RCA 9-X-571 beginner project

[Ncotham]

Hello everyone. As some of you may know, I've recently acquired an Admiral C2226Z television to restore and it was suggested that I try my hand at an old radio first before tackling the TV. I got hold of this RCA 9-X-571 from the same people that had the TV - they asked if I wanted the radio as well as the TV and I said sure. I have a few general questions right off the bat that I'm hoping someone can answer.

It was not working and right off the bat I saw that the power cord insulation was crumbling to pieces and bare wire was exposed along its length. I replaced that with a new power cord first thing. Next came the dreaded power on test, which in fact was not so bad thanks to Phil Nelson's documentation on how to construct a dim bulb tester. Many thanks, Phil! You can see mine in the photo. It worked flawlessly and dimmed properly as the radio warmed up, a good sign.

When I plugged the radio in, it worked! At first I thought not very well, because it would only pick up a few stations. I never listen to AM, so I went out to my pickup and set the radio to AM, and to my surprise, only a few AM stations was all I could get. Is AM dying a slow death in the wake of FM and satellite radio? Just curious.

Now, a question about the schematic - can anyone tell me what the circled and apparently detached circuit is? Is it there to simply illustrate the two types of grounds, chassis and common?

Lastly, I think I may have screwed something up up already. In the repair documentation discussion on dial calibration, it states that with the tuning condenser fully meshed, the dial pointer should be set to the first score mark at the far left hand side of the dial backplate. The four score marks represent max cap on the far left, 600 kc, 1400 kc and finally min cap on the last mark on the far right.

I got to looking at the dial and the pointer would only go to about the 600 kc mark on the left instead of mac cap mark further to the left when the tuner was fully meshed. I figured that was wrong and set about the task of getting the pointer in the correct place by detaching it from the dial cord and then moving it to the correct position according to the manual. Done. Then I noticed that the strongest station I received was just barely to the right of the 600 kc (does anybody really call this kilocycles any more or is the proper terminology kHz? kc is what is in the manual). That was all fine and good, except for the fact that actual frequency of the station was 790, quite a ways farther right from where the pointer was. Looks like the dial may have been right to begin with, but that doesn't jive with what the manual says?? Can anybody clear this discrepancy up for me? Can the old capacitors cause the tuner to be "off"? I've got a feeling this was a noob mistake on my part.

That's about all I have for now. Getting ready to order caps and set about that task. Seems a shame to take a chance on screwing the radio up when it's working already, but I need the practice for the TV.

Thanks!

[Ncotham]

I see now that my question regarding the schematic was pretty dense. My apologies as I haven't looked at a schematic in quite some time and it didn't register that the circuit in question wasn't "detached". It simply indicates that there is a 220 ohm resistor and a .01 mf capacitor in parallel between the common wiring and chassis ground.

Would still like to know what gives with the dial calibration, however, if anyone can answer that.

Thanks

[Winky Dink]

This is advice from another novice. My total experience is six prewar, AM radio restorations.

I would set aside the dial calibration for now and proceed with the recapping plus replacing any other defective components that you can identify. Follow the instructions that you have about "dressing" (I think that means positioning and routing) various leads and wires. Refer back to Phil's website frequently. Every time I reread a section I find something that I overlooked the first time.

Don't even plug in the radio until you're pretty sure all the components are working and wired properly. Then, when the radio seems to be working properly, tune in a known station (i.e. "This is the Big Bozo, 1150 on your AM dial") and place the pointer there. Then see if it points accurately for other station.


Finally, living near Boise, Idaho, I get good reception of only six to eight area AM stations during the daytime. I can listen to religion, religion, religion, spanish music, government conspiracy, government conspiracy, sports, or spanish music. My next project will be an FM radio.

Good Luck.

[Phil Nelson]

I suspect you have answered your own question about the dial pointer by now. It was probably close in the first place, and you may as well set it back where it was for the time being.

I would go ahead and recap the radio and see how it works. An advantage of recapping a radio that already works (at least somewhat) is that you can try it out after every cap replacement or two, to make sure you haven't gone backwards.

Bad old caps wouldn't change the dial tracking. If you want to align the radio after recapping, part of that procedure will affect tracking. Keep in mind that these simple old radios are not precision laboratory instruments, so if you get the pointer to track pretty closely through the entire scale, that's victory.

Have fun.

Phil Nelson
http://antiqueradio.org/index.html