[Ron Ramirez]

Today's progress so far:

[Image: http://www.philcoradio.com/images/phorum...770-26.jpg]

Or if you prefer, a photo:

[Image: http://www.philcoradio.com/images/phorum...770-27.jpg]

It's starting to look like a radio underneath the chassis again. As you can see, more wires have been installed, and some resistors and capacitors are now in place.

Using a highlighter on a copy of the schematic as I go along helps me to make sure things are getting put back in place as they should (wiring, capacitors, resistors, etc.).

Next, I need to restuff some more paper caps as I have run out of some values that I need to use under here.

[klondike98]

If you click ALT+Tab+F1+Ctrl you can see what Ron's really doing....  

[Image: https://dl.dropboxusercontent.com/u/5462...PacMan.jpg]

[Ron Ramirez]

[sam]

[Eliot Ness]

Starting to look good. 

I've also been known to use a highlighter and colored pencils when redoing a chassis needing a lot of work or redoing a hack job.  Like you said, it helps to make sure everything is where it should be.  

Kirk will say we just like to color

[sam]

Kirk will say we just like to color [Image: http://philcoradio.com/phorum/images/smi...on_lol.gif]
I think I just p**s myself  
great one

[sam]

ron
never having to replace tube socket what size are they and do you keep clicking it until it pops the rivet ?
I would think it would brake socket ?

[Ron Ramirez]

The pop rivets I'm using are 1/8" diameter, medium length. The washers I used under each tube socket (on top of the socket if you're looking at it from under the chassis) are soft aluminum and keep the pop rivets from breaking the socket as this way, the pop rivets expand into the washer instead of into the socket.

I know, I should be using brass eyelets. But I don't have any, and have never used them. One of these days, I'll get some, and the proper tools, and try that method out.

[Ron Ramirez]

Okay!

Today's progress, on the schematic:

[Image: http://www.philcoradio.com/images/phorum...770-28.jpg]

and looking under the chassis:

[Image: http://www.philcoradio.com/images/phorum...770-29.jpg]

It may not look like much was done today, but I replaced all of the wires running from the volume and tone controls to their respective points under the chassis. (I have not yet replaced the wires which run to the power switch.)

[Image: http://www.philcoradio.com/images/phorum...770-30.jpg]

In addition, I lengthened the wires of the audio output transformer, as needed, and installed it.

[Image: http://www.philcoradio.com/images/phorum...770-31.jpg]

Oh, and I also rebuilt the dial lamp socket which is used on the left side of the dial, and installed a new wire for that socket.

I think from here, I will next move to the other side of the chassis and address a long terminal board which has several resistors and one capacitor. I am going to save the RF and det-osc tubes for last, as well as checking the coils.

[KCMike]

Having changed just a few wires (Cloth covered) and rewired a few speaker plugs to speaker.
I can tell that is a lot more work than it looks like. Good job.

[Ron Ramirez]

Thanks, Mike; and yes, it is a lot of work to do this.

I worked on it some more this evening. I moved over to the right side of the chassis where there is a long terminal strip with many resistors, and wires coming from it which go to various places. I removed all of the resistors, and all of the interconnecting wires. I have almost all of those wires replaced, and started replacing the resistors with new ones.

So it's coming right along...

[KCMike]

Just curious. Did you ever think about trying to do the mold your own dogbone resistors?

[Arran]

Well, Arran, when these sets were new, all Philco cared about was getting the thing assembled. They were not concerned with the poor repairman who would have to work on these cheaply made sets down the road.

And yes, from 1939 (mid-1938 ) on, Philco's products became noticeably more cheaply made. Actually, I think the cheapening began in 1937 (mid-1936), with the introduction of those awful RF units; became more pronounced in the 1938 season; and definitely so from the 1939 season onward. It was in the 1939 season that these crappy golden yellow sockets first appeared. Plus rubber-covered wires, which I would guess were probably cheaper than the cloth-covered wires?

