hybridfree/eevblog-posts huggingface dataset:
Help on DF20 Hirose connector - Page 1
Forum section: electronics / beginners

author: pizzigri
author_rank: Regular Contributor
timestamp: February 08, 2015, 04:15:01 pm
content: Hello!I have a device which interfaces with the outside world through a DF20F-30DP-1H(59) Hirose connector. It's a 30 pin, 1mm spacing, double row connector(here's the datasheet:http://www.mouser.com/ds/2/185/e68600100-24449.pdf). The connector has only 15 pins actually used.I have checked the mating connector socket, and I think it is the DF20A-30DS-1C.I have seen these connectors every now and then, especially used in older notebook computers.And now, my problem: I cannot find anyone willing to sell me just one or two such connectors, but the really big problem is the actual contacts: the specific Socket Crimp Contacts used need a dedicated crimping tool that costs various hundreds of dollars /euro!!I cannot afford such costs, especially considering that once the couple connectors are built, I would have no further use for the crimper tool. Is there anyone here that has mercy and that could sell me a couple socket connectors, and 30 crimped UL1571 AWG #28 wires, at least 10cm long each?
[SOLVED] Help on Quick-n-Dirty MUX replacement - Page 1
Forum section: electronics / beginners

author: quantumvolt
author_rank: Frequent Contributor
timestamp: October 20, 2013, 08:42:20 pm
content: The schematic is fromhttp://cds.linear.com/docs/en/demo-board-manual/dc2026afa.pdfThe MUX FSA2257http://www.fairchildsemi.com/ds/FS/FSA2257.pdfswitches on SPI/I2C?The max frequency seems to be:CPU Frequency = 16Mhz on Arduino UnoSCK FrequencySPI2X SPR1 SPR0 Frequency Uno_Frequency0 0 0 fosc/4 4 Mhz0 0 1 fosc/16 1 Mhz0 1 0 fosc/64 250 khz0 1 1 fosc/128 125 khz0 0 0 fosc/2 8 Mhz0 0 1 fosc/8 2 Mhz0 1 0 fosc/32 500 khzI have never used a MUX before, and would like to know if there is any quick&dirty jellybean chip I could test while I am waiting for the part.Thanks.

author: bingo600
author_rank: Super Contributor
timestamp: October 22, 2013, 12:45:55 pm
content: Maybe one of these ..74HC405174HC405274HC405374HC4066I know 4053 was used to switch serial IF's on Atmel M128 MCU's/Bingo

author: quantumvolt
author_rank: Frequent Contributor
timestamp: October 22, 2013, 03:44:42 pm
content: Thanks.Yes - I have used two CD4051. This is a 1 to 8 mux, but by just using 1 to 2 it is controlled by a single bit 0/1. So two chips gives two separate SPDT switches with a single high/low control signal. I checked the frequency in the datasheet. CD4052 is dual/quad (forgot ...) and better (only one chip needed), but CD4051 was all I had.There is another chip from Microchip MCP23017 that I also had (bought just for fun from eBay - almost free) that is used in the Arduino community, but it was max freq 1.3 MHz ore something.Thanks.
Help Oscillloscope GOULD OS3600 + Dm3010 - Page 1
Forum section: electronics / beginners

author: jimiz
author_rank: Newbie
timestamp: March 17, 2018, 06:19:39 pm
content: Hi I need help with this analog old Oscilloscope.I not found a good guide istruction manual (only schematic service...)and nothing about theDM3010 unit (digital measuring unit)It can operate independently but also with the OS3600 to provide digital readout of parameters displayed on the screen.but I not understand how work with ch1 , need handbook ...any one can helpme to found or just send by email a pdf/scanned ?thanks !!!

author: Momchilo
author_rank: Regular Contributor
timestamp: March 18, 2018, 04:02:04 am
content: Here you go:http://bama.edebris.com/download/gould/os3600/Gould-OS3600-Oscilloscope.pdfBy the way, this is the first google link, when you search for "gould os 3600".

author: jimiz
author_rank: Newbie
timestamp: March 18, 2018, 10:52:29 pm
content: Yes thanks, but this I also found....And is only a service manual (circuit)I need help/manual for the DM-3010 , that is a digital measuring unit, addon of the gould os 3600 , and work togheter but how? is explain in the manual...never found!only in ebay $$$$)
MOSFET dual purpose battery cutoff and switching? - Page 1
Forum section: electronics / beginners

author: Mp3
author_rank: Frequent Contributor
timestamp: April 10, 2020, 01:47:43 am
content: Let's say there is a very simple circuit in which a battery is inserted into its holder to switch the circuit on, and the battery is be removed to switch it off. There are no protections of any kind in the circuit.The battery measures 4.2v when full, and will fairly quickly lower to 3.6-3.8v and stay there for a very long time. Don't want to allow the circuit to work if the battery gets low, like close to or just under 3V.Question:If I was to pick a 3V-12V MOSFET for switching, would this double as a low voltage cut-off circuit when the battery reaches 3V?I am thinking maybe NDP6020P, but i don't know if it's ideal for my application.

