- What can I buy at Walmart for dial string? - 9 Updates
- Radial X2-AC Safety Capacitors (Question) - 15 Updates
- Dial Stringing - 101 - 1 Update
| oldschool@tubes.com: Aug 24 12:35PM -0400 >Dental floss? >I've salvaged the string (plus knobs, ICs and IF resonators and >coils)from loads of basic tuners over the years, before dumping the rest I salvage a lot of parts too, but dial string is NOT one of them. That stuff just gets weak from age, and it's not (should not be) a high priced item. Considering the amount of tedious work involved in replacing them, I want NEW string, because that's one job I dont want to do twice. Back when brick and mortar electronic parts stores still existed, I could buy a spool of this stuff (made exclusively for dial strings) for a couple bucks. But these days the stuff seems hard to find, and is over priced. The dental floss was discussed and I wont be using it. Fishing line seems to be the most recommended. I was also wondering if the thick thread made for sewing canvas and furniture would work too? (Having done some sewing on canvas tents, I know this stuff is strong, easy to get, and cheap to buy). |
| oldschool@tubes.com: Aug 24 12:38PM -0400 On Tue, 22 Aug 2017 11:56:24 -0700 (PDT), dansabrservices@yahoo.com wrote: >> Thanks >I have an entire spool of the stuff. how much do you need? >Dan I probably only need 6 or 7 feet for the two radios I presently need to restring, but I'd like to get at least 25 ft. because I know there will soon be another antique radio needing a new dial string. (And antique radios are mostly all I work on). |
| oldschool@tubes.com: Aug 24 12:42PM -0400 On Wed, 23 Aug 2017 11:28:20 +1000, Trevor Wilson >Yes, I am in Australia. I cannot believe that it is unavailable in other >places. >https://www.wagneronline.com.au/dial-cord/ps/ Seems that Australia is the place to get dial string. Not sure why..... Everything else comes from China these days. But from what I saw on ebay, I am not willing to pay the shipping from Australia.... And considering that this is just string, I dont see any reason to import it. It's just string (or thread). I'll look to get suitable fishing line. |
| oldschool@tubes.com: Aug 24 12:49PM -0400 On Wed, 23 Aug 2017 05:03:22 -0700 (PDT), "pfjw@aol.com" <pfjw@aol.com> wrote: >Note that there is considerable flexibility in actual use anyway. >Peter Wieck >Melrose Park, PA That sounds good..... I had to google "Dacron" to see what it is: It's a synthetic polyester (polyethylene terephthalate) with tough, elastic properties, used as a textile fabric. I wonder how critical the gauge is? I'm sure that thicker is better as far as having a longer life. So, if I buy a spool of something fairly thick wont it work for all radios? |
| "malua mada!" <fritzo2ster@gmail.com>: Aug 24 10:53AM -0700 Consider the string that is used to close feed sacks. It is very strong . |
| N_Cook <diverse@tcp.co.uk>: Aug 24 07:21PM +0100 > thread made for sewing canvas and furniture would work too? (Having done > some sewing on canvas tents, I know this stuff is strong, easy to get, > and cheap to buy). The main point about dial stringing , is that it is prestretched. Anything else , other than monofilament, floss or thread ,you need to break some to find its UTS and then stretch a long length of it to a bit less force than the UTS |
| rickman <gnuarm@gmail.com>: Aug 24 02:22PM -0400 > But from what I saw on ebay, I am not willing to pay the shipping from > Australia.... And considering that this is just string, I dont see any > reason to import it. It's just string (or thread). You can't afford $1.58? For $6 you can have 33 feet of 30 mil dial cord delivered to your door. I wouldn't drive to the store for this when it is delivered so cheaply. You will have to buy a lot more fishing line and spend a lot more money. You seem to have a habit of running into a small obstacle and seeing it as a mountain. There is very affordable dial cord available from many sources, so there is no reason to not buy the "right" stuff. If there is nothing wrong with the radio tuning mechanism that is wearing the cord abnormally a properly done restringing will last longer then you do. Why muck around with a substitute when you can get the real stuff so easily (or would it be "reel" stuff)? BTW, here is a tip when searching ebay. When they present the search results you can sort on "Price + shipping: lowest first". This will include the cost of shipping and show you the lowest priced items first. Then you just won't see the vendors who are trying to rip you off on shipping hoping you won't notice. -- Rick C Viewed the eclipse at Wintercrest Farms, on the centerline of totality since 1998 |
