hybridfree/eevblog-posts huggingface dataset:
Siglent SPD3303x-e output issue after firmware hack? (Solved! [I'm a dumbass]) - Page 1
Forum section: electronics / repair

author: Brad808
author_rank: Contributor
timestamp: August 18, 2020, 12:43:34 pm
content: Yesterday I picked up a "new open box" Siglent SPD3303x-e (my guess is it was very lightly used and just sold as new). I got it home and checked all the channels, they seemed to all work fine. I ran it in series and parallel mode, seemed to run fine. Shorted the outputs a few times to check cc mode, everything seemed great.This morning before work I tried to apply the firmware hack to change enable 1mv resolution. It all seemed to go well, no errors or anything like that. I could see it took and I now had 1mv resolution. Went to turn on the channel output and womp womp womp.... Incredibly slow barely moving voltage.I thought that maybe there was an issue with the firmware, so I applied the reverse patch to take it back to a 3303x-e. The firmware seemed to take, back to 10mv resolution... But still the same issueIn my head this seems more like a hardware fault instead of a software fault? Did something not work right with the firmware? It's the hardware just total Chinese garbage? The thing has never even been under an actual load yet minus me shorting the outputs together...I should also note that both channel 1 and 2 are having the problem. I didn't get a chance to check the fixed output before I had to leave for work.Software version: 1.01.01.02.05Hardware version: V3.0Used usb connection to update and the latest version of easypowerPlease see video of what's happening.https://youtu.be/c2xlCL7b4Bo

author: tautech
author_rank: Super Contributor
timestamp: August 18, 2020, 12:50:26 pm
content: It's working as it should with a zero current setting.I won't say any more as you should have enough now to work it out......or RTFM.

author: Brad808
author_rank: Contributor
timestamp: August 18, 2020, 01:14:58 pm
content: Yep I'm an idiot 😂. Guess that's what I get for trying to work on things when I first crawl out of bed. When I first got it home last night it came set to full current so I wasn't even thinking.Thank you.

author: tautech
author_rank: Super Contributor
timestamp: August 18, 2020, 01:20:02 pm
content: No worries, you won't forget to have a current setting now.Enjoy your new PSU.Oh, BTW did you understand why the meter was creeping up ?Because it's a HiZ load it allowed the voltage to slowly build whereas if the PSU had a load on it the voltage would've remained at zero.
Siglent spectrum analyser baffling behavior - power supply ??? - Page 1
Forum section: electronics / repair

author: Mike Jung
author_rank: Contributor
timestamp: April 06, 2023, 01:52:19 am
content: My son's has a 2nd hand Siglent spectrum analyser SSA 3021x - I think... This machine behaves as follows :Pushing the power button the "machine" seems to want to start and two other keys light up on and off, or rather their intensity varies every two secs or so. Nothing more happens, the machine does not start.HOWEVER, if one removes the fuse, looks at it and places it back the machine starts and works perfectly including of being started and stopped for a few hours. Next day, back to square one.This is beyond baffling and I wonder if anybody has any idea as to what could be happening.

author: m k
author_rank: Super Contributor
timestamp: April 07, 2023, 05:48:36 pm
content: First something overloads something else, varied intensity implicates that power supply tries to start but fails and tries again.Removing a fuse set input energy level falling and at some point it's not overloading anymore and remaining energy actually loads that overload something away.Until long enough time drains that something and it start overloading again.
Sigma R700 (858D) hot air repair - Page 1
Forum section: electronics / repair

author: jmbinette
author_rank: Contributor
timestamp: August 16, 2019, 04:18:29 am
content: Hi to all,I have a Sigma R700 (858D clone) and would like to repair it.PCB is marked SBK858D 2017.01.03The heater is always ON no matter it is on the holder or not. I troubleshooted the whole circuit and the reed switch is good.On microcontroller input P0.1, I get 5V when off the holder and 0V when on the holder.Am I missing something here ? Any other conditions in the firmware would keep the heater ON all the time ?Thanks !

author: Rasz
author_rank: Super Contributor
timestamp: August 16, 2019, 02:24:39 pm
content: start with the triac if it has one

author: jmbinette
author_rank: Contributor
timestamp: August 16, 2019, 02:38:25 pm
content: Quote from: Rasz on August 16, 2019, 02:24:39 pmI originally thought about it but it controls according to temp setpoint. This part seems to work.Standby function isn't working, but it heats to whatever temperature I set.

author: Rasz
author_rank: Super Contributor
timestamp: August 17, 2019, 03:01:37 am
content: you didnt mention temp control workingI see you already found the diagram as I did using your P0.1 cluehttps://blog.enbewe.de/posts/2018-06-21-saike-858d-original-schematic/sure looks like bad microcontroller, or typical Chinese firmware half assednesshow hot is the heater when you put it on the stand? full blast or some low setting? maybe optocoupler is leaky? you could try desoldering transistor in front of it and checking if its still producing heat
Sigmastar datasheet - Page 1
Forum section: electronics / repair

author: dc101
author_rank: Regular Contributor
timestamp: October 07, 2021, 05:58:22 pm
content: Does anyone have a datasheet or reference manual for this Sigmastar chip? I haven't been able to find any info on it at all. The only thing even close was a random website that mentioned sav anything, but it was like a sav50 or sav40 or something. I've attached a picture of the chip in question.
Signal Generator AFG3021 not working - Page 1
Forum section: electronics / repair

