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"Percival P. Cassidy" <Nobody@NotMyISP.net>: Dec 11 12:34PM -0500 > store. I had some DeWalt 12 V NiCd packs rebuilt by them for pretty > reasonable money, a couple of years ago. They have cells with tabs, > and the spot-welder to correctly join the tabs together.   I did ask at my local Batteries Plus, who told me that they don't rebuild Li-Ion battery packs. Their after-market battery packs are outrageously expensive.   > you have - for $59+tax. That listing also claims that the battery has > a 3-year warranty; is it possible that your battery is younger than > that?   The defective one is a P104, and I have no idea when I bought it. Even if it were, theoretically, in warranty, I've voided the warranty by taking it apart and peeling off the adhesive foam covering the ends of the cells; it never occurred to me that it *might* still be in warranty. It appears that Ryobi warranty service is obtained by returning items to a service center -- no indication that one can simply exchange a defective item at Home Depot.   A two-pack of the 4AH P108 packs is only $99. I don't know whether that's a year-round deal, but I did take advantage of the same deal around this time last year. I suspect that's a year-end deal, as a single P108 is the same price.   Perce

Jeff Liebermann <jeffl@cruzio.com>: Dec 11 09:59AM -0800 On Fri, 11 Dec 2015 11:13:35 -0500, "Percival P. Cassidy"   >This battery pack does have connections from every between-cells >connection to the PC board, so I am assuming that this was supposed to >be part of the balancing circuitry.   I wasn't aware of that. Progress lurches forward, usually when I'm not looking.   This might be of interest if you want to repair your battery pack: "Cell Re-balance of Ryobi One+ 18V Li-ion Battery (130501002)" <https://www.ifixit.com/Guide/Cell+Re-balance+of+Ryobi+One%2B+18V+Li-ion+Battery+%28130501002%29/13286> "Rebuilding Ryobi 18v Batteries" <http://toolboyworld.com/eBay/Ryobi_Batt_Rebuild.htm> Looks like the balancing circuitry is in the battery pack, not the charger.   >I can buy two of the 4AH packs for $99, so replacing all ten cells (five >*pairs*) in the present one would probably cost about the same for less >capacity as one new one.   <http://www.homedepot.com/p/Ryobi-18-Volt-ONE-High-Capacity-LITHIUM-Battery-2-Pack-P122/204321540> I would not trust the battery capacity (ma-hrs) as stated on the label. However the goood price and less risk of buying these is probably better than trying to rebuild a pack.     -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558

"Percival P. Cassidy" <Nobody@NotMyISP.net>: Dec 11 03:52PM -0500 On 12/11/2015 12:59 PM, Jeff Liebermann wrote:     > This might be of interest if you want to repair your battery pack: > "Cell Re-balance of Ryobi One+ 18V Li-ion Battery (130501002)" > <https://www.ifixit.com/Guide/Cell+Re-balance+of+Ryobi+One%2B+18V+Li-ion+Battery+%28130501002%29/13286>   I might try that.   > <http://toolboyworld.com/eBay/Ryobi_Batt_Rebuild.htm> > Looks like the balancing circuitry is in the battery pack, not the > charger.   He deals with minor voltage differences between cells, not the huge differences I have (mV only, from the one paralleled pair).   > I would not trust the battery capacity (ma-hrs) as stated on the > label. However the goood price and less risk of buying these is > probably better than trying to rebuild a pack.   Any less trustworthy than the alleged 2.4Ah capacity of the present one?   Perce

