hybridfree/eevblog-posts huggingface dataset:
Why the SMPS gives normal 24 V if Q is used but 35 V otherwise - Page 1
Forum section: electronics / repair

author: abdulbadii
author_rank: Frequent Contributor
timestamp: February 10, 2023, 01:36:25 pm
content: As try fixing SMPS having improper lower current than the output rating 2.5 A 24V, encountered that the SMPS gives output 24 V if Q is used in normal i.e. jumper is closed, but 35 V otherwise, all without sufficient current/power produced as the claimed rated oneAny clear make-sense reasoning why it is so, and what is the culprit that fails having the proper, adequate current/power, so that can troubleshoot and fix the best way?

author: Zero999
author_rank: Super Contributor
timestamp: February 10, 2023, 02:00:27 pm
content: The schematic doesn't make any sense. Check you've reversed engineered it properly.What sort of SMPS is it? Does it take mains as input? I can't see a bridge rectifier and smoothing capacitor.

author: tunk
author_rank: Super Contributor
timestamp: February 10, 2023, 02:19:40 pm
content: Photos, both sides?Wouldn't have a clue, but R4+R5 could look like a TL431 divider.
wierd kindle paperwhite error message - Page 1
Forum section: electronics / repair

author: grumps
author_rank: Newbie
timestamp: April 06, 2024, 10:25:21 am
content: Just bought secondhand Paperwhite.Indicates I am connected to WiFi but error message says I,m not.Doesn't recognise my email or password even though they work on other devices.Amazon's bot say it's irreparable and want to sell me a new one - what a surprise!!Anyone come across this problem beforeThanks

author: Haenk
author_rank: Super Contributor
timestamp: April 06, 2024, 01:59:56 pm
content: I can only assume, it is still bound to the original owners account. Whose name does not really sound turkish, to be honest.So, if this is a legitimate purchase, ask the original owner to remove this device from his account.I'm pretty sure it will work once the device lock is removed.

author: tooki
author_rank: Super Contributor
timestamp: April 06, 2024, 02:04:01 pm
content: If it’s an old model, it may have missed a critical software update that is needed to be able to connect.This page contains a list of affected models, and says that amanualupdate over USB can be performed on them — automatic updates fail because it can’t connect!https://clark.com/technology/amazon-kindle-emergency-update-required/
Wifi Camera stop working - Page 1
Forum section: electronics / repair

author: sdancer75
author_rank: Frequent Contributor
timestamp: September 02, 2020, 09:31:39 am
content: Hi,I used for about 1.5 year a Security Robotic Eye camera fromhttps://cvmore.com/en/smart-security/.It seems that it has the same board you can find in DOG-1W-V5 from Shenzhen CYLAN Technologyhttps://fccid.io/2ADHE-DOG-1W-V5/Internal-Photos/Internal-Photos-4017528.The camera is not working and it seems that the board problem, it burned also the USB charger.I noticed that the speaker is getting too hot as well as the IC8310 which at the 1st glance searching on the internet is a "16 steady-state current LED driver" but its probably wrong since the output of the speaker is getting out from this IC. So I think its an older model of ES8311 IC which is a Low Power Mono Audio CODEC (I suppose they are compatible)https://pdf1.alldatasheet.com/datasheet-pdf/view/1132836/EVEREST/ES8311.html.Due to the small package size (QFP) I can not test the input analog and digital voltages pins (DVDD, PVDD and AVDD). How to handle this situation?Regards,***Edit 08/09/2020Everest Semiconductors provided me the original datasheet of the ES8310 IC. Because I didn't find anyway in the web, I attach it here for anyone that is interesting about.
Wii U not turning on and has power light - Page 1
Forum section: electronics / repair

author: Pepeu
author_rank: Newbie
timestamp: August 07, 2019, 09:41:55 pm
content: I bought a second hand Wii U with this issue to see if I can fix it because it was really cheap for something that came with gamepad, power supply, sensor bar, etc.So, when I press the Power Button or turn on using the Gamepad, the red light blinks but nothing happen.I opened the motherboard and found a mising SMC capacitor and another one that wasn't working.I changed the capacitor and put the SMS one in the right place, but still no success.I think the RAM is responsible for this, it seems the voltage is not going to the chips, and probably that's why the console is not turning on.What I did? I bought a bricked one with the 160-0103 error to replace the parts.Still, I'm not sure if the RAM is indeed the responsible.. what do you guys think?
Will an iMac boot if EFI is bad or fried? - Page 1
Forum section: electronics / repair

author: Zataralos
author_rank: Newbie
timestamp: August 18, 2020, 07:46:33 pm
content: changed the EFI chip (firmware lock) on my iMac and now it won’t boot. Symptom is LED1 on, LED2 flashing every 5 seconds. The PS seems to be ok, I can measure 12V getting to the logic board. Power button does nothing. Before I start looking for shorts, etc, wondering if the new chip is either bad or fried during installation. It's a 2017 iMac 21.5 4K.Any help would be appreciated?

author: aqibi2000
author_rank: Regular Contributor
timestamp: August 20, 2020, 10:04:31 pm
content: Put the old one back on and confirmIt’ll only take you 10 min to strip down and some hot air for do the swapWhy would you start looking for “shorts” before doing the above?

