sci.electronics.repair@googlegroups.com

Google Groups

mhooker32@gmail.com: Feb 14 05:16PM -0800 i have a gq-4x( willem) burner. i need to combine a 128k rom and a 256k rom into a 512k image. the command line is:   copy /b CPU_5B.128 + CPU_5B.128 + CPU_5C.256 CPU_5C.512   how do i do that with the rom burning software?   thanks

Andrew Smallshaw <andrews@sdf.org>: Feb 15 02:45PM > i have a gq-4x( willem) burner. i need to combine a 128k rom and a 256k rom into a 512k image. the command line is:   > copy /b CPU_5B.128 + CPU_5B.128 + CPU_5C.256 CPU_5C.512   > how do i do that with the rom burning software?   You really need to provide more context here. At the risk of stating the obvious that is an MS-DOS/Windows command line command to combine two copies of the first ROM followed by the second into a single image - presumably the ROM images are in binary format and the secnd copy of the first is being used as a spacer to pad the second ROM to the correct starting offset. You'd execute that in a Windows command line window (Windows key+R, type "cmd" and press enter, cd to the folder containing the files and enter that command) With that done you have a single 512k ROM image to burn as one file with your device programmer and and software.   It's not clear at what step of the process you have issues so you really need to be more specific.   -- Andrew Smallshaw andrews@sdf.org

N_Cook <diverse@tcp.co.uk>: Feb 15 08:44AM On 15/02/2019 06:32, Unlisted wrote: > concrete. It's too hard to be plaster, since it cant be scratched with a > fingernail, like plaster can.   > I'm just curious what the material is?   My guess its like epoxy potting , where epoxy is pretty expensive so spun out with mixing with chalk . In the power R case, fire-cement , padded out with sand

"pfjw@aol.com" <peterwieck33@gmail.com>: Feb 15 05:57AM -0800 On Friday, February 15, 2019 at 3:44:39 AM UTC-5, N_Cook wrote:   > My guess its like epoxy potting , where epoxy is pretty expensive so > spun out with mixing with chalk . > In the power R case, fire-cement , padded out with sand   It is, in fact, sanded grout - which is a mix of white Portland cement, sand and water, often with an admixture that permits very thin coatings. As the material cures, it is then passed through the sand to get the coating. Look up SikaFlex or Thoroseal to understand the concept. But there was (and is) no epoxy involved - not that you stated such. So, it would be a bit of phenolic board with a nichrome wire wrap, crimped ends, coated in grout, then rolled in sand to oversimplify the process.   Keep in mind that "sand resistors", while not precision resistors by any description are rather delicate beasts and acted as a sort of fusible link in many radio designs from the 40s through the 60s - most especially those that were AC/DC/Battery.   Peter Wieck Melrose Park, PA

Unlisted <unlisted@nomail.com>: Feb 15 12:32AM -0600 Many of the power resistors have a coating that appears to be a sand-like coating on them. In some ways, it looks like some sort of concrete. It's too hard to be plaster, since it cant be scratched with a fingernail, like plaster can.   I'm just curious what the material is?

etpm@whidbey.com: Feb 14 11:25AM -0800 Finally last night I was able to sit down and figure out the probe adjustment. I have 5 probes. One 10x Tek probe, one 20x Tek probe, one Probemaster 1x & 10x probe, and two other 1x & 10x probes from China. The 10x Tek and the Probemaster probes are 100 MHz rated and made in the USA. The Tek 20x probe is 200Mhz rated and USA made. The Chinese probes are 100MHz rated. I realized the probes need to be adjusted only in the 10x mode. I didn't know that. That for sure was part of the problem. Looking at signals from my function generator it seemed that the voltage was off. Then I realized that my meter displays the RMS value of the AC signal and the 'scope displays the peak values. I got all the probes to display a nice square wave in the 10x setting. I don't know why I got really weird results before but it may be because I was in my machine shop with CNC machines running. At home with everything quiet all the probes behaved like they were supposed to. At the 10x setting. But with the probes set at 1x the square wave isn't quite square. The 3 probes that have the 1x setting all act the same, with the square wave being slightly distorted. It didn't seem to matter if the 'scope was set to AC or DC coupling. It also didn't matter if the signal being measured came from the 'scope or from the function generator. Is this normal, for the square wave displayed to be perfect in the 10X setting and slightly distorted in the 1X setting?   The 'scope is a Tek465B. The 20X probe is a TEK model P5120 The 10X probe is a Tek model P6053B The Probmaster is model 3901-2 The Chinese probes only have a model number-P6100   So, as near as I can tell, the probes are all right, at least they all act the same. But what causes the distorted square wave at the 1x setting? Thanks, Eric

