[murf]

Brought  this home and tore into it Saturday.
Started out the usual way with a cleaning, tube check and replace, re-cap, looked for open resistors, checked cadohm resistor etc.
Powered it up and just has very faint audio with very faint reception.
Seems that something is wrong in the audio section.
Still have to check voltages.
Anyone have any suggestions?
Thanks in advance.
murf

[Paul Philco322]

It seems like a fine set, nice looking. Here is some info, not sure what chassis you have but I bet schemtic is easily available, good luck. 

http://www.radiophile.com/silv4586.htm

Paul

[Arran]

I see to recall reading somewhere, it may have been the A.R.C that the cabinets for these Silvertones were designed by one Edward Coombs, the same man who designed the Philco model 70, 90, and several other cabinets for Philco. Regardless of this fact Sears and Roebuck sold a lot of model 4586 consoles and related models. I don't know much about this particular model but one common failure in many sets is the plate load resistor on the first audio amplifier tube, but I think you checked those. Another fault could be a flaky solder joint on the grid cap/s of one or more tubes, or the solder joint on the grid cap lead. I was going to suggest a failed audio interstage transformer but this  radio doesn't have one, the output transformer would be another one to check but I doubt that would be it since you are getting sound. It could also be a wiring error due to the recap, some of you guys really shouldn't rush this, after you verify that there are no short circuits, power the set up first on a variac then recap it.
Regards
Arran

[murf]

Aaran,
I did bring it up on a varied first to look for problems before re-cap.
Had no noticeable audio or signals present.
After re-cap I now have low volume audio and it does pick up stations.
Which tube are you referring to and what is the resistor number on the schematic?
Thanks Aaran.
Murf

[Radioroslyn]

The resistor Arran is referring to would be R5 and R24 the 210K and the 110K.
http://www.nostalgiaair.org/pagesbymodel...017120.pdf
I would start off measuring the DC voltage around the 6F6's (pins 3, 4, and 8).
Rider's has a lot of documentation so have a look and see if your voltages are close.
If you touch the top of the 6F5 do you get a loud buzz???

[murf]

Hi Terry,
No loud buzz from touching the grid cap on 6J5.
Plate voltage on pin 3 of one of the 6F6 tubes zilch.
Other 6F6 tube measures good.
Appears this would be the cause of the audio problems.
Have to find out where I am losing it.
murf

[tbone]

I see you are working on another radio. I think that no plate voltage on one tube could be a bad OP transformer. a quick ohmmeter check of each side to the CT will prove out this condition.

Also, check out this Schematic as it has some modifications done to the output section.

http://www.nostalgiaair.org/pagesbymodel...024689.pdf

[murf]

Yeah, I usually have 2 on the bench at a time.
This one seems to have missing current to pin 3 of one of the 6F6 tubes.
If it ain't one thing its the other.
Murf

[Arran]

Murf;
  This looks like a suitable replacement, it even has the taps on the secondary like the Hammond universal transformers have, but are more reasonable(ish) priced. That is if you want to go new, if used look for a transformer out of a unit that uses #42s, 6V6s, 6L6S, or 6BQ5s, or NOS look on fleabay or see about the Play Things of the Past guy.
https://www.tubesandmore.com/products/tr...output-8-w

Disregard what I said about needing a 12 Watt unit in the P.M, the service info actually rates this set at 3.5 Watts which surprised me for a set with P-P outputs, most of the ones I have with P-P 6F6s are at least rated at 5 Watts, it doesn't really make sense to me since they are running the tubes with 265 Volts on the plate and screens, but none the less an 8 Watt transformer should be more then sufficient.
Regards
Arran

[murf]

Thank you Arran.
Have a great weekend.
Murphy

[murf]

Looks like the new tranny has appeared in my mailbox, but I will be vacationing in AZ for a week.
Will have to look at it when I return.
Have 3 Silvertones with similar voltage issues.
Did they make these things to self destruct after 75 years or what?
murf