author: zarkusnm
author_rank: Newbie
timestamp: May 13, 2025, 07:39:00 pm
content: Hi, so I got an AFG3021 from outside a nearby university lab as surplus with “screen display not working” on it, and when I turn it on the buttons light up, and backlight is lit on the LCD, but none of the buttons do anything and the output BNC doesn’t read anything on my oscilloscope. I opened it up as per the troubleshooting manual instructions, and the inverter works, the fan works, but I’m not sure if the LCD is the problem or the CPU board, and if the CPU board really needs to be replaced or if there’s something I can do to narrow down the problem and fix it. I’d really not like the whole unit to go to waste and as a college student this would be really useful for me, so any help would be appreciated!! Should I part it out? Should I try and replace the cpu board? Thanks for the help!

author: ZGoode
author_rank: Frequent Contributor
timestamp: May 13, 2025, 09:50:11 pm
content: Take a look a the service manual. Based on what you are saying, I'd unfortunately hazard a guess that you are right about the CPU board being faulty. The troubleshooting flow chart on page 130 of the SM points to that being likely. Given that there is another manual specifically for CPU board replacement, I would assume this might have been a common problem with this family of AWGs?https://w140.com/tekwiki/wiki/AFG3021

author: zarkusnm
author_rank: Newbie
timestamp: May 13, 2025, 11:13:49 pm
content: I see, I saw that service manual flowchart and just wasn't sure if the "buttons are active" meant the buttons being lit up (which they are) or able to be pressed and changing things like the output or factory reset (which they are not). Do you reckon it's worth it to replace the CPU board for the price?
Signal Measurement in Op Amp Amplifier circuit - Page 1
Forum section: electronics / repair

author: rodd
author_rank: Regular Contributor
timestamp: May 24, 2022, 03:58:11 pm
content: Step Amplifier -Diag3.pdf(672.85 kB - downloaded 104 times.) [ Specified attachment is not available ]Dear all,I am trying to troubleshoot the circuit below.I can detect a staircase signal from pin 6 of U350B up to pin 3 of U380A, as expected.However, I can't detect any signal at U380A output, pin 1 or the base of the Darlington transistors ( I am using a scope for that).What I can't understand is that the signal appears again at either transistor collectors.why this happens?This has happened before in similar circuits, so my understanding of this topology is nonexistent and I decided to ask for help.Thank you in advance,RogerStep Amplifier -Diag3.pdf(672.85 kB - downloaded 104 times.)

author: CounterEMF
author_rank: Newbie
timestamp: May 24, 2022, 08:55:27 pm
content: So what exactly is the problem (or are you just trying to understand the circuit)? By the looks of it I'm assuming this is the step generator output for something like an old Tek curve tracer. Since this circuit works in both current and voltage modes you have to pay attention to probe reference. For example have you measured across R381 rather than from there to common? Is there an output at P429? Have you verified power supply voltages and both relay and E/I switch operation? I guess I really need to know what you're looking for (troubleshooting help or topology theory).

author: rodd
author_rank: Regular Contributor
timestamp: May 25, 2022, 01:30:50 pm
content: Thank you for your reply CounterEMF.You are right. This is the step generator circuit of a TEK 577 curve tracer I am trying to fix.I have two objectives with this question.1 - Understand the circuitI have tried to follow signals in circuits with this topology: one op amp followed by two transistors in "push pull" and it never "works" - No signal at the op amp output. Why?2- Fix the strange behavior of this particular circuit is showingThere is a "bump" on the staircase signal at the output of Q386.I will post a photo of the signal as soon as I fix the power supply that was damaged due to a short that happened while trying to to some measurements
Significant votage spikes in QW-MS3010D DC power supply - Page 1
Forum section: electronics / repair

author: exampler
author_rank: Newbie
timestamp: February 07, 2021, 05:56:32 am
content: Hi All,Just been getting into electronics myself and invested in my first oscilloscope OWON SDS1102 and a cheap QW-MS3010D DC power supply. Naturally the first thing I did was test the output on the power supply and noticed a massive peak to peak (upwards of 2V peak to peak noise at 12V and at 5V), I am aware that switching power supplies are noisy but I figured there's no way that this type of deviation is a fit for purposes product?I've attached some screenshots of my oscilloscope, here's what I think I understand interpreting the data:- Peaks appear periodically at about 60kHz (I cannot find the switching frequency for this supply but I presume this is it).- According to FFT though, the largest peaks are actually occurring at more like 1.35MHz (somewhat at odds with the above but ok). Worth noting that further checks showed a more consistent spread of noise.- Getting massive voltage spikes on a DC power pack also which don't seem to show up as a periodic signal on FFT.Points to note:- Power Supply negative is not connected to ground but doing so produces no change. I was cautious here thanks to Dave.- A DC battery with a similar probing and wiring setup (breadboard) produces no noise.- A cheap 12V isolated DC supply for an external hard drive is producing peaks also, with massive spikes which are not really registering at all on the FFT. Images of readouts also given.- I placed a 24VAC transformer of the input and measured. Perfect sine wave as expected.Questions:1. Based on my read of the data I was about to ask for a refund on the power supply... Is my DC power supply QW-MS3010D just a really bad switching power supply or is something afoot? What should I look into next based on attached information?2. From the online videos I've seen people measuring DC never seem to have this type of issue, this goes to question 1, is there something else afoot and if not is this just because they are using better units?3. My probing method wasn't best practice but with this level of noise I figured something else was afoot, how likely is my probing method the problem here?4. With the level of peaking I'm seeing even in my DC power pack (images also attached). Should I be concerned about all my connected devices having to deal with constant spiking or is such just typically assumed to happen and catered for in the device design (Band filters, decoupling caps etc...)?5. The ultimate question... as Dave would say... Have I come a gutser or has my DC supply?Any thoughts would be appreciated. I'm sure its just a newbie question.
Silvercrest SIRD 14 E1 Internet Radio muted - Repaired - Page 1
Forum section: electronics / repair