author: xani
author_rank: Frequent Contributor
timestamp: April 10, 2020, 03:05:11 pm
content: Rds(on) voltages are not exact, and it is not a hard knee but a transition region.Just look up the graph in datasheet, or TL;DR version - it would not "turn off" below, it would just have higher resistance, probably enough to discharge battery in case of Li-ion rechargable, probably kill it.Either use cell with builtin protection circuit, or add one. You couldprobablyreuse the transistor for that purpose, or just look at specialized chips
Help picking a  replacement for outdated voltage regulator? - Page 1
Forum section: electronics / beginners

author: Mp3
author_rank: Frequent Contributor
timestamp: April 19, 2020, 08:35:37 am
content: When I was reading the datasheet for TI PCM2902 (obsolete), Figure 37 on page 28 gives an example with an external voltage reference. The circuit references an obsolete TI regulator "REG103-A". Pin 10 of PCM2902 needs something like 3.6-4.0V to override its internal voltage reference.http://www.ti.com/lit/ds/symlink/pcm2902.pdfhttps://www.ti.com/lit/ds/symlink/reg103.pdfI'm considering TI TPS79501DCQR to use instead, since it has adjustable voltage (can set it to something nice like 3.8v), correct output current, otherwise looks correct. But it requires a 1uf ceramic capacitor for stability. Some different REG103 models are still for sale, but they are almost 3x as expensive.http://www.ti.com/lit/ds/symlink/tps795.pdfIf I use that TPS795 regulator instead of REG103, set it for 3.6-3.8V, i simply put the 1μF ceramic cap and diode between the output pin of TPS795 and pin 10 of PCM2902?Many thanks!

author: Mp3
author_rank: Frequent Contributor
timestamp: April 19, 2020, 08:48:36 am
content: Quote from: blueskull on April 19, 2020, 08:39:25 amI didn't even think of using it for a virtual dmm.... that is a really cool idea.I know PCM2902 is a POS, but i still like how it sounds and i want to try see what happens with a proper voltage reference.

author: Mp3
author_rank: Frequent Contributor
timestamp: April 19, 2020, 09:08:14 am
content: Is this correct to integrate a 1uF capacitor for regulator stability into this circuit? (My additions in red)

author: Mp3
author_rank: Frequent Contributor
timestamp: April 19, 2020, 09:46:18 am
content: Quote from: blueskull on April 19, 2020, 09:30:37 amI thought the OUT goes into the 1uf cap, then the 1uf cap goes to both C1 and the 22 k-Ohm resistor.

author: Mp3
author_rank: Frequent Contributor
timestamp: April 19, 2020, 10:15:40 am
content: Quote from: blueskull on April 19, 2020, 09:55:13 amI think I understand. Is this correct?

author: Mp3
author_rank: Frequent Contributor
timestamp: April 20, 2020, 06:09:04 am
content: Quote from: blueskull on April 19, 2020, 10:30:02 amThank you very much for your help. I apologize for the stupid question, but it IS the beginners forum. By MLCC stable, does that mean it's stableas long asit has a MLCC in the circuit of correct capacitance?

author: Siwastaja
author_rank: Super Contributor
timestamp: April 20, 2020, 09:49:43 am
content: If at all possible, always pick a modern regulator whose datasheet brags about "stable with ceramic output capacitor" and explicitly specifies no minimum value for ESR. Some regulators require hundreds of milliohms, even several ohms of resistance in series with the output capacitor, meaning either a MLCC+explicit resistor series combo, or a tantalum capacitor, which internally provides the ESR.
Help please 858d - Page 1
Forum section: electronics / beginners

author: borngborn
author_rank: Contributor
timestamp: August 22, 2018, 07:29:11 pm
content: Ive heard decent things about these hot air guns i just took some pics it looks grounded properly i just dont want it to kill me when i turn it onSent from my SM-N950U using Tapatalk

author: floobydust
author_rank: Super Contributor
timestamp: August 22, 2018, 08:24:36 pm
content: Check that "hot" on mains goes first to the fuse, then the on/off switch. Not neutral, as some are wrongly factory wired.Check continuity between the wand nozzle metal can, and mains earth-ground. The nozzle is stainless steel and usually the GND wire is loosely wrapped around a hole, making a flaky connection. You need special solder.Ensure the ground wire from the back of the GX-16 connector goes to earth-ground, usually at a second bolt on the power transformer.I drew up aschematic of 858D06.PCB and wandincluding the original on/off switch safety mistake.Best to never leave it plugged in when you are not using it.The wand connector on the front panel has hazardous live present, so never mess with it unless the unit is unplugged.

author: anvoice
author_rank: Frequent Contributor
timestamp: August 23, 2018, 03:01:12 am
content: So basically if one gets an 858D station one has to be careful to ensure they are wired properly? Will have to watch out for that, that's the station I'm looking at.

author: iainwhite
author_rank: Unknown
timestamp: August 23, 2018, 12:22:15 pm
content: There is more detail on the issues in this thread:https://www.eevblog.com/forum/chat/deadly-wiring-fault-atten-858d-hot-air-rework-station/msg46035/
Help please HP pro curve J9306a - Page 1
Forum section: electronics / beginners

author: Maztech1
author_rank: Newbie
timestamp: June 18, 2023, 05:49:16 pm
content: I purchased a server power supply to supply a Riden R6024 however i cant figure out how to hot wire it to start. The connection on the back is different than most and i cant find any information on the pin out.HP part#5189-6864Model#DCJ 16002-03p
Help Pls! Replacement power supply board/Magnavox LED TV didn't work, no power - Page 1
Forum section: electronics / beginners

author: Tricia0723
author_rank: Newbie
timestamp: May 19, 2018, 11:25:39 am
content: Good Day! I thought replacing the power supply board on my Magnavox LED TV would solve the No Power problem. My red standby light does come one. But after replacing the board, I still have the same problem. The set is about 5 years old. I double checked that I received the correct replacement part by matching the part numbers. Can anyone help? Thanks so much! I posted a similar message on the Repair Board, but while I got about 20 reads, no replies yet. Guess I shouldn't have posted there. Oh well.... Thanks again.