Jeff Liebermann <jeffl@cruzio.com>: Dec 11 01:22PM -0800 On Fri, 11 Dec 2015 15:52:58 -0500, "Percival P. Cassidy"   >Any less trustworthy than the alleged 2.4Ah capacity of the present one?   Well, I don't know if Ryobi tests their cells, where they get them, or what they're charger is doing to them. If they're like most laptop and UPS computah battery manufacturers, the prime directive is to quickly kill the batteries in order to sell the customer a replacement battery or UPS. I suppose cordless tools are much the same.   If you want the best cells, various individuals have already done the work: <http://lygte-info.dk/review/batteries2012/Common18650Summary%20UK.html> <http://www.torchythebatteryboy.com/p/18650-batteries-chargers.html> <http://www.candlepowerforums.com/vb/showthread.php?257543-LiIon-18650-battery-comparison> Also, search on candlepowerforums.com for battery tests: <http://www.candlepowerforums.com>   I do my own using a West Mountain Radio CBA-II. For example, here's an Ultrafire 3000 that manages to barely squeeze out 850 ma-hrs at 1C: <http://802.11junk.com/jeffl/LiPo/> <http://802.11junk.com/jeffl/LiPo/Ultrafire%20LiPo%203000%20ma-hr%2018650.jpg> <http://802.11junk.com/jeffl/LiPo/Ultrafire%2018650%20test.jpg> I know garbage when I buy it.   Note that your 2400 ma-hr battery is usually rated at 0.2C or 480 ma discharge current. The test is also at room temperature. Vendors sometimes cheat and test the batteries in a water bath. The problem is that your drill probably draws about 30A, split between two strings of cells or 15A per cell, or about 6C. If you look at the typical LiIon 18650 family of curves, 6C isn't even on the graph. Much depends on at what voltage you want to declare the battery to be discharged. Panasonic uses 2.5v. Good quality LiIon batteries do not loose much capacity at these discharge rates. Junk drops drastically in capacity. Without knowing more about what you have, and testing the cells, I can't guess(tm) the capacity at 15A discharge.   Incidentally, if you're considering buying or building a battery spot welder (I am), this might be interesting: <http://www.ebay.com/sch/i.html?_nkw=battery+spot+welder> I made my own CD (capacitor discharge) system, but it sucks and is in need of replacement.   Good luck. -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558

"Ian Field" <gangprobing.alien@ntlworld.com>: Dec 11 09:26PM "Jeff Liebermann" <jeffl@cruzio.com> wrote in message news:71ok6b5hggqf5ujg249gcaca91dk5uupji@4ax.com... >>using copper flashing?   > The cases on most 18650 cells are stainless steel. You won't be able > to solder to those.   The flux I bought in a plumbers supply yard works perfectly OK on stainless, but sometimes needs the stainless to be lightly abraded.   Often I see a warning on lithium cells not to expose to more than 212F - or boiling water in other words.   Whenever I need to solder lithium cells; I just trim back the stainless strip so it still has a bit spot welded to the cell - its just that little bit more thermal resistance between the iron and the cell.   A fully charged cell can provide a fair bit of entertainment if the heat of soldering melts the seal and causes a short - solder first, charge later.

Jeff Liebermann <jeffl@cruzio.com>: Dec 11 03:26PM -0800 On Fri, 11 Dec 2015 21:26:03 -0000, "Ian Field"   >The flux I bought in a plumbers supply yard works perfectly OK on stainless, >but sometimes needs the stainless to be lightly abraded.   Paste or liquid flux? I've had no luck soldering stainless with either. Mostly, I try to solder to button cells, not 18650, which might be different. The paste flux made for copper pipe doesn't seem to work for stainless. For example; <http://www.homedepot.com/c/flux_and_solder_HT_BG_TH> Can be used on all materials except aluminum and stainless steel.   -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558

"Percival P. Cassidy" <Nobody@NotMyISP.net>: Dec 11 07:17PM -0500 On 12/11/2015 12:59 PM, Jeff Liebermann wrote:   > <http://toolboyworld.com/eBay/Ryobi_Batt_Rebuild.htm> > Looks like the balancing circuitry is in the battery pack, not the > charger.   I tried boosting the voltage of the low-voltage pair but without much success so far. I don't really have a suitable power source.   When I plug that pack into a P117 charger, the red light flashes "for ever" ("Testing"), but after a looong time changes to the slow flash indicating "Defective." When I plug it into a P125 charger, I get the "Charging" indication for just a minute or two, then it switches to "Charged," but of course it isn't: that one pair of cells still shows only in the mV range.   Perce

