- Vintage Radio Dial Cord Replacement - 7 Updates
| Cursitor Doom <cd@notformail.com>: Jan 16 11:34PM Anyone successfully done this? If so, what's the secret? I've been f***-arsing around for 4 hours today trying to do one on a 1972 Grundig portable FM/AM radio and got nowhere. The design is most of the problem. For some reason, the drive pully is completely smooth and affords no grip to the cord whatsoever, so the thing just slips around such that the pointer only moves when it can get a bit of traction. What a f***ing joke. |
| Bob F <bobnospam@gmail.com>: Jan 16 03:57PM -0800 On 1/16/2023 3:34 PM, Cursitor Doom wrote: > affords no grip to the cord whatsoever, so the thing just slips around > such that the pointer only moves when it can get a bit of traction. > What a f***ing joke. Does it need a couple/few turns around the pulley? |
| Bob F <bobnospam@gmail.com>: Jan 16 04:10PM -0800 On 1/16/2023 3:57 PM, Bob F wrote: >> such that the pointer only moves when it can get a bit of traction. >> What a f***ing joke. > Does it need a couple/few turns around the pulley? I suppose a little bees wax rubbed on the cord could help. |
| Jeff Layman <Jeff@invalid.invalid>: Jan 17 09:46AM On 16/01/2023 23:34, Cursitor Doom wrote: > affords no grip to the cord whatsoever, so the thing just slips around > such that the pointer only moves when it can get a bit of traction. > What a f***ing joke. Have you got all the old bits from the dial cord? Is there a spring missing which might have tensioned the cord? Other than that, can you get a rubber band which fits tightly round the pulley so the cord can grip that rather than the metal? Not sure how long it would last, though, before it perished. -- Jeff |
| "Peter W." <peterwieck33@gmail.com>: Jan 17 03:57AM -0800 There are several steps in the process, starting with using the correct material. Over time, I have found that braided *DACRON* fishing line of the correct gauge is best. It comes in many gauges and you want the cheap untreated stuff - no PTFE coating, just the basics. Then, obtain a some liquid resin - such as may be found at any music store that sells violin strings and so forth. I have also found over time that suture needles (arc-shaped) make knot tying much easier. Also, thin, high-quality super-glue (Zap brand is ideal) and a wooden toothpick. Lastly, 'hand' makes a difference - so make sure that you are winding around the pully in the correct direction, or the string will bind. Useful tools - either long-nose hemostats, best with a curved nose, or some hooked dental picks What might also help: A few small springs, and a few brass eyelets. https://www.etsy.com/listing/827996181/15mm-inner-diameter-super-tiny-eyelet-in?click_key=a73c1d6da8f650f841c5d8239e7bd0a47902822a%3A827996181&click_sum=f09bd185&external=1&rec_type=ss&ref=pla_similar_listing_top-1&sts=1 https://www.amazon.com/uxcell-0-7mm-Stainless-Tension-Spring/dp/B01MRUSUK6/ref=sr_1_11?crid=1AKCE236ABGS5&keywords=small+tension+springs+with+hooks&qid=1673955666&sprefix=small+tension+springs%2Caps%2C76&sr=8-11 http://www.segalandassociates.com/Documents/Radios-Televisions/Sams_Dial_Stringing_Diagrams.pdf a) The correct string of the correct gauge - cut to the right length + about 2" (5 cm). b) Pre-stretch the string - put a weight on it (perhaps a pound/500 grams or so) overnight. c) In a perfect world, you will put an eyelet at one end - wind the string around the eyelet and compress it to hold the string. A touch of SG applied with a toothpick will reduce fraying and make the knot stronger. d) Start at the hook, tab or other attachment point on the pulley that DOES NOT have the spring on it (OK, some have two springs, and Trust the Germans for that as they never use one part when three-or-more will do) and guide the new string through the path, maintaining just enough tension that it does not slip off. Use the hemostats/dental picks to get it around tight corners. e) When you get to the actual dial shaft - the one from the knob you turn - wrap it twice around the shaft in the correct 'hand' - you will get a sense of that from the stringing diagrams attached. f) When you get back to the main pulley, and have the extra material left over, insert the spring, and apply tension until the spring stretches about 30% from its resting state. g) Mark that length on the string, and then cut it with perhaps 5mm left over (1/4") This will be to wrap the eyelet or make the knot. h) Make the knot or eyelet, and attach it to the spring - it should still be stretched approximately 30% from its resting state when finished. i) Using a soft paint-brush or Q-Tip, run a light coating of resin over the string. This will add considerable friction, but no harmful residue. Takes longer to describe than to do. Peter Wieck Melrose Park, PA |
| "ohg...@gmail.com" <ohger1s@gmail.com>: Jan 17 06:56AM -0800 On Monday, January 16, 2023 at 6:34:48 PM UTC-5, Cursitor Doom wrote: > affords no grip to the cord whatsoever, so the thing just slips around > such that the pointer only moves when it can get a bit of traction. > What a f***ing joke. Friction, friction, friction... not at the drive pulley where the dial cord grabs but everywhere else. You must eliminate all possible friction from everywhere in the tuning system. Make sure the tuner's bearings are free of hardened gunk and lubed. When disconnected, the tuner should only require a very light touch to rotate. See those little pulley's that handle the string? They absorb all the string's efforts if they're dragging (and get worse with string tension on them). If you can remove them, clean and polish the shafts and apply some graphite. If you can't remove them (some are staked on), then run some non aggressive solvent into the shaft and spin by hand until the move with no effort. With a small jeweler's screwdriver, add some graphite to the hub and tap so the graphite gets inside the pulley. Don't "poof" the graphite in as it will probably get on the pulley's surface and transfer it to the string where it might make it back to the drive pulley shaft. A lot of guys miss the dial indicator.. they're usually just folded metal that slide along the metal dial scale. Those things drag like you won't believe. Sometimes the dial might have a piece of folded fish paper inside as a bearing, but many don't. In any case, clean and polish the edge of the dial with an abrasive if need be to form a highly polished bearing surface. Rub some graphite into the area right where the dial slides along. Careful not to get graphite on the dial itself (unsightly). Before restringing, get a Q-Tip/ISO and clean the drive pulley shaft and all secondary pulleys of lube or wayward graphite. If you excise all possible friction, you'll find it will tune with no dragging, jerking, or stopping even with less turns around the drive pulley than the diagram calls for (resist the temptation of adding more turns than it calls for - it only causes windup binding). I've had people pooh-pooh this advice and end up giving me the radio to restring because they don't believe that tiny amount of friction will prevent the dial cord from grabbing. |
| "Peter W." <peterwieck33@gmail.com>: Jan 17 07:06AM -0800 > See those little pulley's that handle the string? They absorb all the string's efforts if they're dragging (and get worse with string tension on them). If you can remove them, clean and polish the shafts and apply some graphite. NEVER. EVER. GRAPHITE! |
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