| Trevor Wilson <trevor@SPAMBLOCKrageaudio.com.au>: Aug 25 06:18AM +1000 > Australia.... And considering that this is just string, I dont see any > reason to import it. It's just string (or thread). > I'll look to get suitable fishing line. **You've got to be kidding! I just offered to send you some for free! You pay for postage. Can't be more than a couple of Bucks. A couple of Metres will fit in a standard envelope. I wasn't planning on sending a whole spool of the stuff. Stop nickel and diming the thing. Either buy the right stuff to do the job or accept my offer. BTW: My dial cord is made in Taiwan, not China. -- Trevor Wilson www.rageaudio.com.au |
| Ralph Mowery <rmowery28146@earthlink.net>: Aug 24 06:07PM -0400 In article <f08qkkFllqgU2@mid.individual.net>, trevor@SPAMBLOCKrageaudio.com.au says... > whole spool of the stuff. Stop nickel and diming the thing. Either buy > the right stuff to do the job or accept my offer. BTW: My dial cord is > made in Taiwan, not China. He is really tight. This might even be the same cord. $ 5.62 for 10 meters including that high price of about a buck and a half for shipping. http://www.ebay.com/itm/DIAL-CORD-0-8-mm-synthetic-cord-10-metres-to- suit-radios/222592615826?_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao% 3D2%26asc%3D41376%26meid%3Dca3db13179c64681aa64f94629564bb7%26pid% 3D100005%26rk%3D5%26rkt%3D6%26sd%3D391772693645 &_trksid=p2047675.c100005.m1851 eBay item number:22259261582 |
| oldschool@tubes.com: Aug 24 12:19PM -0400 I want to replace the original capacitor which is located across the AC power line in a Zenith Trans Oceanic (tube radio). The original cap is a .047 at 600V (standard capacitor). I was told that these days, standard caps are no longer used across the AC power line. Instead, they use these Radial X2-AC Safety Capacitors. What I'm finding is that these caps are available, but I am not finding any of them rated at 600V. All I can find are rated at 250 or 275VAC, and I did find some .1uf on ebay for 300VAC. Sal's Capacitors http://www.tuberadios.com/capacitors has a .047uf at 275VAC on their webpage. One rule I never violate is the voltage rating of parts. I'll go OVER but never UNDER the original voltage rating. However, the old caps were rated at DC voltages, whereas these Safety Caps are rated at AC voltages. I would think that 275V is sufficient to use across a 120V AC power line (which is what they are made for). Therefore, is is safe to use these to replace the original cap, since I can not find any rated at 600V? I know this will not be the first radio needing a replacement cap across the power line, so if I order one of these caps, I'd rather order several so I have them on hand. That leads me to a second question: How critical is the uf rating on these line caps? In other words, if I use a .1uf instead of a .047uf, will that cause any problems, or is the .1uf offering more protection against power line spikes? Thanks |
| John-Del <ohger1s@gmail.com>: Aug 24 10:38AM -0700 Across the line use a type X cap, and 250V is fine. You could (should) add a fuse in between the cap and the line for an extra margin of safety. |
| rickman <gnuarm@gmail.com>: Aug 24 01:53PM -0400 John-Del wrote on 8/24/2017 1:38 PM: > Across the line use a type X cap, and 250V is fine. You could (should) add a fuse in between the cap and the line for an extra margin of safety. I thought the X and Y capacitors were used when a short would be a safety problem as in a shock hazard. Why would there be a shock hazard if a cap across the power line shorts? If you use a fuse any concern about a fire is eliminated. Then why would you need the X cap? -- Rick C Viewed the eclipse at Wintercrest Farms, on the centerline of totality since 1998 |
| tabbypurr@gmail.com: Aug 24 11:22AM -0700 > use a .1uf instead of a .047uf, will that cause any problems, or is the > .1uf offering more protection against power line spikes? > Thanks 275v ac X-rated is safer than a vanilla 600v DC type. NT |
| tabbypurr@gmail.com: Aug 24 11:22AM -0700 On Thursday, 24 August 2017 18:53:09 UTC+1, rickman wrote: > problem as in a shock hazard. Why would there be a shock hazard if a cap > across the power line shorts? If you use a fuse any concern about a fire is > eliminated. Then why would you need the X cap? Y is for shock risk, X is for fire risk only. NT |
