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A friend has a production company with an audio studio. He switched from reel to reel tape to hard files in the mid 1990s. He called me in panic yesterday when he couldn't access one of his original archival hard files. I went over and was able to "wake the drive" by tapping the hard file with the handle of a large screwdriver, I'd have used a plastic mallet if I'd had one. NOTE: Do not do this until every other trick has been tried! Some hard files have glass platters and I had to tap pretty damn hard and could easily have shattered glass platters. [How hard? Like driving a nail in concrete.] We were able to copy all the audio to a new drive but that raised a question... I've always said there are two types of hard files, those that have died and those that will. I warned him about the various ways hard files die, CD/DVD ROM rot, how audio tape can have the binder (glue) that holds the magnetic material (fancy rust) and become unusable. "Other then clay tablets with cuneiform, all media degrades over time." He also collects "tombstones". Not literally, he's a member of a local history group and they make paper tracings of the information on tombstones. I asked "How many are barely legible?" "Quite a few of the older ones." I have no idea what he's going to do, he's 78, well off financially and may decide to retire. That would be suboptimal for former clients but he is facing a nightmare in time alone to back up all the hard files. Since each client's data is on their hard file(s), I suggested he contact them and give them the hard files with the suggestion "Back this up today!" Most of us don't give much thought to preservation of archival data but maybe we should. Here are two links that look at the issue https://arstechnica.com/gadgets/2024/09/music-industrys-1990s-hard-drives-like-all-hdds-are-dying/ https://arstechnica.com/features/2005/02/hdfailure/ NOTE: I've avoided Apple products and have no idea what magic key strokes he's describing...and I'm happy to remain ignorant. Several friends have contacted me over the last 20 years with I-Omega zip drives with "Data I have to recover!" I wished them luck and told them I have zero experience with zip drives and intend to keep it that way. I have had CD-R/DVD-R fail and 1 early commercial CD music disk lose 2 tracks. I was a bit irritated but found a new CD and tossed the old one. I have a large "archive." [if such a mess of unorganized data can qualify as an archive.] I haven't lost a drive, yet. I'm in the process of pulling the most important data to new hard drives. Since I have several Exabytes of data...yea it's a lot of unfun. I inherited 3 NTSC digital video editing systems after helping upgrade a local production house upgrade to digital. Digital video editing requires very fast RAID hard files, older hard files that were perfect for NTSC won't work. Not needing any video editing systems, I salvaged the drives and sold the stripped carcasses. The 'unlimited' storage allowed me to save anything online I found the least bit interesting. I'm having a difficult time separating the wheat from the chaff. What to save and what to let nature take her course.... or just erase it all...

The following items have been added to the Files area of the [email protected] group. /counter info..pdf By: paul larner <quadzillatech@...> Description: more info on chinese 8 digit counter moduals inc schematics.

The following items have been added to the Files area of the [email protected] group. /aliexpress frequency counter modual manual+ schematic/PLJ-8LED counter.png /aliexpress frequency counter modual manual+ schematic/PLJ-8LED_Manual_Translation_EN.pdf By: paul larner <quadzillatech@...>

Hi all, I have a cheapo PLJ-8LEDfrequency counter modual,it works ok but for anything above hf needs a lot more drive,can anyone recomend or link to a schematic for a wideband buffer and amplifier to make this work upto uhf?,thanks in advance,i have added the manual and schematic to the files section.

Is there software that can convert schematics to a circuit board design? I have some schematics that I want to see if I can make a circuit board from (perhaps to 'recreate' the device that schematics are of).

The following items have been added to the Files area of the [email protected] group. /PLJ-8LED counter.png By: paul larner <quadzillatech@...> Description: counter schematic

This will be my last post on non-LED semiconductors emitting light. First, all of the forward biased semiconductors I tested emitted light. The glass cased silicon diodes were the easiest to verify, I chopped the tops of several TO-3 and TO-5 transistors. All of the emitted light required a night vision (starlight) scope to see. 4th vision nightvision scopes have between 25,000-110,000 gain, the exact gain figures are apparantly restricted by ITAR [International Traffic in Arms Regulations]. However reverse biased semiconductor junctions are a different story. I'll admit I was pleasantly surprised.... A friend gave me this link. Interesting to be sure but I doubt it's practical. http://cappels.org/dproj/Avalanche_Photogenerator/Avalanche_Breakdown_Photoemission_and_the_Photoelectric_Effect_in_Bipolar_Transistors.html And it might be worthwhile to follow the links here https://www.eevblog.com/forum/projects/transistors-die-pictures/ This image is fascinating and I was able to come very close image with a 1980s 2N2222 with the top removed. https://www.richis-lab.de/Bipolar02.htm This light is clearly visible in a dark room. I sacrificed 3 2N3055s. These were older RCA units with excessive leakage. All 3 emitted nice light when the collector to base junction was reverse biased to break down. Note: Limit breakdown current to a few mA. This has been an interesting, if relatively useless experiment.