author: garrettm
author_rank: Frequent Contributor
timestamp: August 21, 2020, 12:13:06 am
content: Couldn't you have used an in circuit programmer to save the old firmware and then flash the hacked firmware? I remember people doing this with PC motherboards to neuter the Intel Management Engine for v11.x firmware. Seems a little easier than unsoldering / soldering in a new chip.https://wiki.gentoo.org/wiki/Sakaki%27s_EFI_Install_Guide/Disabling_the_Intel_Management_EngineI've been building computers since middle school, and even when I flashed the wrong biosthe motherboard would at least still turn on when the power switch was pressed. So you may have damaged something on the mainboard while swapping out chips. Electrostatic discharge kills. I inadvertently euthanized my old PC when I shocked the outer case... Turned out that Silverstone had designed the removable front panel to be electrically floating with the PWR_LED, HDD_LED, PWR_SWT, and RST_SWT running behind it. That shock then went to the closest conductor/s: the front panel wiring and fried the mobo. It was a very sad day for me and my wallet.

author: aqibi2000
author_rank: Regular Contributor
timestamp: August 21, 2020, 09:08:59 pm
content: Garrotte This is not how the HM65 and HM55 PCH architecture worksIt has to pass RSMRST first to get the SIO to transition from the S5 state.The word “boot” really isn’t the right term.There are 5 power up stages
Williams Overture Digital Piano schematic circuit - Page 1
Forum section: electronics / repair

author: PMtech
author_rank: Newbie
timestamp: July 25, 2022, 02:47:08 am
content: HELP!! Need a schematic for Williams Overture digital piano.Originally according to client the unit stopped working but LED still was on but no sound, fuse was replaced on the power supply unit but kept blowing up the replaced fuse.Will appreciate your help.
Wilton S331A Problem - Page 1
Forum section: electronics / repair

author: Boofrmb
author_rank: Newbie
timestamp: July 02, 2022, 07:03:10 am
content: Hi all.Just seeing if there is anyone out there that would be able to assist me with my Wiltron Site Master.Having an issue with it and not sure if I need to send it away for repair, or even if it's worth it.It's a S331A.It has a battery pack that started to leak, so removed it, and built a new one.All good, then after a while, when turned on, it say firmware fails in self test. Now when I turn it on, still firmware fail, but have to reset contrast, and sweep speed appears to be very very slow, like takes minutes to do a cal.CheersRobert
Wiltron 6247D RF - Page 1
Forum section: electronics / repair

author: arno
author_rank: Contributor
timestamp: October 23, 2023, 08:19:31 am
content: Hi,I bought an used Wiltron 610D + 6247D sweep generator. Sometimes - not repeatable - it won't put out any RF below 2.5 GHz. I already changed all caps in the 6247D.Does anybody have experience with these units or can provide a schematic / service manual?Thanks in advance!Arno

author: arno
author_rank: Contributor
timestamp: December 26, 2023, 05:13:48 pm
content: Update: I got the schematics from someone; if anybody needs them as well, please drop me a message.Arno
Wiltron 6409 (2GHz RF Analyzer): CRT fault - Page 1
Forum section: electronics / repair

author: auato
author_rank: Contributor
timestamp: February 28, 2022, 12:38:54 pm
content: Hi all,I am facing a fault on a CRT board (KME MB22) but hard to troubleshoot as it's not available the electric diagram. As you can see below in the video, from time to time, the horizontal driver shuts down for a while.I already tried to move horizontal inductor trimmer, tried to check the solder jonts and replaced the electrolytic caps. Power supply voltages seem OK, as well.There is a red wire starting from the PCB and labeled as "A1" towards the pin_base of the CRT on which I found high voltage (about 450-500Vdc) and everytime the defect appears it goes down as in this videohttps://youtu.be/To5Zq-NKuFYWhat do you think?Thank you

author: BrokenYugo
author_rank: Super Contributor
timestamp: February 28, 2022, 09:00:08 pm
content: Check the solder joints again, with magnification, pay extra close attention to large pins and anything that gets hot. Or flux and reflow everything to remove all doubt.

author: fzabkar
author_rank: Super Contributor
timestamp: February 28, 2022, 09:34:59 pm
content: Tap test, heat with hair dryer, cool with spray freeze ...I always reflow the solder at inductors and transformers.

author: auato
author_rank: Contributor
timestamp: April 04, 2022, 06:09:10 pm
content: I have "reflowed" everything (sucked old tin with braid and resoldered) but the problem persists. Noticed this vaweform on the flyback transformer. It is a 7 pin flyback but, as already wrote, I don't have any schematic diagram and I am not expert on this type of circuitry at allhttps://www.youtube.com/shorts/wFde63Su4PM

author: james_s
author_rank: Super Contributor
timestamp: April 04, 2022, 08:05:51 pm
content: The HV transformer is part of the horizontal scan circuit so if the horizontal shuts down then most of the voltages will fall. Can you tell if that's what's happening?
Wiltron 6647 A - Page 1
Forum section: electronics / repair

author: Ralsup
author_rank: Newbie
timestamp: July 13, 2021, 06:54:44 pm
content: I am restoring a Wiltron 6647A with options 02 and 03 with the serial number 543010 and have a corrupted EPROM. Does anyone know where I can find a copy of the 5 EPROM chips to download?
Wiltron Anritsu 68187B 60GHz generator Power supply not locked (Error 106)  - Page 1
Forum section: electronics / repair

author: DominiqueB
author_rank: Newbie
timestamp: March 19, 2020, 01:52:54 pm
content: Hi all,I contact you for the following.I have one Wiltron Anritsu 68187B 60GHz generator having some problems.When I got it, display was not good, and the CW had side bands. I changed the display, and changed the caps on the A18 PB Board ... and now display is perfect, and side bands are gone.I have one problem left to solve . When running the Selftest program, I get an error "Error 106 Power Supply not locked" ... Looking the Service manual, I have checked the A6 Board which produces a good TTL 440kH as expected, used for locking the frequency of the A18 PS Board.So the problem comes from the A18 Board. The PWM ic (ML4825) works fine, but the frequency of the oscillator is not locked. Instaed of being 440KHz, it is lower, at 320KHz. I have tried to replace the cap in the oscillator circuit, I can modify the frequency, by still not locked ...So, my conclusion is that the PLL circuitery is broken, an I do not know why ...> No schematics (if someone has the schematic, it wold be great, the Service Manual gives only blocks no components level)> No obvious defective componentIf someone has one A18 to trade, or schematics ... I am very interested.Thanks for the reading and help.Regards,DominiqueB - F4HIJ
Wiltron / Anritsu switched frequency doubler module - Page 1
Forum section: electronics / repair

