[mikethedruid]

Lately I have been restoring a Crosley 716 -744, the 716 chassis in the cube cabinet with the speaker on top. http://www.nostalgiaair.org/pagesbymodel...003598.pdf  The cabinet is very rough, so I am going to fabricate a brand new cabinet as a child sized console floor model. I have the whole chassis done, all the electrolytic and paper condensers replaced, and most of the resistors replaced too. Today I got the last resistors I needed in the mail, a 10 watt 10K and a 10 watt 15K to replace the two sections of the candohm, which was completely bad. When I went to install the tubes, I got to the last one, a 6N6, the audio output tube, and realized that the only tube I had left was a 6L6, which some fool must have put in instead of the 6N6 thinking, since it was an audio output tube they must be very similar, which, as soon as I looked at the schematic I realized they are NOT. The 6N6 is an odd type of double triode, where one section drives the other. The 6L6 is a power pentode. This is the first time I have run into the 6N6 used. Looking at the schematic it is clear the substitution would never work. Just to be sure nobody had played around with the circuitry to try to allow the substitution, I rang out and traced everything connected to that socket. It is, indeed, still correct for the 6N6. An old saying of my mother's ran through my head when I realized this situation, "The things you see when you don't have a gun!"

[OZ4]

Your 6N6 Kinda looks like darlington transistor

[mikethedruid]

I am waiting for the 6N6 tubes to arrive; I ordered 3, since I have none in stock and always like to have spares. So, I busied myself with what all I could get done. I double and triple checked all the connections. I found one bad solder joint, which I had to remelt. Yup, happens to us all. The chassis is wired to the speaker. The only thing missing is the audio output tube. I decided to give the radio a pre-test, see if there was any smoke or explosions. Nope, the radio came up as expected, no sound except a very feint hum from the speaker. The only glass tube with an easily visible filament lit up properly. The two dial lights came on nicely. So, here is what the chassis looks like, first, the underside all finished...
[Image: https://64.media.tumblr.com/000d7d0cf7eb...9e2e06.jpg]

Next the whole chassis from the front...
[Image: https://64.media.tumblr.com/9116fa961fd3...2b7ef0.jpg]

And the dial close up, one of the things that REALLY attracted me to this radio, and makes constructing a new, custom cabinet for it worth it, IMHO...
[Image: https://64.media.tumblr.com/2ed64034ed73...b3a401.jpg]

[mikethedruid]

Good news, and some frustration. The 6N6 tubes arrived today. I tested them and they were all very good. I installed one into the Crosley and gave it a try. It came to life. I didn't receive much beyond static and the 60 cycle growl from the high tension power lines on the BCB, although there were feint signs of stations coming through. On shortwave, however there were a lot of stations, and one or two on the police band too. I think with alignment things will really perk up. On the other hand, the dial cord broke. Replacing it entails taking the whole dial assembly apart, which is a bit of a pain, but I have done it. It also gave me a chance to replace the pieces of aluminum foil I was using as reflectors at the corners with silver paint directly on those corners of the dial to reflect the light from the dial lamp bulbs back into the glass, much more professional looking solution. Right now I am waiting for the paint to dry before I put the dial assembly back together. Once that is done, tonight I will proceed with the alignment. After that, later this week, I will have to drive to Morristown, to the Home Depot and Lowe's and see about getting the wood to build the new cabinet, and stop by Harbor Freight and buy a woodworking router and some bits to do a professional looking job on the edges of the cabinet. To be honest, I HATE woodworking although I am a fair to middling wood butcher. However, there is really nothing for it, and the new cabinet, making the radio a child sized console, will be an interesting project. Wish me luck with that. I'll need it.

[mikethedruid]

It took a bit of fiddling as well as grinding using a wheel on my Dremel tool to make a shallow in the small tuning shaft to prevent the dial cord from traveling along it, which kept making the cord jump off the big wheel. That and a little rosin on the shaft for grip and the new dial cord works a treat.
After that I aligned the radio. This took some doing to get the frequencies to actually line up all across the bands. With the IF set at exactly 450 KC, if you got one end to line up well, the other would be a few hundred KC off. All one had to adjust where a frequency came in on the dial was the oscillator adjustment condenser, and that shifted things all across the band. After much trial and error, by re-tuning the IF a little at a time, I was able to get the frequencies to line up within 100KC all across the broadcast band. The police band and shortwave bands both lined up acceptably too.
Careful adjustment of the RF adjustment condensers peaked the signals on each band. Interestingly, I found that the AM band does much better with a fairly short, only about 4 foot, antenna ! This does not give as good results on the shortwave bands as my regular test antenna (about 10 feet long) but it is close enough to be acceptable.
The radio is a pretty decent performer, on par with the Philco 38-10 I recently restored. Tonight I listened to WSM 650 in Nashville, WLW 700 in Cincinnati, WCBS 880 New York, WRVA 1140 from Richmond, WLAC 1510 from Nashville, and many others, all on the short antenna. I was able to receive WWV at 5 MC and 10 MC, and CHU at 7.85MC, as well as many other stations on the shortwave bands, although WWV and CHU required the longer antenna. With the shorter antenna I still am able to receive a lot of stations on both shortwave tuning bands, but not as many as with the longer one, the opposite of how things are on the standard broadcast band.Once I get the new cabinet built, I will work on making an antenna which can fit inside the new cabinet, and can receive decently on all bands in the evening. The fact the the short antenna in my radio room seemed to do well for the broadcast band gives me great hope.