author: Psi
author_rank: Super Contributor
timestamp: May 19, 2018, 11:40:00 am
content: I would look at the main processor reset line, check if there is a power good IC on reset and confirm reset is going high

author: Tricia0723
author_rank: Newbie
timestamp: May 19, 2018, 12:16:04 pm
content: Thanks for your advice, but I'm not skilled in this area. Is the main processor part of the power supply board? I'm not sure what IC means. I don't have electrical tools. I understand if you can't help further. Thanks again!
Help Power conditioning via RLC Circuit via Excel spread sheet - Page 1
Forum section: electronics / beginners

author: cooljm
author_rank: Newbie
timestamp: March 02, 2017, 08:26:45 pm
content: I am not very good with Excel spread sheets and formulaI have the following assignment due... and need help in setting up spread sheet. attached is the assignment

author: cooljm
author_rank: Newbie
timestamp: March 02, 2017, 08:42:29 pm
content: take 2 on inserting spread sheetwhat i have done so far not much

author: danadak
author_rank: Super Contributor
timestamp: March 02, 2017, 09:07:59 pm
content: You know the formula to compute Xc, Xl, then Z = magniutude of all 3 values.Then insert f() in a cell, then copy it to the other cells. Google "youtube excel functions",lots of videos to help.http://keisan.casio.com/has10/SpecExec.cgi?path=06000000.Science%2F04000100.Electricity%20and%20magnetism%2F10030700.Impedance%20of%20R%2C%20C%20and%20L%20in%20series%2Fdefault.xml&charset=utf-8Regareds, Dana.

author: Ian.M
author_rank: Super Contributor
timestamp: March 02, 2017, 09:18:22 pm
content: We don't do homework for you here but will help with specific issues if you are stuck.Personally, I'd use named ranges for the table columns and also the constants as it makes the Excel formulae much more readable as you can avoid all that aggro with alphanumeric cell references, however that's not what your lecturer has asked for. It took about five minutes to do the full table with named ranges, and format it as required. Using MS Equation Editor to display the original formulae will take quite a bit longer.You don't seem to have attempted any formulae.Provided you've used absolute cell references for R, L and C, once you have the first (100Hz) row populated you can simply select the body of the table and fill down.Hint: for the power factor in degrees useCode:=DEGREES(ASIN(expression))replacing 'expression' with the correct expression and cell references.

author: cooljm
author_rank: Newbie
timestamp: March 02, 2017, 09:25:51 pm
content: thanks to you both...i understand not doing the assignment, i didnt want you to do the work... for now I have been doing them on sci. calculator...will look at you advice and helpthanks again
Help powering up a car tv for a raspberry pi project please - Page 1
Forum section: electronics / beginners

author: azigta
author_rank: Regular Contributor
timestamp: April 16, 2018, 11:13:08 pm
content: Hi, I just bought a raspberry pi and I remembered some years ago I stored a car tactile "tv" (only video input actually) that I got for free but I didn't know how to use, and since I didn't needed it I stored it until now. This lcd would be great for my raspberry pi and a project I want to make to make my sdr radio portable. The tv It has a bunch of cables and a vague "schematic" to tell where they go but for the moment I only figured out which are the two going to the 12v supply.You can't see it very clear there but it saysRed line to the + terminal of the battery "black line" to the - terminal of the battery. Green line to ground. "Black line"(again?) to a Key simbol with VACC letters on it.Now the weird thing is that there's no two black cables but because of the section of the cables I figured out what the negative terminal for the battery was. It was a white cable. Connecting the red and white cables to a 12v power supply poweres up the ON button on the tv but pressing it does nothing. I think the key thing has something to do with this.So I have 2 cables left to know what to do with them. A green cable which according to the schematic is ground and a black cable with the letters VACC on it. I measured across them and it's 4.73V. At first I thought the key thing could be just the contact, like you wire that to your car key contact so it powers up when you insert the key. So maybe connecting the green and black wires together should start it up like it's a switch but I don't wan't to short circuit anything so I don't know what else to do.What can I do to start this up? I tried to search for online info but it's a chinese tv with no model or number references on it. Any ideas? Thanks

author: Estefania
author_rank: Newbie
timestamp: April 17, 2018, 05:29:17 am
content: Can I publish it to people who need it?

author: sokoloff
author_rank: Super Contributor
timestamp: April 17, 2018, 08:23:47 am
content: Put the Vacc line to +12V power in addition to your current wiring.In a car, you’d put permanent power feed to the power input and “hot when key is in an turned to accessory or run” to Vacc. This way, the TV would shut down when you turn the car off.

author: azigta
author_rank: Regular Contributor
timestamp: April 17, 2018, 02:52:55 pm
content: Yay It's working now! thank you very much

author: azigta
author_rank: Regular Contributor
timestamp: April 17, 2018, 02:56:01 pm
content: Quote from: Estefania on April 17, 2018, 05:29:17 amDo you mean if you can share my post and answers to other people? I don't understand it very well but In that case, of course you can
Help reading a datasheet - Maximum Ratings - Page 1
Forum section: electronics / beginners

author: dsegel
author_rank: Contributor
timestamp: May 06, 2018, 04:33:08 pm
content: I'm looking at a solid state relay:http://www.ixysic.com/home/PDFs.nsf/www/Lcc110.pdf/$File/Lcc110.pdfThe Absolute Maximum Ratings and Electrical Characteristics list 350V and 120mA continuous as max values.My question is: are these combined values, or independent? Can I run 500mA at 25V through this thing? Or can I not exceed either spec?

author: Twoflower
author_rank: Frequent Contributor
timestamp: May 06, 2018, 04:35:51 pm
content: As soon as you exceed one of these values you leaving the allowed operating conditions.