author: Aiy
author_rank: Regular Contributor
timestamp: January 14, 2022, 08:56:37 pm
content: Hello Everyone,I recently got an Anritsu 69167B 10MHz - 40GHz synthesizer.The unit has a faulty Switched Doubler Module, so almost no output from the synthesizer in the 20-40 GHz range.I have checked the VNA we have at work and found that the 40GHz wiltron VNAs in the 37xxx series are a potential source for an equivalent device.So, I was wondering in anybody has a d28540 SDM module, or a broken Wiltron / Anritsu 37xxx 40GHz VNA that could be sourced for a spare part?I also took some pictures while I was checking over the SDM.On the RF side (picture 1) we have a number of PIN diode switches that enable / disable the path from the 0-20GHz straight path. Along the "straight" path we also have a number of PIN diode switched "stubs" that are used to provide extra filtering of the output signal.The secondary path out makes a side-trip to the right, through an amplifier, is split and passed into two parallel amplifiers, re-combined and dives down into a PCB VIAOn the bias PCB side (picture 2) there is routing from the 15-pin low-density D-SUB to the various feed-through filter positions and a couple of resistors and caps, nothing exotic.Below the bias PCB is a small covering hatch which covers the frequency doubling circuit (picture 3). The via from picture 1 comes in at the top of the picture, is then fed to two diode pairs in a single beam-lead construction (zoomed for glory in picture 4). The diodes in my unit are broken and shorted. As far as I have been able to gather, this is a custom Wiltron/Anritsu part that I cannot find.Best regards

author: Joel_Dunsmore
author_rank: Regular Contributor
timestamp: January 15, 2022, 08:12:20 pm
content: If you happen to attend the ARFTG / RWW conference starting next week, you'll likely find Jon Martens there, and I guess he might have either designed the part or knows a lot about it.www.arftg.orgorwww.radiowirelessweek.org
Winbond W25Q64FV Flash - Page 1
Forum section: electronics / repair

author: TobiasG
author_rank: Contributor
timestamp: March 22, 2024, 11:42:47 am
content: Hello all,Could someone explain which the difference between this specifications:25Q64FVSIG25Q64FVSIQ25Q64FVSIFcan I substitute between them?

author: fzabkar
author_rank: Super Contributor
timestamp: March 22, 2024, 03:59:25 pm
content: https://www.verical.com/datasheet/winbond-serial-nor-flash-w25q64fwssig-789896.pdfQuote

author: TobiasG
author_rank: Contributor
timestamp: March 22, 2024, 04:30:39 pm
content: tks FzabkarThen I can replace each others rigth?

author: fzabkar
author_rank: Super Contributor
timestamp: March 22, 2024, 04:38:09 pm
content: Quote from: TobiasG on March 22, 2024, 04:30:39 pmI'm not sure how QE=0 or QE=1 would make a difference.SFDP would be an optional feature that may or may not be required by your application.
windows blue screen - DPC watchdog violation - Page 1
Forum section: electronics / repair

author: MacIntoshCZ
author_rank: Regular Contributor
timestamp: January 28, 2022, 08:18:37 am
content: When turning pc on, it just freeze at login screen after few seconds.I though its ssd disk and run sfc/ scannnow or chkmdsk /f /rIt works for once. Second day it just freezed again on loging screen. I did factory reset. Again it works.Today it just freezed. So i guess i will reinstall windows and block windows updates.Its pain in the ass. Any health check software reccomendantions?

author: KE5FX
author_rank: Super Contributor
timestamp: January 28, 2022, 08:39:25 am
content: One thing that causes this is a lot of mapped network drives that can no longer be resolved. It may appear to lock up with a blank screen after login for up to several minutes as it tries to reconnect to each of the missing drives. Could be worth checking that if you haven't already.

author: MacIntoshCZ
author_rank: Regular Contributor
timestamp: February 17, 2022, 12:47:42 pm
content: Ok i have found out that laptop freeze when try to connect to 2.4 Ghz wifi. Wifi adapter is RTL8852AE.5GHz works fine.I need to know if wifi card is OK and drivers are bad. What should i do? Does wifi works on linux live cd?

author: amyk
author_rank: Super Contributor
timestamp: February 17, 2022, 02:41:27 pm
content: It depends on which one in particular but Linux drivers are available for it:https://github.com/lwfinger/rtw89

author: abdulbadii
author_rank: Frequent Contributor
timestamp: February 17, 2022, 03:25:20 pm
content: You're correctRTL8852AE has bad reputation esp. in 2.4 GHz, seems aimed more on 5GHz.It's wifi card not of drivers

author: MacIntoshCZ
author_rank: Regular Contributor
timestamp: February 19, 2022, 06:32:41 pm
content: Do you think I can switch wifi card to ax 200? I am able to find only this desktop kit.https://youtu.be/02UZ3kx3CjE
Winegard DA-1036 TV/cable distribution amplifier - Page 1
Forum section: electronics / repair