Hello , I have an intresting phenomena when I am trying to lock my PLL by the system shown below.(from the attached article. My error voltage which is IF of a mixer gets amplified and the amplified signal goes into YIG(VCO) When the phase difference voltage is low and rippling as shown in photo 1, then I see the VCO going crazy back and forth changing the frequency as shown in photo 2. However when I turn the phase shifter and the error voltage is getting higher then I get straight line error shape and a single tone(as shown in the attached video in the link) I wonder about two things : 1.When I put big phase shift then IF signal voltage also is high. High IF signal goes into my amplifier and its getting comppressed (final amount of current going into YIG) So thats in turn creates a final amount of shift in the VCO so thats why i get a single tone. But error signal after the feedback is a straight line. What is the meaning of that? 2. My VCO needs to be connected as negative feedback. Does it act like the feedback is negative in my system? Thanks. /g/electronics101/photo/296358/3860748?p=Created%2C%2C%2C20%2C2%2C0%2C0 /g/electronics101/photo/296358/3860749?p=Created%2C%2C%2C20%2C2%2C0%2C0 /g/electronics101/photo/296358/3860750?p=Created%2C%2C%2C20%2C2%2C0%2C0 /g/electronics101/files/john233/High_spectral_purity_microwave_oscillator_design_using_conventional_air-dielectric_cavity.pdf Video link: https://technionmail-my.sharepoint.com/:v:/g/personal/yefimv_technion_ac_il/ES9y1VBxJVBAlNUUmKMyMT8BGzjR9Kd-cN36A6_6LWSdmg?e=duFpS5&nav=eyJyZWZlcnJhbEluZm8iOnsicmVmZXJyYWxBcHAiOiJTdHJlYW1XZWJBcHAiLCJyZWZlcnJhbFZpZXciOiJTaGFyZURpYWxvZy1MaW5rIiwicmVmZXJyYWxBcHBQbGF0Zm9ybSI6IldlYiIsInJlZmVycmFsTW9kZSI6InZpZXcifX0%3D

paul larner <quadzillatech@...> added the photo album my psu : my psu pics

We've had several requests over the last few years for LED flashers for model train enthusiasts. One problem with most LED flashers is the go from full off to full on whereas old style caboose, water tower, and crossing gate lights were incandescent and ramped up and down. If you look at brake lights on cars in traffic it is easy to see this effect, the LED brake lights come on instantly and the incandescent ramp up when turned on and down when turned off. I have no idea what degree of realism model train types want or can achieve. I remember with my model trains as a child I was unhappy with the 'acceleration curve,' you went from standstill to ~20MPH. And yes I know there are better controllers today. http://cappels.org/dproj/1.5V_Red_fader_blinker/1.5_volt_1970%27s_style_caboose_marker_flashing_led_light.html There is a short MOV you can download to see if the effect is what you want. [I stumbled on this by accident and can offer no advice.]

Right - new moderator off the rails! -- G.T.

I am an idiot. Yep, it is confirmed. I've spent a lot of spare time in the last 2 months getting a hi-impedance analog meter suitable for aligning a radio's intermediate frequency. And I have a perfectly good HP 400E AC voltmeter, response +/-10% full scale 10Hz to 10MHz. I've had this meter for 40+ years, use it several times a week to measure the audio, 10Hz to 20kHz, levels in various audio systems. And 2ish months ago I needed a high impedance analog meter, the 400E has an input impedance of 10 meg. And I never considered I could use this meter for aligning a 455kHz IF strip! Argh...before going to a lot of trouble searching for the proper piece of equipment ... stop and think about your task and what equipment you have. I could even have used my oscilloscope, but no I had to do it the hard way because I became fixated on "I need a high impedance, wide range, RF voltmeter." Well at least I now have a nice Simpson DVM with analog sub-meter and a nice Heathkit FET "VTVM" [their label, to me a VTVM has a vacuum tube] And I've learned an valuable, if embarrassing lesson. Can't wait to share this with the SWL club. They can use a good laugh.

I used SMC, sort of old school term for surface mount components. Here is a better description of various surface mount things... https://www.opledtw.com/blog/what-is-smd-smt-sma-smc/ What is SMD / SMA / SMT / SMC / SMP / SME? What’s the difference? I use SMC for all those tiny bits. Call the language police and have me arrested.