author: tszaboo
author_rank: Super Contributor
timestamp: May 06, 2018, 04:41:11 pm
content: Technically, it cannot be 350V and 120mA at the same time, since one is for conducting the other one is when it is off.Otherwise it is only rated for 120mA, so obviously, you cannot use it for 500mA

author: Gyro
author_rank: Super Contributor
timestamp: May 06, 2018, 05:37:58 pm
content: Remember also that you shouldn't operate a device at Absolute Maximum Ratings, that will lead to unreliability in practice.Pay attention to things like maximum ambient temperature, temperature rise due to power dissipation and de-rate according to the appropriate graphs in the datasheet.
Help reading multimeter data sheets - Page 1
Forum section: electronics / beginners

author: SeanBannister
author_rank: Newbie
timestamp: March 16, 2016, 01:56:07 pm
content: Hi, I'm looking to purchase a multimeter and need to measure current down to 1 microamp, but I'm not familiar with reading multimeter data sheets.As an example I read thedatasheetfor the EEVblog branded Brymen BM235. This is the section on current:Does this mean it can read 600uA and higher?

author: MK14
author_rank: Super Contributor
timestamp: March 16, 2016, 02:02:27 pm
content: What it means is that the most sensitive current range is 600uA.It has a 6000 count display.I.e. 0, 1, 2, ..5,999So at the 600uA range, it can show 0.0uA up to 599.9uA.At an accuracy of 1% + 3 digitsI.e. it can show (0.0uA) 0.1uA and more.Display = Reading in uA's000.1 = 0.1uA123.4 = 123.4uA etc

author: Brumby
author_rank: Unknown
timestamp: March 16, 2016, 02:35:02 pm
content: Each of the values given are the maximum reading for a particular range. The way the values are presented indicate the number of digits displayed and where the decimal point will be.If your measurement exceeds this number when you are in autoranging mode, the meter will step up to the next range up, increasing the limit and decreasing the absolute resolution. Likewise, if your measurement falls into the next lowest range, the meter will drop down to that range, giving you more resolution.(Well - that's the principle. In reality, however, if you had (for example) a voltage that fluttered around 5.9v to 6.1v, you'd get pretty annoyed if your meter kept switching ranges all the time - so some hysteresis is introduced to reduce this problem. As an example, on my EEVBlog 235, if I'm measuring an increasing voltage starting from, say, 5v it will stay on the 6.000v range until it gets to somewhere around the 6.5v level, when it will change to the 60.00v range. Likewise, if I then decrease the voltage, it will not switch back to the 6.000v range until I get down around the 5.5v mark.)

author: SeanBannister
author_rank: Newbie
timestamp: March 16, 2016, 02:56:10 pm
content: Thanks a heap for your help that makes a heap more sense.
Help reading schematics for design reviews - Page 1
Forum section: electronics / beginners

author: dmitko97
author_rank: Newbie
timestamp: July 30, 2024, 07:36:38 pm
content: I'm reaching out to those with more experience in reading electronic schematics. As the Compliance engineer on the team, I primarily handle testing, pre-testing, and certifications. Recently, I've been included in design reviews, which is new territory for me. The schematics are quite extensive (40-50 pages), and I'm feeling a bit overwhelmed.While my input isn't crucial at this stage, I anticipate a greater role in the future and want to be well-prepared. Any advice on how to approach these documents would be greatly appreciated.Thanks,

author: Konkedout
author_rank: Frequent Contributor
timestamp: July 31, 2024, 03:29:07 am
content: I think that your question is too broad. I do not know how to answer it as it is. Why not post a partial schematic and ask specific questions about it?

author: Slh
author_rank: Regular Contributor
timestamp: July 31, 2024, 05:10:30 am
content: I guess you're caring mostly about is it legal to sell and is it robust rather than does it work?I guess you just want to start by concentrating on the pages with external connectors to see if they have suitable filtering for emc/ESD etc.Bring a list of previous failures and ask what mitigations have been put in place for them.

author: selcuk
author_rank: Frequent Contributor
timestamp: July 31, 2024, 07:03:44 am
content: -Expect the simplest mistakes.-Don't review a schematic if it doesn't have full part numbers. You don't need to have them on the drawing. Spreadsheet is easier.-Check symbol pin names and orders with the datasheets then work on that part on the schematic.-You may need to review the board layout as well to identify footprint mistakes.-Make note everything you are suspicious about. After finishing the review, some of them will be more clear and then you decide whether they are errors or not.-Categorize your findings. Error, warning, recommendation etc. Hardware designers do not want to update everything you find. You can force them fix errors at least.-You need to understand the design very well, or you don't see some of the errors.I've never reviewed a 50-page schematics. I hope you have enough time to do the job.
Help replacement 51 pin flat cable for TV screen  - Page 1
Forum section: electronics / beginners

author: Bondy
author_rank: Newbie
timestamp: June 20, 2021, 03:50:18 pm
content: I was wondering if you can help me with finding a suitable replacement for a flat (51 pin I think) cable, that I need to repair my TV. The cable I need is for a Samsung 55” TV. (Model # - UN60FH6200FXZC… Serial # - 01SC3CRDB00205V) The cable # is CNJS E308724 AWM 20861 105C 60V VW-1 HF. It connects the board to the screen. If you can’t help me with this item or a suitable replacement, maybe you can suggest where I might be able to purchase it.I've contacted Samsung Parts Depot and they advised me that the cable has been discontinued. They advised me to contact Samsung support directly. I did that and struck out there as well. They advised me to contact Samsung Parts... LOL. completing the loop. The existing cable ends are severely corroded. I cleaned them up the best that I could, using a scriber and contact cleaner, but when magnified still looks like crap. Retried anyway and the TV was no better. Screen works for a short period then lines throughout finally black screen...sound still great at that point.Thanks James

author: antimatter503
author_rank: Contributor
timestamp: June 20, 2021, 10:45:56 pm
content: How long and whats the pin pitch, connector or no connector? Regardless, every parts seller will have some sort of ribbon cable its a very generic and easy to find item. They are even on amazon here is an example:https://www.amazon.com/uxcell-Flexible-Ribbon-Player-Laptop/dp/B07S1BB6HQ/ref=pd_lpo_1?pd_rd_i=B07S1BB6HQ&psc=1

author: BrokenYugo
author_rank: Super Contributor
timestamp: June 21, 2021, 12:56:21 am
content: Have you tried eBay? Something like "UN60FH6200FXZC ribbon cable", or just "Samsung 55 ribbon cable" if that doesn't get hits you might also try asking the sellers that are selling used boards for that model.