Fox's Mercantile <jdangus@att.net>: Feb 14 01:47PM -0600 > The Chinese probes only have a model number-P6100   That alleges they are clones of the Tek P6100   > So, as near as I can tell, the probes are all right, > at least they all act the same. But what causes the > distorted square wave at the 1x setting?   All scopes have a basic input impedance. For a 1:1 probe to "look right" the probe has to match that. Mostly it's a matter of the scopes input stage being properly compensated for the probe's cable.     -- "I am a river to my people." Jeff-1.0 WA6FWi http:foxsmercantile.com

Jeff Liebermann <jeffl@cruzio.com>: Feb 14 01:09PM -0800 >So, as near as I can tell, the probes are all right, at least they >all act the same. But what causes the distorted square wave at the 1x >setting?   It's caused by the lack of high frequency response (i.e. rise time) in X1 mode. For a typical X10/X1 switchable problem, the frequency response is MUCH higher in X10 than in X1. For example: <https://www.tiepie.com/en/usb-oscilloscope/accessories/oscilloscope-probe-250mhz-x1-x10> Notice that the bandwidth is 250MHz in X10 but only 6MHz in X1. This one is closer to what I think you bought: <https://www.tiepie.com/en/usb-oscilloscope/accessories/oscilloscope-probe-60mhz-x1-x10> 60MHz bandwidth in X10 and 6MHz bandwidth in X1.         -- 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

Phil Allison <pallison49@gmail.com>: Feb 14 04:04PM -0800 > So, as near as I can tell, the probes are all right, at least they > all act the same. But what causes the distorted square wave at the 1x > setting?   ** What frequency is your test wave ?   About 1kHz is usual.     ... Phil

Mike <ham789@netscape.net>: Feb 14 04:30PM -0800 > But with the probes set at 1x the square wave isn't quite square. > The 3 probes that have the 1x setting all act the same, with the > square wave being slightly distorted.   If you emailed your doctor and said, "I feel slightly bad," what diagnostic would you expect?   At least describe it in such a way that one could draw an accurate picture from your description. And yes, the time dimension is relevant.     What's the output impedance of your function generator? What do you see when you plug the function generator directly into the scope, via what kind of cable?

ggherold@gmail.com: Feb 14 05:50PM -0800 > setting? > Thanks, > Eric   Cool. Hey Eric, I just want to say that one reason I enjoy sharing whatever small amount of knowledge I have with you, is that you'll always follow up and tell me how it turned out.   I wish I had more customers like that. They send me a problem... I send them off a few potential solutions, and then ~1/2 the time I don't hear back. I assume something worked... but I don't which of the three solutions it was, or they made some bone head mistake and are embarrassed.   Oh, here's a machinist question for you. When tapping holes in an easy metal, Al 6061 say, with a through hole I've got these 'gun'* taps that shoot the chip out the bottom of the hole. If I'm doing a blind hole is there a tap that shoots the chip back up the tap. (chip may not be the right word.) I tap mostly small stuff 4-40, 6-32, 2-56... in approximate order of usage   George H. *gun taps is what I call them, there is a GN on the stem.

