I have an old portable CD player, still works. Runs on 2 AA batteries. The other day, a CD was skipping, on the third track. I tolerated it for a minute, then forwarded. Other tracks also damaged. The battery charge indicator read zero. Dead battery or smushy disc? I pop in another CD, works fine. Try the bad CD again, same symptoms repeated. How does a dodgy disc muck the battery charge sensing circuit? Sherlock Holmes, paging Detective Holmes, please report to sci.elect.design - -- Rich
explain this
Started by ●January 28, 2023
Reply by ●January 28, 20232023-01-28
On Saturday, January 28, 2023 at 8:55:01 PM UTC-4, RichD wrote:> I have an old portable CD player, still works. > Runs on 2 AA batteries. > > The other day, a CD was skipping, on the third > track. I tolerated it for a minute, then forwarded. > Other tracks also damaged. > > The battery charge indicator read zero. Dead > battery or smushy disc? I pop in another CD, works > fine. Try the bad CD again, same symptoms repeated. > > How does a dodgy disc muck the battery charge > sensing circuit? > > Sherlock Holmes, paging Detective Holmes, please > report to sci.elect.design -Did you try changing the batteries? Is it possible that one disc has something on it that takes more current than the other discs? Check the batteries. -- Rick C. - Get 1,000 miles of free Supercharging - Tesla referral code - https://ts.la/richard11209
Reply by ●January 29, 20232023-01-29
On a sunny day (Sat, 28 Jan 2023 16:54:57 -0800 (PST)) it happened RichD <r_delaney2001@yahoo.com> wrote in <dcd6f2e6-9443-4c32-bfe2-7cb97a28437bn@googlegroups.com>:>I have an old portable CD player, still works. >Runs on 2 AA batteries. > >The other day, a CD was skipping, on the third >track. I tolerated it for a minute, then forwarded. >Other tracks also damaged. >The battery charge indicator read zero. Dead >battery or smushy disc? I pop in another CD, works >fine. Try the bad CD again, same symptoms repeated.So check CD for finger prints and dirt, clean with dishwash detergent and lots of water and use tissue paper to whipe it clean. That is what I do, If still bad .. try a better CD reader. My LG Mdisc reader (in a PC) is good at reading stuff it seems.>How does a dodgy disc muck the battery charge >sensing circuit?Motor speed control variations trying to re-read the same sectors?
Reply by ●January 29, 20232023-01-29
On 29/01/2023 00:54, RichD wrote:> I have an old portable CD player, still works. > Runs on 2 AA batteries. > > The other day, a CD was skipping, on the third > track. I tolerated it for a minute, then forwarded. > Other tracks also damaged. > > The battery charge indicator read zero. Dead > battery or smushy disc? I pop in another CD, works > fine. Try the bad CD again, same symptoms repeated. > > How does a dodgy disc muck the battery charge > sensing circuit?It doesn't. It makes the tracking servo work a lot harder drawing much more current from the poor unfortunate "on their last legs" batteries. In normal tracking it barely has to do much except constant velocity movement with a slight wobble to handle any eccentricity of the mount but with a scratched disk then all bets are off.> Sherlock Holmes, paging Detective Holmes, please > report to sci.elect.design --- Martin Brown
Reply by ●January 29, 20232023-01-29
Jan Panteltje wrote:> RichD wrote: > >>I have an old portable CD player, still works. >>Runs on 2 AA batteries. >> >>The other day, a CD was skipping, on the third >>track. I tolerated it for a minute, then forwarded. >>Other tracks also damaged. >>The battery charge indicator read zero. Dead >>battery or smushy disc? I pop in another CD, works >>fine. Try the bad CD again, same symptoms repeated. > > So check CD for finger prints and dirt, > clean with dishwash detergent and lots of water > and use tissue paper to whipe it clean. > That is what I do, > > If still bad .. try a better CD reader. > My LG Mdisc reader (in a PC) is good at reading stuff it seems.You may want to limit yourself to lens tissue. I personally always use a soft cloth on all things optical - even plastic - to avoid minuscule wood scratches from paper products. Sometimes a simply different, and not necessarily better, CD reader works for me. I surmise a different readers's optical alignment varies slightly (while within tolerances) to track a random scratched CD more optimally. Danke, -- Don, KB7RPU, https://www.qsl.net/kb7rpu There was a young lady named Bright Whose speed was far faster than light; She set out one day In a relative way And returned on the previous night.
