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Baron <baron@linuxmaniac.net>: Mar 07 08:14PM Jon Elson prodded the keyboard with: > for general email, web browsing, writing papers for school, etc.   > Works for me.   > Jon   I've been running Linux since my wife bought me a book with Yggdrasil Linux bound into it, about 1994/5. In those days you had to compile everything yourself. Fun times...   -- Best Regards: Baron.

jack4747@gmail.com: Mar 08 08:19AM -0800 Il giorno martedì 7 marzo 2017 21:14:26 UTC+1, Baron ha scritto:   > I've been running Linux since my wife bought me a book with Yggdrasil > Linux bound into it, about 1994/5. In those days you had to compile > everything yourself. Fun times...   half a day to compile the kernel :D and then you found out that you forgot to include a driver, so it didn't boot.   Bye Jack

makolber@yahoo.com: Mar 08 08:20AM -0800 Do not use a long extension wire for the USB.   mark

Baron <baron@linuxmaniac.net>: Mar 08 04:38PM > and then you found out that you forgot to include a driver, so it > didn't boot.   > Bye Jack   I don't recall having that problem ! I do remember struggling to find the code for some driver or other, and then having to mod code because some address was different or wrong. Off by one was a popular mistake. You soon became very familiar with PC hardware in those days.   -- Best Regards: Baron.

"David Farber" <farberbear.unspam@aol.com>: Mar 07 09:45PM -0800 Jeff Liebermann wrote: > (...)   > "How to take apart a UHF U2 Shure wireless Microphone" > <https://www.youtube.com/watch?v=UFcDXRhNEhQ> (1:28)   Hi Jeff,   That microphone is not at all physically similar to the one that I am servicing. I told the user it wasn't worth fixing. You can buy a new one, though not a Shure model, for under $100.   Thanks for your reply. -- David Farber Los Osos, CA

makolber@yahoo.com: Mar 08 08:11AM -0800 On Wednesday, March 8, 2017 at 12:45:25 AM UTC-5, David Farber wrote: > -- > David Farber > Los Osos, CA   623 is UHF TV channel 39 in the USA.   If you have an analog UHF TV set for off the air mode (not cable) and tune it to Channel 39, you should see some change in the snow when you turn the mic on and off. I doubt it will demod the audio but you should see some effect of the mic onto the snow. That will tell you if it is putting out RF or not. m

bitrex <bitrex@de.lete.earthlink.net>: Mar 07 10:40PM -0500 On 02/28/2017 06:46 AM, N_Cook wrote: > One tip for dealing with these, small cable ties between top and base, > to act as a hinge for probing access to the internals and keep > everything in reasonable registration so no strained cables.   My Alpha Juno 2 from around the same timeframe had a problem with the membrane switches on the front panel not activating correctly; I traced it down to a bad pullup resistor in one of the SIP packages attached to the bus headed from the switch board to the demultiplexer IIRC.   Might be worth looking at too...

N_Cook <diverse@tcp.co.uk>: Mar 08 07:59AM On 08/03/2017 03:40, bitrex wrote: > it down to a bad pullup resistor in one of the SIP packages attached to > the bus headed from the switch board to the demultiplexer IIRC.   > Might be worth looking at too...   That makes sense, for losing a third set of keys, as in the process of probing the 40245 I bent the data bus SIP R more vertical slightly, to give a gap, as was leaning against that side of the IC. But otherwise I don't remember having come across a failed SIP R pack.

N_Cook <diverse@tcp.co.uk>: Mar 08 12:27PM Replaced TC40H245P with 74HC245 and all keys now working. Cold DVM-D test of the old 245, to either supply pin, showed no forward drop in any direction, to the gates used by D5,D6,D7 unlike to the other pins. Some of the front panel switches came back to life but switches 1 to 8 of 16 bank, no function or Midi LED flash. Hopefully just failed "ribbon" 33 yearold age hardened copper wire that gave up the ghost with all this unaccostomed flexing of connecting and disconnecting the main pcb.

N_Cook <diverse@tcp.co.uk>: Mar 08 02:43PM Must have been sat on or similar, to squash area near sw16, down onto the ps h/s and cracked the pcb. There is a H&S factor with these, bad enough that main pcb is secured to chipboard base by wood screws, so loosish screws that could fall away. But the mains carrying pcb is also just woodscrewed to the chipboard as well.

