hybridfree/eevblog-posts huggingface dataset:
Modify Fluke GFCI tester - Page 1
Forum section: electronics / beginners

author: zetsubou
author_rank: Contributor
timestamp: August 13, 2017, 07:21:05 am
content: Hi everyone,I have a Fluke T+Pro that comes with a GFCI test built in. It's rated at 150 V - 240 V < 12 mA but I require a 30mA test current.Would this be a simple modification?

author: Electro Detective
author_rank: Super Contributor
timestamp: August 13, 2017, 07:52:30 am
content: Have you tried it? My Fluke T100 trips any 30ma GFCI/RCD without a problemThey usually trip anywhere between 15 to 25ma anyway.Give it a try, but make sure you understand and follow the Fluke instructions

author: zetsubou
author_rank: Contributor
timestamp: August 14, 2017, 12:05:26 am
content: Hey thanks for replying. I've tried it on different brands and types of RCBOs and RCDs, single and three phase. Prongs in Active - Earth, GFCI button to make the +- lights dance but the outlet doesn't trip. I've verified RCD functionality with a solenoid tester.I had a quick look at the T100 manual and I think it's rated for 10 and 30mA tests. This might explain why it works when the <12mA T+Pro doesn't.

author: Zero999
author_rank: Super Contributor
timestamp: August 14, 2017, 07:54:18 am
content: Perhaps you've got the US version?In the US, they have one GFCI (as they're known there) per socket, so the trip current can be lower, without nuisance tripping. I believe in Australia, one RCD is used for an entire circuit on a 16A breaker, so a higher tripping current is necessary to avoid nuisance tripping.I'm always weary about modifying test equipment, especially the type used to test a safety critical device such as an RCD. I strongly recommend you buy one with the correct current setting, rather than modifying it.

author: Electro Detective
author_rank: Super Contributor
timestamp: August 14, 2017, 09:56:46 am
content: Second vote to 'no mods', not worth it from many anglesIt may be the Fluke T+Pro is designed to not trip RCD/GFCIs whilst CAREFULLY prodding aroundYou could stuff about with external addon tripping resistors, but why risk a bad hair day when gadgets like this for $29 get the job done really wellwww.ebay.com.au/itm/CABAC-POWER-POINT-GPO-TESTER-V2-RCD-TRIP-AUSTRALIA-POWER-OUTLET-230V-10AMP-NEW-/222038857753?hash=item33b28c1819:g:x1gAAOSw~otWdy0rDatasheet:www.cabac.com.au/shop/media/Pdf/Product/datasheet/0010/tel1tlv2.pdfIt's nowhere near as comprehensive and detailed as a proper digital RCD tester, nor does it test at 180 degrees polarity,but with selectable 10ma to 35ma trip settings, you can't beat it as an RCD-GFCI 'go/no go' testerI have one as a backup, and when it agrees with the digital unit, I know the RCD/GFCI will trip when it shouldIt also tells you at a glance if the power socket is ok.. or miswired and treat someone soon to a Darwin AwardYou could in theory rig up a 240v socket to lead probes adapter if the GPO style doesn't suit your working habits.I haven't tried it, as I do it the hard way, with long extension cords going to outlets under test, and trip and reset at the board (note: only when working solo)
Modify Harman / Kardon Soundstick USB speakers to add AUX input (IC has AUX IN) - Page 1
Forum section: electronics / beginners

author: gotoid
author_rank: Newbie
timestamp: July 21, 2017, 08:34:06 am
content: Hello all,I want to modify the Harman / Kardon Soundstick speakers that currently only have digital input through USB, to also receive input form an AUX source - without canceling the USB input.I have found this french site (Google Translated)http://translate.google.com/translate?hl=en&sl=auto&tl=en&u=https%3A%2F%2Fwww.logre.eu%2Fwiki%2FSoundsticks_USB_vers_jackwhich lists the steps to make this modification by bypassing the DAC and using the USB cable wires to convert to a 3.5mm jack plug.What I would like to do is keep the digital in from the USB, but also add an AUX IN.From the french site I have found the data sheet for the UAC 3552A IC which handles the USB connectivity and DAC:https://www.logre.eu/mediawiki/images/7/7a/Uac3552a.pdfReading though the data sheet, it appears that the IC has an option to receive AUX.My question is how to go about adding the AUX IN using the functionality provided by the IC. I am having some difficulty in figuring out what the circuit would look like.The plan is to add a 3.5mm jack socket to the woofer so I can use a standard 3.5mm jack to jack cable to connect the speakers to devices.Would I need to add a switch to select between USB and AUX, or is there some way to wire the socket so that the IC switches to AUX when a jack is plugged in? In the data sheet it states that "AUXEN (33) Aux enable. This pin must be connected to VSS if an analog source is connected to the AUX input. Otherwise connect to VDD".The data sheet also states that the input signals for AUXL AND AUXR should be connected by capacitive coupling: "AUXL (36) AUXR (37) The AUX pins provide two analog stereo inputs. Auxiliary input signals, e.g. the output of a conventional receiver circuit or the output of a tape recorder can be connected with these inputs. The input signals have to be connected by capacitive coupling.". If I am reading the "4.2. Typical Application" correctly, I would need to add one 470nf capacitor on each AUXL and AUXR. The diagram states "470n" which I guess means 470nf?Basically I am a bit in over my head regarding the information I am reading in the data sheet, and I need some help to decipher the "4.2. Typical Application" diagram witch I guess provides all the information I need, but I just don't understand everything.P.S. there is also a note on Page 8 "Table 2–1: AUXEN pin" that I don't really understand and don't know if I should be concerned about, because I don't know if BassBoost is even enabled when connected through USB: "The AUXEN pin also keeps the UAC 3552A from entering the low-power mode when an analog source is connected. Please note that in this mode, the UAC 3552A is not USB compliant. If the USB is not connected the GPIO pins work as an USB-independent volume control (see Table 2–2). BassBoost is not supported in this mode."Thank you for taking the time to read this. Hopefully someone can help me with the circuit for this mod. Please let me know I can provide any additional info.
modify LED torch to remove the multi-press mode to change to simple on/off  - Page 1
Forum section: electronics / beginners