Reply by ●January 29, 20232023-01-29
On 1/29/2023 8:52 AM, Don wrote:> You may want to limit yourself to lens tissue. I personally always use a > soft cloth on all things optical - even plastic - to avoid minuscule > wood scratches from paper products. > Sometimes a simply different, and not necessarily better, CD reader > works for me. I surmise a different readers's optical alignment varies > slightly (while within tolerances) to track a random scratched CD more > optimally.Rip the original and put it away. (All of my music collection originals reside in a set of boxes hiding under a bed; DVD originals on spindles tucked in a clost) Use the ripped (ISO on spinning rust or a real optical medium) "copy" until *it* becomes unreadable. I've noticed the local library has started doing this with purchased materials -- even including the "dust jackets" (print a new copy when the circulating copy gets lost or tattered)
Reply by ●January 29, 20232023-01-29
On a sunny day (Sun, 29 Jan 2023 09:32:40 -0700) it happened Don Y <blockedofcourse@foo.invalid> wrote in <tr6739$2r7um$1@dont-email.me>:>On 1/29/2023 8:52 AM, Don wrote: >> You may want to limit yourself to lens tissue. I personally always use a >> soft cloth on all things optical - even plastic - to avoid minuscule >> wood scratches from paper products. >> Sometimes a simply different, and not necessarily better, CD reader >> works for me. I surmise a different readers's optical alignment varies >> slightly (while within tolerances) to track a random scratched CD more >> optimally. > >Rip the original and put it away. (All of my music collection originals >reside in a set of boxes hiding under a bed; DVD originals on spindles >tucked in a clost) > >Use the ripped (ISO on spinning rust or a real optical medium) "copy" until >*it* becomes unreadable.A good light proof CD box helps: http://panteltje.com/pub/CD_box_IXIMG_0547.JPG http://panteltje.com/pub/CD_box_binnenkant_IXIMG_0549.JPG Is full now, 1000 CDs.. CD-R.. CD-RW .. Bluray Disks are numbered from 1 to 1000 There is one big text file that has an entry for each one, what it contains, how it was made and how to read it, for example: 927 BD-R-25 Platinum 4x inkjet printable LG BH10LS38 ext2 filesystem Raspberry debian 8 GB SDcard image with librtlsdr, xforms, fftw3, xpsa, dump1090 Risc OS image Original debian image Method: dd if=/dev/zero bs=1000000000 count=25 > bluray.iso mke2fs bluray.iso mount -o loop=/dev/loop0 bluray.iso /mnt/loop cp ... /mnt/loop/ # stay below about 22.3 GB du /mnt/loop umount /dev/loop0 growisofs -speed=4 -dvd-compat -Z /dev/dvd=bluray.iso # l /mnt/loop total 13882600 drwx------ 2 root root 16384 Feb 2 17:55 lost+found/ -rw-r--r-- 1 root root 1939865600 Feb 9 04:44 2013-02-09-wheezy-raspbian.img -rw-r--r-- 1 root root 159063 Mar 6 13:56 Raspberry-Pi-R2.0-Schematics-Issue2.2_027.pdf -rw-r--r-- 1 root root 109401 Mar 6 13:59 RPi_Low-level_peripherals.html drwxr-xr-x 2 root root 4096 Mar 6 13:59 RPi_Low-level_peripherals_files/ -rw-r--r-- 1 root root 229735 Mar 6 14:01 bcm2835-1.22.tar.gz -rw-r--r-- 1 root root 102683388 Mar 8 15:27 riscos-2012-11-01-RC6.zip -rw-r--r-- 1 root root 42 Mar 8 15:30 sha1sum_riscos-2012-11-01-RC6.zip.txt -rw-r--r-- 1 root root 42 Mar 10 13:26 sha1_sum_rasbian_zip -rw-r--r-- 1 root root 41 Mar 10 13:41 sha1sum_2013-02-09-wheezy-raspbian.img.txt -rw-r--r-- 1 root root 1590 Mar 10 16:17 how_to_raspberry.txt~ -rw-r--r-- 1 root root 1590 Mar 10 16:17 how_to_raspberry.txt -rw-r--r-- 1 root root 8193572864 Mar 10 17:16 raspberry_with_rtlsdr_xpsa.img -rw-r--r-- 1 root root 3965190144 Mar 10 17:36 media_4GB_sdcard.img -rw-r--r-- 1 root root 41 Mar 10 17:38 sha1sum_raspberry_with_rtlsdr_xpsa.img.txt -rw-r--r-- 1 root root 41 Mar 10 17:39 sha1sum_media_4GB_sdcard.img So basically in that case I just make an empty file of the right size, put a filesystem on that file, copy all stuff I want to keep to that file and use it as image that I then burn to the disk. mount -o loop can then load the disk and you have a directory with all your stuff Linux of course Sometimes I just write stuff as image... movies too. 94 Nashua slimline 4x DVD+RW MASTER SOURCE as image Use tar -zxvf /dev/dvd in /video to unpack Very long list of what is in the tgz follows this entry ... ... Everything in UNIX is a file after all, There is more.... So far data retention is impeccable, main way to keep the written disks: Keep It In The Dark. It is the same thing as with old film camera and exposure time * light intensity does it. If you leave your burned disk on the bookshelf in the sun you get data errors after 2 hours, Tried that Keep it in the dark and > 20 years is no problem.