- Finding the cmos battery - 8 Updates
- Reliablest cars - 2 Updates
| Chuck <chuck23@dejanews.net>: Jan 08 11:44AM -0600 On Thu, 07 Jan 2021 23:35:36 +0000, Cursitor Doom <cd@noreply.com> wrote: >my initial idea of using a lithium button cell in series with a diode >to prevent it being charged. > Anyone see any issues with that approach? Here is one that is genuine and exactly like the ones I used to use as a replacement. https://www.newark.com/kemet/ft0h474zf/supercapacitor-0-47f-5-5v-radial/dp/78AC5690 |
| Cursitor Doom <cd@noreply.com>: Jan 08 05:55PM On Fri, 08 Jan 2021 11:44:55 -0600, Chuck <chuck23@dejanews.net> wrote: >Here is one that is genuine and exactly like the ones I used to use as >a replacement. >https://www.newark.com/kemet/ft0h474zf/supercapacitor-0-47f-5-5v-radial/dp/78AC5690 Thanks, but you guys have avoided answering the question about replacing the supercap with a cell of whatever capacity in series with a low reverse-leakage diode. Anyone know what the likely voltage that cell would need to be? NB: when I say "whatever capacity" I refer to A, AA, AAA, C, D etc. cells. |
| "Peter W." <peterwieck33@gmail.com>: Jan 08 10:52AM -0800 There is a somewhat detailed answer to that question. a) Do you know what voltage is needed to keep the memory function in operation? b) Given that a battery is the mother of all capacitors, just a bit slower as a chemical engine, you should be able to do a proof-of-concept. c) And once you have determined the operating voltage (somewhere between 1.2 and 3.5 VDC at a guess), you will have several choices, including your diode option. BUT: Caveat: Batteries do not like seeing a dead/partial short. So when diode you install is not in use and the circuit is OFF, the battery is in parallel with whatever device is in place, whether a super-cap or a button cell, or something else. If that is shorted, so is the battery. OOPS! It really does behoove you to find the OEM source and repair/replace it as designed. You do not want to wake up one morning and find that your installed battery has spilled its guts all over everything. Remember the Revox B760 tuner? It had two AA cells under the fold-down door on top of the faceplate. Trust the Swiss to take the very simple brute-force approach. Peter Wieck Melrose Park, PA |
| Cursitor Doom <cd@noreply.com>: Jan 08 07:23PM On Fri, 8 Jan 2021 10:52:24 -0800 (PST), "Peter W." >b) Given that a battery is the mother of all capacitors, just a bit slower as a chemical engine, you should be able to do a proof-of-concept. >c) And once you have determined the operating voltage (somewhere between 1.2 and 3.5 VDC at a guess), you will have several choices, including your diode option. BUT: >Caveat: Batteries do not like seeing a dead/partial short. So when diode you install is not in use and the circuit is OFF, the battery is in parallel with whatever device is in place, whether a super-cap or a button cell, or >something else. If that is shorted, so is the battery. OOPS! It really does behoove you to find the OEM source and repair/replace it as designed. You do not want to wake up one morning and find that your installed >battery has spilled its guts all over everything. I'm grateful for your observations. I would just point out that it was never my intention to leave the original power source in situ! I'm not quite *that* stupid! >Remember the Revox B760 tuner? It had two AA cells under the fold-down door on top of the faceplate. Trust the Swiss to take the very simple brute-force approach. ical I don't know that item,I'm afraid. My experience of electronic repair is typically 95% vintage boat anchor test equipment, generally at *least* 25 years old minimum and more likely closer to 40+. Thanks again. |
| "ohg...@gmail.com" <ohger1s@gmail.com>: Jan 08 01:54PM -0800 On Friday, January 8, 2021 at 12:55:24 PM UTC-5, Cursitor Doom wrote: > replacing the supercap with a cell of whatever capacity in series with > a low reverse-leakage diode. Anyone know what the likely voltage that > cell would need to be? Generally speaking, I've found that supercaps used as memory devices are generally run *very* close to their voltage rating, so if your supercap is a 2.7V, there's a good chance there could be 2.5 volts on it. But, you don't need to make this complicated. Plug the radio in and see what the voltage is across the supercap. Most of the supercaps I've changed just go low value/high ESR and don't short. Whatever the voltage is under test, add that via cell. Since the value you need is unlikely (Murphy's Law) to be a direct value of a cell you want to add, you may have to add more than one diode to drop the voltage to or even a bit below the memory voltage. |