author: steve65
author_rank: Newbie
timestamp: May 18, 2023, 12:09:51 pm
content: I have a 3xAAA cell LED torch which has several modes - Bright, Dim, Flashing, Off - selected by repeatedly pressing a switch.For various reasons, I want to change the way it operates so that as soon as power is connected, it turns on in the first mode ie Bright, without the need to press a switch.The circuit and photo of the board is shown in attachments - there are only 5 components the LED, a resistor, a capacitor an IC and the switch.The IC has 6 pins, and has the numbers 51 and 2 printed on top.I've spent some time searching for clues on the IC or how the circuit might be modified, but no joy.Could anyone explain how the existing circuit works? What is the IC - a microcontroller?Many thanks...

author: Old Printer
author_rank: Frequent Contributor
timestamp: May 18, 2023, 01:34:49 pm
content: Quite certain it is a MCU. I can't help much beyond that except I have the same type of light and the three different options are a PITA. Would love to convert it to simple on/off just haven taken the time yet so I will watch this with interest. It should be pretty straight forward I just don't have the time right now to look into it and my knowledge of MCU's is very limited so I would likely go around that, but it would be fun to reprogram it.

author: steve65
author_rank: Newbie
timestamp: May 18, 2023, 01:49:28 pm
content: Thanks for your comments.One thought I had was to replace the switch with an electronic switch circuit, (using transistors?) to somehow replicate a single-press when power is applied.Another was to bypass all the circuitry and just connect the LED in series with a resistor to battery, but it would be nice to keep the MCU - presumably it has some smarts to shut down if the battery is low or limit the current etc.

author: edavid
author_rank: Super Contributor
timestamp: May 18, 2023, 03:13:33 pm
content: It's a dedicated flashlight IC rather than an MCU.You could replace it with a resistor, or with a current regulator like the common 7135. Obviously you'll need to measure the LED current.

author: Old Printer
author_rank: Frequent Contributor
timestamp: May 18, 2023, 04:32:34 pm
content: Quote from: edavid on May 18, 2023, 03:13:33 pmThanks,Not realizing that existed, it certainly makes more sense than programing a pic, and probably more durable.
Modify PIR sensor motion detector circuit - Page 1
Forum section: electronics / beginners

author: fixit7
author_rank: Regular Contributor
timestamp: May 15, 2019, 05:18:43 pm
content: Can this be modified to use a piezo buzzer?https://circuitdigest.com/electronic-circuits/pir-sensor-based-motion-detector-sensor-circuitThanks.

author: soldar
author_rank: Super Contributor
timestamp: May 15, 2019, 09:41:47 pm
content: Yes but wouldn't it be simpler to just buy one with a buzzer? Like the ones they have in stores when a customer walks in or out. They are very cheap.

author: fixit7
author_rank: Regular Contributor
timestamp: May 15, 2019, 11:49:57 pm
content: Quote from: soldar on May 15, 2019, 09:41:47 pmI could but I would not learn as much.And I want to be able to modify the circuit.

author: soldar
author_rank: Super Contributor
timestamp: May 16, 2019, 12:01:59 am
content: You can try this.

author: floobydust
author_rank: Super Contributor
timestamp: May 16, 2019, 12:20:36 am
content: The HC-SR501 IR motion sensor uses the BISS0001 motion sensor IC. It has a weak output. You need to add a NPN transistor to drive piezo beeper or relay.For more information, look for BISS0001 circuits.

author: fixit7
author_rank: Regular Contributor
timestamp: May 16, 2019, 12:54:10 am
content: Quote from: soldar on May 16, 2019, 12:01:59 amCan you tell what the components are in the circles?https://www.dropbox.com/s/304fxi6qtm4g5ne/MotionDetector.png?dl=0

author: techman-001
author_rank: Frequent Contributor
timestamp: May 16, 2019, 01:12:28 am
content: Quote from: fixit7 on May 15, 2019, 05:18:43 pmSure easy peasy , learn about transistors and or fets and use one in place of the led, to drive a buzzer.

author: fixit7
author_rank: Regular Contributor
timestamp: May 16, 2019, 02:05:53 pm
content: Quote from: techman-001 on May 16, 2019, 01:12:28 amThanks.I am reading Practical Electronics for Inventors.I could use some more details on your recommendation.I am a relative beginner.
Modifying a cheap fan control - Page 1
Forum section: electronics / beginners