N_Cook <diverse@tcp.co.uk>: Mar 08 04:04PM Before I got to this, an electrician had removed all the keys without some sort of sequence marking, so I ended up with a carrir bag of them. I assumed out there, via google bunging in roland keyboard keys, CF1,EB2,CF, D, A ,G , C ,23 someone would have put out there the sequence required to lay up a Roland keyboard moulded with those cryptic alphanumerics, but apparently not. Any pics I've found is ambiguous as the degree of left and right throws on the white keys, let alone the unseen pivot slot widths that vary. C D E F G A B C is not very helpful

Kare Ojaniemi <kare.ojaniemi@gmail.com>: Mar 08 07:25AM -0800 Hi everybody   Ages ago I bought the Mishibishi HS-M55 to be used for taping music only, at half speed. I was extremely pleased with the high quality machine. The performance was impeccable and the sound characteristics (wow & flutter, for instance) better than in my B 77.   The weak point, of course, are the rubber belts that dry unfunctionable. They were changed at least once but now there's no spares to be found anywhere - let alone finding a repairman who would work with these oldie goodies . . .   My big question is, is there a machine with similar or better performance than the HS-M55 but designed with rods instead of rubber belts ? I do realize that the whole VHS concept is way out-of-date, only that I have 40-odd tapes filled with good music, 300+ hours.   If I find, with the help of you, that there is/was a high quality Hi-Fi Nicam Stereo VHS player with half-speed and rods, then I can start chasing it from e-bay or similar places. They sometimes offer the weirdest unused machines in unopened factory packages . . . Well, one can always hope !   Appreciating all your help in beforehand.     Best regards,   Kare Ojaniemi Helsinki, Finland

Jeff Liebermann <jeffl@cruzio.com>: Mar 07 10:04AM -0800 On Tue, 7 Mar 2017 09:11:34 -0000 (UTC), gregz <zekor@comcast.net> wrote:   >I used to like using a Tek Hall sensor probe. I liked it checking DC shorts >on boards. >Greg   Yes, but have you seen the prices? <http://www.tek.com/current-probe> The cheapest model that does DC is $1,600.   I rolled my own. I took an old Honeywell SS495A Hall effect sensor, built a suitable amplifier, hot melt glued it to a piece of plastic, and calibrated it by shoving DC through various PCB traces. It's ugly, not very sensitive (3mv/gauss or 30uV/uT), and goes nuts near magnetic fields from xformers, inductors, steel mounting brackets, wall warts, etc. However, it's cheap and easy. I don't use it for troubleshooting very often.   The original suggestion sounds much like an RF current probe. <http://www.lowfer.us/k0lr/currprob/currprob.htm> <https://interferencetechnology.com/the-hf-current-probe-theory-and-application/> However, these cannot be used to measure current though a PCB trace.       -- 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

Cursitor Doom <curd@notformail.com>: Mar 07 06:16PM On Mon, 06 Mar 2017 20:56:02 -0500, Michael A. Terrell wrote:   > Let's see you use it to find a stray 100 mA DC on a crowded circuit > board. :(   Oh come along now. You know it's not intended for that sort of usage!

Cursitor Doom <curd@notformail.com>: Mar 07 06:18PM On Mon, 06 Mar 2017 20:56:00 -0800, John Larkin wrote:   > Or maybe they just like > coming to San Francisco.   Unlikely. ;->

gregz <zekor@comcast.net>: Mar 08 09:06AM > <http://www.lowfer.us/k0lr/currprob/currprob.htm> > <https://interferencetechnology.com/the-hf-current-probe-theory-and-application/> > However, these cannot be used to measure current though a PCB trace.   I was using a NASA owned probe. Thought about trying to make one.   Greg

Winfield Hill <hill@rowland.harvard.edu>: Mar 08 05:44AM -0800 Cursitor Doom wrote... >> on a crowded circuit board. :(   > Oh come along now. You know it's not intended for > that sort of usage!   I ordered one from Newark, and plan to use it on my messed-up switching power-supply designs. Qualitative results will be fine.     -- Thanks, - Win

Cursitor Doom <curd@notformail.com>: Mar 08 02:52PM On Wed, 08 Mar 2017 05:44:39 -0800, Winfield Hill wrote:   > I ordered one from Newark, and plan to use it on my messed-up switching > power-supply designs. > Qualitative results will be fine.   Mine arrived today. I plan to monitor fuel injection impulses with it firstly just to see what kind of di/dt responses it's capable of. I'm not quite as confident as you are, though!