[Arran]

That's a good question Murf, I'm not familiar with the Silvertone sets as I just don't run into that many of them here, but the 1939-42 Philco sets are notorious for having failed output transformers, at least the push pull, chassis mounted ones, in their AC sets. In fact if you read the testimonials under that transformer you got one of them is from someone who needed a replacement for the one in his Philco 40-150? In any event it doesn't matter, the 40-180, 150, 195, 41-280, ad infinitim all have the same general layout, though the better ones actually have a phase inverter tube rather then the screen grid inversion setup. In my personal experience I have found maybe three output transformer failures overall in all of the stuff I have worked on, one was a Rogers (basically the same as a U.S built G.G Majestic), the second was a in an early 40s Canadian Westinghouse set, and possibly one on a Philco H series speaker but I haven't confirmed it yet.
   Just out of curiosity, with regard to these Silvertones with suspect failed output transformer primaries, are they Stewart Warner built, Colonial Radio built, or were they built by someone else? I'm just curious if there is a pattern here like there in with the Philcos I mentioned, maybe whoever made them bought them from the same supplier as Philco? It's funny that you are headed to Arizona, if you were headed to the Tempe area you could have probably saved yourself on having them shipped, maybe you still could on the ones for the other Silvertones?
Regards
Arran

[Arran]

Murf;
  In answer to your question about hooking up a push-pull output transformer, the center tap on the primary side goes straight to the B+, the two legs of the primary go to the plates of the power output tubes, either directly or through the speaker cable depending on where the output transformer is mounted. As for the secondary do they not have any instructions or a diagram that came with the AES output transformer you bought? Usually they want you to select a combination of two out of the six terminals to end up with the right ratio between your speaker and whatever power output tubes your set has, in this case 6F6s?
Regards
Arran

[murf]

Hi Arran,
looks like terminals C & 1
These must be the 2 that come out of the voice coil and connect directly to the transformer?
Red to the plug pin with the double wires,
blue to pin 3 of 6F6,
Brown to the other 6F6.
Am I on the right track?
I assume the double wires going to the plug pin could be replaced by one wire?
Will tackle it when I get home next weekend.
Thanks,
murf

[Arran]

Murf;
  The two red wires in the speaker cable are connected together at the plug, one goes to one side of the field coil  the other goes to the output transformer center tap, the red and blue wire goes to the other side of the field coil. It looks like from the diagram that the speaker plug has four pins, two are closer together, the other two are further apart, the ones that are further apart go to the field coil and the center tap of the output transformer, or are there two fat pins and two thin pins like a tube socket? Why they chose to add a second red wire from the plug up to the output transformer only the manufacturer could explain, if I were wiring the speaker cable I would have eliminated one of the red wires and tied the O.T primary center tap and the one leg of the field coil together at the speaker, as it is I would leave it alone unless you have to replace the speaker cable. The two yellow wires go to the outside legs of the output transformer primary, the other end goes to the plug, and through the speaker plug socket to the plates of the 6F6 tubes.
On the voice coil side the way it works is that the voice coil should be connected in series with the hum bucking/neutralizing coil, if you copy the hookup between the O.T secondary on the old transformer exactly, and transfer those connections to the proper pair of taps on the O.T secondary you should be fine. To me it looks like one leg of that secondary connects to something other then the voice coil in the diagram on page 7 here: http://www.nostalgiaair.org/pagesbymodel...017120.pdf Is this the frame of the speaker? Is that what you were trying to ask me about? If so then one end of the hum bucking coil is connected to the speaker frame and through the frame to one end of the O.T secondary. In the instructions with your new O.T there should be something telling you which pair of taps to select on the secondary to match the tubes to the voice coil, since the service info doesn't give you the impedance of the voice coil I would use a pair of clip leads to try a few pairs using the table under 6F6s as a guide.
Regards
Arran