| John-Del <ohger1s@gmail.com>: Aug 24 11:31AM -0700 On Thursday, August 24, 2017 at 1:53:09 PM UTC-4, rickman wrote: > Rick C > Viewed the eclipse at Wintercrest Farms, > on the centerline of totality since 1998 I agree with you, but the company line says to use X caps across the line.. These vintage radios rarely were equipped with fuses and generally used standard caps across the line. In all my years in consumer electronics I only saw a few of them short (spectacularly) and they were in RCA tube TVs in the 60s. They all made a bloody mess under the chassis but none caused fires. RCA issued a recall that included new ceramic tubular caps and we changed them whenever we serviced these chassis. I've replaced some in my own radios with mylar caps but always fused them. Nowadays I've got tons of late model power supplies that are donors for all kinds of parts, X and Y caps included. |
| rickman <gnuarm@gmail.com>: Aug 24 02:37PM -0400 >> across the power line shorts? If you use a fuse any concern about a fire is >> eliminated. Then why would you need the X cap? > Y is for shock risk, X is for fire risk only. Ok, I stand corrected. But the question remains. Fuse and X cap is like wearing a belt and suspenders. -- Rick C Viewed the eclipse at Wintercrest Farms, on the centerline of totality since 1998 |
| dplatt@coop.radagast.org (Dave Platt): Aug 24 11:32AM -0700 >problem as in a shock hazard. Why would there be a shock hazard if a cap >across the power line shorts? If you use a fuse any concern about a fire is >eliminated. Then why would you need the X cap? You can't count on a fuse to eliminate all of the risk of a fire. Some types of cap can fail with a "near short circuit" - they get leaky enough to start drawing a good fraction of an ampere, but aren't a dead-short. Imagine what happens if such a cap is "protected" by a 1-ampere fuse, but is drawing 100 mA at 120 volts... that's more than 10 watts, heating up the capacitor. If the cap doesn't either short itself well enough to blow the fuse, or go "open", it can definitely heat up enough to smoke and burn. I've seen this happen... a non-X/Y-rated film cap was used "across the line", and it overheated and nearly started a fire. "X" and "Y" caps are intended to be at least somewhat self-healing... if they develop a pinhole and start to short, the localized heating burns away the metallized film in the area of the short, and it opens. If I recall correctly they're also required to use an insulating resin which is at least somewhat flame-resistant. If you're going to the trouble of replacing an across-the-line cap in some equipment you're refurbishing, I'd suggest going right to a suitable "Y" cap. The additional cost is modest and the labor to install is the same. |
| rickman <gnuarm@gmail.com>: Aug 24 03:46PM -0400 Dave Platt wrote on 8/24/2017 2:32 PM: > in some equipment you're refurbishing, I'd suggest going right to a > suitable "Y" cap. The additional cost is modest and the labor to > install is the same. Ok, so there is a failure mode where the cap won't draw enough current to blow the fuse, but can locally heat up enough to smoke and burn. Isn't that true for other parts in the device? What is the purpose of this cap anyway? I assume noise filtering. Wouldn't that be just as effective on the secondary of the transformer? -- Rick C Viewed the eclipse at Wintercrest Farms, on the centerline of totality since 1998 |
| John-Del <ohger1s@gmail.com>: Aug 24 01:05PM -0700 On Thursday, August 24, 2017 at 3:46:15 PM UTC-4, rickman wrote: > Ok, so there is a failure mode where the cap won't draw enough current to > blow the fuse, but can locally heat up enough to smoke and burn. Isn't that > true for other parts in the device? It's a possibility, but in my opinion it's highly unlikely for that to happen. A line capacitor that becomes leaky *and* with at least 20 amps of source current available to it will avalanche as it builds heat and short hard - in any case pulling more current than the small fuse installed in front of it. |
| "pfjw@aol.com" <pfjw@aol.com>: Aug 24 01:29PM -0700 |
| "pfjw@aol.com" <pfjw@aol.com>: Aug 24 01:33PM -0700 X & Y caps are designed to reduce the risk of shock in one case, and fire in another. Eschewing needless complexity, let them do their jobs and install a fuse - if desired - to cover then entire appliance, designed specifically for the load involved, starting surge and so forth. Peter Wieck Melrose Park, PA |
| tabbypurr@gmail.com: Aug 24 02:58PM -0700 On Thursday, 24 August 2017 19:37:11 UTC+1, rickman wrote: > > Y is for shock risk, X is for fire risk only. > Ok, I stand corrected. But the question remains. Fuse and X cap is like > wearing a belt and suspenders. You need belt & suspenders since both fail. Just don't put the pics online. :) NT |
