in there or something. I don't think I need to buy a bunch of Sozos or something. I do feel like a need some reasonable advice on what sort of approach to take with this project. I don't plan on selling this, but I'd like to have it working well and sounding good for another 85 years. I want to show some respect and retain it's original vibe... but I'd also like the ability to feed in a line level signal in somewhere as well, so I can play from other music sources as well (I can do a mono-summing feed into it or something). But first things first.
What the heck are some of these things?!?!?! Why do the resisters look like they are all hand-painted or something? I assume these skinny black cylinders that are painted different colours are some sort of larger resisters:

20230902_161823.jpg

What is this metal looking thing?

20230902_161837.jpg

And what the heck is this weird orange thing that looks like its wrapped in rice-paper or something?

Weird Orange thing.jpg

Anyways, I'll have more questions... but that's some of the more foreign looking things for now.

[sluckey]

The painted resistor... The colors reveal the value. The code is body, end, dot. Body color is first digit. End color is second digit. Dot is multiplier. For the resistor in your pic it is green, black, orange, or 50,000Ω.

The blurry metal thing... No idea. Locate it on the schematic to identify.

The orange thing... Probably a coil wrapped on a resistor body? Locate it on the schematic to identify.

[bcmatt]

The painted resistor... The colors reveal the value. The code is body, end, dot. Body color is first digit. End color is second digit. Dot is multiplier.

Interesting! I hadn't heard of this before. So I guess back in the day, it was sometimes job to paint resisters all day!

The blurry metal thing... No idea. Locate it on the schematic to identify.
The orange thing... Probably a coil wrapped on a resistor body? Locate it on the schematic to identify.

Ya, that's what I'll have to do. I was just wondering if they were a certain type of component to explain the different look... like maybe there is an interesting story, like "ya, those are asbestos-monkey-dung capacitors. They could handle higher power before they were outlawed".

[martin manning]

I guess I ought to replace all these wax covered capacitors... and I maybe I should re-stuff the cap cans or something. Even though it's my radio, I don't want to do anything too non-kosher when updating this. I don't feel like I need to cut the jackets off the wax caps or anything... but I'm not totally against it if it seems offensive to see a bunch of orange drops in there or something. I don't think I need to buy a bunch of Sozos or something. I do feel like a need some reasonable advice on what sort of approach to take with this project.

Yes all the wax caps should go. IC (Illinois Capacitor) film caps are a good choice for those. They are high quality, and have long leads. I see some tubular ceramic caps in there, but they rarely go bad. You may be able to disconnect the large electrolytics and connect modern radials inside the chassis, adding a terminal strip if necessary. No shame in that, IMO. One thing that might cause problems is capacitors inside the IF transformers, which are often silvered mica, and tend to deteriorate. You can open the IF cans and replace them, if you know what the value is. Sometimes they are marked on the schematic and sometimes not, but your schematic shows part numbers.

[bcmatt]

I guess I ought to replace all these wax covered capacitors... and I maybe I should re-stuff the cap cans or something. Even though it's my radio, I don't want to do anything too non-kosher when updating this. I don't feel like I need to cut the jackets off the wax caps or anything... but I'm not totally against it if it seems offensive to see a bunch of orange drops in there or something. I don't think I need to buy a bunch of Sozos or something. I do feel like a need some reasonable advice on what sort of approach to take with this project.

Yes all the wax caps should go. IC (Illinois Capacitor) film caps are a good choice for those. They are high quality, and have long leads. I see some tubular ceramic caps in there, but they rarely go bad. You may be able to disconnect the large electrolytics and connect modern radials inside the chassis, adding a terminal strip if necessary. No shame in that, IMO. One thing that might cause problems is capacitors inside the IF transformers, which are often silvered mica, and tend to deteriorate. You can open the IF cans and replace them, if you know what the value is. Sometimes they are marked on the schematic and sometimes not, but your schematic shows part numbers.

Thanks Martin! This is exactly the type of information I need.
It's good to know I shouldn't be ashamed if I don't try to re-stuff the can caps or put wax carcasses on new film caps.

[bcmatt]

So, for something like a .3uF cap, would you just use a value that IC actually has like .22 or .47 because it is close enough, or would you use a different brand?