mike <ham789@netzero.net>: Dec 11 06:22PM -0800 On 12/11/2015 1:22 PM, Jeff Liebermann wrote: > I made my own CD (capacitor discharge) system, but it sucks and is in > need of replacement.   > Good luck.   It's not clear how those welders work. Looks like timed pulse??   I spent a LOT of time messing with battery tab welding. You need a LOT of heat QUICKLY. I put a SSR on the primary of a modified microwave oven transformer and counted the number of cycles of 60 Hz. to set the power delivered. Problem with low voltage is that it is extremely sensitive to resistance in the path. I could get very good welds about 80% of the time. On average, I got all good welds on about 0% of the packs.   You really want a fixed amount of energy delivered independently of contact resistance.   Capacitive discharge is the way to go. But, to get repeatability, you need to be switching the energy at high voltage. It's not easy to switch 1000 amps or more.   I gave up on DIY when I found a 125 Watt-Second CD system on ebay for cheap. That puppy can put 7000A single pulse into .001 ohms. Repeatability improved dramatically. Battery doesn't even get warm.

Clifford Heath <no.spam@please.net>: Dec 12 12:41AM +1100 On 12/12/15 03:05, Percival P. Cassidy wrote: >> Any Li-ion 3.7V 18650 will do as a replacement (peak charge voltage >> 4.2V) - but get a matched set of 5. > If I have to get a matched set -- of ten (five *pairs*)   When did your need for five cells become ten?   > -- rather than of two, I might as well get two 4AH ones for $99.   To my knowledge, no-one has worked out how to make a 4AH 18650 cell yet.   The best cells are below 3.5AH, and five of those are already more than $49 without building a case. Ryobi is Chinese now, so they're almost certainly lying.   If you value high capacity, buy your own branded cells.

"Percival P. Cassidy" <Nobody@NotMyISP.net>: Dec 12 09:35AM -0500 On 12/11/2015 08:41 AM, Clifford Heath wrote:   >>> 4.2V) - but get a matched set of 5. >> If I have to get a matched set -- of ten (five *pairs*)   > When did your need for five cells become ten?   Reread my original message in which I referred to four *pairs of paralleled cells* showing 4.1x Volts and the other *pair* showing only 2.1mV.   >> -- rather than of two, I might as well get two 4AH ones for $99.   > To my knowledge, no-one has worked out how to make a 4AH 18650 cell yet.   That's why they use *paralleled pairs* of 18650 cells.   > $49 without building a case. Ryobi is Chinese now, so they're almost > certainly lying.   > If you value high capacity, buy your own branded cells.   BTW, a few years ago I found a Web site dealing with battery packs for power tools that reported that all the packs they had disassembled used the same Sanyo 18650 cells -- including the RIDGID packs with the lifetime warranty and the Craftsman "19.2-volt" (for how many seconds after they come off the charger?) ones.   Perce

"Gareth Magennis" <sound.service@btconnect.com>: Dec 11 10:38PM "Gareth Magennis" wrote in message news:aIF9y.963250$FM6.274839@fx42.am4...   This is doing my head in.   Marhall JCM 600. http://www.classictubeamps.com/schematics/Marshall/jcm600_60w.pdf     Turning the distortion channel's gain/volume/master volume combination up too high will break into oscillation (a few kHz) above a certain gain. This doesn't happen unless the pre-amp is unmuted by inserting a (shorted) jack in the input socket.   As these 3 series gain controls approach the point of oscillation, you can hear the inpending frequency that will feed back rise as the gain is increased. (i.e. before feedback, the boosted frequency is gain dependent)   (Under certain test conditions it will oscillate massively ultrasonically. It's probably best not to do that very often)     Another amp repairer has been inside this amp and has attempted to fix the problem by the looks of it. He's put small caps across some electrolytics, and there was a resistor piggy backed over the top of R4, feeding VR5. Not sure why. I haven't found any other "mods", but that's not to say there aren't any.     Anyway, I've tried to isolate various things to discount them, but am going round in circles and need some ideas my head doesn't have right now.   There's some frequency dependent positive feedback going on somewhere, but since it's a complete loop broken by muting the input, it's kind of hard to isolate anything really. (Actually the input jack mutes both the input and the signal at CN6)     Any quick hints or tips from anyone? (It's not the Prescence feedback circuit, or the valves)                 Come on Phil, give us a clue, I'm stuck here.     Gareth.

