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N_Cook <diverse@tcp.co.uk>: Mar 07 04:27PM All that pallaver of swapping corroded 74LS373 (but good) and I'm back to loss of Data5 and Data7 keys but now D6 keys gone west also, continuity checks out fine and should be there as before. D0 to D7, correspond to keys 1 to 8 of each octet of keys, not octave. So went back to original plan, but now with no D6 to swap to D7. So cut the trace to D3 input of the 40245 keyboard scan IC and fed the D7 line to that pin. Powering up, the 4th key of each batch of 8 now sounded at the pitch of "7" not "3" and midi LED flashed. So looks like swapping out the 40245, I think, but perhaps wrong, as it seems functioning correct signal on D7 line but not getting through the 40245 nor D6 nor D5, input to outputs , for keybd scan. Pitch number 8 of each octet would sound (and 6 and now 5) , if the keyboard scanning funtion was working correctly, I hope.

"Michael A. Terrell" <mike.terrell@earthlink.net>: Mar 06 08:56PM -0500 Cursitor Doom wrote:   > For the *real* cheapskates out there, there's this alternative:   > http://www.ebay.com/itm/201842524936   > Claims to be able to handle up to 100A!     Let's see you use it to find a stray 100 mA DC on a crowded circuit board. :(     -- Never piss off an Engineer!   They don't get mad.   They don't get even.   They go for over unity! ;-)

Winfield Hill <hill@rowland.harvard.edu>: Mar 06 06:06PM -0800 John Larkin wrote...   > We just demoed a cool new thermal imager ...   Names, please. And results, later.     -- Thanks, - Win

"tom" <tmiller11147@verizon.net>: Mar 06 10:05PM -0500 "Winfield Hill" <hill@rowland.harvard.edu> wrote in message news:o9l4j601vp8@drn.newsguy.com...   > -- > Thanks, > - Win   We don't believe it until there are pictures.

John Larkin <jjlarkin@highlandtechnology.com>: Mar 06 08:56PM -0800 On 6 Mar 2017 18:06:30 -0800, Winfield Hill <hill@rowland.harvard.edu> wrote:   >John Larkin wrote...   >> We just demoed a cool new thermal imager ...   > Names, please. And results, later.   I'm not sure I can name names yet. It's still in development.   We've become sort of a beta tester for these people. They send us units and get our feedback, and we can keep them. Or maybe they just like coming to San Francisco.     --   John Larkin Highland Technology, Inc   lunatic fringe electronics

gregz <zekor@comcast.net>: Mar 07 09:11AM > The one is use is by LEM and has response to 100kHz, allows me to see > currents as low as 1mA and up to 100A peak.   > .... Phil   I used to like using a Tek Hall sensor probe. I liked it checking DC shorts on boards.   Greg

"Gareth Magennis" <soundserviceleeds@outlook.com>: Mar 06 09:56PM This is a bit weird.   I have an audio power amplifier that uses what looks like strips of pink silicone sheet between the output transistors and the heatsink. But these strips have degenerated and are kind of squidgy, a bit like when Speaker surrounds fall apart. Not come across this before.   They have got so bad that an arc occurred through one strip, beneath one of the transistors, which has burnt a small hole in the heatsink, blowing the amp and the SMPS, which I repaired.     So what kind of material could this pad be made of? Surely silicone wouldn't do this?       This is the amp, you wouldn't expect this kind of problem on something like this.   http://www.dbaudio.com/en/systems/details/d12-amplifier.html       Cheers,     Gareth.

stratus46@yahoo.com: Mar 06 03:02PM -0800 I have not seen the pads break down. I have replaced mica with silpads to get away from heatsink grease.   You can likely find replacements here.   http://www.digikey.com/products/en/fans-thermal-management/thermal-pads-sheets/218   BEWARE that some of the pads are electrically conductive.   G²

Jon Elson <jmelson@wustl.edu>: Mar 06 05:35PM -0600 Gareth Magennis wrote:   > This is a bit weird.   > I have an audio power amplifier that uses what looks like strips of pink > silicone sheet between the output transistors and the heatsink. Hmmm, I've seen these pink ones in old power supplies and such, many years ago. I haven't seen them in anything recent. Some of the Bergquist pads have some kind of fabric in them that makes them quite robust.   They also have some Gap-Pad material that is designed to be very squishy. It is not designed to provide electrical insulation, but to accomodate uneven parts that have to conduct heat to a heat sink.   Jon