author: 0xdeadbeef
author_rank: Super Contributor
timestamp: February 04, 2013, 06:52:15 pm
content: Lately I decided to add a new fan with temperature control to an USB3 HDD enclosure and since I was lazy, I ordered a cheap SMD fan control branded H-Tronic together with a Sunon 0.8W fan. Anyway, while the fan control was assumed to lower the voltage down to <6V at room temperature, it lowered it only to ~8.5V with my Sunon fan. I figured it was designed for bigger fans with higher wattage, so I thought about modifying it a bit to fit my fan better.Originally I thought the circuit would be something like this:http://members.financial.com/~schmaus/luefter/luefterSchaltplan.gifYet when looking more closely at the circuit, I came up with another circuit though. I'm not sure about the transistors. I suppose that T1 (BLD 2H) is a NPN and T2 (BK2 2D) is a PNP. I measured the NTC as 7.6k at room temperature. Don't take the exact types too serious, I just selected them for the schematic (and simulation) without putting to much thought into it.The resistors are obvious - except for R1, which is labeled "010" as far as I can tell, which doesn't seem to make much sense. Besides, I measure it as ~7k which seems to be plausible as this would fit the NTC.I simulated the circuit in NI Multisim and it seems to be very close to the real thing. Based on this schematic, I think I should select ~200Ohm for my Sunon ML 4010-12 S (12V, up to 0.065A ).So do you think the schematic makes sense and fits the circuit? What puzzles me a little is that the 75Ohm resistor R4 is a 1206 package, which should be only 0.25W. Yet the manual claims that the circuit was meant for up to 400mA at 12V (4.8W). With T1 off, and assuming that the load resistance was around 30Ohm for a 4.8W fan, the current flowing through R4 would be ~114mA. This would be nearly 1W at R4 which is four times what it could take.Even with a load resistance of ~75Ohm, the current would be 80mA resulting in ~0.5W which is still twice as much as the maximum value.

author: Simon
author_rank: Unknown
timestamp: February 04, 2013, 09:04:38 pm
content: unussual

author: 0xdeadbeef
author_rank: Super Contributor
timestamp: February 04, 2013, 09:14:01 pm
content: That's what I thought when I realized the 75 Ohm resistor was connected directly between 12V and the output. So it takes the complete current when T1 is off. This came a bit unexpected and I'm still not sure whether this is such a brilliant idea.I first assumed that the concept was to split the current between transistor and resistor to distribute the dissipation, but indeed at maximum voltage, the main current flows through the transistor and the resistor takes only like 10mA.
Modifying a Class A amplifier design for more gain - Page 1
Forum section: electronics / beginners

author: AlessandroAU
author_rank: Regular Contributor
timestamp: February 27, 2015, 12:01:15 pm
content: Hi all,I've built this small circuit and am using it as a microphone preamplifier:http://sound.westhost.com/p13_fig2.gifsource:http://sound.westhost.com/project13.htmIt has a maximum gain of about 30dB. Would be feasible to increase the gain to around 50dB by adjusting values with the existing circuit topology or would a different design be required?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 27, 2015, 12:49:38 pm
content: Different design. Or cascade more.Trying to obtain much higher gain from a simple amplifier will also see your bandwidth shrink. Better to use more stages of less gain.Tim

author: German_EE
author_rank: Super Contributor
timestamp: February 27, 2015, 04:44:21 pm
content: Rod Elliott knows what he's doing when it comes to audio design and I would be very reluctant to change any of the component values. Also, think of this, a gain of 50dB is about a x316 voltage gain which is a lot for one stage. Best to cascade them.

author: Zero999
author_rank: Super Contributor
timestamp: February 27, 2015, 08:01:07 pm
content: Configure the amplifier so the current through the transistor is constant.http://david.alfa-romeo.eu/elektro/Elektor_Electronics/2004/Elektor%202004-10.pdfhttps://www.eevblog.com/forum/testgear/state-of-the-art-oscilloscopes-10-years-ago/msg564674/#msg564674
Modifying a CM6206 audio controller? - Page 1
Forum section: electronics / beginners

author: shawly
author_rank: Newbie
timestamp: January 20, 2023, 01:09:57 pm
content: Hi!Does anybody know if it is possible to modify aCM6206 audio controllerto disable SCMS?I've been trying to fiddle around withhttps://github.com/vestom/cm6206ctlto unmute the audio when the copy protection kicks, but I didn't get the controller to unmute the sound. So I thought that there might be a hardware solution.I've been using a Creative X-Fi PCIe soundcard to record or rather pass through digital audio through SPDIF to my headphones for years and it ignores the copy-bit, but I'm trying to achieve the same thing with a USB sound card so I can finally free up the PCIe slot in my computer.20 years ago there was a copy-bit killer device, but build instructions and probably part availability has been lost to time, apart from the fact that it is quite big by today's standards.Or do you know any other way that is not analog? In the end I'm "just" trying to listen to the sound from my HDMI audio extractor through my PC, so I'm basically mixing PC audio and HDMI audio from my HDMI devices with the least possible delay (I actually don't notice any lag).Been skimming through the net for years, but it's just a niche scenario since most people don't need this, so there aren't many solutions to this problem apart from the PCIe card.
Modifying a TDA2822M board to have wider bandwidth - Page 1
Forum section: electronics / beginners

author: Amish_Fighter_Pilot
author_rank: Regular Contributor
timestamp: June 01, 2025, 10:52:19 am
content: I have a generic Chinese TDA2822M audio amplifier board that I want to raise the ceiling on the low pass filter. I would assume it's set up with a crossover at 15-20KHz, but I'm not certain yet as I have not had a chance to test that.Can anyone give me a general idea what values I can change these to in order to put the cutoff at closer to 100KHz(I believe the chip itself can only go to maybe 125KHz, so that's why I picked that number to be safe).

author: ahsrabrifat
author_rank: Regular Contributor
timestamp: June 01, 2025, 12:32:39 pm
content: If you have an oscilloscope + function generator, sweep a sine wave and watch the output roll-off.