author: Bondy
author_rank: Newbie
timestamp: June 21, 2021, 03:26:42 pm
content: Thanks will try that
Help required in field strength calculation. - Page 1
Forum section: electronics / beginners

author: kumar
author_rank: Contributor
timestamp: August 28, 2014, 06:55:27 am
content: I have a signal generator which generates fast rise time pulses and I wish to couple them to IC pin using a E-field probe. Given below are the specs;1) Voltage at the tip of the probe: 250V DC2) Distance bet. IC and probe: 1cm.3) Rise time of the signal: 1nSWhat will be the field strength in terms of V/m ( will it be 25000?) and 88dBm ?Can any of the experts please comment ?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 28, 2014, 12:19:47 pm
content: If the probe is large and planar, and the circuit is large and planar and grounded, the field should be around that, yes. If you require knowing that it is 25 000 +/- 0.5 V/m, you'll have to do an awful lot more work.What kind of a test is this? MIL something?! EMC is done up to 20 V/m or so. You're practically doing ESD. Except over an internal connection.Tim

author: kumar
author_rank: Contributor
timestamp: August 30, 2014, 07:31:28 am
content: Thanks for your reply.I am using a DIY pin probe to troubleshoot the EFT/ESD issues in a microcontroller pcb. How much voltage you think is sufficient to locate them? Can you please specify separate values for EFT and ESD troubleshooting? I have made provision to reduce the voltage, so I will test the pcb as per your suggestion.
Help, resistor - Page 1
Forum section: electronics / beginners

author: klaus11
author_rank: Unknown
timestamp: November 13, 2015, 10:25:18 am
content: This resistance is 1% tolerance? I think not, you have to have a single line in the 2nd digit to be 1%.You can help me.

author: GNU_Ninja
author_rank: Regular Contributor
timestamp: November 13, 2015, 10:42:28 am
content: Here:http://www.hobby-hour.com/electronics/smdcalc.php#smd_resistor_code

author: tec5c
author_rank: Frequent Contributor
timestamp: November 13, 2015, 10:45:47 am
content: Aww, I thought there had been a new component invented called 'help resistors'.What tolerance do you think they are and why?

author: klaus11
author_rank: Unknown
timestamp: November 13, 2015, 10:57:56 am
content: Quote from: tec5c on November 13, 2015, 10:45:47 amQuote from: GNU_Ninja on November 13, 2015, 10:42:28 amAre 1%, "some manufacturers provide full line"Thank you

author: tec5c
author_rank: Frequent Contributor
timestamp: November 13, 2015, 11:02:19 am
content: Quote from: klaus11 on November 13, 2015, 10:25:18 amAnd as you can see thereisa line through the 0 (2nd digit).They are 0603 3k 1% resistors.
Help reverse engineering a Nippon Primex Printer interface plug. - Page 1
Forum section: electronics / beginners

author: makerimages
author_rank: Regular Contributor
timestamp: March 29, 2018, 06:30:24 pm
content: Heyall, I managed to obtain a Nippon Primex NP-F413FA (yuck) branded thermal printer, from an old Sega Console. Figured out where the power goes, and got it to print it's self test. Said test reads:LTP2000 Series interfacePT222P01 Ver 1.04Mechanism LTP2442Apparently it can do both Parallel and various flavours of Serial connections. Despite being older than me, if the DIP's are configured for denser text, it prints with a rather nice quality.I tried contacing the manufacturer, to see if they'd support a hobbyist with the documentation and pinout of the data connection. They simply replied this:QuoteThe printer's data connection is a Molex(?) that looks like seen in the following Dropbox. It also has a label, which is also in the dropbox. I for one fail to guess, what could be going on here. Is there anyone on this forum who might have some ideas?https://www.dropbox.com/sh/kfevdcwyovktfs9/AADOsqfbOLn2uHnq5pkiA2P1a?dl=0Thanks a lot!
Help reversing the AC Infinity UIS protocol? - Page 1
Forum section: electronics / beginners

author: victorhooi
author_rank: Regular Contributor
timestamp: June 21, 2023, 11:11:42 am
content: Hi,I have some AC InfinityIonbeam S11 LED lights, which have a AC Infinity "UIS" port on the side of the wired remote:The idea being that you can use this to plug in AC Infinity's proprietary controllers to this port (e.g.AC Infinity 69 Pro)My understanding is that this is mechanically a USB-C port - but I don't believe it's the actual USB-C protocol going over it.I've taken some photos of the wired remote board as well, in case that helps:Long shot - but does anybody have any info at all on controlling AC Infinity gear, or using this UIS port?Or more generally - does anybody have any ideas on how to figure out this protocol? Or how to go about attacking this problem?(I did notice there's four debug pads on the wired remote - would they help? Would a USB-C breakout likethishelp? Not quite sure how I'd use that though.)Thanks,Victor
- Help selecting a dual channel programmable AFG and a few other components - - Page 1
Forum section: electronics / beginners