author: Datman
author_rank: Regular Contributor
timestamp: September 28, 2024, 02:24:01 pm
content: Hi all.I'm sharing an experience of mine, which could be useful to someone.Last night I opened* the LIDL Silvercrest SIRD 14 E1 radio, which arrived a few days ago from Germany (purchased from LIDL.de via mailboxde.com for €124.05 in total):https://www.lidl.de/.../silvercrest.../p100341448to dim the white circles around the knobs, which do not dim together with the display. To do this, I inserted a 47 ohm SMD resistor in series with the common of the 4x 100 ohm resistors in series with each of the 4 LEDs (2 for each encoder).I tested it, closed it, tried again and put it on the bedside table, leaving it on at night. At 4:45 Teo, my cat, woke me up meowing and I realized that the radio had turned off. I turned it back on, but it remained silent, even though all the menus worked properly. This morning I continued testing and I realized that nothing was coming out of the headphone jack, nor from the line jack. Nothing could be heard even when putting a signal on the Aux input.I opened it again (this time removing the 8 screws with the electric screwdriver and the long bit!) and I also removed the internal plastic panel that covers the electronics (the one on the front panel is only for control). I removed the electronics, unsoldering the coaxial cable of the whip antenna (which also has a small internal ground plane, made with a sheet of copper!) and I started to observe the board.I noticed the SC2314 integrated circuit, which I discovered to be the switch/preamplifier/equalizer/loudness controlled via I2C. Going to check the power supply on pin 1, I noticed that it was missing! It came from a 78M08, which had nothing at the input... Power to it came from a SOT-23 marked 3415E, a P-channel mosfet. Since it had a Vgs of about -9V it should have been in full conduction, instead it was blocked... Tested with the Chinese component tester, it was a simple capacitor! I replaced it with an AO3401, of which I had purchased from Aliexpress about ten pieces years ago, and it worked!---*: to open it, you have to lift and remove the front grille, using pointed tweezers or the tip of a burnished electric screwdriver screw on the side, then unscrew the 8 cross-head screws in the deep holes; then, using a sturdy blade (e.g. Argentax n.44), you lever to remove the entire light gray part (including the speakers) from the dark gray rear shell.
Simchan software for Spirent GSS6300 - Page 1
Forum section: electronics / repair

author: chinhcheng
author_rank: Contributor
timestamp: October 04, 2022, 08:02:45 am
content: Are there any body have Simchan Software for GSS6300 Multi-GNSS Signal Generator?Please send me a coppy file if you have.Tks so much in advance.
Simple Electronic Counter on Row Machine  - Page 1
Forum section: electronics / repair

author: Solares
author_rank: Contributor
timestamp: January 29, 2022, 09:49:31 pm
content: I own a rowing machine.It works great. However, there is a simple digital computer on it.It counts the number of strokes you do. A very simple counter.However, every so often the screen with freeze. The whole display will go to 8888. If you try to press any buttons. Nothing happens. You have to physically take out its single AA battery to reset it.Now I have the opportunity to buy an exact replica computer. Same model and same hardware revision number. It costs €100 to replace.Am I wasting my money here, do you think the new one might be affected by the same problem? Could there be some "wonky" signal coming from the sensor itself which is the real problem? Anyone care to speculate?
Simple question, Hard to find answer. Fluke 8840A or 8842 VFD - Page 1
Forum section: electronics / repair

author: sampler1
author_rank: Regular Contributor
timestamp: April 15, 2020, 01:30:31 am
content: Hi all,I am looking for the dimensions of the VFD on a Fluke 8840A or 8842. Looked around on the net and cannot find any info..Greatly appreciated!

author: M0HZH
author_rank: Regular Contributor
timestamp: April 15, 2020, 09:50:00 am
content: The VFD is the biggest problem on these, as it goes dim. I think there is a LED replacement:http://bbs.38hot.net/forum.php?mod=viewthread&tid=828474I have an 8840A "for parts or not working" on the way, I could get you the answer in a few days if no one else comes back by then.

author: wn1fju
author_rank: Frequent Contributor
timestamp: April 15, 2020, 11:44:58 am
content: I make the VFD on my 8840A to be: 120 mm wide, 33 mm high, 8 mm deep. The little bulb in the top left corner sticks out 5 mm. I can't see the back of the VFD so don't know what the pin spacing is.But you can definitely see the problem with mine !!!