author: Amish_Fighter_Pilot
author_rank: Regular Contributor
timestamp: June 01, 2025, 07:43:11 pm
content: I have a Fnirsi DSO510, but I don't know how to do a sweep with it. The FG-200 might be able to, but I can't find a manual for it anywhere. I can do it the slow way without a sweep when I get a chance.

author: mikerj
author_rank: Super Contributor
timestamp: June 01, 2025, 08:20:46 pm
content: I don't see anything on the PCB that would suggest a low pass filter on the input to the amp, it appears to be the standard reference circuit from the datasheet. Bear in mind that the TDA2822M has not been made for quite a while, so these modules are very likely to have counterfeit/clone part whose performance is not necessarily the same as the genuine IC.

author: Amish_Fighter_Pilot
author_rank: Regular Contributor
timestamp: June 01, 2025, 08:32:31 pm
content: I am not savvy on the world of fake chips, but do they typically at least kind of follow original spec? Some of these knock-offs seem very sophisticated. I guess I'll find out what it can and cannot take. The plus side is that these boards are about $2 USD each.....

author: edavid
author_rank: Super Contributor
timestamp: June 01, 2025, 08:54:15 pm
content: It is interesting that the TDA2822M datasheet does not give even a hint what the bandwidth is.The TDA2822D has a vague, typical-only power bandwidth spec of 120kHz, but no hint what distortion is at that frequency.OP, if you want to build a 100kHz amp, you are probably going to need a better IC.

author: Amish_Fighter_Pilot
author_rank: Regular Contributor
timestamp: June 02, 2025, 08:30:12 am
content: Yeah you're right. I was being impatient and hoping I could repurpose one of these for a stop-gap measure. I will just have to wait until better parts arrive. I still may try to torture test one of these and figure out what it really can do.
Modifying an Alarm Clock Using Mosfets  - Page 1
Forum section: electronics / beginners

author: menimitz
author_rank: Contributor
timestamp: April 18, 2013, 06:58:33 pm
content: I wasn't sure whether to ask this here or on another part of the forum, but this feels like a beginner's issue so here it goes.I have an alarm clock that I would like to modify so I can control it with a micro-controller. I eventually want to build my own alarm clock for this project, but don't have time at the moment to do that.I want to be able to switch the alarm mode on and off using the uC. Below is a rough diagram of what I believe the switch does after cracking it open:(I can't seem to figure out how to post an image so...)Sliding Switch______ ONVdd_________/______ OFFON and OFF run under the 7-Segment Display to what I assume is a uC.How can I replace this switch with a transistor setup?I couldn't find common inside the clock, and most of the main pcb is covered by the 7-segment display which is held down with sonic welds I don't want to break.Any thoughts on how to switch this would be greatly appreciated. I don't have any experience with mosfets but would like to use them more just to get acquainted with their use.Thanks for any advice here.

author: PA0PBZ
author_rank: Super Contributor
timestamp: April 18, 2013, 07:31:28 pm
content: You can probably just switch it with a digital output of a uC, it's likely just a 1/0 input.Can you see what kind of chip is in there? Maybe find a datasheet and see how the alarm is switched on and off.If that is a dead end you can measure what the switch does (you have a DMM I hope), and if it looks like weird signals or voltages you can always use an analog cmos switch.

author: menimitz
author_rank: Contributor
timestamp: April 20, 2013, 02:38:37 am
content: I do have both a DMM and an old Tek scope I just didn't have a chance to take any real measurements yet. I guess my real question here is how do you switch a load using a fet in that configuration. I only know how to use them with the source connected to ground. Is it possible to use one in that crude circuit above.This has really turned academic at this point because I think I may scrap the project in its current form anyway.
Modifying battery level indicator circuit - Page 1
Forum section: electronics / beginners

author: bryanh2
author_rank: Newbie
timestamp: March 17, 2023, 11:46:47 pm
content: Hey guys,I bought some cheap battery level indicators a few years ago. They work for 3s 10.8v-12.6v batteries. I was wondering if it was possible to modify one to work for 5s 18-21v batteries. They sell varients that do this and they seem to use the same basic circuit boards. Does anyone see where I can replace a resistor or diode to change this value?Thanks much appreciated.

author: james_s
author_rank: Super Contributor
timestamp: March 18, 2023, 12:09:54 am
content: What is that IC? I can't read the number in the photo.I think it's highly likely that you can change the range by altering the value of a resistor. I would look for a pair of resistors that are in series, with one of the free ends connected to the + rail and the other to ground.

author: Kim Christensen
author_rank: Super Contributor
timestamp: March 18, 2023, 12:23:08 am
content: I'm guessing the chip is a LM324... Looks like changing R7 for a higher value might work, but not 100% sure because we are just guessing at the circuit. Do you have any documentation or part numbers for these boards?

author: bryanh2
author_rank: Newbie
timestamp: March 18, 2023, 12:56:17 am
content: You are right it is a LM324. No I can't find any documentation about it.https://a.aliexpress.com/_mNYQWKIIts a very cheap part so I'll try change that resistor and if it doesn't work I'll just order the 20v version. Thanks for the help!