author: coredump4
author_rank: Newbie
timestamp: March 11, 2024, 11:34:33 pm
content: Hi all,I just pulled a non-working Winegard DA-1036 distribution amplifier for repair. Does anyone know where to grab schematics for old Winegard gear?thank!
Wire Cutter Repair - Page 1
Forum section: electronics / repair

author: rfdes
author_rank: Regular Contributor
timestamp: November 27, 2021, 04:01:41 pm
content: I have (had) a beautiful, precision (aka expensive) set of wire cutters that were damaged by an unknowing user that were abused. In other words the cutting edges were cobbled. Is there a service where they could be repaired at a reasonable cost? My guess is no, the cost would exceed the price of the cutters and not be worth it. These cutters are priced in the $80 range, so maybe there is some hope.Any suggestions?ThanksJim

author: Shock
author_rank: Super Contributor
timestamp: November 27, 2021, 05:35:56 pm
content: You can get needle files from hobby stores, possibly hardware stores and (obviously) online. If you don't have a sharpening stone get some wet and dry sandpaper and use water or oil as a lubricant. You can wrap it around a flat needle file, a butter knife, sand small piece of wood flat or even use a small piece of pcb. Ladies emery-boards (for shaping their nails) work in a pinch as well. If you have a small benchtop vice it makes things like this even easier.

author: Audiorepair
author_rank: Frequent Contributor
timestamp: November 27, 2021, 06:30:33 pm
content: Don't ever lend your cutters to a guitarist.They will cut guitar strings with it.Leaving big holes in the blades that are impossible to put back.

author: CaptDon
author_rank: Super Contributor
timestamp: November 27, 2021, 08:55:45 pm
content: Don't lend your cutters to ham radio guys either. They like to 'trim' stainless steel whip antennas to proper length!!!! $80 wire cutters?Never seen any in that price range.And I thought my G.E. Forge (George Earnst) hoof nippers at $220 were expensive. Well,at least they did offer several years of 'free maintenance' at that price!!!

author: WattsThat
author_rank: Frequent Contributor
timestamp: November 27, 2021, 09:11:45 pm
content: Bin ‘em. Yes, an expensive lesson. $80 sounds like Linstrom.There is no restoring the material that is missing, now a hole that shouldn’t be there. You can grind them down to where the edges meet once again but they’ll never cleave as well as before. Duplicating the angle and straightness of the edge is the challenge.

author: rfdes
author_rank: Regular Contributor
timestamp: November 27, 2021, 09:19:05 pm
content: Hi -Thanks. I may give it a try. I purchased 2 pairs of these cutters at an estate sale at a great price and have been taking very good care of them up until recently. i.e. Trust No One!Take care -Jim

author: Gregg
author_rank: Super Contributor
timestamp: November 27, 2021, 09:32:35 pm
content: Diamond honing sticks like these are thin, wide and flat enough to touch up flush cutters.https://www.amazon.com/EZE-LAP-PAK5-Color-Coded-Diamond/dp/B002RL83DQTry to take the same amount off of each side. Also be aware the edges do not meet exactly together or they will destroy each other.
Wire for AA batteries - Page 1
Forum section: electronics / repair

author: laispais
author_rank: Newbie
timestamp: May 26, 2023, 11:31:50 am
content: ​Im going to relocate the batteries in the xbox controller to where the rumble motors used to be. So I need some wire to connect the batteries to the circuit board. How thick wire should I use?

author: Psi
author_rank: Super Contributor
timestamp: May 26, 2023, 11:36:56 am
content: Just about any wire will work fine for that, if you need a number use 24 AWG.That is good for 3.5A in this application, and you're never going to be pulling that out of AA'sUse stranded core (not solid core).
Wireless mouse repair - part identification (LiPo charger?) - Page 1
Forum section: electronics / repair

author: Strand17
author_rank: Contributor
timestamp: July 23, 2023, 10:23:31 am
content: Hello,I am trying to repair a wireless mouse and need help identifying a part.The part in question a the SOT23-5 marked H1KH, see picture below. It is probably controlling the LiPo battery charging. Pin 4 is connected to 5V from the USB and pins 2 and/or 3 go to the battery positive pole. The positive and negative battery inputs are currently shortened, which may be caused by the unidentified SOT23-5.The SOT23 marked 6525 is a 3.3V voltage regulator and the diodes provide "selection" between battery or USB 5V power to the regulator.Thank you in advance!Best regards,Jonasedit - image attachment failed. See later post for image.

author: Strand17
author_rank: Contributor
timestamp: July 23, 2023, 10:47:57 am
content: ...here is the image.Best regards, Jonas

author: tooki
author_rank: Super Contributor
timestamp: July 23, 2023, 12:49:33 pm
content: I think it’s the ME4054 (probably specifically ME4054AM5G or ME4054M5G) from Microne. In every image of it I can find that shows a chip with the Microne logo, it’s marked H1xx, so I suspect H1 is the part and the last two are a date or lot code.There are countless 4054 chips from both big manufacturers (like ST) and cheaper options like Microne. Any should be fine, just choose one with the 25uA shutdown current like this one — some manufacturers also make versions with higher shutdown currents.

author: Strand17
author_rank: Contributor
timestamp: July 23, 2023, 02:23:46 pm
content: Thanks a lot tooki! I will try with an LTC4054.Best regards, Jonas

author: Strand17
author_rank: Contributor
timestamp: November 14, 2023, 03:33:33 pm
content: Just a follow-up...The problem turned out to be a shorted capacitor.However, I had already changed the charging IC to a LTC4054 and I can confirm that the mouse works with this IC.Best regards, Jonas

author: tooki
author_rank: Super Contributor
timestamp: November 21, 2023, 07:53:31 am
content: Thanks for the follow up. Glad to hear you got it working!
wiring diagram plotter HP 7225A - Page 1
Forum section: electronics / repair

author: hnjmkl
author_rank: Regular Contributor
timestamp: September 23, 2020, 04:30:36 pm
content: In the net i did not find the wiring diagram of the HP 7225A plotter, i wound like to try the repair, someone help me?