>I've noticed the local library has started doing this with purchased >materials -- even including the "dust jackets" (print a new copy >when the circulating copy gets lost or tattered) > > >
Reply by ●January 29, 20232023-01-29
On 30/01/23 02:52, Don wrote:> Jan Panteltje wrote: >> RichD wrote: >>> I have an old portable CD player, still works. >>> Runs on 2 AA batteries. >>> >>> The other day, a CD was skipping, on the third >>> track. I tolerated it for a minute, then forwarded. >>> Other tracks also damaged. >>> The battery charge indicator read zero. Dead >>> battery or smushy disc? I pop in another CD, works >>> fine. Try the bad CD again, same symptoms repeated. >> >> So check CD for finger prints and dirt, >> clean with dishwash detergent and lots of water >> and use tissue paper to whipe it clean. >> That is what I do, >> >> If still bad .. try a better CD reader. >> My LG Mdisc reader (in a PC) is good at reading stuff it seems. > > You may want to limit yourself to lens tissue. I personally always use a > soft cloth on all things optical - even plastic - to avoid minuscule > wood scratches from paper products.Exactly; wood products (even the softest of tissues) contain silica particles that will scratch any glass. Enough repetitions of sub-wavelength scratches eventually produces visible artefacts. Clifford Heath
Reply by ●January 30, 20232023-01-30
On a sunny day (Mon, 30 Jan 2023 10:28:42 +1100) it happened Clifford Heath <no.spam@please.net> wrote in <173eeb638870abde$1$2212660$9aa1ccb1@news.thecubenet.com>:>On 30/01/23 02:52, Don wrote: >> Jan Panteltje wrote: >>> RichD wrote: >>>> I have an old portable CD player, still works. >>>> Runs on 2 AA batteries. >>>> >>>> The other day, a CD was skipping, on the third >>>> track. I tolerated it for a minute, then forwarded. >>>> Other tracks also damaged. >>>> The battery charge indicator read zero. Dead >>>> battery or smushy disc? I pop in another CD, works >>>> fine. Try the bad CD again, same symptoms repeated. >>> >>> So check CD for finger prints and dirt, >>> clean with dishwash detergent and lots of water >>> and use tissue paper to whipe it clean. >>> That is what I do, >>> >>> If still bad .. try a better CD reader. >>> My LG Mdisc reader (in a PC) is good at reading stuff it seems. >> >> You may want to limit yourself to lens tissue. I personally always use a >> soft cloth on all things optical - even plastic - to avoid minuscule >> wood scratches from paper products. >Exactly; wood products (even the softest of tissues) contain silica >particles that will scratch any glass. Enough repetitions of >sub-wavelength scratches eventually produces visible artefacts.Nope Using the same soft cloth over and over again accumulates dirt and particles on it, exactly what you do not want. Simple tissiue paper you throw away (I hope ;-) ) after use, and take a clean one for the next job. How often do you clean your CDs etc? once clean keep fingers of it. I use this method to clean my reading glasses too, using warm water, that removes any fat etc. Never noticed a problem, always very clean. If you have a lens with expensive coating maybe not. But OTOH my Xiaomi smartphone's 48 megapixel camera still gives very good pictures without me ever having cleaned the lens, My Canon camera lens I have never cleaned I think, have taken it 100% apart though once to fix something. Webcams, never needed cleaning, security cams neither.. CDs etc fingerprints mostly.