author: james_s
author_rank: Super Contributor
timestamp: March 18, 2023, 06:57:31 am
content: The circuit is going to be wired up as four comparators, each driving one of the LEDs. There will be a single voltage rail that each of them looks at and that's going to be the output of a divider, shouldn't be too hard to figure out. Might help to draw the circuit.
modifying old soudcard to output DC? - Page 1
Forum section: electronics / beginners

author: dentaku
author_rank: Frequent Contributor
timestamp: November 09, 2013, 03:13:19 pm
content: I know this sounds a bit strange but...Does anyone think it's possible to modify an old soundcard (PCI SoundBlaster etc.) so that they output DC?I have some old soundcards lying around and the real Creative Labs one has some regular electrolytic caps on it so if one of those is a decoupling cap for the output it seems like I might be able to short it and have the output send DC.At the moment only professional MOTU audio interfaces seem to be DC coupled.

author: garak
author_rank: Contributor
timestamp: November 09, 2013, 05:47:54 pm
content: Yes, this is certainly possible, and people frequently do it. Without seeing your specific card I can't say which exact capacitors you would need to bridge, but I doubt they'll be electrolytics. My money's on ceramic SMD jobbies. Trace the signal lines from the jack back to the DAC, you should be able to find them without much hassle.

author: dentaku
author_rank: Frequent Contributor
timestamp: November 09, 2013, 09:34:56 pm
content: Since it's a SoundBlaster Live! CT4830 I was hoping the output was using the easy to modify through hole Nichicon caps but of course I'm just hoping it's those because they're easier to work withWe'll see. I guess it will be a learning experience for me to track down the path to the line-out.Quote from: garak on November 09, 2013, 05:47:54 pm

author: tszaboo
author_rank: Super Contributor
timestamp: November 09, 2013, 09:41:16 pm
content: I would rather build a peak detector circuit, and use that to create DC signal from a soundcard. Output a 10KHz signal, volume is the DC.

author: dentaku
author_rank: Frequent Contributor
timestamp: November 10, 2013, 01:42:53 am
content: When I watched this video a while ago I wondered if it would be useful for creating control signals for a VCO.http://www.eevblog.com/2013/06/29/eevblog-490-peak-detector-circuit/It would still be great to modify an old unused soundcard and use it to control a VCO though. It's just to experiment with something similar to MOTU Volta.http://www.motu.com/products/software/volta/body.htmlQuote from: NANDBlog on November 09, 2013, 09:41:16 pm
Modifying vintage toy: Adding sound, and automatic turn off - Page 1
Forum section: electronics / beginners

author: ampliwire
author_rank: Newbie
timestamp: January 28, 2018, 04:11:27 pm
content: Greatings everyone!I recently started a new project. I'm going to modify a vintage toy powered by two D batteries in series.The plan is to add ''sound'', and automatic switch off.Delay circuit:As of today the unit stays on till you turn it off, but I would prefer if it stopped after 12 secounds. I was woundering if it is possible to add a relay delay circuit, but the voltage from the batteries is only 3V..I briefly read a bit about 555 timers, but I didn't quite understand if this is something I could use.The toy has a standard SPST switch, but I'm soldering a spring loaded one instead, so I can use one of the relay poles as a holding circuit. (that is if I could use a relay of course)The talking function:So I'll use a tiny D class amplifier, and a tiny speaker. But I don't know what to use as a file source, I do believe arduino could be usefull for this? Never used one before, but I hope it's not too hard to program.The functions I need is for it to play the sound file when voltage is applied. I will add several files so it need to have a random function as well. This is because I don't want it to play the same file, everytime I turn it on. Later I was thinking of maybe just using a old .mp3 player, but they don't come with automatic turn on when voltage is applied..Also I'd like to do the mod as cheap, and small as possible because of space issues.Anyone have a solution?

author: 0xdeadbeef
author_rank: Super Contributor
timestamp: January 28, 2018, 05:26:18 pm
content: Dunno if that helps but for a fun robot project I used one of these ultra-cheap "DF player mini" clones from China. They sell for 1-3€ from China.Mine had a YX5200 chip on it which can be controlled through UART and has a 3W amplifier integrated. But I think there are derivatives with other chips.I chose the YX5200 as it can be controlled through UART, but there are also four input pins to control it. Didn't test it, but I understand you could use four pins to control it.Anyway, also given that the XY5200 needs some time to boot/scan, I guess for your purpose, there are other MP3 chips/boards which might work better.E.g. there's module called BY8001 which has five IO pins to control playback. Can't really tell if it would play track 1 if you tied IO1 to ground, but it's worth a try.Otherwise you'd need at least a little timer and a transistor to trigger the pin for a certain time. Can't tell about boot time though.
Moding server power Supply - Page 1
Forum section: electronics / beginners

author: Charlie86
author_rank: Regular Contributor
timestamp: January 26, 2019, 09:31:58 pm
content: Hi,I want to use power supply from old server for powering my 10w HF radio.This power supply is capable supplyin 62A at 12V. This is total overkill for my usage.I did some simple mod which I find on this pagehttp://pinoutguide.com/Power/dell_server_24_6_psu_pinout.shtmlto reduce speed of fan.It works, but is it possible to reduce fan speed even more?Second question is, if it is possible to step up voltage to 13.8V? I found little trimmer inside and I was capable to set voltage to 12.6V, but for my radio ideal voltage will be 13,8V and no fan noiseThanks and have a great day!

author: nsrmagazin
author_rank: Regular Contributor
timestamp: January 27, 2019, 11:43:19 am
content: Why not disconnect the fan if the supply is not getting hot? How is the fan controlled and connected, can you put a resistor between the fan and is power?