author: Plasmateur
author_rank: Regular Contributor
timestamp: August 22, 2016, 12:33:16 am
content: I am building a plasma source and need a 13.56MHz sinusoidal signal with at least 100 watts of power. Preferably 400watts. I understand the function generator alone cannot due this, and that shielding will need to be considered as not to violate any FCC related rules. It would be nice to have at least 30MHz of bandwidth, but I can make due with 20Mhz.On one channel the 13.56MHz signal is bursted with a set amount of cycles. That signal would go through some kind of amplification then two tunable capacitors, and ultimately to an inductive water cooled coil wrapped around a glass cylinder where the plasma is produced.The second channel will be used to generate whatever waveform I need independently of the other channel.I have recently purchased a Rigol 1054z and a Rigol 832 and those decisions was largely based off of what I've read on these forums when lurking, and of course, Dave's reviews.I am now considering a Rigol DG1022 or DG1032Z for this application. Are these as good of a bang for your buck as the other Rigol equipment I have purchased? Also, what is the least expensive way for me to amply these signals as well as tune the impedance as to minimize the forward and reflected power of the 13.56Mhz? I would have to monitor these values as well. (cheap digital SWR meter that can handle 56dbm?)

author: Plasmateur
author_rank: Regular Contributor
timestamp: August 23, 2016, 03:25:12 am
content: I've decided to go with the SDG2042X after seeing Dave's video.It appears that the best bang for your buck equipment out right now isRigol DG1054z - OscilloscopeRigol 832 - Power SupplySiglent SDG2042X - Arbitrary Waveform Generator
help selecting ic for hot swappable battery pack - Page 1
Forum section: electronics / beginners

author: kiyoshi
author_rank: Newbie
timestamp: December 17, 2020, 04:13:37 pm
content: Hi, I am trying to create a hot swappable 18650 battery pack for a project of mine that should not be turned off and will use two of these packs (one for redundancy). I have never done anything that involves charging and discharging batteries. As I was searching on newark I found two categories, battery charger and manager ic, but i'm not sure of the differences between the two. I am between a MAX1737http://www.farnell.com/datasheets/1917366.pdfor a ISL94202http://www.farnell.com/datasheets/2256514.pdf. I prefer the ISL94202 because of its power up operation. I have already started drawing the circuit for the MAX1737, but I am unsure of the ICs I found. Are these ICs overkill for a simple project like mine? I plan on making a simple digital circuit to 'select' a pack to use so only one pack is used at a time.thanks for you time

author: m k
author_rank: Super Contributor
timestamp: December 18, 2020, 03:56:58 pm
content: Lithium cells are sort of unstable.You need to monitor their use also.

author: kiyoshi
author_rank: Newbie
timestamp: December 18, 2020, 07:03:41 pm
content: thanks, but wouldn't the ISL94203 already take care of that?

author: m k
author_rank: Super Contributor
timestamp: December 19, 2020, 12:18:21 pm
content: Yes, but don't overlook the safety issues, even with small cells.They can get very hot and then be initiators for bigger things.

author: kiyoshi
author_rank: Newbie
timestamp: January 13, 2021, 12:04:12 am
content: thanks, I looked more into the datasheet and it has two NTC thermistors. According to the datasheet at 55C it raises a fault bit and disables the battery so it seems to have some thermal protection. I basically got the circuit for the evaluation kit (pg 27,https://www.renesas.com/us/en/document/man/isl94202evkit1z-user-guide?language=en) and altered it slightly. I changed the current sense resistor so at around 8 amps it turns on the Overcurrent protection with the default configuration, lower than what was 'built-in', and I added two polyfuses and split the charge and discharge 'lines'. If something I've changed raises any flags please let me know, thanks.I attached the kicad documents with the schematic and pcb layout if someone wants it. Though it still isn't tested, which I will with 3 batteries (minimum for the ic)
Help selecting PCB connector for potentiometer - Page 1
Forum section: electronics / beginners

author: Falken
author_rank: Contributor
timestamp: June 28, 2023, 04:43:29 pm
content: Hi,I have a small PCB with two variable pots soldered in place . I want desolder these and install a connector in their place. The on the pot I want to install the corresponding connector with wires so I can mount the pots through a case wall and have the PCB inside the case, wires will be roughly 10 cm long . I have experience with Molex connectors but having troubles finding the correct one with the correct leg spacing etc . Perhaps Molex is not the best choice? I dunno and would appreciate any input on this.Attached is a picture on the PCB with the kids ruler as reference , the spacing is just shy of 5mm I would say … all 6 legs are in use so the connector need to be 3x2Thankful for any input on this

author: Buriedcode
author_rank: Super Contributor
timestamp: June 28, 2023, 09:01:58 pm
content: Looks like ~5.08mm pitch. For cost and convenience I'd solder two 5-way pinheaders with pins 2 and 4 removed, then use two 5-way "dupont" female-to-female ribbon cables to your second PCB. Thats two ribbon cables per pot, so one cable per "gang".2.54mm/0.1" headers are ubiquitous and cheap, as are the "dupont" cables.

author: SmallCog
author_rank: Frequent Contributor
timestamp: June 28, 2023, 09:24:01 pm
content: Or solder wires directly to the board and pot and put a small inline connector at a convenient place in the cable to allow it to be unplugged for threading through holes etc.

author: Falken
author_rank: Contributor
timestamp: June 29, 2023, 07:19:55 am
content: Thanks for your suggestions , the header idea is good I think , I have a set of duponts connectors . Will try that . One of my first ideas was to have the connector on the cabeling but thought it would be a good learning to move it to the PCB instead
Help soldering to a amorphis solar panel - Page 1
Forum section: electronics / beginners

author: poot36
author_rank: Frequent Contributor
timestamp: March 08, 2015, 12:11:09 am
content: I have a solar panel from one of those 1.5 Watt or so car battery maintainers and wanted to attach different wires to it, however the panel will not accept solder no mater how much flux I use. It is one of those glass brown/red colored ones. Got any ideas?