Phil Allison <pallison49@gmail.com>: Dec 11 05:22PM -0800 Gareth Magennis wrote:     > Come on Phil, give us a clue, I'm stuck here.   ** Most times I've seen such a problem, it was due to lack of shielding between the output valve plate wiring and input signal wiring. Maybe a shielded signal wire really isn't or the plate wires need to be twisted, tidied and pushed against the chassis.   Everything in the JCM600 is crammed together making unwanted coupling more likely.   Other times it has been due to high resistance grounds on pots or jacks - or because some fool decided to put the OT next to the inputs jacks.   .... Phil

N_Cook <diverse@tcp.co.uk>: Dec 12 12:31PM On 11/12/2015 22:38, Gareth Magennis wrote:   > Come on Phil, give us a clue, I'm stuck here.   > Gareth.     I assume you've swapped out valves one by one, in case there is an internal electrode problem , not picked up in a valve tester. Another idea, moving a piece of mumetal around in likely areas? Do aluminium valve shields actually screen from stray, to any great extent, rather than just for valve retainer function?

"Gareth Magennis" <sound.service@btconnect.com>: Dec 12 12:35PM "Phil Allison" wrote in message news:22272735-e7a9-4080-b4d2-8c88646a60cf@googlegroups.com...   Gareth Magennis wrote:     > Come on Phil, give us a clue, I'm stuck here.   ** Most times I've seen such a problem, it was due to lack of shielding between the output valve plate wiring and input signal wiring. Maybe a shielded signal wire really isn't or the plate wires need to be twisted, tidied and pushed against the chassis.   Everything in the JCM600 is crammed together making unwanted coupling more likely.   Other times it has been due to high resistance grounds on pots or jacks - or because some fool decided to put the OT next to the inputs jacks.     .... Phil           Thanks, Phil, things are indeed particularly tight in this amp, and there are loads of those pesky jumpers from PCB to PCB. Makes the whole thing rather unenjoyable.   I'll have a look at the cable dressing etc, maybe something's not been put back properly by the previous not very skilled repairer.     Cheers,     Gareth.

"Gareth Magennis" <sound.service@btconnect.com>: Dec 12 02:11PM "N_Cook" wrote in message news:n4h3tc$6i9$1@dont-email.me...   On 11/12/2015 22:38, Gareth Magennis wrote:   > Come on Phil, give us a clue, I'm stuck here.   > Gareth.     I assume you've swapped out valves one by one, in case there is an internal electrode problem , not picked up in a valve tester. Another idea, moving a piece of mumetal around in likely areas? Do aluminium valve shields actually screen from stray, to any great extent, rather than just for valve retainer function?         I changed all the valves for a "test set" of known good new ones. No difference to the originals. (One output valve was faulty)   I checked all the pot values (and their soldering), in case someone had put the wrong one in. They hadn't.     I guess if I can get it to the point where I can hear the obvious frequency lobe building, I can start poking and moving cables around to see if anything increases or decreases the lobe. That will be monday.       Cheers,     Gareth.

Jeff Liebermann <jeffl@cruzio.com>: Dec 11 09:47AM -0800 >Any more recent successs stories to brag about?   If you enjoy reading such stories, there are quite a few in the "Made by Monkeys" section of various trade magazines. These highlight quality control and design failures: <http://www.electronicsweekly.com/made-by-monkeys/> <http://www.designnews.com/archives.asp?section_id=1367> If you're planning on designing the next big thing in consumer products, or are wondering why some things just can't be repaired, these columns (blogs) should be mandatory reading.     -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558