author: ZayneTech
author_rank: Contributor
timestamp: January 28, 2019, 06:24:23 am
content: Maybe put a small resistor in series with the fan to reduce the speedHope it helps

author: james_s
author_rank: Super Contributor
timestamp: January 28, 2019, 06:58:52 am
content: Every one of these that I've dealt with monitors the fan, if you disconnect it the PSU will shut down.Some power supplies of this type are very quiet though, I have some IBM 39Y7201 that I got on ebay, two for $16 shipped, that's practically free. I use them to power my RC LiPo chargers, one single unit and another pair I modified for series operation. I really like these particular PSUs because they're compact and nearly silent. The fan has an internal thermal control and ramps up only as needed.

author: mariush
author_rank: Super Contributor
timestamp: January 28, 2019, 07:19:44 am
content: Check this thread :https://www.rcgroups.com/forums/showthread.php?1750411-Converting-Dell-7000814-Server-Power-SuppliesIt explains how to configure the psu to output 12.5v (not 13.8v but better than 12v) and how to reduce the fan speedI found the page by googling one of the part numbers listed on the page you linked to, with the connector.
Modular Computer Power Supplies and Their SATA Cables - Page 1
Forum section: electronics / beginners

author: pianowow
author_rank: Newbie
timestamp: January 19, 2021, 02:47:20 pm
content: Hey everyone, new member here. I assume this topic is widely known, but newly discovered to me.I tried to use SATA power supply cables from one modular power supply with a different power supply. This destroyed two disks that were connected with the wrong cable. It screams of negligence to me that such cables have the same connector, but are dangerously re-wired from one power supply to the next. Seems to me if you're going to change the layout of the wiring, the connector should change as well, so that the wrong cable wouldn't even fit.Anyone else experienced this? I've heard the drives from this type of damage are irrecoverable.... but how irrecoverable? Presumably the data is still on the magnetic disks, but the circuitry to control those disks is fried. Would swapping the board from a working drive of the same model work? Maybe there's an even easier swap?

author: BravoV
author_rank: Super Contributor
timestamp: January 19, 2021, 03:02:00 pm
content: Sorry, can't help much on the recovery.Yes, they are and I'm aware of it when I bought different brands of modular PSUs, say like Seasonic, Corsair and etc.Luckily I did test them when I bought my 2nd modular PSU maybe decade ago, and it was quite shocking to find out how dangerous they are if mixed with other brand.One habit I developed is, as I only use modular PSUs, when unpacking them while new, I diligently and instantly labelled "all" cables that where they belong to, as we all know, somehow through times, maybe for years until we forget them, where we tucked all of these unused cables, stacked and scrambled in drawer and pulled one out to use it, dire accident is just waiting to happen.

author: pianowow
author_rank: Newbie
timestamp: January 20, 2021, 01:43:16 pm
content: According to this:the controller board and the disks store data independently that have to match up in order for the drive to fully function. So it looks like I won't even try to swap them with new parts. One of the drive controller boards has visible damage to a chip, the other looks good, but I don't have any hope anymore. Bummer.

author: Ranayna
author_rank: Super Contributor
timestamp: January 20, 2021, 01:49:27 pm
content: You have learned the most important lesson regarding modular power supplies: *Never* assume compatibility. Not even within the same manufacturer! At least doublecheck with the manufacturer.There are essentially no standards at all regarding the power supply side of the cables. And since there are not *that* many different connectors available, they might physically fit.
Modular design by Dell - Page 1
Forum section: electronics / beginners

author: qoole
author_rank: Contributor
timestamp: April 14, 2013, 08:09:21 pm
content: Hi all!Recently acquired an old (~2000 vintage) non-functioning rackmount Dell Poweredge server.So I thought I would harvest it for parts. Some of the design is quite interesting too!On the motherboard there were three vertical removable daughter-boards which appear to be 4-way SMPS boards. (see "4Way_SMPS" photos).There were also three soldered daughter-boards which appear to be 2-way SMPS boards. (see "2Way_SMPS" photos).At some point I will reverse engineer them and work out what voltage input/output they regulate! From the server PSU I guess it's a 12V input!I guess they made them daughter-boards for better heat-sinking and the removable ones so they could be replaced if they failed.I also notice a distinct lack of electrolytic capacitors on the boards. There were about 10% of the number I'd expect on a motherboard. I guess so as to limit the points of failure.I hope the photos are of interest to someone out there!http://imgur.com/a/Mqdyu

author: codeboy2k
author_rank: Super Contributor
timestamp: April 14, 2013, 11:06:13 pm
content: Quote from: qoole on April 14, 2013, 08:09:21 pmDefinitely interesting, thanks for taking them. If one of the 4-phase modules are working, you have a nice settable 1.8, 1.5, 1.2 Volt, 4-phase supply at about 100Amps probably... if you gave it enough input power.With the VID setting, you can set any output voltage between about 1.1 up to 1.9 I think, but those 3 I listed are the interesting ones I'd like to have hardwired on my bench. Put it in a box with an old 12V laptop PSU, bring the VID settings out to the front panel, and use a settable, electronic fuse on the output so you can set some kind of current limit.

author: qoole
author_rank: Contributor
timestamp: April 15, 2013, 08:28:26 pm
content: I don't see any reason the supplies wouldn't work as it was a more physical/gravitational fault that killed the server some Useless Parcel Service (which will remain nameless) dropped the (admittedly poorly packed) server.How did you work out the specs so fast? Have you seen these devices before? Got any data on them?