author: picburner
author_rank: Frequent Contributor
timestamp: September 23, 2020, 07:36:41 pm
content: I guess you are looking forthis

author: hnjmkl
author_rank: Regular Contributor
timestamp: September 25, 2020, 03:49:13 pm
content: Solved the problem, found the circuit.
Withings Body+ with broken LCD - Page 1
Forum section: electronics / repair

author: sandoval
author_rank: Newbie
timestamp: February 15, 2020, 04:02:53 pm
content: Hello everyone. I have Withings Body+ smart scale with broken display. I managed to open the unit, however I am unable to find fitting replacement LCD anywhere. I found this product number on the ribbon cable, but unfortunately I was unable to find anything: TM12864L9GFWGWAFPC1-01It has 16 pin cable, but I was unable to find any similar displays with 16 pin cables from Chinese sellers which are familiar to me.Any help is welcome.

author: Arken Sparq
author_rank: Newbie
timestamp: February 18, 2020, 03:43:07 am
content: I joined this forum, because I too am looking for help sourcing a specific LCD. Hopefully, my replying here increases traffic and improves our chances of someone else joining the conversation. Your display sounds like it might be a bit more common than what I'm looking for though. Can you provide a little more info (dimensions, number of digits) or a photo of the LCD? I'll do my best to help you look, while we wait for someone more experienced to show up.

author: sandoval
author_rank: Newbie
timestamp: February 19, 2020, 02:03:46 pm
content: Thank you for your reply.Here is the one photo of the LCD. If more are needed please let me know.Don’t have it now close to me but according to the maker LCD is (2.4”x1.6”), 128x64 pixels. The size is available in freedom unit only.Thanks
WM-P1070D JVC Wireless Mic not connecting to system - Page 1
Forum section: electronics / repair

author: Nick84
author_rank: Newbie
timestamp: March 17, 2025, 06:45:10 am
content: I have a WM-P1070D wireless mic that powers on, but doesn't connect to the receiver.Current information:When set to the same group/channel settings as a working mic, it doesn't connect, but will interfere with a working mic. If the working mic is on and the LED for the channel on the receiver is on indicating a mic connected, the LED will turn off if the bad mic is turned on to the same channel and neither mic will work until the bad one is turned off.The second channel on the receiver seems to be broken as even the good mic won't be detected, but that's a puzzle for another day.Opening the mic, one of the 2 ICs (Toshiba VHC165) that convert the switch settings to a serial signal for the processor was cracked and had a couple of what looked like gouges in it (see photo). I was able to order replacements and replaced both chips, but the behavior didn't change.I took resistance to 0v on the working mic on both ICs on both a known working mic and this one and the resistances were pretty much dead on with the switches in the same positions on both mics. I traced the connections and it looks like one of the chips connects to the serial in on the other, then that chip goes out to cn702 on the sub board and into CN2 on the main board then through a resistor before going to an inner layer to go to the processor.The discoloration on the sub pwb board label is from flux and IPA getting on it during soldering, so not a symptom of the issue.CN701 goes to the physical microphone, CN1 goes to the antenna (2 wires looping in the handle), J1 and CN3 are unused.None of the capacitors seem to be shorted to 0v andIf anyone with experience with wireless mics or something related can point me in the direction of something to test to find something fixable, it'd be much appreciated. If you need to know any measurements in particular, let me know (don't have an oscilloscope yet so can only test resistance/voltages at the momentI have an oscilloscope on order. Should arrive within a couple of weeks. This was a good enough excuse to buy one).
Working on SMD-setting the hot air station at 400 degree celsius, is that ok? - Page 1
Forum section: electronics / repair

author: Yamin
author_rank: Frequent Contributor
timestamp: October 11, 2020, 06:56:31 pm
content: Hi everyone,I've been practicing on working on SMD component (trying on scrap boards of course). Many resources I came across online calls to set the temperature at 350 degree celsius and the air at half. I am able to remove components on some of the boards sometimes set at those values and they are mostly on older boards, but like I said mostly its a hit and a miss. I do experiment with slightly higher temperature and different air settings. I never go above 380 degree celsius though.Then I came across a youtube instructional video which suggest to use the temperature at 400 degree celsius. Could that be right? Would that be an ok temperature to set at especially if I'm planning to reuse the removed components? Setting my station at that temperature definitely gets the components removed very easily.I am having particular bad luck removing DPAK packages specially the body connection. I haven't tried using 400 degree celsius on those yet. I do use RMA-223 flux.Looking forward for your thoughts and any further tips would be greatly appreciated.Thanks

author: sirloin
author_rank: Newbie
timestamp: October 12, 2020, 04:03:50 pm
content: I'm also somewhat new to this hot air repair in terms of temperatures.What I found made a huge difference is getting something like a hakko FR830. (or similar). Basically allows you to heat from the bottom of the board and make it easier and less stress than heating one small point on the board. So say you set the PCB heater to 200C or 175C, then your hot air tool doesn't need to blast as much heat onto the board to remove some of these tricky larger componenets.For thin/small PCBs the lower temperature is fine since it isn't sucking the heat away from the component you are heating as fast.Again, I am no expert and still struggle with this myself. My overall thinking is to reduce the max temperature and also reduce the thermal stress on the pcb/components by heating only one small point on the board.