jurb6006@gmail.com: Dec 11 10:10AM -0800 >"I was charged with fixing his re-do's and generally cleaning up the >chaos he <had left behind. "   Steve's TV, I doubt they are still around. Quit, went back a couple of times. One time they needed bo TV techs but needed an audio tech. Figured, hell I'll give audio a whirl. Not that I hadn't done any, just not exclusively.   Well there is this whole big stack of recalls (or redos) from the last guy. The Delco 2000 series car stereos. The guy's bench setup had a common ground for the speakers and he blew the audio output chip out of EVEY ONE OF THEM.   These are true four channels radios but not quad. these are not some elcheapo LAXXXX six buck chip. They were DM-165 mostly and they were over twenty bucks each, and he blew BOTH of them in each radio.   That was one of my last commission jobs. I made money. And after that SNAFU was cleared up the boss(es) standing around said "We're finally making money on audio". That part was a bit hellish. Back then we didn't even have a Hakko and those Delcos were among the first things that (regularly) came in that two sided boards with plated through holes.   Every last one of them. With the type B tape decks in them the belt would break and it would not eject, so no radio either. So many customers decided to pry the tape out, breaking the cassette guides. The belt is a buck, a set of these plastic pieces it twenty. Even though they were assholes who cost themselves some money there, they did happen to notice when the front speakers didn't work anymore after they got it back.   And then they bring it back and because of the common ground the bench speakers would play the L-R like the back channels of a quasi quad unit and when you turn the balance to one side it would sound almost normal. "Nothing wrong with it". Yeah right.   You can't really work techs on commission anymore. Back then, so many repairs involved simple parts that it could work with a guy who is good. There were shops though that I would not. If I do not see a good parts department fuck that. I ain't coming in and diagnosing all this only to wait weeks to complete the job to get paid. What's more, forget the free estimate, I ain't doing it.   When the shop[ makes money, the tech makes money on commission. One place I did work commission worked out pretty well. I was running though some of my old shit and part time, one week I made $480 in 12 hours. One week I worked about 30 hours and took home $775. And that was in the 1980s. Later, that job converted to hourly, at a quite good rate. It was slightly less money but it was steady. I liked the money steady and they liked the fact that I could no longer refuse jobs.   And that paid off for them.   Actually, now this is a LONG time ago and at $23 an hour, they threw me a set I had already been stumped on before. they said it is a do or die. It may have been a contract job, and when you cannot fix a contract job that is very bad. You can't just refund the money, you have to buy them another TV.   This was an RCA CTC 169. (I should have put thios in my other post but did not recall it then) Intermittently it would start up with the OSD shifted and no sound. Now this was a normal symptom for this chassis and I do not recall what the fix was, but in this case where the OSD is usually shifted to the right, this one was shifted to the left. (or vice versa but you get the idea, the other way)   it would never do it with the chassis flipped up. About ten people resoldered almost every joint on the board to no avail.   RINALLY I got it. It was a weak 503 KHz crystal at the jungle IC. the hell you say ? Well when the micro tells the set to come on it expects a source to come up right away which is scan derived. this feeds the EPROM which then reads its contents into RAM with the specific setup info and settings.   I started noticing that when this happened, the HV did not come up immediately. What it was is the crystal was weak or whatever and the oscillator took too much time to start. The micro is only sensitive to that data for a limited time and the window was closed by the time the EPROM spoke up. That chassis had a system that is operable without an EPROM. When it is in that mode it uses a set of parameters that do not match the hardware installed. Actually I do not recall ever seeing a CTC169 without an EPROM, but other models did. Some of them would autoprogram first time they were turned on after being unplugged. Those were the elcheapo models, but of other chassis'. I guess they used the same micros or at least similar code in them though.   So we got :   No sound - 503 KHZ crystal for horizontal osc. No sound - vertical shaping IC. Loses blue and green after CRT replacement - adjust vertical height.   I'd like to see some weirder ones than that.