author: sampler1
author_rank: Regular Contributor
timestamp: April 15, 2020, 02:06:16 pm
content: Thank you so so much for the information. It is so greatly appreciated,There might be an LED display coming from Europe this summer .. I was just curious about this info.for myself.Ill get back on this in the future..Stay well
Simple remote fix - Page 1
Forum section: electronics / repair

author: tautech
author_rank: Super Contributor
timestamp: April 26, 2023, 02:52:03 am
content: It just so happened that when you need a single button remote to work flawlessly the darn thing plays up !So with a bunch of guests having arrived to bust some clay birds our trap machine 433MHz keyfob remote decided it was time to protest about the many 1000's of presses it had over several years previous. Needs a new battery I thought..... and lucky I have another for a substitute and preprogrammed into the receiver.So after getting more 27A's while out this morning and installing one the darn thing still wasn't quite right.However tactile switches being a mechanical device which do fail in time, concern filled my mind until finding the pack of them brought many years ago.This will be easy I thought.......Well I had what seemed like apart from color an exact replacement however after removing the old from its PCB only to find it was TH and not SMD like the new one I had.......darn !However a few minutes customisation with small pliers had its gullwing leads reformed to represent TH and just long enough to get good soldering to from the bottom side.again !Now any intermittency is gone and it's working again like new.

author: inse
author_rank: Super Contributor
timestamp: April 26, 2023, 08:34:32 am
content: This is how we do it!
SIMPSON 228 leakage current tester - Page 1
Forum section: electronics / repair

author: hitecelec
author_rank: Regular Contributor
timestamp: January 10, 2020, 07:14:56 am
content: hi Alllooking out for the value of the burnt resistor(marked) near the output Gnd terminal . Jpeg attached and schematicsThanks in Advanceregards
Simpson 260-6XLP Protection Relay Always Tripped - Page 1
Forum section: electronics / repair

author: Ultron81
author_rank: Contributor
timestamp: October 29, 2021, 08:06:54 pm
content: I recently picked up a Simpson 260-6XLP VOM for a great price. Problem is, as soon as I connect the internal 9V battery, the protection relay trips and disconnects the COM terminal from the rest of the meter. When I hit the RESET button, it will not reset. The reset button latches the relay contact in place and closes the circuit, and when the relay is energized, this disconnects the contacts and keeps them open.According to the manual, it should only trip when the input to the protection circuit is 4 to 5 times above the meter movement range. But in my case, the protection relay is on and won't reset even without any input applied to the meter.I removed R44 to try and eliminate any input to the circuit. The circuit still energizes the relay and I can't reset it. I tested all the diodes in the protection circuit and they seem OK (they are 1N100 germanium diodes, except for the diode across the relay coil). The transistors test OK as well, and I even replaced them with NTE equivalent parts (NTE123AP for the NPNs, and NTE159 for the PNP).Running out of ideas here, any help would be appreciated!I attached schematics and a theory manual, thought the manual is not for my specific model, it does give somewhat of a description of the protection circuit. The 6XLP includes an extra NPN to drive the relay coil.

author: floobydust
author_rank: Super Contributor
timestamp: October 30, 2021, 02:45:05 am
content: You've replaced most of the parts, so it's a bit of a puzzle.I would suspect the transistors because they all turn on to activate the relay. Not much else can cause the circuit to trip.Note the wonky pinouts, in case that got messed up:NTE159 PNP has Japanese JEITA pinout ECB.NTE123AP NPN has American JEDEC pinout EBC.Check capacitor C5 1uF is not open.When there is 9V power and the relay is on, measure some voltages on the transistors, C5 etc. Pressing the RESET button should make the relay click assuming the circuit is stuck on.
Simpson 260 multimeter resistors - Page 1
Forum section: electronics / repair

author: C-47
author_rank: Regular Contributor
timestamp: March 04, 2023, 12:01:05 pm
content: Obtained a while a go a Simpson 260 - 5 multimeter, while the DC side works as the meter calibrated ok to 50uA 250mV, the AC side has been been overcooked though, with a number of resistors way out of spec, any leads on where the 1 watt 1% resistors may be obtainable would be appreciated. The usual places I have checked in Oz / USA show no stock especially in the 1 meg or above range.Overall the meter appears in good condition, no internal corrosion and a good exterior, carry case though beyond it as stitching has failed, so maybe worth the effort to revive it. Thanks, Alan.

author: TimFox
author_rank: Super Contributor
timestamp: March 04, 2023, 02:57:33 pm
content: A quick check on Mouser shows some 1% MF leaded resistors at about $3.00 USD, in values at or above 1 megohm.What values do you need?Can you fit two resistors in series to replace a toasted one?

author: C-47
author_rank: Regular Contributor
timestamp: March 05, 2023, 12:42:14 am
content: Hi Tim, thanks, the ones I'm after are Meg Ohm 15, 3.75 and 1, all 1 watt 1% except for the smallest value at 1/2 watt.I'll measure them out of circuit to make sure I'm on the right track first. The internals look good considering age, but have read to look closely at the selector switches, even though I've cleaned them with deoxit since the photo was taken, maybe the lower side contacts need another dose.