I am guessing the same was probably true of Electrohome. Once the bean counters take control, quality goes out the window.

Ron;
  Oddly enough Dominion Electrohome, which was famous for making private label sets, used all cloth covered wire in their radios, and Canadian Westinghouse tubes, I'm not sure who made the speakers but that seems to have varied. I'm not sure about who made the power and output transformers either but I've never run into a bad one of either so those must have been made properly. In the set that I am currently working on the trimmers and padders were made by E.F Johnson, and the capacitors made by Aerovox or Solar.  I think that since Electrohome had their own cabinet plant and a proper sheet metal shop in house it looks like the tubes sockets was the only corner cutting they engaged in, that is assuming that these sockets were chosen because they were cheaper and not out of some engineer's personal preference. 
 In the case of the set I'm working on it's rather a poor design mechanically, a 3'' deep chassis where the converter tube is right in the rear corner, and there are terminal strips mounted along the inside rear apron below other things, so that means that I have had to use some funny angles to get to the 6SA7 tube socket terminals. Most of their sets have a fairly open design with chassis maybe half that deep or less. One thing I will say is that when they are working properly the performance is decent, they used pretty standard RCA style circuits, so they obviously didn't cut corners on the front end designs.
Regards
Arran

[Ron Ramirez]

Arran - I meant maybe Electrohome was making sets as cheaply as possible? It sounds like I was wrong in that regard. But I am admittedly not familiar with Electrohome.

Just curious. Did you ever think about trying to do the mold your own dogbone resistors?

That sounds too much like work! Anyway, by the time the 39-770 was made, Philco had pretty much stopped using dogbones in favor of the more modern looking resistors, in more familiar looking tubular cases. Only they had not yet adopted the modern color coding scheme; they were still using the body-end-stripe method, which was a variant of the older body-tip-dot scheme.

I suppose I might consider something like that if I were working on, say, an AK 55 or 60. But not this 39-770.

[Ron Ramirez]

I worked on the 39-770 literally all day today. It doesn't look like I did much, but I made some major strides towards completion of this project.

I mentioned in post #41 above what I did last night to this chassis. I began this morning by replacing the remaining resistors on that long terminal strip on the right side of the chassis, near the set's power transformer. I also had to remove the reactor/transformer in the tuning lamp circuit and attach new wires to it.

I ran new wires to where they will attach to the input electrolytic capacitor once I have restuffed and reinstalled it.

And, yes, the bakelite block was restuffed with new X/Y safety caps.

Here is how the right side of the chassis looked when I had done all of that:

[Image: http://www.philcoradio.com/images/phorum...770-32.jpg]

I then moved to the top of the chassis and replaced the wires running to the power switch, rebuilt the right side dial lamp, and attached a new wire to the tuning lamp. Later on, I flipped the chassis back over and attached the power switch leads, dial lamp lead and tuning lamp lead.

I also made a new speaker wiring harness and attached those wires inside the chassis.

While I was working above the chassis, I replaced the grid leads at the tuning condenser, and also replaced the two 250 pF mica caps and 1 meg resistors connected at the tuning condenser.

[Image: http://www.philcoradio.com/images/phorum...770-33.jpg]

Once all of that was done, I decided to attach a power cord, install new dial lamps, and turn it on with no tubes installed, just to see the dial illuminated.

Here it is:

[Image: http://www.philcoradio.com/images/phorum...770-34.jpg]

[Image: http://www.philcoradio.com/images/phorum...770-35.jpg]

After that, I removed the dial scale, wrapped it in a towel and put it in a safe place. Now that I'm nearing the home stretch, I don't want anything to happen to it!

The next job is to rewire and clean up the two IF transformers. Next will be final wiring at the RF and det-osc tubes, then install any remaining capacitors, and finally restuff and install the electrolytics.

Barring any coil issues, this set should be singing again sometime this coming week.