Clifford Heath <no.spam@please.net>: Feb 15 01:59PM +1100 > George H. > *gun taps is what I call them, there is a GN on the > stem.   GN for Gun Nose.   You want a spiral flute tap, see pictures here: <https://www.cnccookbook.com/different-types-thread-taps-complete-guide-choosing/>   Clifford Heath.

etpm@whidbey.com: Feb 14 11:41AM -0800 I have decided to shop around for a couple new oscilloscopes. Most likely one new and one used. Even though I like the Tek 465B the thing is a tank. It is big and heavy and hard to lug around. And the cord keepers/feet on the back of the unit have started to fall apart. The plastic has gotten weak and brittle. So the 465B needs to stay on its roll around stand. The 'scopes I'm looking for are an analog and a DSO. The analog mainly for looking at audio signals. Just for hobby work. Just because I'm curious about the audio stuff. The analog 'scope needs to be smaller and lighter than the 465B. The DSO 'scope should probably be new or fairly new. I don't know how much bandwidth but it would be used for both hobby audio stuff and for looking at the type of signals found in CNC controls. Right now the 465B is plenty good enough, way more than good enough, to look at signals from the CNC machines but it is a big pain to use much of the time and a light 'scope that I can hang in a CNC control cabinet would be great. My budget is about $100 for the analog and $300 for the DSO. So, any advice? Did I leave out something? Thanks, Eric

"pfjw@aol.com" <peterwieck33@gmail.com>: Feb 14 11:47AM -0800 > My budget is about $100 for the analog and $300 for the DSO. > So, any advice? Did I leave out something? > Thanks,     Unless you go small-screen Chinese, you left out at least one 0 in the budget lines. Or get extremely lucky.   https://www.ebay.com/itm/Fluke-196C-ScopeMeter-1GS-s-Dual-Input-100MHz-HandHeld-Color-Oscilloscope/143130682552?epid=96937775&hash=item215340e4b8:g:eWEAAOSwt5dcZGoM:rk:7:pf:0   Is one option that will do nicely.   https://www.ebay.com/itm/Tektronix-MDO4104B-6-1-GHz-4-16-Channel-6GHz-RF-Mixed-Domain-Oscilloscope-CALD/352591154296?epid=1021994560&hash=item5218120c78:g:uDAAAOSwPsRcYLDI:rk:23:pf:0   Overkill, I agree.   More likely:   https://www.ebay.com/itm/Tektronix-TDS-2012-2-Channel-Digital-Storage-Oscilloscope-100MHz-1GS-s-Color/153378414566?epid=96950736&hash=item23b610dfe6:g:kl0AAOSwYUZcJP89:rk:6:pf:0   Or...   https://www.ebay.com/itm/Rigol-DS1052E-50MHz-Digital-Oscope-with-2-Channels-USB-Storage-Access-1-GSa-se/303061791574?epid=26027068917&hash=item468fe3f356:g:dD4AAOSwCuBcZPw7:rk:12:pf:0   Peter Wieck Melrose Park, PA

Michael Black <mblack@pubnix.net>: Feb 14 02:57PM -0500 > keepers/feet on the back of the unit have started to fall apart. The > plastic has gotten weak and brittle. So the 465B needs to stay on its > roll around stand. The 465 is a tank?   The 545 is a tank. It was working the last time I used it, but I mostly gave up on using it because it wasn't convenient, it took up too much space, and I couldn't move it around because it was heavy and big.   I had the use of a 455 (I think it was) in the seventies, and that thing was way more portable.   Michael

Fox's Mercantile <jdangus@att.net>: Feb 14 02:45PM -0600 On 2/14/19 1:57 PM, Michael Black wrote: > The 465 is a tank?   > The 545 is a tank.   The 465 is a reasonably sized scope. Quite good all in all,until the triggering fails. Good luck finding tunnel diodes these days.   If you think the 545 is a tank, I have a 511A. AC coupled, 10 MHz and ONE input channel. Of course, the 511 was Tek's first production model.   -- "I am a river to my people." Jeff-1.0 WA6FWi http:foxsmercantile.com