author: C-47
author_rank: Regular Contributor
timestamp: March 06, 2023, 09:52:42 am
content: Update:Further digging reveals R29 is open circuit and R26 is all over the place, the others above which I initially thought were toast are ok, but as a precaution shall also replace R30 as its the same 5K value. Does anyone know the specs for Diode D1 & 2 as they measure in the maybe zone. Thanks Alan.
Simpson 420 function generator (also wavetek 420) - Page 1
Forum section: electronics / repair

author: Filippo52
author_rank: Regular Contributor
timestamp: May 03, 2023, 05:34:56 pm
content: I found an old signal generator and since it turns on I tried to get it working again regularly.Everything works but the waveforms have a very strange shape, especially the sine wave.I wanted to ask if anyone has a service procedure for calibrating the various trimmers in the generator.I found a schematich diagram which I am attaching together with a photo of the apparatus

author: wasedadoc
author_rank: Super Contributor
timestamp: May 03, 2023, 06:06:31 pm
content: If all the waveshapes are wonky first suspect would be the output stages, Q7 onwards. Check the signals going into there by scoping the slider of that pot at Q7 base.And check all the supply rails.

author: wn1fju
author_rank: Frequent Contributor
timestamp: May 03, 2023, 06:12:38 pm
content: Didn't you ask about calibrating the Simpson 420 back in a thread you started on April 10, 2023? Someone replied to you back then with a description of what the pots do and how you should adjust things.

author: floobydust
author_rank: Super Contributor
timestamp: May 03, 2023, 07:41:20 pm
content: If there are defective components, you can't calibrate a "fix" it's a waste of time. Troubleshoot first, calibrate last.

author: Filippo52
author_rank: Regular Contributor
timestamp: May 05, 2023, 10:27:13 am
content: There are no shaky waveforms, they are all stable. It is the shape that is wrong, the sinusoid does not look like a sinusoid, the square wave is not symmetrical.However I have found the address of the manufacturer who has responded satisfactorily.Thanks anyway

author: Filippo52
author_rank: Regular Contributor
timestamp: May 05, 2023, 10:28:09 am
content: I don't think there are any faulty components; I just think it's out of tune.Thanks for the advice anyway

author: Filippo52
author_rank: Regular Contributor
timestamp: May 05, 2023, 11:30:16 am
content: Yes, you're right, I missed that thread.However, in the meantime the manufacturer, indeed the technical office managed to get me a precious document with the calibration procedures, which I now share immediately to make up for the double articleI hope they will be useful to someoneI inform you that I have the highest quality uncompressed copy and also a cropped and improved copy of the user manual.However, both are too bulky for the site, if you are interested, ask me and I will put them on google drive

author: alm
author_rank: Super Contributor
timestamp: May 05, 2023, 12:22:01 pm
content: You could upload all documents to one or more of these manual sharing sites:KO4BBxDevs.comBAMA

author: Filippo52
author_rank: Regular Contributor
timestamp: May 07, 2023, 09:31:36 pm
content: done; i put the document in Bama,However if someone are interested, ask me and I will put them on google drive
Simpson 460 Series 3 multimeter calibration - Page 1
Forum section: electronics / repair

author: bin10
author_rank: Contributor
timestamp: May 23, 2025, 06:10:33 am
content: Hello,I am looking for a service manual or calibration procedure for a Simpson 460 Series 3 multimeter?Thanks.

author: Runco990
author_rank: Frequent Contributor
timestamp: May 24, 2025, 02:24:43 am
content: This should help: It has schematics and info in it.
SINAD Measurement - Page 1
Forum section: electronics / repair

author: spongella
author_rank: Contributor
timestamp: May 13, 2020, 10:02:18 am
content: When measuring SINAD, what level should the volume of the DUT be at? I've done a few before but the service manuals never state what the volume should be. I just set it at normal listening volume. Thank you.

author: 2N3055
author_rank: Super Contributor
timestamp: May 13, 2020, 10:21:29 am
content: In radio receivers, it is usually specified as this much SINAD at that signal level.With A/D converters, level is either specified or it is presumed to be against full scale.If you didn't already, take a look athttps://www.analog.com/media/en/training-seminars/tutorials/MT-003.pdf

author: mojoe
author_rank: Frequent Contributor
timestamp: May 14, 2020, 09:35:39 am
content: This should help.

author: Ringmodulator
author_rank: Regular Contributor
timestamp: May 14, 2020, 04:31:30 pm
content: Hi,in therory, the SINAD is independent of the vloume, because it is a relative measurement where the absolute audio level is cancelled.In practice, you may have a residual hiss, when the volume ist set very low. If the volume is set verry high, you may have excess distortion.The recommended audio level is normally specified in the documentation of the SINAD Meter. SINAD meters have a certain input range for accurate measurements.If you know nothing, start with the volume control at 10/11 o´clock and use a 4 or 8 Ohm terminator for the audio line.RegardsChris
Single earbud for PS4 (Playstation) need help how to re-wire jack plug - TRRS - Page 1
Forum section: electronics / repair

