Classic Hifi Care

I have two of the wooden cabinet models and one bakelite model along with a spare chassis. This is the nine-tube RC 1129 chassis. Allegedly one step up from the RC 1102 chassis found in the 1R81. This particular set came from an antique shop in Vancouver, Washington. My brother-in-law found it, bought it, then brought it to me when they came to visit for Christmas, probably at least 30 years ago. This was my first big RCA radio. This one has always had a slippy dial drive cord. Dial cord restringing is not one of my favorite jobs, so I've never messed with it. I got bored today while I am waiting for parts and decided to tear into it. It looks to me like the dial string isn't routed right. For one thing, it is way too tight. Second thing is I can hear something squeaking as I turn the tuner knob. I'm going to pull the chassis out of one of the other ones and compare the two. Something about this one doesn't look right to me. This radio doesn't appear to have ever had anything done to it, outside of a couple of tubes have been replaced. I don't see much difference in performance between this radio and the 1R81. And, yes, Chris, I have pictures. I got lazy and haven't transferred them to my computer.

Someone has kluged the dial string on this radio. It has been like that ever since I've had it. The dial works fine as you go lower on the dial, but slips when you go higher. I have lubed everything I can see to lube which certainly helped. The wheel under the dial is supposed to be timed. It has to be in a certain position so the string will pull the tuner to higher frequencies. I'm not looking forward to this project, but I have a correctly-routed dial cord on another chassis I can use for reference.

I tinkered with the dial string on this set for a bit. The string that was on there was not long enough if it is properly routed. I don't have enough on hand to do the job. I didn't realize I was so low on dial string. I took some pictures that may help for reference.

This is how the dial cord was routed on the 6-RF-9 This is the correct routing. This chassis is out of the bakelite version the 6-RF-91 There was only two turns of cord on the 6-RF-9 3 1/2 turns on the 6-RF-91 Only one end of the dial cord had tension on it. This is why the dial would pull one way, but would slip the other way. The antenna setup is somewhat different in the two cabinet styles. Date codes on the 6-RF-9 are the 4th month of 1952. The first one is the 6-RF-9.

I hate working with dial cords.

Bill

I could have had success the first time if I had enough dial cord on hand. I didn't realize my supply was so low, but then I don't remember the last time I had to restring a dial. Yeah, not my favorite job, either.

braided fish line is a substitute for official dial cord.

Chris Campbell

Thanks, Chris, that is a good idea. Maybe I can get some at Walmart. Tony wants $3 for 24' of dial cord, but they want $7.85 for shipping for orders under $150. If I can't find something more economical, this radio will have to wait until I need more items to justify shipping cost.

I've successfully used braided fish line, but avoid the teflon variety. I suspect it would be inclined toward slippage.

Violinists use rosin on the bows. The purpose is to make the bow hairs sticky on the string, catch-and-release, to make the vibrations. I'm not sure what the rosin is--looks like a tree sap, hardened. Know any violinists who might let you experiment with a touch of it on the tuning shaft where the cord is slipping?

By the way, if you've ever heard an elderly cassette tape squeal while playing, it's because of binder breakdown making it sticky so it does the catch-and-release thing. If it happens while trying to record, the physical squeal modulates the recorded audio.

Chris Campbell

Thanks for the tip about Teflon on fishing line. That makes sense. I don't know where to buy rosin. I have heard of using that on a slipping dial drive. The cord on this radio was misrouted. I need to make that right, then see what I need to do. Maybe some sandpaper used on the drive shaft might help.

Careful with the sandpaper--it'll take the plating off. Maybe alcohol to clean it?

Chris Campbell

When I ordered the caps and other supplies from Just Radios for the RCA TV project, they have a minimum order of $25 plus shipping. I ordered some shrink tubing and a hank of dial cord to make the order large enough for their minimum. Of course, I put it somewhere it wouldn't get lost, then forgot where that was. I was cleaning and looking for something else I had forgotten where I put it, when I ran across the dial cord. I reckon, so I don't lose it again, it might be best to replace the dial cord on this radio. Dial cords are not my favorite activity, so all I can do is hope for the best.....

I got the dial restrung and it works! I had another radio to use for a pattern. Something in the dial mechanism seems like it turns too hard. I took everything apart, cleaned and oiled it. SOMETHING fixed it, I have no idea what. Something I lubed is happy now and turns easier. I cleaned the function switch and the volume control while I had the chassis out. Not the worst dial cord I ever did. It actually went pretty well....

Like you, I hate doing dial cords I have no patience when it comes right down to it. It takes 6-8 times before I get it right.

Bill