Ralph Mowery <rmowery28146@earthlink.net>: Feb 14 03:59PM -0500 In article <36gb6e17j1ks4trm400f1p45cfrc6julhk@4ax.com>, etpm@whidbey.com says... > be great. > My budget is about $100 for the analog and $300 for the DSO. > So, any advice? Did I leave out something?   Look at this Hantek scope. I bought one a couple of years ago. It should come with the probes.   https://www.circuitspecialists.com/hantek-200mhz-digital-storage- oscilloscope-dso5202p.html   There are a few other DSO scopes at the same place.

dplatt@coop.radagast.org (Dave Platt): Feb 14 02:21PM -0800 > The 545 is a tank.   A friend of mine has a 535, which will do for a tank. He used it through his whole career at GE, and then bought it for around $20 via the company's surplus-equipment auction a few months after he retired.   Still works, still a nice bright trace, and it's still on its original set of tubes. He loves it.   It suffered the first malfunction in roughly forever, a few weeks ago; the vertical gain fell off sharply. He didn't even have to move it off of the stand to fix it - just opened up the side, exercised the vertical gain pot a few times (it was noisy... apparently some oxide had built up over the years), recalibrated the gain, and put the side back on. All fixed.

Jeff Liebermann <jeffl@cruzio.com>: Feb 14 10:03AM -0800 On Thu, 14 Feb 2019 11:16:24 +0000, Martin Brown   >I won't use Duracell any more. I can't tell if it is a problem with high >quality counterfeit or their actual genuine manufacture batteries. There >was a time in the past when they were the copper topped gold standard!   <http://www.learnbydestroying.com/jeffl/pics/Duracell/index.html> Boom when shorted, probably because the gas vent plug was either defective or missing. I didn't do the test or take the photos, so I wasn't able to determine if they were real Duracell Procell or counterfeit.   -- 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

"pfjw@aol.com" <peterwieck33@gmail.com>: Feb 14 10:48AM -0800 About the only sure method I have found to determine what is counterfeit and what is real, other than by very close examination of the 'fit and finish' is the weight.   Real batteries are typically significantly heavier than the fakes, even discernible between two AAA types. And if you have a 4, 6 or 10 pack to compare, it is even more obvious.   You would also find out when you send that damaged piece of equipment back to Duracell or Eveready and have them inform you whether the batteries are real or not.   Peter Wieck Melrose Park, PA

Jeff Liebermann <jeffl@cruzio.com>: Feb 14 01:02PM -0800 On Thu, 14 Feb 2019 10:48:54 -0800 (PST), "pfjw@aol.com"   >Real batteries are typically significantly heavier than the fakes, even >discernible between two AAA types. And if you have a 4, 6 or 10 pack >to compare, it is even more obvious.   Yeah, that worked for a while with LiIon 18650 cells. <https://www.instructables.com/id/How-to-know-a-fake-18650-battery/> Then, I started getting cells that all weighed about 65 grams, which is rather high for an 18650. So, I cut one apart and found that it was topped off with sand and some hot melt glue to hold the sand in place. Foiled again.   >You would also find out when you send that damaged piece of equipment >back to Duracell or Eveready and have them inform you whether the >batteries are real or not.   In this case, the friend that sent me the photos had already thrown out the 9V battery. It didn't explode inside any equipment. I blew up on his incredibly messy desk/workbench when the exposed terminals were shorted by something conductive. If I had possession of the remains, I would have doing my own autopsy on the battery, instead of sending it to the manufacturer.   -- 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

Fox's Mercantile <jdangus@att.net>: Feb 14 10:41AM -0600 > Here in the States we have ~2mm tip jacks which fit the probes on your > typical DMM. As a silly idea maybe replace all the connectors with 2 mm > tip jacks?   That was my thought as well.     -- "I am a river to my people." Jeff-1.0 WA6FWi http:foxsmercantile.com

You received this digest because you're subscribed to updates for this group. You can change your settings on the group membership page. To unsubscribe from this group and stop receiving emails from it send an email to sci.electronics.repair+unsubscribe@googlegroups.com.