author: paul_b_78
author_rank: Contributor
timestamp: July 29, 2020, 09:16:15 am
content: I have a single earpiece PS4 earbud with Mic build in which came with the PS4, and although I have another headset sometimes I like to keep one as a spare just in case the other fails.It has a TRRS jack (Tip/Ring/Ring/Sleeve) with 4 cables: Solid Red, Red/Copper, Solid Copper and a Solid White, on dissecting the jack plug I noticed that some of the wire weren’t soldered and were literally making some kind of contact from just the black pvc casing holding them in place, therefore I am now unsure which points they should have been soldered too.I am okay with a soldering iron and I understand that the cables are as follows:White = MicSolid Copper = PositiveSolid Red = NegativeRed/Copper = Common GroundMy question is which pin should I solder to on the jack plug i.e. the Tip (left Audio) or the Ring (right Audio)And would it cause a problem if the Left Audio or Right Audio is left with no cable affixed.I have tried to research via Google/Bing and everything links to a 2 piece (Left and Right) earbud or headphone.Your kind assistance would be kindly appreciated so I can repair these and set them aside in desperate times.Please refer to attached images, apologies if they are not the clearest, however I hope you can see where I am referring.- image (Original_TRRS jack1) you can just about see the white (MIC) wire is connect the the Sleeve, however the other wire attached I cant work out because it is moulded in with the black plastic.- image (Inside_single earbud1) you can just work out that the wires used are solid Red, and solid Copper.- image (Front_PCB_inside_Mic slide switch1) you can see the slide switch and the Mic.- image (Back_PCB_Inside_ Mic slide switch1) you can just work out the wires as I previously mentioned above and the 3 SMD components used.Again apologies for the images and possible lack of information, had a realised this was going to be a mission then I may have just binned in, but since I have it apart (using my ESD wrist strap and mat) I feel I need to complete this repair and give myself a pat on the back hahaha
Sino KA-500 5µm - Optical Linear Scale | "Flickerking"/bad readings  - Page 1
Forum section: electronics / repair

author: HiddenBear
author_rank: Newbie
timestamp: August 02, 2025, 04:15:31 pm
content: HelloI have a Sino linear scale kit for a lathe. Sadly one of the scales don't work correctly, it's ''flickers" while reading (video in zip file). It's not the display it self, because it work fine. Things I check :- Connections - Cleaned the RS 232 connectors for the scale as well the main unit. No change.- Swaped the order connections - The order in with the scales where connected didn't metter in any way. The working scales were working and the non working one didn't work.- Glass scale [From the not working scale](for cracks, dirt or scratches) - Swaped it to a working scale and it worked as intended.After that I'm asuuming that the fotoemiter/fotodetector unit is malfunction, because it's a optical scale encoder type. Checked the SMD resistors and the where fine. So I check the diodes and that what I found.Diode D4, D3 and D2 where working correcly to my knowlage as normal LED probaly IR LEDs. The D1 is probaly damaged because it showed 0.963V on forward diod test and 1.056V on reverse. The D5 isalso probaly damaged because it's showing 0.340V in forward and reverse. The reciving detectors had from 0.420V to 0.361V in forward and didn't conduct in reverse.So the conclusion is that D5 nad D1 diods are nok to my knowlage. Have some one an idea where can I order such IR LEDs in Europe? Maybe via Aliexpress or other side. The LEDs are in a specific shape asyou can see on the photos, with a half-sphare bottom.May someone had the same problem or a similar one.

author: HiddenBear
author_rank: Newbie
timestamp: August 02, 2025, 04:16:32 pm
content: Video

author: Uunoctium
author_rank: Frequent Contributor
timestamp: August 02, 2025, 05:27:42 pm
content: maybe this type fits:"available with gullwing or reverse gullwing mounting, clear, untinted plastic packages (with lens)"Vishay VSMY2850RG, VSMY2850G→ mouser:https://www.vishay.com/docs/83398/vsmy2850.pdfhttps://eu.mouser.com/ProductDetail/Vishay-Semiconductors/VSMY2850RG?

author: HiddenBear
author_rank: Newbie
timestamp: August 10, 2025, 01:30:46 pm
content: Thanks for the link to them. I ordered them already, they're a bit smaller than the current that I have, non then less maybe they will work.If they will come I'll give a update on the situation.
SINPRO SPU45E-303 Triple output supply - Page 1
Forum section: electronics / repair

author: perdrix
author_rank: Frequent Contributor
timestamp: April 08, 2020, 02:53:09 pm
content: This is supposed to supply +5V and +/-15VThis one supplies +5V and +15V just fine, but the -15V is low at about -13.86V.Has anyone reverse engineered one of these - I suspect that it's just an out of specification resistor but w/o a schematic I can only play guessing games. I have my suspicions, and will open it up to see what I find.But in the meantime if someone has been there and done that ...Thanks, David
Sirius Pro mXa 6000 info - Page 1
Forum section: electronics / repair

author: gaztech
author_rank: Newbie
timestamp: May 22, 2022, 01:04:06 pm
content: Hi guys,I have a Sirius Pro MXA 6000 DJ mixer in for repair. It's a very complex unit and has a nasty fault on it (routing is all over the place) so without any schematics I'm dead in the water with it.Would anyone here have a service manual or a schematic for this model?I've asked Thomann in Germany who are the importers now and have been met with the usual line... "we don't give out schematics".What the hell is wrong with companies these days? Do they really think that they will ever get repeat sales with this sort of attitude? I even called Braun, the previous distributor only to be told to contact Thomann.I used to think that Thomann were a very switched on, helpful company. It seems not - they are just like the rest of the big companies that don't give a damn about their customers.Can any one point me in the right direction with this?Many thanks!
sitop - Page 1
Forum section: electronics / repair

author: Abbas47
author_rank: Newbie
timestamp: November 10, 2024, 01:38:21 pm
content: Dear friend,I need to schematic diagram of Sitop 6EP1 437-2BA10.I hope you can help me.Thanks

