[gary rabbitt]

I usually replace all the paper and electrolytic caps before I replace the power cord. That way I'm not tempted to power it up or lose track of what I am doing when several sets are being worked on.

Hi,
That might be fine for those experienced in working with a set. But for new restorers replacing all the caps at once might invite trouble.

The bakelite block that the cord is attached to has capacitors inside that must be replaced. You can still do that job with the cord attached at this point. Next time though it may be easier on this block to replace the cord second.

Also for the new restorer, I would suggest that the filters be changed first, then a quick test. At that point you will usually hear some kind of reception. That shows all the circuits on the receiving ends are working. (Colis, tuning capacitor, etc.)

Once you hear it is receiving, power the det down, and begin to rebuild the bakelite blocks, and the free standing caps one, or two at a time. Then briefly test again.

The reason for doing it that way is that sometimes a wiring mistake is made, and rarely a bad part is installed. Changing one or 2 caps at a time makes it easier to see where you made a mistake if the radio sudenly doesn't work. Changing all at once (which some of us with more experience do) is harder to track down where the mistake was made.
Replacing 20 caps, then have a non working set, where do you start looking? It can be done but takes more time to locate the mistake.

Chuck's site has a good tutorial on how to rebuild the bakelite blocks, and data on what is inside them. Each person has their own way to do those. Some completely remove the block for rebuilding. It really isn't necessary in most cases. Removing the hold down bolt to the chassis, and flipping the block on it's side you can rebuild like that. Saves you from removing a lot of wires and components, then reinstalling.

I use a small embossing heat gun that has a 3/8" nozzle, to warm the casing just enough so the tar block comes out in one piece. (Along with the old caps). Don't get it so hot the tar starts to melt. Reinstall new caps, solder them onto the lugs and reinstall the block bolt. NO need to refill the block with tar, glue or anything.

Sorry for long post, let us know how you come along.

PS: That output trans can be saved. When you strip off wires like that, don't use the grab and pull method to strip. It can pull the wire right out of the transformer.
Carefully, cut the insulation off, without pulling on the wire. Now, add a wire to the bare and and solder it. Slip a piece of shrink tubing around your new lead, and shrink it over the solder joint.

[Marsupial]

I too am currently working on a 47-1230.

gary rabbitt, what is this bakelite block you are talking about? I fail to see it in my chassis, or on the pictures in this thread. Maybe there's something I am missing?

[Marsupial]

When I first started to look at my own 47-1230, I saw this thread.

now that I am a lot more familiar with the radio and its chassis, I can be of some help with the wires.

here are some of the cords coming out of the back:
[Image: http://farm6.static.flickr.com/5220/5456...47d6_z.jpg]
Power + ??? by robertwsimpson, on Flickr
I know the middle is the power (also, I was wondering, does the polarity matter on this? I need to hook up a new plug, and I was wondering if it mattered which way I solder the wires... I'm thinking not.). I have no recollection of what the outside ones are. I'm guessing one is the speaker, but I haven't had time to look at the schematic very well.

the pair that we see on the left of this picture is the lightbulb for the phono. It is supposed to pass to a limit switch at the door, and power the phono bulb only when the door is open. On mine, it was cut. You don't need that to get the radio working again.

The middle one is the power cord. I changed mine with a 3-prong grounded cord and added a fuse.

the 3rd connector is in fact a connector, you can pull on that one. I didn't think it was a connector either, it seems like it is sealed there. It is the power to the phono. You can leave it unplugged for the early stages of restoration.

here are the cords coming out of the side:
[Image: http://farm6.static.flickr.com/5213/5455...5ef6_z.jpg]
Antenna + phono cords? by robertwsimpson, on Flickr
I think the group of 4 are the phonograph controls, but I haven't had time to look up underneath the phonograph unit to see what they look like. I think the large one is the antenna (it is co-axial).

the group of 4 are the speaker wires. They are supposed to go to a bakelite connector and control the speaker's 2 coils.

the other one is the phono input. It is supposed to be some kind of RCA connector that goes connects to the audio transformer at the bottom of the cabinet, this being the transformer for the phono arm.
You don't need that to get the radio working either and can wait later to fix it.

Question: do you have some kind of metal plate on the underside?

[gary rabbitt]

Hi Marsupial,
The block where you soldered your line cord is a bakellte block. Inside should be the two line capacitors, as shown in the schematic.(C100 and C101) I can't see the rest of your chassis, but there may be other blocks that look similar. Sometimes, there is only one cap inside, sometimes two. Occasionally there is a resistance element inside too.

This block is easy to figure out, and one side of both of the .01 line caps goes to ground. The other lead of each cap goes to one side of the AC line you soldered in. (See diagram.)


Here are two pages you can look at to see what it's all about.

http://www.philcoradio.com/tech/blocks.htm
http://www.philcorepairbench.com/capbuild.htm

Some people remove the block, and add in a terminal strip, seperate caps and then have to connect any other wires that were on the terminals. IMHO, that is creating more work than it is worth. Plus you lose the originality of the chassis. rebuilding the blocks is easy, once you have done one or two.
Good luck!