author: poot36
author_rank: Frequent Contributor
timestamp: October 13, 2020, 02:27:37 am
content: Try setting the air at 6 (if your SMD rework station has a dial that goes to. It will help heat the board faster. I only use a lower air flow for small components when I am trying to re-install them. I usually go for 350C for the lead based solder and 400C for the lead free stuff (or components with a large thermal mass). I have yet to knowingly damage a component with the hot air that was not already failed or ready to fail soon.

author: coromonadalix
author_rank: Super Contributor
timestamp: October 13, 2020, 03:02:23 am
content: Really depend of the board thickness i work mostly with 4 layers and they have thick mass planes, i have to push the heat to the max to get some results, sometimes i use a preheat "bed" for the pcb, or i do a crazy thing like using an heat gun and do circular patterns on the other side on the section i need to work, it can help a lot to remove some stubborn parts
Working Through The HP 3563a CSA - Page 1
Forum section: electronics / repair

author: lancelotburt
author_rank: Contributor
timestamp: January 24, 2019, 05:55:40 am
content: I'm working my way through the start-up sequence to get this HP 3563A going. As it arrived - powers on, no display, no keyboard response. The power supply checked out. Battery dead so I replaced that. After reseating all the A2 processor board chips and jumpers, and resetting the battery jumper (non-volatile ram), it makes it through the start-up LED ROM/RAM sequence without errors, the keyboard is responsive, but the display is still dark. The A38 Memory board has a single red LED on it that lights as the A2 processor is 1/2 way through the High Level Power-up Tests. I have scoured both service manuals and find no info on the A38 LED and no schematic for the A38 board.Any 3563A experts out there? Red LED good or bad?

author: lancelotburt
author_rank: Contributor
timestamp: January 24, 2019, 04:36:53 pm
content: Found it in the 3562a manual I'm thinking, even though the boards are somewhat differently layed out on the 62a. The Ram board has a single LED on the top edge of the card that indicates RFD on the system bus. It is not used for board diagnostics.On to the CRT PS check.

author: lancelotburt
author_rank: Contributor
timestamp: January 25, 2019, 04:01:09 am
content: So, the 1A fuse on the CRT Low Voltage, -15v supply is being blown. Looks like the culprit is on the A81 Analog X, Y, Z board. The negative voltage regulator on that board has been replaced before, though the 100uf/25v electrolytic right before it hasn't, and has an ESR of 5.8 ohms.

author: lancelotburt
author_rank: Contributor
timestamp: January 26, 2019, 01:58:13 am
content: Uhh. Misread that. ESR is .58.A bit further into the -15v, the - shorted supply voltage for the D/A converters, I found the culprit, a little, shorted tantalum bugger. Have to replace all of those.

author: lancelotburt
author_rank: Contributor
timestamp: March 10, 2019, 08:40:37 pm
content: I ended up getting another display unit with a bad tube and swapped out the A81 XYZ and the digital interface board. Now everything works and my original tube (3019A...) is very good. Happy.Now Self Tests. FFT ROM and FFT Global Interface fail. I forgot to reset the profile. See if that helps...

author: lancelotburt
author_rank: Contributor
timestamp: October 07, 2019, 12:47:28 pm
content: Replaced FFT board. Everything is working. Nice old box!
Worth buying faulty Hantek DSO5202B? - Page 1
Forum section: electronics / repair

author: szevlin
author_rank: Newbie
timestamp: September 15, 2021, 01:35:15 pm
content: Is it worth buying a Hantek DSO5202B scope as faulty or is there little to no hope in fixing these?The seller says that the scope displays a trace but the trace doesn't change when a signal is connected. (like as if it was always coupled to ground when its not)Thanks

author: Runco990
author_rank: Frequent Contributor
timestamp: September 15, 2021, 04:58:09 pm
content: That's up to you.... and depends on how much money you are willing to loose.My personal experience has been that modern cheap crap like this is generally not repairable or not worth repairing, unlike older gear that you can at least get a schematic for.Also, I find that with the asking prices on used, often ancient and clapped out test gear, it may actually be cheaper and better to buy a NEW piece that has a warranty and is IN SPEC.It's fun to repair old Hewlett Packard, Tektronix, etc. But Stuff Like already cheap Hantek, etc....Really depends. For under $100 I MIGHT try it.... but only because I can afford to loose $100. Not really, but it won't kill me if it's junk.

author: magic
author_rank: Super Contributor
timestamp: September 15, 2021, 08:11:27 pm
content: A few years ago Hantek DSO5xxxB scopes have been reverse engineered by people on this forum, at least HW revisions up to 1007.One crazy even upgraded the analog frontend to 300MHz.Download the schematic and decide if you feel like messing with it. The analog frontend is right on the first page.https://www.eevblog.com/forum/testgear/hantek-tekway-dso-hack-get-200mhz-bw-for-free/

author: james_s
author_rank: Super Contributor
timestamp: September 15, 2021, 09:49:27 pm
content: How much are they asking for it? If the price is right I would buy it given the opportunity, anything like this is a gamble but overall I've done very well in the casino of broken electronics. YMMV.