"Gareth Magennis" <soundserviceleeds@outlook.com>: Mar 07 12:04AM "Jon Elson" wrote in message news:hrqdnfBopoyebyDFnZ2dnUU7-QudnZ2d@giganews.com...   Gareth Magennis wrote:   > This is a bit weird.   > I have an audio power amplifier that uses what looks like strips of pink > silicone sheet between the output transistors and the heatsink. Hmmm, I've seen these pink ones in old power supplies and such, many years ago. I haven't seen them in anything recent. Some of the Bergquist pads have some kind of fabric in them that makes them quite robust.   They also have some Gap-Pad material that is designed to be very squishy. It is not designed to provide electrical insulation, but to accomodate uneven parts that have to conduct heat to a heat sink.   Jon       *************************************************************       The parts under the transistors seems to have been compressed by the heavy spring clips used, as it seems way thinner than normal, but firmly stuck to the heatsink. Probably why one arced.   The parts not under transistors and exposed to the environment are squidgy and thicker, and not at all stuck on the heatsink, and just break into chunks when you move them.       Gareth.

ohger1s@gmail.com: Mar 06 04:05PM -0800 On Monday, March 6, 2017 at 4:56:49 PM UTC-5, Gareth Magennis wrote:   > Cheers,   > Gareth.   I haven't had one fail in use, but have had a bunch fail when the device is replaced for other reasons. Often they'll be so acclimated to their heatsink they're virtually bonded, and they tear when removal is attempted. In a pinch I've used mica washers and a tiny schmear of 3M compound. I also have tons of older plasma SMPS that used them, so I have donors. They're also available from most supply houses.

N_Cook <diverse@tcp.co.uk>: Mar 07 08:14AM On 06/03/2017 21:56, Gareth Magennis wrote:   > Cheers,   > Gareth.   Stay with mica slivers, been around for geological time, no plasticer to leach out. The only time I've come across failure of a mica insulator was when some swarf got under it at manufacture, that would do for all other insulators as well. Trouble with mica is it is dirt cheap and not patentable.

N_Cook <diverse@tcp.co.uk>: Mar 07 08:16AM On 06/03/2017 21:56, Gareth Magennis wrote:   > Cheers,   > Gareth.   How old, to get an idea of service life for this silicone junk?

"Gareth Magennis" <soundserviceleeds@outlook.com>: Mar 07 08:34AM "N_Cook" wrote in message news:o9lq40$rf2$2@dont-email.me...   On 06/03/2017 21:56, Gareth Magennis wrote:   > Cheers,   > Gareth.   How old, to get an idea of service life for this silicone junk?     **********************************************************************************         These amps are currently extensively used in the Pro Audio (Hire, Touring, Venue) world, and are probably still in production. I suspect this one might me a rogue event.     Gareth.

jurb6006@gmail.com: Mar 06 06:06PM -0800 >"The **actual plate voltage** swings up to nearly double in operation, single ended or push pull. The 2.4kV figure I posted is the max, zero current plate voltage that is guaranteed. IOW, the insulation rating. "   I am not exactly sure what you're saying here. Are you saying that tubes such as this are rated in such a way are expected to operate at twice their "max" rating ?   I never got into tubes all that much, when was getting into the field it was going solid state and I was adapting to it.   >"You know absolutely NOTHING about tube output stages."   You're pretty friendly today, did you find a good pot dealer or something ?   >"Don't fret too hard, hardly anyone does. "   How come so kind ?   But actually tubes are a bit harder to understand than like transistors etc. Take your transconduct and and mu and sll of that and give me hfe and HFE.   But that's just one Man's opinion. If you can counter with an argument that tubes are better, bring it on.   >Don't fret too hard, hardly anyone does."   I was working in the music industry. These MFs got where they have dual purpose valve sockets and via a micrprocessor will adjust the bias for you. I mean they got sockets that will take a KT88 or a 6BQ5. I am not fretting but I am considering a career in flipping burgers. It is getting that bad, to the point where I quit my job.   Next.

Phil Allison <pallison49@gmail.com>: Mar 06 06:19PM -0800 > >"The **actual plate voltage** swings up to nearly double in operation, single ended or push pull. The 2.4kV figure I posted is the max, zero current plate voltage that is guaranteed. IOW, the insulation rating. "   > I am not exactly sure what you're saying here. Are you saying that tubes such as this are rated in such a way are expected to operate at twice their "max" rating ?   ** What I am saying is simple:   The only *plate voltage limit* on a power tube is the breakdown voltage of the insulation.   The usual weak spot is between pins 2 and 3, the heater and the plate of many audio power tubes. Having a plate connection on top of a tube instead helps a lot.   The other limits are with max cathode current and max dissipation of the plate structures or screen grids.     ..... Phil

Jon Elson <jmelson@wustl.edu>: Mar 06 05:43PM -0600 Phoena Greene wrote:   >> that they now contain around 29.5Gb, but the free space on the HDD is >> only showing about 5Gb - I did try emptying the trash folder, but no >> result there.   Probably if the transfer fails, it doesn't remove the files from the source. It wants to make SURE the files on the stick are safe before removing the old ones. That makes good sense!     >> This looks a lot like a bug in Lubuntu!   >> Thanks for any help.   > I think just about everything in Linux only half works.   Well, while there have been a few issues over the years, I've been using some version of Linux as my main desktop for almost 20 years! I also have a number of devices that are run by PCs (or Beagle Bones) running Linux. My family is almost exclusively running Linux for general email, web browsing, writing papers for school, etc.   Works for me.   Jon