author: codeboy2k
author_rank: Super Contributor
timestamp: April 16, 2013, 04:06:16 am
content: Quote from: qoole on April 15, 2013, 08:28:26 pmThe ADP3164 controller is a typical 4 phase synchronous buck converter. The datasheet ishere. The datasheet has a typical schematic, you'll find it will be quite close to the real one. The 100A I quoted is not a real spec, just a guess on my part. The datasheet actually shows an 80A design. It really depends on the MOSFETS on the board and the over-current sense resistor they used, which you'll have to work out from looking at the board.The VID setting is done through pins 1-5 on that controller chip.
modular platform - Page 1
Forum section: electronics / beginners

author: metebalci
author_rank: Frequent Contributor
timestamp: September 23, 2023, 01:31:26 pm
content: I am thinking to do something on a modular platform. Not sure if modular platform is the correct name, I mean things like Eurorack or PXI (I am aware they are very different). I do not need a high speed backplane and connections can be done from front like the analog synth modules of Eurorack. The main reason is to be able to make and use the PCB as quick/easy as possible, without making case, have standard dimensions etc. Eurorack looks OK to me but I do not know if there are alternatives. Are there alternatives to Eurorack ?

author: dobsonr741
author_rank: Frequent Contributor
timestamp: September 23, 2023, 01:42:54 pm
content: Eurorack is perfect for synths. The backplane is just a power rail, on ribbon cables.https://en.m.wikipedia.org/wiki/Eurorack
Modulated Laser Driver with f > 300MHz and I p-p = 80mA - Page 1
Forum section: electronics / beginners

author: DROBNJAK
author_rank: Contributor
timestamp: December 15, 2012, 11:30:28 am
content: I am trying to make a voltage driven, modulated current laser driver, with frequency of 300MHz or more, that can vary the laser diode supply current 100mA peak-to-peak.So far I succeeded "reaching" f = 30MHz, but current modulation was only approx. 20mA. I was driving it from DDS AD9850 frequency generator (limited to 70MHz), that produces sinusoidal signal 1 Vp-p. I used BC548C transistor, with fT= 300MHz and Ic<= 100mA.My circuit was redesign of this one:http://www.electronics-tutorials.ws/transistor/tran_2.htmlMy biggest limitation is that I am a noob an I do not know if I had chosen the right method.Can you please throw in some ideas of how to achieve this?

author: Thor-Arne
author_rank: Unknown
timestamp: December 15, 2012, 07:39:33 pm
content: Quote from: DROBNJAK on December 15, 2012, 11:30:28 amYou mean you want to modulate the laser with a analog signal?If that's the case, I suggest you rethink your project using digital signals.A laser isn't meant to be modulated by analog signals, but it can easily be modulated with a digital signal (on/off).
Modulating bench supply output - Page 1
Forum section: electronics / beginners

author: PeterFW
author_rank: Frequent Contributor
timestamp: April 17, 2016, 08:22:04 am
content: Hello!I would like to put something on the output of my bench supply that will make me able to either get a current limited PWM voltage source or frequency modulated.As well as a inverter to get a square AC output.So, basically just a H Bridge with a controller, the controller is no problem, my focus is on the "power" part for now.The thing should work over the whole voltage range 0-12V and should work up to 20A to 30A.The circuit will have a seperate power supply, i have stable 3.3V, 5V and 12V.My best solution for now would be a ir2110 with a N-FETs and P-FETs.Regular H-Bridge motor drivers all seem to have a undervoltage feature, wich i do not want.Greetings,Peter

author: Kleinstein
author_rank: Super Contributor
timestamp: April 17, 2016, 11:53:04 am
content: Depending on the minimum frequency needed I would look for a bridge with 4 N channel Mosfets and bootstrapping drivers. The IR2110 is exactly that kind of driver - so I don't think it would work well with N and P channel.If you need very slow operation an auxiliary supply / charge pump is needed to provide a little current for the high side drivers while constantly on.

author: PeterFW
author_rank: Frequent Contributor
timestamp: April 18, 2016, 11:31:38 am
content: Quote from: Kleinstein on April 17, 2016, 11:53:04 amThat is the reason i wanted to go with N and P channel FETs, i have not been able to find a driver that will work with 100% duty cycle.

author: Kleinstein
author_rank: Super Contributor
timestamp: April 18, 2016, 05:21:51 pm
content: With P-MOSFETs you would need a negative supply and a suitable driver too. So the P_MOSFET is not attractive when the bridge voltage can go below about 5 V.With most of these drivers one can add a charge pump / extra positive supply so they will then work with 100% duty cycle. It needs only little current (e.g. 0.1 mA) and maybe a zener diode to limit the voltage in the bootstrapping capacitor.Thats likely easier than getting a negative supply.
Module specifies 3.6v max: How do I easily power it from a LiPo? - Page 1
Forum section: electronics / beginners

author: poodyp
author_rank: Regular Contributor
timestamp: August 05, 2012, 07:44:33 am
content: I'm going to try using a Microchip MRF24J40MA in a project, and in the datasheet it states a min-max voltage of 2.5 to 3.6. I'm going to be powering some 3v motors, and I'd like to be able to use a LiPo for density, weight, and compatibility with the motors.So what's an easy way to drop 4.2v to 3.6v while also keeping it powered to 2.5v?Thanks.

author: T4P
author_rank: Super Contributor
timestamp: August 05, 2012, 08:02:36 am
content: Use LiFEPo4.Or you can use a buck-boost converter

author: amyk
author_rank: Super Contributor
timestamp: August 05, 2012, 08:32:59 am
content: Looking at the datasheet for your device it's really designed for 3.3V and draws <50mA so a 50mA 3.3V LDO should be sufficient.If those "3V" motors are the standard brushed types, they'll probably be quite fine with 4.2V (which you get only from a fully charged cell.)