author: perieanuo
author_rank: Frequent Contributor
timestamp: September 16, 2021, 11:01:54 am
content: my bet is on "no"but if you like challenge and you can use another scope to diagnose the dead one, it's your call
WORX drill repair - switch - Page 1
Forum section: electronics / repair

author: mintsoft
author_rank: Contributor
timestamp: July 26, 2020, 05:22:41 pm
content: Hey,I've just been given a WORX drill driver to repair as it's flashing when you press the trigger. Quick multimetre test shows that the 4/5 of the switches contacts are all shorted together. I was trying to get a replacement however the markings on it are:DLK-2036R and JIABEN (I assume this is these guys:http://www.jiaben.com/en/index.asp). I can't find that part anywhere at all, I'm wondering if this is maybe a standardised switch and someone might know of an alternative?Pic attachedThanksRob

author: coromonadalix
author_rank: Super Contributor
timestamp: July 27, 2020, 06:05:36 am
content: since you have 3 wires red black and yellow going out of it, the switch is not a simple switch, i has some electronics in itapparently this one is a substitutehttps://www.ebay.com/itm/1pc-USED-JIABEN-DLK-2036R-20A-36VDC-Trigger-Switch-VA51-CH-/184322919785
Would anyone be able to identify this connector? - Page 1
Forum section: electronics / repair

author: aaron94
author_rank: Newbie
timestamp: November 30, 2019, 05:45:19 am
content: HiLink to image:https://1drv.ms/u/s!ArCROuT6bRvPilFN2raZQIJcH6oGI have the crimping tool already and the smaller type of these connectors that I use now and then but these are a bit bigger.It’s from a temp controllable laminator I bought. Mains flex and supplied AU plug is unbelievable. Absolute rubbish. Earth cut off inside the metal chassis and as soon as I put the smallest amount of pull force on the connector shown in the picture, the neutral pulled out. Must have been holding on by a strand.Rest of it is decent enough but it’s amazing there’s not more house fires with stuff like this...Thanks!

author: madao
author_rank: Frequent Contributor
timestamp: November 30, 2019, 06:01:05 am
content: Pleas upload pictures here. I hate slow page as google drive and mircodoof (german mircostupid) onedrive.This is a JST VH, if Pin pitch = 3,96mmregardsmatt
Would this be a Bluetooth interference problem or something else ? - Page 1
Forum section: electronics / repair

author: MathWizard
author_rank: Super Contributor
timestamp: February 14, 2024, 01:25:46 pm
content: I just got some BT earbuds and I'm using them with a MP3 player that has a touch screen. And so far in a few hours I used them, with them in my coat pocket and the screen locked, the mp3 track has moved back 1 file, and another time it seemed to skip a few tracks ahead or back IDR.I don't know the circuits in this MP3 player, but if you just have some external switches and pins into a MCU, can the RF from the BT be enough to make the MCU think the button was pushed, turning on some gate or base of a transistor ?I walked ~12km (7.5mil) 2 days ago, using wired earbuds, and never had the track skip ahead to another track once.Maybe some cap in the switch circuit is dodgey and the BT RF puts energy into the circuit and puts it over the edge ?But there is no external track skip button, that's all on screen. But there is a button for locking the screen.

author: tom66
author_rank: Super Contributor
timestamp: February 14, 2024, 01:38:38 pm
content: Almost certainly not Bluetooth.A common fault with switches especially on portable products is grime/sweat/moisture gets into the switches and forms conductive bridges which make the player think the buttons are randomly pressed.A possible solution would be to gently clean the switches (once disassembled) with some IPA.It's possible to save money/pins on the MCU they use an analog divider to select different functions. So one voltage encodes play, another encodes stop, and so on. If the missing voltage is being generated by a conductive bridge it could access 'unavailable' functions.

author: coppice
author_rank: Super Contributor
timestamp: February 14, 2024, 01:40:41 pm
content: Its easy to interrupt BT communications with interference, but accidentally faking an action is hard, as there is error checking on the received data.

author: MathWizard
author_rank: Super Contributor
timestamp: February 14, 2024, 02:00:42 pm
content: Sometimes it did happen with wired HP, but not lately until yesterday/today with the BT ones. IDK maybe moisture gets in there, and yeah the touch screen seems to do funny stuff when snow falls on it, or getting pushed in in a pocket the wrong way. Or maybe yeah something is just wearing out.I've pulled apart MP3 players before, and it's always been a black box problem. Power would work, and besides some ram and the MCU, there's not much to check. And IDK MCU hacking so I get nowhere.

author: wasedadoc
author_rank: Super Contributor
timestamp: February 14, 2024, 04:10:31 pm
content: The Bluetooth AVRCP profile (https://en.wikipedia.org/wiki/List_of_Bluetooth_profiles) provides control of the player from the audio (and video) output device. If your player and earbuds implement that profile it is possible that you have unknowingly activated track skips by touching the earbuds. Consult the manual for the earbuds.
Would this speed controller sold on Ebay suit a sewing machine from the 70's? - Page 1
Forum section: electronics / repair

author: wilfred
author_rank: Super Contributor
timestamp: October 21, 2022, 03:29:40 am
content: I just caught this old video BigClive did 6 years ago about a speed controller he bought on Ebay. It was an interesting video with reverse engineering of the circuit. BC learned something he didn't know. So did I of course.He referenced this App-Note describing a key feature.https://www.littelfuse.com/~/media/electronics/application_notes/switching_thyristors/littelfuse_thyristor_phase_control_using_thyristors_application_note.pdf.pdfI searched on Ebay and found this which looks like the one.https://www.ebay.com.au/itm/394249590685I recently acquired an old Husqvarna 5610 sewing machine without the foot pedal. I think machines of this vintage just used a rheostat but I'm not sure this one did. My question is would this device be suitable for this application as a replacement throttle control. The 4kW might be a bit fanciful but a sewing machine is nowhere near that anyway.BC also mentioned the RF noise this circuit would generate since it doesn't have any suppression components. Where would you add the choke? And could it be an old one from a PC power Supply? I have a collection of them.