[sluckey]

You will need to replace those two bias cells (BC1 and BC2). You may be able to just put a jumper across the dead cells. Google search for "replacement bias cell for old radio" for ideas.

[bcmatt]

I realized I was struggling to read a really low res image of the schematic when I also had this one.

rogers_14-106_chassis_9r1092_sm.pdf

I replaced the crappy pdf in my original post now.
I'll make it viewable as jpgs too.

Ritz Schematic.jpg

Ritz Tube Layout.jpg

[bcmatt]

I take it these must be the BC-1 and BC-2:

20230904_160723.jpg

And this weird thing looks to be c51... which I haven't found anywhere on the schematic yet but it's described as a special condenser or resister:

20230904_161445.jpg

[bcmatt]

Ok, please help me understand this guy first:

20230904_161152.jpg

It would be this on the the legend of the schematic stating that it is a resister coiled around a capacitor:

Orange thing.jpg

Here it is in it's place on the schematic:

23ohm100uF.jpg

So, I understand this to be a 23ohm resister wrapped around a 100uF capacitor? Is that right, 100uF to ground? What voltage would that need to be? It is pretty tiny considering it is only about 10% the size of a 2uF 150V in this thing. I feel like I must be reading the value of this cap wrong. I'm hesitant to pull it apart to investigate in case I have to keep using it...

[sluckey]

Most likely 100pF. There's probably nothing wrong with it. I would not mess with it. You don't have to understand the purpose for every little thing in that old radio.

[bcmatt]

Most likely 100pF. There's probably nothing wrong with it. I would not mess with it. You don't have to understand the purpose for every little thing in that old radio.

Thanks! You're right. I'll leave it. I'll just replace all the brown waxy caps and the can caps for now.

[martin manning]

Discussion on bias battery cells here: https://antiqueradios.com/forums/viewtopic.php?t=165638

[bcmatt]

Discussion on bias battery cells here: https://antiqueradios.com/forums/viewtopic.php?t=165638

Haha! That's the same thread I actually landed on when I google searched according to Slucky's key words.

BC1and BC2.jpg

After reading the whole thread, I surprised myself and am actually leaning toward not changing the circuit. I'll try throwing them in boiled water. Then if that doesn't rejuvenate them (assuming they need it), I think I'll put some CR2032 batteries in their place, along with a note for my next-of-kin inside the cabinet to swap them out every 10 years.

What should I expect the result to be to the radio when they are dead?

Anyways, I am easily swayed by more expert opinions here. I had followed B.C.2 and saw it is going to the control for the top knob on the cabinet... main volume I assume. Only the Music<->Voice control is labelled (second knob down). Below that must be the frequency tuning knob because the big one at the bottom switches Broadcast bands.

[bcmatt]

Another thing I found interesting that you never see anymore (probably because we aren't using field coil speakers), is that the B+ from the recitifiers go to the speaker socket, and the actual plug makes the connection to allow the B+ to travel to all the tube plates. So if someone unplugs the speaker, you are also stopping all the high voltage to the whole amp. Neat feature.

Power.jpg

Why aren't we using Field Coil speakers anymore?
I think it would work super effectively with VVR. As we lower the B+ voltage, we also lower the efficiency of the speaker "magnet", getting even more effective power scaling for bedroom levels.

I'm curious how they sound with my regular guitar amps. I have one in my Hammond M3 and have plugged in my guitar to the phono input before.... but that was more to experience my Leslie 142. That's actually how we also run my Rhodes on stage at church. Running the Rhodes through the Hammond's amp and the Leslie seem to give it the best balanced sound compared to any other amp I've tried (and the use of the Leslie controlled with a footswitch). Unfortunately, it never cuts through like the Hammond and it is using the same mics/channels, so unless the sound techs are really paying attention, the Rhodes ends up too quiet in the mix... especially if the Hammond was already used in the set like yesterday...
Hammond played earlier:
https://www.youtube.com/live/1AqZxYG9Sl ... zYF&t=1180
Rhodes buried later in the service:
https://www.youtube.com/live/1AqZxYG9Sl ... HB4&t=4104

But I majorly digress with this post! (B+ through field coils speaker, VVR, Rhodes through Hammond and Leslie, Rhodes getting buried)