| Cursitor Doom <cd@noreply.com>: Jan 08 10:53PM On Fri, 8 Jan 2021 13:54:04 -0800 (PST), "ohg...@gmail.com" >Generally speaking, I've found that supercaps used as memory devices are generally run *very* close to their voltage rating, so if your supercap is a 2.7V, there's a good chance there could be 2.5 volts on it. But, you don't need to make this complicated. Plug the radio in and see what the voltage is across the supercap. Most of the supercaps I've changed just go low value/high ESR and don't short. Whatever the voltage is under test, add that via cell. Since the value you need is unlikely (Murphy's Law) to be a direct value of a cell you want to add, you may have to add more than one diode to drop the voltage to or even a bit below the memory voltage. Thanks! Just the kind of details I wanted. Must admit I hadn't thought about using diodes to 'trim' the cell(s) to the correct voltage. |
| legg <legg@nospam.magma.ca>: Jan 09 09:23AM -0500 On Thu, 07 Jan 2021 23:35:36 +0000, Cursitor Doom <cd@noreply.com> wrote: >my initial idea of using a lithium button cell in series with a diode >to prevent it being charged. > Anyone see any issues with that approach? Do you know what the original back-up source is, yet? You were just looking at it, in the last report. You should be able to do a simple repair, without a lot of useless speculation. RL |
| Fox's Mercantile <jdangus@att.net>: Jan 09 10:20AM -0600 On 1/9/21 8:23 AM, legg wrote: > You should be able to do a simple repair, without a lot > of useless speculation. > RL You forget who we're dealing with. -- "I am a river to my people." Jeff-1.0 WA6FWi http:foxsmercantile.com |
| "Peter W." <peterwieck33@gmail.com>: Jan 08 09:52AM -0800 The internet is your friend. https://www.pewforum.org/religious-landscape-study/compare/views-about-human-evolution/by/state/ https://www.forbes.com/sites/niallmccarthy/2018/01/11/the-share-of-americans-holding-a-passport-has-increased-dramatically-in-recent-years-infographic/?sh=75d31c733c16 https://www.census.gov/newsroom/press-releases/2020/educational-attainment.html https://www.forbes.com/sites/lealane/2019/05/02/percentage-of-americans-who-never-traveled-beyond-the-state-where-they-were-born-a-surprise/?sh=48f4c78c2898 https://www.wyliecomm.com/2020/11/whats-the-latest-u-s-literacy-rate/ There area many other sources - but the US Census is the most comprehensive. The key that obscures the statistics are that in some categories such as travel, trips are counted, not individuals in some counts. Example: 10% of all Americans traveled overseas for any reason in 2019. No, There were about 30,000,000 trips taken in 2019. By about 14,100,000 individuals. So, less than 5% in total. And, make sure that the count includes only Americans, not visitors. First, visitors and naturalized Americans tend to travel more, have far better educations and more languages than native-born Americans. So a population with a high level of naturalized Americans will 'look better' that one that that is mostly native-born. So, one has to read through an entire source to make sure that what is actually being counted is what is wanted to be counted. Peter Wieck Melrose Park, PA |
| three_jeeps <jjhudak@gmail.com>: Jan 08 03:19PM -0800 On Friday, January 8, 2021 at 12:52:56 PM UTC-5, Peter W. wrote: > So, one has to read through an entire source to make sure that what is actually being counted is what is wanted to be counted. > Peter Wieck > Melrose Park, PA Thank you. I found the article about literacy interesting. I didn't know how bad a shape the country is in. I also found it a little amusing that the article title uses the words Literacy Rate. Rate means 'something' per unit of time. All of the data that was presented is a sampling done at a specific point in time. They acknowledge that this sampling is done every 10 years but the data comparisons do not show increasing/decreasing values per unit of time, e.g. 10 years. e.g. they did not correlate the data over a time period. Could it be the people who are (allegedly) literate above and 8th grade level did not accurately title the article??? From my perspective, the concept of rate is presented somewhere between 7-9th grade science classes and definitely in a high school physics class. Then again, I believe HS physics in today's HS is (still) an elective, and many ppl don't take it because it is 'too hard'..... The graph at the end that compares literacy competence by country make me wonder how the data was normalized to arrive at the generalized literacy score? Is there some standard somewhere that says this document (in any language) is the basis for assessing reading comprehension? Well, I guess that is more of an OT thread and subject to some google searches. Thanks J |
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