Steve & Lynn <peter@is.gay>: Mar 06 01:44PM > Well then go back to your Usenet posts from ten fucking years ago and change those URLs.   > You cool with that ?   Would you change your Usenet post from ten years ago:   Path: g2news2.google.com!postnews.google.com!v23g2000prn.googlegroups.com!not-for-mail   From: ZZa...@aol.com   Newsgroups: sci.electronics.repair   Subject: For the people who fuck with me   Date: Sun, 21 Oct 2007 22:08:06 -0700   Organization: http://groups.google.com   Lines: 32   Message-ID: <1193029686.880494.113850@v23g2000prn.googlegroups.com>   NNTP-Posting-Host: 66.72.196.128   Mime-Version: 1.0   Content-Type: text/plain; charset="iso-8859-1"   X-Trace: posting.google.com 1193029687 15870 127.0.0.1 (22 Oct 2007 05:08:07 GMT)   X-Complaints-To: groups...@google.com   NNTP-Posting-Date: Mon, 22 Oct 2007 05:08:07 +0000 (UTC)   User-Agent: G2/1.0   X-HTTP-UserAgent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1),gzip(gfe),gzip(gfe)   Complaints-To: groups...@google.com   Injection-Info: v23g2000prn.googlegroups.com; posting-host=66.72.196.128;   posting-account=ps2QrAMAAAA6_jCuRt2JEIpn5Otqf_w0   Xref: g2news2.google.com sci.electronics.repair:12585       OK, I have killed twelve people and never did a day in jail over it, you want to fuck with me, accuse me of not having street smarts ?   This is not a threat, it is an invitation to whatever you make it. You come to me. What happens to you is, howevwer, your fucking problem.   Now here is a threat. If you continue to disrupt the operation of this newsgroup I will find out who you are, and I will shut you down. DO YOU UNDERSTAND ME ? I didn't fuck with anyone. But that could change.   You keep it up you can be assured of getting the newest and bestest virus in the world, I'll fuck up your registry. I mean you are fucking with the wrong per,,,,,people here. Let this NG operate as it does. There is this and there is that, but no MOTHERFUCKER is going to tell me what I can or cannot post. You are a fucking hind tit on a wild boar.   When you buy usenet and pay my fucking bills get over here. I haven't put my fist though anything in a long time.   And for those who want to say something about me hiding or anything like that, let me tell you something. When I put my fist through a wall it comes out the other side. I live on west 16th in Cleveland Ohio. C'mon down. I'll get rid of your carcass, and drive your car until the fucking plates expire. And when the cops stop me EVEN drunk in this town, they will not take me to jail.   Now who do you want to fuck with ?   Terminator.

Jerry Peters <jerry@example.invalid>: Mar 06 09:08PM >> How do they do 48v with D batts?   > They don't use D batteries. > <https://assets.wired.com/photos/w_3360/wp-content/uploads/2016/09/Payne003.jpg>   You aren't current, Verizon is now distributing a "Voice Backup Device" which uses 12 D batteries. That's what I got when I switched to FIOS last year. I would have preferred a lead-acid gelcell rechargable, but they've discontinued those for new installs.

"pfjw@aol.com" <pfjw@aol.com>: Mar 06 01:26PM -0800 The question was how do they get 48 VDC, not how home-equipment is backed up.   To my way of thinking, not automatically providing such back-up as part of the package verges just short of criminal. Keep in mind that Great Aunt Esmeralda may not understand this distinction, and be left flapping when Great Uncle Percival needs emergency services - or vice-versa. Fine print notwithstanding, critical services should not be a self-service thing, but they should stand on their own. Water, sewer, Phone, Power. One failing should not in any way affect the others. Full Stop. Only the "Phone Companies" are getting away with this. And we are sitting by allowing it to happen.   Peter Wieck Melrose Park, PA

Steve & Lynn <peter@is.gay>: Mar 06 01:36PM > When copper goes away, so will "robust" phone systems, big central switches > and line-powered devices such as ringers and flashers (for deaf people).   DO YOU EVER THINK BEFORE YOU TYPE. I DON'T HAVE A "COPPER" LINE BUT MY LANDLINE RINGS JUST AS FINE.   > Although we have a generator, our phones never failed during that time, even for a moment.   SO YOU MUST HAVE HAD A LOT OF GAY FONE SEX THEN.   > And for those who are really paranoid - a conventional dial-type ringer phone on a copper network fed from a > central switch remains pretty much immune to EMPs. Lot of good that will do, except for, perhaps, the roaches.   SO WHEN AN EMP HITS YOU CAN STILL HAVE YOUR GAY FONE SEX JUST AS LONG AS THEY SUPPORT ROTARY DIAL FONES.

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