author: poot36
author_rank: Frequent Contributor
timestamp: March 08, 2015, 04:19:08 am
content: Sorry there is no more solder to attach to. I have attached pictures to this post.

author: poot36
author_rank: Frequent Contributor
timestamp: March 08, 2015, 07:55:02 am
content: Ok, so it looks like what I am trying to do won't work. Since it came in a plastic frame would it be a good idea to try some springs attached to the wires and then sandwiched between the back of the panel and the back cover of the frame?

author: German_EE
author_rank: Super Contributor
timestamp: March 08, 2015, 11:56:30 am
content: Clamp your wire to the panel then use a large amount of the conductive paint used for PCB repair. Once the paint has set and you are SURE that the connection is good cover everything with a layer of epoxy for mechanical strength.

author: electr_peter
author_rank: Unknown
timestamp: March 08, 2015, 01:01:19 pm
content: Try adding very aggressive flux. Conventional flux is too weak for such work.
Help sourcing this potentiometer or a similar one for a hotplate stirrer?  - Page 1
Forum section: electronics / beginners

author: artvandalai
author_rank: Regular Contributor
timestamp: February 25, 2025, 10:30:02 pm
content: I wasnt able to find this exact one on digikey or mouser for my Corning 420 hotplate stirrer. Does this potentiometer use a 6mm inner diameter knob?

author: jumpstart
author_rank: Newbie
timestamp: February 25, 2025, 10:58:46 pm
content: I can't decipher the part marking from the datasheet, but looks like it is a 10K pot from Piher PC-16 family - Comes in 4mm or 6mm shaft diameter, the pictures look more like 6mmDatasheet:https://mm.digikey.com/Volume0/opasdata/d220001/medias/docus/5846/Potentiometer.pdf
Help testing LM13700 Op Amp (interpretation of circuit diagram) - Page 1
Forum section: electronics / beginners

author: mike-k
author_rank: Contributor
timestamp: January 07, 2021, 11:25:08 am
content: Hi all,First post here.I'm troubleshooting an old audio circuit which has stopped working. I want to test whether the LM13700 IC is good, as I suspect it's not behaving properly.To do so I have breadboarded a VCA circuit from the LM13700 datasheet:The pins for the LM13700 are as follows:This is how I've breadboarded it:Does it look correct? In particular I'm unsure about the symbol for the input, and how it seems to be connected to earth. I have just connected the input to the 1KHZ test signal from my oscilloscope.In my oscilloscope the input voltage shows as a 3V pulse signal.I have tested 4 LM13700 ICs. For two of them, the output voltage is just -12V. For the other two it is about -1.2VNeither is what I expected. Can anyone suggest what I should be seeing and how to identify the dud chips?

author: fcb
author_rank: Super Contributor
timestamp: January 07, 2021, 12:41:52 pm
content: LM13700 isn't the easiest part to test, as I'm sure you're finding. Probably better to test the signals that feed the LM13700 in your suspect device than to build a test rig for the IC.Also, the 1K isn't a potentiometer on your board and there's no centre tap to GND?

author: mike-k
author_rank: Contributor
timestamp: January 07, 2021, 01:29:06 pm
content: Hi, yes I don't have a 1K pot, so I just used a fixed value. Do you think it's relevant? I have a 2K trimmer I could try.The thing about testing it in the original circuit is that the circuit is not working and I'm not sure that the problem is related to the LM13700. So I want to try to eliminate the LM13700 as a suspect.

author: fcb
author_rank: Super Contributor
timestamp: January 07, 2021, 04:06:42 pm
content: The 1K pot with wiper-to-gnd (treat as two 500R resistors for the same of simplicity) is to act as a gain control and also somewhere to sink leakage currents from the LM13700 - it kinda works by allowing you to trim for null, at the expense of altering the gain (which you overcome by increasing/decreasing control currentgain to suit).If you don't care about null (which you probably don't), then probably just replace the pot with potential divider made from a couple of 470R resistors. That should sort your test circuit out.

author: mike-k
author_rank: Contributor
timestamp: January 07, 2021, 05:53:46 pm
content: Excellent - that worked.I managed to find that just one of the 4 LM13700s was working.I put the working one in the original circuit and it's making sound again.Thanks!

author: fcb
author_rank: Super Contributor
timestamp: January 07, 2021, 06:14:46 pm
content: Did you find both sides of the faulty LM13700's were faulty?

author: mike-k
author_rank: Contributor
timestamp: January 07, 2021, 07:02:07 pm
content: I only tested the one side. But the original circuit uses both sides of the chip, so the good one is clearly working fully. I could hang on to the others and see if they are working on the other side.
Help to build a new keypad for old Sears 31D302A garage opener - Page 1
Forum section: electronics / beginners

author: Mestizia
author_rank: Newbie
timestamp: August 10, 2025, 09:03:56 pm
content: Hi everyone,I have an old Sears 31D302A garage door opener keypad that no longer works. I called multiple companies and they all told me there’s no replacement available — they suggest replacing the whole unit, which feels wasteful since it’s only the keypad that’s bad.It’s an older keypad made by Sears (I’ve included another picture of it upside down so the model number can be read). It stopped working during winter — the LED doesn’t turn on anymore. I tried changing the code, disconnecting and reconnecting everything, but nothing.I don’t have much experience in electronics, but I’d like to make this a small project and be proud of building my own working keypad for it. I’ve opened the unit and discovered I can activate the opener by pressing on the two push buttons on the board (with the enclosure off).My idea:Design and build a new keypad that can connect to the existing board (via the 6-pin header ideally)I need help because I don't know where to start. I try to look for a keypad with a 6-pin but I don't know where...Well, if someone could help me, could tell me what to do. I would be happy to show my progress here.Thanks in advance!