I've been working on a Simpson 460-3 DVM with analog sub-meter. There are 2 primary scales, .200V and 2.0V, all the higher voltages are attenuated to one of those. The zero and +/-2.0V was a breeze, the .200V has been a nightmare. Two controls interact. After switching the Vin bananas a few dozen times I decided enough and rigged a special 'calibration cable' with a 4PDT switch with gold/palladium contacts as a DPDT to reduce any contact resistance. To change from Vcal+ or - to the opposite means flipping the switch. I've got it so the V+ is 10.00V, and the V- 10.01, I'd prefer V- to be 10.00 but I'll accept what I've got. I obtained this meter because of the analog sub meter. Aligning RF stages is a challenge with a DVM, the analog meter is an ~3 inch wide and ~0.5 inch wide edge meter and very nice for peaking and nulling RF stages. My next project is assembling a Heathkit IM-28 VTVM. While labeled as a VTVM it is actually a FET and opamp meter. As I've noted before, I no longer use alkaline cells because of repeated leakage problems and use primary lithium. Lithium cells have a ~10 year life expectancy and don't leak. Can you drown in test equipment.

I went with a friend to a shop that specializes in kitchen remodeling. They have many 'blanks' left over after they cut out the space for kitchen sinks. Different shops probably deal with these "blanks" but we were given as many as we could load in a SUV. The blanks are a bit on the small size but suitable for mounting items like drill presses, grinders, etc, or a table for a SMC workstation. We stopped by Habitat For Humanity and I picked up a rough small table and I've sat up a dedicated SMC workstation. This might be an inexpensive way to obtain work surfaces.

Hello , I have the following component shown below which needs to be used as frequency detector. Is there some datasheet for this component? I could not find datasheet in google. /g/electronics101/photo/296358/3858703?p=Created%2C%2C%2C20%2C2%2C0%2C0

Been using hard drives ever since that first ST-225 (which I still have!) and have a couple of boxes of "ATA" drives, along with an external drive interface that will hook up to those, SATA, laptop drives, etc. What I'm seeing is that when I hook a drive up to this interface (which has its own power brick and power interfacing cables) I can hear/feel the drive spinning up, but that's about the extent of what I get. The computer just doesn't seem to "see" the drive at all. I can't tell if the drive is initialiizing properly or not. What I'm wondering is what goes wrong on the electronics of these? Before I go ahead and tear 'em apart for scrap. Any ideas as to how I can proceed further with testing these? -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, a critter that can be killed but can't be tamed. --Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin

The IEEE is like Disney, they are extremely protective of their intellectual property. I took a chance and deleted a post that gave a link to bypass a paywall. I believe it violates Groups IO terms of service. I'd like for other mods and owners to confirm my action was proper.

Hello,I have made of a system which is based on the article attached. I tuned the YIG to the resonance of the resonator, then i measured the output of the IF on a scope as shown below. When I tuned to ph2 pase shifter i see the "error voltage" level shanges which need to go back to the YIG "FM" port as shown below. Also i need to make sure that the signal going back to the YIG is something which the YIG could make changes so It will be sensitive to the signal. How do i need to tune the phi2 phase shifter so I wull get a lock in the resonance frequency? https://www.artisantg.com/info/Avantek_AM_4060M_Manual2_201622493619.pdf /g/electronics101/photo/296358/3858955?p=Created%2C%2C%2C20%2C2%2C0%2C0 /g/electronics101/photo/296358/3858956?p=Created%2C%2C%2C20%2C2%2C0%2C0 /g/electronics101/photo/296358/3858957?p=Created%2C%2C%2C20%2C2%2C0%2C0

A digital audio sinewave generator that uses delta modulation is supposed to have one output only (one MCU pin, for example). It outputs a delta bits stream which, after filtering, gives a low THD (around 1%) sinewave. The audio spectrum is, typically, from 20 to 20,000 Hz. I asked this question because I work on such generator since about 2 years (though not full time, just in my free time). I used to call its project ‘Delta Sinewave Synthesis, DSS. As most of you know, there is already DDS, Direct Digital Synthesis, generators. So, if we call DDS a parallel DAC, DSS would be called a serial DAC. The goal of my project is to let the hardware very simple. For example, the LPF could be just a passive 3 RC one (3 poles). This is possible if the frequency of the delta clock is made to be much higher than of the highest sinewave one of interest. In my project, it is 2,000,000 Hz (100 times higher than 20 KHz). But perhaps I was just re-inventing the wheel :( Kerim