author: floobydust
author_rank: Super Contributor
timestamp: October 21, 2022, 04:12:52 am
content: What type of motor does it have? Nah, it would not work well.Nevermind that speed controller is pretty junky, mine didn't last before a blown triac and potentiometer, and I had to mod it for reasonable 120VAC operation as discussedhere.I did some repairs and schematics on Elna sewing machine controllers. Those are a brushed DC motor with back-EMF monitoring so they are controlling for near constant speed despite required torque varying. An SCR and bridge rectifier are used in the pedal.So that 4,000W eBay special would be awful to control speed with and might not even be compatible with your motor.A better controller is used on power tools, where you want constant speed regardless of load, like discussedhere.Those controllers are more sophisticated and use an IC.

author: james_s
author_rank: Super Contributor
timestamp: October 21, 2022, 06:50:52 am
content: Older sewing machines have brushed universal motors, the original foot controls are just variable resistors, I believe they use a carbon pile. Anything that varies the average voltage the motor sees ought to work, triac speed controller, variac, rheostat, etc. I bet you can buy replacement old style foot pedals.
WVC 1400 grid tie inverter Frankenstein version - Page 1
Forum section: electronics / repair

author: monkeyisland
author_rank: Newbie
timestamp: October 03, 2022, 06:53:28 am
content: Welcome to the WVC 1400 Frankenstein inverter:My WVC 1400 R3 failed after only two weeks of use, and using it at 50% capability ( only x2 solar panels instead of x4).Two AC output MOSFETs failed. And also the main fuse, but that was my fault insisting with the circuit breaker.I claimed AliExpress and they will send MOSFETs replacement which will take weeks to arrive.Meanwhile I decided to buy MOSFETs myself, nowhere to find the original STB40N60M2 in D2PAK format at reasonable cost and low quantities. The chip shortage crisis seems to be also affecting semiconductors as many UK component sellers are giving 6 month delivery date and the prices are well higher up, at least compared with a few years back.Pulling some information from YouTube and eevblog forums I found out that "similar" WVC inverters has been equipped with at least 3 different AC MOSFETs, the Vdss seems to be equal: 600-650v but "gate charge", "rated current" and "RDSon" are completely different between mine and them:RDSon 0.078ohn mine, 0.13 and 0.36 others.Gate charge: 57Nc 100Nc 27NcRated Current: 34A 25A 11A... that made me think I could play up with specs finding the cheapest MOSFET available for experimentation. I bought the TOSHIBA TK25E60X in TO-220 package, pins bent and mounted on the air with direct fan cooling.The main Fuse was not possible to be removed with hot air gun or with solder tip even when using fresh solder wire, hence the "double decker"fuse sorry looking.The lid can not be closed but the is indoors, now mounted in a bigger control unit metal box with 2 cooling fans for the front and rear of the PCB board.Has been working perfectly for two weeks, but final conclusion when I upgrade to 4 panels and perform the 1400w output rating.

author: monkeyisland
author_rank: Newbie
timestamp: October 03, 2022, 06:56:45 am
content: WVC inside metal case with double cooling fan

author: jonpaul
author_rank: Super Contributor
timestamp: October 03, 2022, 06:59:39 am
content: schematic? BOM? specs of switch FETs? line transients scope capture ?j

author: monkeyisland
author_rank: Newbie
timestamp: October 04, 2022, 01:15:24 am
content: Schematic not available for the WVC 1400 R3.It is a sub 150$ grid tie inverter, the repair is obviously a DIY more than electronics repair shop so please understand that not worth to buy the oscilloscope to get the curves.Original AC MOSFETs STB40N60M2Vdss 600vRDSon 0.078total gate charge 57NcRatedCurrent. 34AMax gate treshold Volt 4vReplacement MOSFET chosen by me:Toshiba TK25E60XVdss 600vRDSon 0.125total gate charge 40NcRatedCurrent. 25AMax gate treshold Volt 3.5vIn TO-220 package.MOSFETs in the inverter by YouTuber "How to guys"30NM60NDVdss 650vRDSon 0.13total gate charge 100NcRatedCurrent. 25AMax gate treshold Volt 5vMOSFET by "All in the family'member comment in the same YouTube linked above:STD13NM60NDVdss 600vRDSon 0.36total gate charge 27NcRatedCurrent. 11AMax gate treshold Volt 4v
Weller WXUP handle not detected - Page 1
Forum section: electronics / repair

author: sako
author_rank: Newbie
timestamp: September 27, 2023, 09:48:13 am
content: Hello,I have Weller WXUP handle that is not detected by WXD2 station.Currently I suspect incorrect EEPROM content.Does anyone have or can read EEPROM content from handle.Regards,Pawel

author: sako
author_rank: Newbie
timestamp: September 27, 2023, 08:09:21 pm
content: Fixed.Issue was caused by old firmware in WXD2. After firmware upgrade everything works fine.
X1 and X2 Capacitors - Page 1
Forum section: electronics / repair

author: Mad Axeman
author_rank: Contributor
timestamp: January 05, 2024, 08:11:59 pm
content: I've got a device that uses a dropper cap for it's power. The original has gone t1ts up, 474k X1 330V. Can this be replaced with an X2 474k 330v ? The X1 seems either a stupid price or places like RS, CPC & Farnell want minimum orders of 5 or 10 plus delivery. What difference/problems would I get substitution a X2 cap for an X1 ?

author: Vovk_Z
author_rank: Super Contributor
timestamp: January 05, 2024, 08:20:08 pm
content: X1 cap is a bit more reliable. It is designed to work with pulse applications. X2 caps are rated for general purpose application mostly.

author: fzabkar
author_rank: Super Contributor
timestamp: January 05, 2024, 08:23:15 pm
content: https://www.allaboutcircuits.com/technical-articles/safety-capacitor-class-x-and-class-y-capacitors/

author: Mad Axeman
author_rank: Contributor
timestamp: January 05, 2024, 09:09:17 pm
content: Thanks both for the info. The link was very useful