| tabbypurr@gmail.com: Aug 24 03:00PM -0700 On Thursday, 24 August 2017 20:08:08 UTC+1, Dave Platt wrote: > in some equipment you're refurbishing, I'd suggest going right to a > suitable "Y" cap. The additional cost is modest and the labor to > install is the same. All my Y caps are of far lower values than the Xs. Ys are intended to be for line to chassis use, hence far lower values than used for X caps. NT |
| tabbypurr@gmail.com: Aug 24 03:03PM -0700 > X & Y caps are designed to reduce the risk of shock in one case, and fire in another. Eschewing needless complexity, let them do their jobs and install a fuse - if desired - to cover then entire appliance, designed specifically for the load involved, starting surge and so forth. > Peter Wieck > Melrose Park, PA Fires & shocks used to happen due to dc rated cap failure. Hence X&Y were developed. Old radios lacking any fusing don't meet modern safety standards. The mains plug or distribution unit fuse can't be relied on to always provide satisfactory cover. You can repair them as is or can add a fuse, the latter is safer of course. NT |
| "pfjw@aol.com" <pfjw@aol.com>: Aug 24 12:09PM -0700 Back in the day, dial cord was mostly made from 'natural' fibers of one sort or another. Natural fibers age out and decay. So, now anywhere to around 90 years later, lots-O-dial cords are failing. Today, there are those who impart magical properties to dial cord. In the words of Gershwin, it ain't necessarily so. All it needs be is a cord that has reasonable friction properties and can take reasonable tension and is reasonably resistant to abrasion, while not being abrasive on its own. Braided Dacron fishing line, gauge-for-gauge is vastly stronger than any 'original' dial cord as was ever made, and will stretch less. It is cheap as hell relative to the amount purchased as there is nothing magical about it as (we all know) there is with true dial cord. Perhaps that lack of magic makes some resistant to the idea of it. Back in the day, one of the issues with dial-cord was taking knots. Lots-O-accommodations were created to handle this, including neat little brass eyelets that were folded over the ends as hold-opens and knot-makers. Dacron fishing line takes very good knots and those knots tend not to fail. But, a toothpick with a dab of Cyano-Acrylate glue (AKA "Super Glue") will eliminate the possibility in any case. And jewelers' crimps: https://media1.riogrande.com/Products/Images/Large/630193.jpg https://img0.etsystatic.com/021/0/6489112/il_570xN.479884104_gprb.jpg Will eliminate the need for knots altogether. Even if you purchase them in silver-plate, at 20 for $3, they are still cheap. Springs are available from any ball-point pen, as well as from McMaster-Carr, an old-fashioned hardware store and many more sources. https://www.mcmaster.com/#extension-springs/=192zprq Given that one has all sorts of good stuff available for-cheap that save steps and trouble, some other factors now come into play: Diameter: Generally, I try to use the largest diameter practical that does not hang up or interfere with other parts. Why? More bearing surface on the sheaves and shaft(s), so better grip with less tension and less abrasion. For complex stringing endeavors, some even with two loops, one still has the option of increasing tension if needed. The idea is to stretch the spring to about 50%-60% of capacity and let it absorb the stretch over time. Knots: Crimps are good. A curved suture needle is useful if one is rigidly old-school. Small hemostats do a great job of holding tension or acting as a third-hand where needed. Eyelet/grommets: Note that some of the crimps have eyelets built in. And those are only two of many styles. Anyone near a moderate city with a Jewelers' Row - look for a "Findings" company and you will see all this stuff on-the-hoof. Sam's Dial String Guide - from the 1920s into the 1990s, it's all there. So, for less than $15, one may have: 200+ feet/70+ meters of appropriate stringing material. Two or three small hemostats A variety of curved needles A variety of jewelers' crimps A variety of springs Again, there ain't no magic to it. Oh, and about those eyelets? https://www.etsy.com/listing/533505429/18-inch-eyelets-gold-color-100pk?ref=related-2 $15 over the course of many radios and other things with dials is picayune. Peter Wieck |
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