Winfield Hill <hill@rowland.harvard.edu>: Mar 08 07:18AM -0800 Cursitor Doom wrote... > impulses with it firstly just to see what kind of > di/dt responses it's capable of. I'm not quite as > confident as you are, though!   I do a lot of fast HV pulsing circuitry, and don't expect it'll be helpful for that kind of work. But the 5MHz bandwidth should be fine for looking at inductor current ramps, cap charge-discharge, etc.     -- Thanks, - Win

isw <isw@witzend.com>: Mar 07 09:46PM -0800 In article <o9lpvg$rf2$1@dont-email.me>, N_Cook <diverse@tcp.co.uk> wrote:   > 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.   Also somewhat poorer thermal performance ...   Isaac

N_Cook <diverse@tcp.co.uk>: Mar 08 08:25AM On 08/03/2017 05:46, isw wrote: >> Trouble with mica is it is dirt cheap and not patentable.   > Also somewhat poorer thermal performance ...   > Isaac   If you mean mica is poorer, don't go by product data sheets. I did a realworld expt one time , comparing mica and sillypads on an amplifier. Running with fixed input and controls and load, and monitoring the temp of the heasink and IR thermo of devices. The mica'd version ran with noticably hotter heatsink and cooler devices. IIRC the datasheets quote an (fraudulent?) impossible degree of squashing of pads, not obtainable with one screw thru a tab.

Phil Allison <pallison49@gmail.com>: Mar 08 02:56AM -0800 N_Cook wrote:   > version ran with noticably hotter heatsink and cooler devices. > IIRC the datasheets quote an (fraudulent?) impossible degree of > squashing of pads, not obtainable with one screw thru a tab.   ** Thin mica (0.05mm) is still the best performing insulator material for semiconductors you can get at a sensible price AND will easily handle 200V or more. Just a smear of white, silicone grease on each side and you are there.   The reason makers ever use silicone pads is saving assembly time.   If the power per device is high (ie over 20 watts) then forget silicone pads.   Forget published specs too, pad makers lie.       .... Phil

Jon Elson <jmelson@wustl.edu>: Mar 07 06:01PM -0600 > I never saw any such thing. Are you sure you were not "tripping"? That > may have just been a common 6L6 tube in a guitar amp, and your > hallucinations made it look really BIG.... :)   Nope, this was at the Fox Theater in St. Louis. Yes, there were certainly some people tripping on various substances, but I was not. I can't prove it was an AM broadcast modulator, but I can't imagine any other package that would look like that and be available as a unit. There was even an article in the local paper about that event, and how the band had all their equipment confiscated for non-payment, and had to scramble for gear the day of the show. I seem to recall Bob Heil came to the rescue and loaned them this equipment.     > Who ever heard of wearing earmuffs at a Grateful Dead concert.....   Only, me, I assure you! I protect my hearing, that's why I still have most of it. > And since you mentioned it. What the hell is wrong with them British? > Valves are plumbing parts. Tubes are electronic parts!!!   yeah, they have funny names for EVERYTHING that was invented since 1776. side curtains (side windows) bonnet (hood) accumulator (car battery) boot (trunk) gear change (gear shift) and there are plenty more...   > thousands of watts range. But to use that kind of tube would require > custom output transformers that would likely mimic the pole transformers > used to feed our homes....   Well, I'm no expert, but apparently the modulation transformer does a pretty fair job of being an audio output transformer. I'm guessing there may be some change to the output winding to lower the output impedance, or else you just wire a bunch of speakers in series. And, don't ANYBODY touch that rig while it is running, it could be lethal!   Jon

Michael Black <et472@ncf.ca>: Mar 07 07:34PM -0500

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