Jeff Liebermann <jeffl@cruzio.com>: Dec 11 10:18AM -0800 >various sizes with a razor blade, jig and a tube of super glue that >was supposed to be used to make belts for consumer electronics >equipment. I had never seen super glue before so I tried it. Once.   Those are still sold and work reasonably well: <https://www.google.com/#q=o-ring+splice+kit>   The trick is to cut the o-ring or whatever at an angle. That does three things: - It increases the surface contact area so that the glue has a better grip. - It converts some of the stresses from tension to shear, where cyanoacrylate adhesives are stronger. - When used as a compression seal, crushing the glue joint does NOT crack the rather brittle glue joint.   The only gotcha I've run into is dealing with tight turns such as very small diameter drive pulleys. Cutting the o-ring at a large angle causes the glue joint to be longer. Too long, and it will crack if wrapped around a small pully. Just size the angle for covering no more than about 60 degrees around the pully, and I think it should be ok.   Note: Super glue doesn't work if there's little contact area, so splicing thin and flat belts doesn't work. I've had some luck using contact cement with these, but not reliably.   -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558

whit3rd <whit3rd@gmail.com>: Dec 11 12:34PM -0800 On Thursday, December 10, 2015 at 1:00:55 PM UTC-8, Ralph Mowery wrote: > person I was with usually could locate the bad parts and get our project > going first. Got to be a joke that the ones that got theirs to work had the > lucky box with all good parts for that design.   I was teaching one such lab, with bar magnet/coil experiments, and had an inspiration. I got some iron filings and sheets of paper, and had the students lay the paper over their bar magnet and sprinkle the filings over it.   There were a dozen bar magnets in the 'materials' box, and half of 'em had odd fields. One had five identifiable poles. Using only the dipole-type bar magnets, the class got better compliance than usual with the expected behavior of poles and coils in motion.

adrian@poppyrecords.invalid.invalid (Adrian Tuddenham): Dec 11 08:38PM > Maybe we could share some "war stories" of cool repairs we have done in the > past.   I was called in unofficially to have a look at an X-ray machine in a university crystallography lab, there was an intermittent fault which shut it down after a few seconds of operation. The running time was getting shorter and shorter and the manufacturers had given up on finding the fault.   On the way there, I mentally ran through what I could remember about X-ray machines (apart from the obvious dangers) and realised that most of what I knew had come from reading my father's hand-written course notes in the 1950s; they dated from when he was trained as an army radiographerat the outbreak of WWII. I knew what an X-ray tube looked like as a symbol, but what did one look like in reality?   On being introduced to the faulty machine, I glanced around the room and saw a number of copper-and-glass objects on a shelf - and concluded that they must be spare tubes. Luckily, the manufacturers had furnished a full set of circuit diagrams and the lab had managed not to loose them, so I knew what I was dealing with, even if I didn't initially know how most of it worked. The circuits were all discrete components with intermixed transistor, diode and relay logic.   By the end of the first day, I had gained a fair idea of how the power supplies and safety circuits worked and had been instructed in the necessary safety drill by the technician, so I was able to fire the machine up and watch what happened. The fault showed up, but it all happened so quickly that I wan't able to spot what was going on.   Luckily, on the morning of the second day, I happened to spot the tube current meter flicker downwards and the voltmeter kick upwards just as the fault occurred. Careful monitoring of the primary of the mains transformer showed unstable mains voltage, which the control loop had been over-compensating and then tripping out on over-voltage.   The cause was a burnt contact in the main contactor, so I stripped it down and sandpapered the contacts, much to the amusement of the staff.   Fault cured - machine saved from the scrapheap.     -- ~ Adrian Tuddenham ~ (Remove the ".invalid"s and add ".co.uk" to reply) www.poppyrecords.co.uk

jurb6006@gmail.com: Dec 12 12:19AM -0800 Been there done that. Good site. The name seems to imply it is a comedy site but it is not. I hope people are not too disappointed.

jurb6006@gmail.com: Dec 11 10:17AM -0800 Do you realize you responded to a five year old thread ?   I see alot of people doing that who use Google to get here. It is not like it is a huge problem but it does clutter the recent threads page because (as you know) it does not give the date of the OP there.   What I don't understand is how you are finding these old posts, are you doing a search ? Because something five years old would be on about page 310 or so if you are just browsing the posts as they are in reverse chronological order.   Another thing to realize is that not everyone sees your posts because they have gmail blocked because there are a lot of spammers on it. I haven't seen a whole lot of it on the sci.electronics groups but they are not all of Usenet.

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