author: BILLPOD
author_rank: Frequent Contributor
timestamp: November 10, 2024, 02:40:13 pm
content: Good Morning Abbas47, A specification sheet is here, if that helps:https://adegis.com/media/asset/17e7f507220132db2429f7c0fac0069819a973ac39a35f723ef3ea0a6abdb1bb.pdf
Skyrc Imax B6v2 "external temp. is too high"  tried multiple resets and updates - Page 1
Forum section: electronics / repair

author: randygreen007
author_rank: Newbie
timestamp: June 01, 2019, 05:33:27 am
content: nothing I do brings it out of Temp. to high mode, upon startup all is normal until 5 seconds then flashes "External Temp. is too high" even when the temp. sensor is unplugged. I contacted the supplier 3 different times and they treat people like retards. Any suggestions?? Thanks a lot Randysden

author: paul8f
author_rank: Regular Contributor
timestamp: June 01, 2019, 08:45:39 pm
content: Welcome to the forum. I've only limited experience with balance chargers. Does it charge the Lipo batts and Li-ion batts regardless of this warning? When you say 'multiple resets' does that include a full factory reset (if available?)I'm guessing the sensor is a basic thermistor at heart, so find out if it has aPorNtype thermal-coefficient. Might start you off in the right direction??
Skytronic 650.682 dials not working - Page 1
Forum section: electronics / repair

author: tuffgong
author_rank: Newbie
timestamp: July 02, 2022, 01:09:19 pm
content: Hi there guys - Hoping someone can chip in on how I could repair a Skytronic 650.682 bench power supply. It powers on fine however none of the dials work (displays 0.00), I have tried putting a volt meter in the terminals to see if anything registers - nothing. Opened it up and cannot really see anything obviously blown or burnt out, any ideas if its repairable or not?Many thanks in advanceCheers,VJ

author: Uunoctium
author_rank: Frequent Contributor
timestamp: July 02, 2022, 07:08:50 pm
content: maybe your model is the same as VellemannPS310/PS320 whose wiring diagrams you can find herehttps://elektrotanya.com/velleman_ps3010_3020_power_supply_um.pdf/download.html#dlWhat voltage can you measure across the fat electrolytics? Is at least one relay clicking at powerup?Is the auxilary psu working? 7812, TL431 reference?Voltage at base oft output transistors, than back at driver transistors, out at 741 voltage regulator. If psu out is inhibited by current limit amp, it seems that can isolated by desoldering on pin of diode V15

author: tuffgong
author_rank: Newbie
timestamp: July 04, 2022, 09:26:56 am
content: Hi there Uunoctium - I have not measured voltage across the Fat Electrodes. When powering up, its almost silent apart form the fan that spins. Not sure how to check the auxiliary PSU, there is 3 separate boards on the PSU. Would it be the board that has all the Fat Electrodes on it?Would the V15 diode be on the board where the Dials are on?Many thanks in advance,Cheers,VJ

author: Uunoctium
author_rank: Frequent Contributor
timestamp: July 04, 2022, 03:04:58 pm
content: The fat electrolytic capacitors are on the smaller rectifier board. Also voltage regulator 7812 and probably voltage reference TL431I suggest doing this first to ensure, that the raw voltages plus auxiliary are present. That to exclude the worst case, an faulty transformer. All other defects are fixable.The drawing is the closest to your model. Therefore components and their numbering are different, so you have to fiddel out their exact location on the boards.(If realized the same manner in your device, the auxiliary voltages are measured against the (+) terminal.)

author: tuffgong
author_rank: Newbie
timestamp: July 06, 2022, 07:35:29 am
content: Hi there Uunoctium - that is fantastic, thank you so much for providing a test plan. I shall try in the next week or so to test and report back.Thank you again!Cheers,VJ
Slaughter 4320 hipot - Page 1
Forum section: electronics / repair

author: hitecelec
author_rank: Regular Contributor
timestamp: September 05, 2019, 05:52:18 am
content: helloUnit displaying Keylockout the moment set key is pressed.Any hints how to restore the default settingsRegardsAnand

author: hitecelec
author_rank: Regular Contributor
timestamp: September 05, 2019, 06:04:23 am
content: helloAttached screen shotregardsanand

author: BravoV
author_rank: Super Contributor
timestamp: September 05, 2019, 06:09:52 am
content: All you need is just google.

author: hitecelec
author_rank: Regular Contributor
timestamp: September 05, 2019, 06:37:53 am
content: hellook. just downloaded the service manual and followed the instructions for disabling keylock onproblem resolved

author: BravoV
author_rank: Super Contributor
timestamp: September 05, 2019, 07:02:48 am
content: As usual, just lazy.
Sleuthing a cooked MOSFET - anyone care to guess? - Page 1
Forum section: electronics / repair

author: rx8pilot
author_rank: Super Contributor
timestamp: September 27, 2019, 06:05:43 pm
content: On the non-isolated side of a power supply - this part is cooked beyond recognition. It appears to be a MOSFET with pins 5-6-7-8 tied together and pin 4 (presumably the gate) has an isolation slot cutout.I don't have the physical PCB in my hands yet, but I would expect this to be a fairly high voltage area. The unique-ish nature of a 7pin SOIC [pin 3 deleted] should narrow it down along with what appears to be a portion of a logo.Any guesses, hypothesis, etc would be appreciated.

author: rx8pilot
author_rank: Super Contributor
timestamp: September 27, 2019, 06:06:26 pm
content: Larger view.......