[mikethedruid]

Today I went to Home Depot and bought wood and other supplies to build the cabinet. I cringed at the price of good wood, not to mention the stain, and shellac to seal the wood. I'm going to use Tung Oil as the top finish since I am very familiar with it. This is going to be an expensive radio when it's done. I went by Harbor Freight and bought a router and router blade kit and extra saber saw blades. If the weather holds up, tomorrow I will begin to design and then build the cabinet. For me it will be a lot bigger challenge than the chassis was.

[mikethedruid]

Last night I got to playing with my Crosley 716 again. I noticed that the tone control did not seem to have any effect. The on/off switch worked on it, but the tone did not vary when you turned the control through its range. Here is the schematic...
[Image: https://64.media.tumblr.com/d449a54cc586...35ee42.jpg]
Part 44Z is supposed to be 100K ohms. It is supposed to have a .1mfd condenser, part 17, in series with it. What I found was a pot, 478K ohms, with an OPEN WIPER ! It is a long shaft pot. I looked at the usual sources on line, and could find short shaft, splined shaft pots, but not what I actually needed. Fortunately I had an old Olympic junk chassis hanging around. I had already scavenged parts from it to restore an Olympic a couple of years ago. It had a 500K audio taper pot with switch. The shaft is longer than I need, but I can cut it. I installed the replacement, and added another condenser in parallel with the .1mfd up to .147mfd. The tone control works OK now. I have to cut the shaft still, and being an audio taper pot, all the adjustment is down at one end, but it works. I guess the original was a linear taper pot. I have one on order, I just hope the shaft is long enough. If not, I'll just leave the one I have in there now.

[mikethedruid]

Today I thoroughly checked out the original tone pot. Between the two end terminals there was ZERO conductivity ! Open ! Infinite ohms. And between the wiper and either terminal, no matter the position, there was also infinite ohms. I took the thing apart, just to see if thorough cleaning within would help, but no. There was continuity from the wiper terminal down to the wiper, but it was as if all the resistive material on the wiped surface was GONE, from either terminal to anywhere on the surface was infinite ohms. Even trying on the actual resistive surface from one point to another was infinite ohms. Very strange. I've never encountered a potentiometer which has failed in this way, this completely.

[mikethedruid]

I'd been thinking about the replacement pot I used, which is audio taper. I wondered if I changed the wire going to P2 of the 6N6 and the speaker transformer from one end of the pot to the other would improve the control, since it would shift the control to the more gradually increasing end of the pot. I tried this today, and the pot works a treat now, so I cut the shaft to length and that concludes the work on the chassis. It has been raining here off and on for the past few days, so my cabinet work is on hold. It poured last night and this morning here. With all the rain we have had the past few days my grass has grown a LOT, and I really should get out and mow the next good day, before I think about building radio cabinets. Always something to do when you have a little farm.

[mikethedruid]

Yesterday was beautiful, so I mowed the lawn around my house and in my orchard, and across the highway at my well house. Today was equally nice so I began the cabinet work. I got most of the pieces cut, still have some to do, those which will best be measured during the actual assembly. If it's nice tomorrow I will continue.

[mikethedruid]

The weather has been nice over the past few days. I finished all the woodwork on the new cabinet. It doesn't look half bad for being made by someone who does not claim to be a cabinet maker at all, just a humble wood butcher. Yesterday I sprayed the inside of the upper, chassis, area with black paint, as well as the front of the lower speaker section in a small area around the speaker hole. Today I used a wet rag and rubbed it all over to raise the grain. I let the cabinet sit for a few hours until it was well dried, and then sanded the whole exterior until it was very smooth, first with 150 grit, and then with 320 grit paper. I then used a tack cloth to remove any traces of sawdust, and then went over it with Minwax "Provincial" spray stain. When I was done it looked pretty good. I am letting it sit now. Tomorrow will begin the rubbing on of layers of tung oil finish, and then sanding with 1000 grit between the last few layers. It represents too much work to use a spray poly finish. Meanwhile I am awaiting the arrival of the grill cloth I have ordered for it.

[mikethedruid]

The Crosley 716 is DONE. It is in the new cabinet, and working. I am listening to it on AM right now. The interference from the power lines is pretty bad right now in the daytime. Tonight, after about 7 PM it will settle down as the load on the lines decreases. Also, at that hour skip reception begins. Despite the interference, with the radio working on my outside antenna I was able to pick up WWV at 5 MC and 10 MC very clearly, as well as several other shortwave stations. Here are pictures of what the radio looks like with the new, custom child sized console cabiner.



[Image: https://64.media.tumblr.com/39e553e9caf9...e22d2b.jpg]



[Image: https://64.media.tumblr.com/a88f1dbab724...20d579.jpg]



[Image: https://64.media.tumblr.com/83f1ee6018c4...7b8fd6.jpg]



I also made a custom label to go inside the custom cabinet using Lotus Word Pro....


[Image: https://64.media.tumblr.com/241b793d9400...c5a319.jpg]

[mikethedruid]

And, the video, for those who would like to hear it playing...

[Video: https://www.youtube.com/watch?v=xOeMvJICqfs]

[Paul Philco322]

Very interesting, either a little console or big table radio. Like it Mike.


PAul

[Eliot Ness]

Nice save Mike