PS:
Here is how easily most of the tar insides come out. When you have heated it just enough so it breaks free of it's casing, it can be pushed out with a piece of stiff wire through one of the rivet holes.
[Image: http://antiqueradios.com/gallery/d/13200...+plugs.JPG]

I did a little image search and found many people with a huge mess of chipping, and digging out the tar. Sometimes I see them melt the tar out. It get stinky, and is not necessary.
I can usually rebuild a block, still wired in in, way less than 5 minutes.

[Marsupial]

Hey Gary!

I might be wrong, but I tought the C100 and C101 were mica caps. The power cord gets in to the location where I think the schematics on Riders identifies C100 and C101, and they looks like this: (pictured before I changed my cord)

[Image: http://i146.photobucket.com/albums/r253/...0_9028.jpg]
See the brown wires of the cord. That looks to me like a terminal strip, and I think that's what is described in Riders-19-71

I don't think there's any bakelite blocks in this chassis. Might be wrong.

regardless, those line filter caps; .01mF. Those needs to be changed urgently? I have .01mF 1600V orange drops that can go there, if it is required...

but I tought mica caps were to leave as-is to begin with.

[Marsupial]

Riders draws C100 and C101 like that:
[Image: http://i146.photobucket.com/albums/r253/...0-c101.jpg]


I understand that as being caps connected to a terminal strip, which correspond to what I understand seeing visually in the chassis.

Aren't those mica caps?

Do they need being changed?

[ipwizard]

Here is a picture of the bakelite block in my 39-116. Yours could have 1 or more.

[Image: http://i1129.photobucket.com/albums/m501...lock-1.jpg]

PS. Look at all the pretty new wiring..

[Marsupial]

Thanks Keith.

Those are a lot smaller than what I tough bakelite blocks would be.

I'll give another look specifically for that next time I open the radio (still waiting for correct lug strips to replace the electrolytic caps)

but I don't think there's any bakelite blocks in the 47-1230. At least, the line filter caps seems to be mica caps, not bakelited paper caps.

I'll post if I find anything, at least for the purpose of helping the next guy working on a 47-1230... threads like this helped me start when I first got my radio!

[gary rabbitt]

Hi Marsupial.
I was going by the photo that Robert Simpson had posted of his chassis. I thought you were working on the same set, the 47-1230? Or, maybe I am confused

Maybe Robert's chassis was an earlier run that used the block, yours wasn't. I see on the parts list, they show 2 seperate caps and no block # designation. Along with the pictorial of the two seperate caps.


In his photo you can see the block where the white cord is attached to.
[Image: http://farm6.static.flickr.com/5176/5464...8520_z.jpg]

So, I thought you had the same in your set. Those 2 caps you show are not mica caps, they are still paper. Change them out just like the others. Yes, the orange drops you have will work.
If these are open , they could introduce what is called modulation hum into the signal. That's a hum when tuned to a station, but no hum in between. The caps filter out this potential hum.

ANyhow, that's what the block would look like, perhaps you set didn't have any. You can also see othe other photo posted showing another block.
At least now, you know what they are next time you run into them.

[Marsupial]

Mine too is a 47-1230. Code 121. We can recognize the rest of the radio being the same, but the block isn't there. It is just plain confusing, to say the least.
Maybe they had changes made somewhere in the production?

How do we differenciate a mica cap from a paper cap?

[gary rabbitt]

Hi,
The value of those caps are generally too large to be a mica cap. (.01) Some line filter caps were made by the Micamold company, and look like a molded mica. But inside they are paper. I have a couple around here someplace that had split open and burst it's paper/foil out.

I would change those. The hum you hear is not like a filter cap hum. It is heard when a station is tuned in. You will hear no hum between stations, but tuning in the station the sound is slightly garbled when it is mixed with the stray AC hum. I need to make a small video of what it sounds like.

Here is a page that tells a lot about the importance of line fiters, and what happens when they fail. you can use the Safety Caps mentioned in the text.
(Scroll down to read about modulation hum)
http://www.justradios.com/safetytips.html

Take care,
Gary.

[Marsupial]

Thanks a lot for the help, Gary, but now you've lost me.

what is a safety capacitor? Should I get a set of safety capacitors and junk my orange drops?

I am more confused than anything by reading this article...


BTW I have a hum, but at all time.

[ipwizard]

Safety caps are used on the ac line. They are designed to always fail safe (open) instead of failing and creating a short from the line to chassis.

Your orange drops can be used on the line but I believe there is a 50/50 chance they could either fail open or cause a short.

Otherwise orange drops can be used anywhere where else in the radio where an old paper cap was. Back in the day I dont believe they had safety caps so their only choice was to use paper caps.

[Marsupial]

It makes good sense. So the best would be to purchase .01 300V safety Y2 caps?
Any place I can get those, aside digikey? (how do we find them... are they stated "Y2 safety cap, .01, 300V"?)

[Ron Ramirez]

Mouser Electronics has them.

http://www.mouser.com/ProductDetail/Vish...KdlehKA%3d

Specify X1/Y2 safety caps. The one in the link above is X1/Y2, .01 uF.