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 27, 2019, 06:27:15 pm
content: TOPSwitch. Anyone's guess what amperage.Tim

author: rx8pilot
author_rank: Super Contributor
timestamp: September 27, 2019, 07:09:48 pm
content: Impressive!Looking like a TOP25xG after chasing down those tips. Not sure yet where to get them, but at least I know what I am looking for.Thanks @T3sl4co1l and @blueskull

author: tautech
author_rank: Super Contributor
timestamp: September 27, 2019, 08:55:42 pm
content: Quote from: rx8pilot on September 27, 2019, 06:05:43 pmNot uncommon for SMPS controllers.But SOIC ? Isn't it a DIP ?

author: rx8pilot
author_rank: Super Contributor
timestamp: September 27, 2019, 10:15:44 pm
content: Quote from: tautech on September 27, 2019, 08:55:42 pmI think you are correct - it indeed looks like a DIP package. Expecting to have the physical PCB in my hand on Monday and Mouser has the DIPs and SOIC's in stock so good either way.
Slippery slug -how to keep variable inductor tuned - Page 1
Forum section: electronics / repair

author: neillnz
author_rank: Contributor
timestamp: September 16, 2025, 08:00:40 am
content: I have a green phosphor CRT composite video monitor. It is part of an art installation of some historical significance. I don't want to replace it with something modern, the owner is prepared to spend as much time on it as required.It does work O.K. the only issue is the horizontal adjustment, it is done with a variable inductor. The issue is that the slug does not engage with the threads inside the core. It is as if the slug has shrunk(surely not) or the core has increased in size. The slug can slide up and down inside the core, such that it just falls all the way to the bottom.So I'm wondering what I might do, some sort of sealant / adhesive that will stay soft to allow tuning but also hold it in place.Anyone got any ideas?

author: Kwakerman
author_rank: Regular Contributor
timestamp: September 16, 2025, 08:18:17 am
content: Way back in the old daysYou would often get a small length of thin rubber that was placed lengthwise in the hole (so that it comes out of both ends). The slug was then screwed in and the rubber acted as a friction brake / retainer. Something like a small / thin elastic band that has been cut may be suitable. If you stretch the band while inserting the slug will make things easier and the band will expand and grip the slug when you release the tension.

author: tggzzz
author_rank: Super Contributor
timestamp: September 16, 2025, 08:19:47 am
content: Perhaps some plumbers PTFE tape. Cheap, thin, easily removable if it doesn't work.

author: Ian.M
author_rank: Super Contributor
timestamp: September 16, 2025, 08:21:09 am
content: IIRC I used to see inductors like that with rubber packing. A single strand of thin rubber was stretched through the former's core hole, stretched and secured, then the slug was screwed into place and adjusted. The tension on the rubber was then released, so it became shorter and thicker, holding the core securely in place, and excess rubber cut off. If it was done this way, the old rubber probably dry rotted and crumbled away.Edit: Two other replies while I typed this. Good I'm not the only one who's seen the rubber.

author: Kwakerman
author_rank: Regular Contributor
timestamp: September 16, 2025, 08:31:37 am
content: This type of arrangement

author: neillnz
author_rank: Contributor
timestamp: September 16, 2025, 09:19:45 am
content: Thanks for the replies everyone.There is no sign of the rubber at all but not surprising given the age of the thing.I will try a section of rubber band.

author: Grandchuck
author_rank: Super Contributor
timestamp: September 16, 2025, 01:28:33 pm
content: Wax?

author: neillnz
author_rank: Contributor
timestamp: September 16, 2025, 11:42:14 pm
content: Ended up using a length of slit heatshrink tube. It allows the slug to wind in and out as well as hold it in place.Thanks for the suggestion.
SMA connector for 1.6mm dia steel cable antenna - Page 1
Forum section: electronics / repair

author: peteb2
author_rank: Regular Contributor
timestamp: December 10, 2023, 07:22:44 pm
content: I’ve searched high & low for a supplier of such an SMA connector to repair UHF receiver antennas. The original antenna uses a short length of stainless steel cable, appx 1.6mm DIA. All forms of crimp SMA connector i have located all have a center pin with a very tiny solder bucket so completely useless. Has anyone ever seen such a connector with a large solder bucket? Cheers!
Small Ali express Oled Buck Converter no Power output. - Page 1
Forum section: electronics / repair

author: gersrt
author_rank: Newbie
timestamp: January 01, 2022, 01:09:21 pm
content: Just learning electronics so hoping someone can give me some help to troubleshoot this little buck convertor. I've attached photos.I was putting it inside a housing that I had made and unfortunately something shorted and I got the dreaded burning smell. Any way device and screen still turning on and recognising the Voltage input. Unfortunately their is no voltage output and keeps tripping over current protection when I turn on. Obviously something is blown. Could someone guide me where I should start looking for faulty components. Thanks in advance.

author: madires
author_rank: Super Contributor
timestamp: January 01, 2022, 03:16:59 pm
content: Welcome to the forum! Start with looking for burnt components. Then check the transistors and diodes for shorts.

author: abdulbadii
author_rank: Frequent Contributor
timestamp: January 01, 2022, 04:55:47 pm
content: identify the type or Pcb, then search the closest similar ref. or schematic

author: kripton2035
author_rank: Super Contributor
timestamp: January 01, 2022, 06:12:57 pm
content: looks like this one :https://www.rcscomponents.kiev.ua/datasheets/dc-580%20v1_1-english_manual.pdf