Reply by ●January 30, 20232023-01-30
Jan Panteltje wrote:> Clifford Heath wrote: >> Don wrote: >>> Jan Panteltje wrote: >>>> RichD wrote: >>>>> I have an old portable CD player, still works. >>>>> Runs on 2 AA batteries. >>>>> >>>>> The other day, a CD was skipping, on the third >>>>> track. I tolerated it for a minute, then forwarded. >>>>> Other tracks also damaged. >>>>> The battery charge indicator read zero. Dead >>>>> battery or smushy disc? I pop in another CD, works >>>>> fine. Try the bad CD again, same symptoms repeated. >>>> >>>> So check CD for finger prints and dirt, >>>> clean with dishwash detergent and lots of water >>>> and use tissue paper to whipe it clean. >>>> That is what I do, >>>> >>>> If still bad .. try a better CD reader. >>>> My LG Mdisc reader (in a PC) is good at reading stuff it seems. >>> >>> You may want to limit yourself to lens tissue. I personally always use a >>> soft cloth on all things optical - even plastic - to avoid minuscule >>> wood scratches from paper products. >>Exactly; wood products (even the softest of tissues) contain silica >>particles that will scratch any glass. Enough repetitions of >>sub-wavelength scratches eventually produces visible artefacts. > > Nope > Using the same soft cloth over and over again accumulates dirt and particles on it, > exactly what you do not want. > Simple tissiue paper you throw away (I hope ;-) ) after use, and take a clean one > for the next job. > How often do you clean your CDs etc? once clean keep fingers of it. > I use this method to clean my reading glasses too, using warm water, > that removes any fat etc. > Never noticed a problem, always very clean. > If you have a lens with expensive coating maybe not. > But OTOH my Xiaomi smartphone's 48 megapixel camera still gives very good pictures > without me ever having cleaned the lens, > My Canon camera lens I have never cleaned I think, have taken it 100% apart though > once to fix something. > Webcams, never needed cleaning, security cams neither.. > CDs etc fingerprints mostly.I instinctively use a /freshly laundered/ cloth to clean the coating on my expensive eyeglasses and other optical surfaces. Because, as you insinuate, a dirty used cloth leaves smudges behind. Yes, it is indeed interesting how outside security cameras exposed to the weather never need to be cleaned. Nor does my old "not a Nikon" SLR Pentax camera. The "fingerprint factor," so to speak, must explain it. Anyhow, my easy-to-use phone camera seems to be pushing the old Pentax into retirement. About a decade ago one of my clients told me how patent protection for imagery used in satellites and other expensive endeavors was set to expire soon and thereby release the technology to the masses. Danke, -- Don, KB7RPU, https://www.qsl.net/kb7rpu There was a young lady named Bright Whose speed was far faster than light; She set out one day In a relative way And returned on the previous night.