author: poodyp
author_rank: Regular Contributor
timestamp: August 05, 2012, 07:36:40 pm
content: Quote from: T4P on August 05, 2012, 08:02:36 amMost LiFEPo4's have a pretty flat discharge curve so that'll probably work, I'll just need to look for some charge controllers.I've been looking for info on buck-boost converters, but there isn't much to be had. So far I've found the LTC3444 and TPS53020/30, but other than datasheets I can't find much.Quote from: amyk on August 05, 2012, 08:32:59 amAnything besides maximum current and lowest dropout I should look out for? Am I wrong in assumingthisdoesn't have a minimum load current like an LM317?

author: RCMR
author_rank: Frequent Contributor
timestamp: August 05, 2012, 11:16:16 pm
content: I've been facing the same problem recently -- how to run a 3.3V device from a single-cell lipo (3.1v - 4.2V)I thought of using a shunt regulator (anyone remember those) but figured it would be an awful waste of the meagre energy resources on offer.I looked at LDO linear regulators but once the battery voltage got to 3.4V or so then the regulator would no longer be "regulating"So I opted for a boost/buck converter. More components, more weight, more bulk -- but the ideal solution.An LiFePO4 cell would have been an option except that 3.6V was too high for this device (absolute 3.3V maximum) and besides which, I couldn't find an LiFePO4 cell with a small enough capacity (or low enough weight) for this application.

author: T4P
author_rank: Super Contributor
timestamp: August 06, 2012, 12:08:09 am
content: Ahh, shunt regulators

author: poodyp
author_rank: Regular Contributor
timestamp: August 06, 2012, 02:06:25 am
content: Quote from: RCMR on August 05, 2012, 11:16:16 pmHave you decided on a controller? I found the TPS63001, which looks to be a TPS63030, but fixed at 3.3v. Only problem is it's $2.5 in single quantity, and I have no SMPS experience.The amp or so from the motors will dwarf even the extra draw of a shunt regulator powering maybe 40mA, so I'm not too worried about efficiency.
Moisture sensitive devices warning - Page 1
Forum section: electronics / beginners

author: ledtester
author_rank: Super Contributor
timestamp: June 28, 2020, 06:00:44 pm
content: I bought some LDO regulators and they came with this warning...I can't make out what the guy wrote for 3a - what do you think it says?

author: Siwastaja
author_rank: Super Contributor
timestamp: June 28, 2020, 06:13:05 pm
content: 168 hours. LEVEL 3, i.e., MSL 3 says it all.

author: jmelson
author_rank: Super Contributor
timestamp: June 28, 2020, 06:31:05 pm
content: But, really, people go crazy over this stuff. There are some large FPGAs and such that will suffer damage if left out for weeks and then reflowed without baking. But, I routinely leave parts like this out for MONTHS in my basement (it is "conditioned air space, but a bit humid in summer) and have NEVER had any issues. And, it is not just tinkering in my basement, I am a small manufacturer, and have a pick and place machine and a homemade reflow oven.I HAVE had PC boards that have sat around for a year blister in the reflow oven, so I bake those out at 50 C then 70 C for an hour or two before stuffing and reflowing them.Jon

author: David Hess
author_rank: Super Contributor
timestamp: June 28, 2020, 09:43:18 pm
content: That has to do with reflow soldering requirements. If the plastic packaging encapsulation absorbs too much water from the atmosphere, then the parts will "popcorn" during soldering.
Molex Crimping, dauntingly huge range, help! - Page 1
Forum section: electronics / beginners

author: peps1
author_rank: Regular Contributor
timestamp: January 21, 2016, 04:30:51 pm
content: I have been using Dupont connector up until now, and am wanting to use something a little more secure for some projects.So, I looked into Molex, and was quickly baffled by the huge range of products, so finding it a little hard to find the wood for the trees!I'm just after a system that will let me have 4/3/2 pin connections for things like sensors and stepper motors (~28-18AWG) and alow me to use my current Engineer PA-09 crimp tool that I love(here is what it will crimp in the Molex Crimp Series… picoblade micro-latch microblade mini-lock mini-spox kk mini-latch micro-fit spox mini-fit 1190 1189 1381 c-grid / sl milli-grid pico-spox).Could someone possibly hold my hand and guide me though the world of Molex?
Molex KK 254 female - Page 1
Forum section: electronics / beginners

author: Cloud
author_rank: Regular Contributor
timestamp: March 22, 2016, 01:59:52 pm
content: I have ordered molex kk 254 male two pin connectors from Farnell. And because I was in hurry I accidentally ordered wrong female connectorsNow I was looking and can't seem to find on farnell female connectors, that fit on kk 254 (that plastic thingy)

author: rdl
author_rank: Super Contributor
timestamp: March 22, 2016, 02:47:12 pm
content: Is this it?http://si.farnell.com/molex/22-01-2025/crimp-housing-2-54mm-2way/dp/143126
Molex PICO-SPOX crimping tool - Page 1
Forum section: electronics / beginners

author: pedromorgan
author_rank: Newbie
timestamp: November 10, 2018, 08:47:03 pm
content: So, having now identified the connector, I am faced with a new problem! I am used to JST connectors, but my crimping tool is too big for these tiny connectors (in fairness, its done about 20 years service, only cost a fiver and its about time I got a new one anyway!).But I cant possibly justify the £400 on the correct Molex crimping tool.Can anyone suggest an alternative?Peter

author: joeyjoejoe
author_rank: Frequent Contributor
timestamp: November 14, 2018, 01:21:17 am
content: Engineer PA-09 will do fine.