author: amyk
author_rank: Super Contributor
timestamp: August 11, 2025, 02:29:21 am
content: Quote from: Mestizia on August 10, 2025, 09:03:56 pmResolder all the connections, then check the electrolytic capacitors.
Help to choose shelves for new lab. - Page 1
Forum section: electronics / beginners

author: FriedMule
author_rank: Frequent Contributor
timestamp: April 08, 2019, 12:39:24 am
content: I am about to invest in shelves for mostly old and some new-ish gear.I have a 6 x 3 feet table and want shelves over that.Some of my big old gear, demands 12 inch + 4 inch space behind, so a total of 16 inch deep and is 19 inch wide.I have a stone wall to mount the system on, but floor standing is also possible.The max weight is hard to answer, you know that gear has a tendency to just appear without you knowing where it came from;-)

author: 0culus
author_rank: Super Contributor
timestamp: April 08, 2019, 12:49:34 am
content: https://www.eevblog.com/forum/testgear/quality-shelvingracks-deep-enough-for-boat-anchors/I started this topic a while back in test equipment, might be some good suggestions.

author: FriedMule
author_rank: Frequent Contributor
timestamp: April 08, 2019, 04:01:43 am
content: Thanks for the link. It looks like a normal rack system was the main focus.I hope to get my 2 meter x 1 meter table to be up against the wall, beneath the shelves. Do you think that it is great solution for that also?

author: 0culus
author_rank: Super Contributor
timestamp: April 08, 2019, 04:46:12 am
content: I don't know. I am still looking for a house right now, so I don't yet know what space I will have. I was primarily trying to gather ideas.Whatever you do, make sure it is properly braced for the weight you want to put on it. A month or so ago, another member had a catastrophic failure that dumped a number of very difficult to replace bits of vintage computers onto his bench and the floor.

author: FriedMule
author_rank: Frequent Contributor
timestamp: April 08, 2019, 04:49:18 am
content: WOW!! That's sad to hear, have you heard more?I'll defntly remember to check that it can take the load, maybe a solution like Daves is the best, but where do I get that, and what is it called in English?
Help to find the correct pins on Atom C2000 board - Page 1
Forum section: electronics / beginners

author: Starkis
author_rank: Newbie
timestamp: October 21, 2021, 10:28:02 pm
content: Hey folks, I have a 10Gbps network switch that stopped booting and I think it got the infamous Intel Atom C2000 bug. Reading around it seems its possible to fix by putting a pull-up resistor between pins "LPC_CLKOUT0" and "3.3V".The switch is totally dead so I thought I might as well give it a try but I'm having trouble finding the right pins. I'm attaching some pictures. This PCB is part of another main PCB responsible for switch port offloading. I also found a PDF which shows off a very similar board but I'm not sure it's exactly the same.

author: amyk
author_rank: Super Contributor
timestamp: October 22, 2021, 01:30:32 pm
content: You need to find something on the LPC bus to get the signal. If the board has a TPM or connector for one, that would probably be the easiest. According to the third image (strange that your images showed up only after I clicked Reply - I was going to tell you that you didn't have any) it could have a TPM, so see if you can find it on the board.

author: Starkis
author_rank: Newbie
timestamp: October 24, 2021, 08:18:25 am
content: Strange about the images, here are direct links if other people are having the same problem:https://i.imgur.com/mnI9dzw.jpeghttps://i.imgur.com/sc1Z01M.jpeghttps://i.imgur.com/Oz2DG4E.pngEDIT: Looks like it's automatically embedding imgur links, so copy/paste above links should work if anyone else is having issues.Thanks for the TPM suggestion, I will take a look!
Help to get better indication on 20cent  LED VUMeter  - Page 1
Forum section: electronics / beginners

author: dave_j_fan
author_rank: Regular Contributor
timestamp: March 12, 2018, 07:33:55 am
content: This is small circuit of a LED vu meterdesign goals:No extra power to be added: no chips just basic partsThis running well on speaker wiresI have made 2 of this and shoots LEDS from centerHere is videodont need ic or DC power ,i have added a voltage doubler with 1N4148The low LEd gets on at 3.2V and high at 8,4vProblem :it needs atleast 30% volumeneed a ways to improve the voltage doubleror shall i add a joule thief for getting better voltage
Help to Identify 6-PIN SMD IC - Page 1
Forum section: electronics / beginners

author: FFT
author_rank: Newbie
timestamp: June 08, 2025, 05:50:14 pm
content: Hello dear community. I would appreciate if you could help me to identify two ICs, I have tried on the internet search engines and IC search engines with different combinations but I have not been able to find them.The circuits correspond to lithium battery chargers CR2032 type that I bought in AliExpress and I want to identify if it is really possible to charge the battery or it is just a series resistor.The first SMD IC is "CaC46" and the board says 2024/07-22 REV 1.0.The second SMD IC is the "67b442" and the board says 2024 12.26-V1.1 HSX-RSC2201 (Model RSC-X2-2)Attached are the images of both of them.Best regards,

author: fzabkar
author_rank: Super Contributor
timestamp: June 08, 2025, 06:04:57 pm
content: TP4067-4.20V-SOT26-R, Top Power, 3mA-600mA Linear Li-lon Battery Charger, 4.2V, marking 67bYWW, SOT23-6:https://toppwr.com/uploadfile/file/20230304/64030221415f5.pdf

author: FFT
author_rank: Newbie
timestamp: June 09, 2025, 05:37:51 pm
content: Thanks fzabkar for your reply.Looking at the datasheet, I noticed that it is for charging LIR2032 batteries and not CR2030 batteries, which is what the seller advertised.