hybridfree/eevblog-posts huggingface dataset:
Xiaomi projector Green flash then no light - Page 1
Forum section: electronics / repair

author: thitou
author_rank: Contributor
timestamp: July 22, 2023, 11:20:30 pm
content: Hello everyone, I've recently picked up a xiaomi mi smart compact projector (I think is the 1st version).I'm trying to fix it.. Here is the story :When I'm turning the projector on, I see the white led on the top of the unit blinking (this is normal), and suddenly the screen flash all green 2/3 times for less than 1 second. I think I can see the "Mi" logo in the center of the picture. After that all the screen is black, without any light, but the projector is still running and responding (I can turn it off with the remote control).I have tried some things, with not result :- Boot to the recovery mode- Try with a different wall adapter- Check the RGB leds one by one- Disassemble all the unit and check all the connectionsI have tried to put a constant led light directly in the optical engine (By disassembling the green led and putting it in its place) to see if the projection is normal in the screen with the lights on, but it's all black and no picture is visible. Whatever the issue is, it's seems to interfere with the DMD imaging process and the leds.I still found something though! One of the chip on the DMD/led board is very very hot. I don't know exactly the temperature but I can't put my finger on it, it's really burning me quickly.The chip is a TCA0372DW, referring to the datasheet it's a "dual power operational amplifier" Maybe this chip is bad, I'm not really sure what this exactly does in the circuit.There's something strange about it, when I'm unpluging the connector right next to the chip (see picture) and turn the projector on again, the chip is not hot anymore. However, the projector is still blinking weirdly green then no light. The problem doesn't change.I don't know what is this wire for, it's seems to go inside the optical engine.. Maybe a light sensor or something like that. I need to investigate more on this point.Thank you a lot for reading me! All replies will be highly appreciated.Has anyone ever had a similar problem?In your opinion what can the tca0372dw be used for?

author: sooo
author_rank: Newbie
timestamp: March 18, 2024, 02:23:38 pm
content: Bonjour,j'ai vu que vous aviez un problème similaire au miens concernant votre projecteur, je voudrais savoir si vous aviez réussi a le réparé ou non ? Car ayant le même problème je vous avouerais que je suis un peu perdu sur la réparabilité de ce dernier.Merci de votre réponse.Cordialement

author: thitou
author_rank: Contributor
timestamp: March 18, 2024, 02:32:50 pm
content: Hello, sorry to hear that you also have a problem with your projector. Unfortunately no, I couldn't fix it.
Xiaomi robot vacuum mysterious cliff sensor fault - Page 1
Forum section: electronics / repair

author: 1337ralfy
author_rank: Newbie
timestamp: November 27, 2023, 02:48:40 pm
content: Hi, guys. Just bought myself second-hand Xiaomi vacuum mop essential, that had dead battery issue. Thought, oh, easy fix as i have lots of 18650 cells lying around.So one cell was bad, so just replaced it (just to see if it works) with good one, and yes, robot now powers on. Set it to clean, and it worked - on dark and gray tile floors.But after sitting for a while, now it just gives me cliff sensor error. And the weird thing is that now it only works on darker floors, not gray ones.Disassembled and fully cleaned sensors for inside and outside. All 4 emitters are working (camera test). But no luck.On gray floor it shows that sensors are blocked/needs cleaning. But on darker ones, it works...Pretty sure tile floor absorbs more IR light and thats why it has weak signal on receive side of that sensor, any ideas how to fix that? I know that there is that hack when you turn both diodes "face to face" but dont want to lose cliff sensor function completely.Feels like i need to offset voltage a bit on those IR receivers (so i thinks it getting bit more voltage, and than mby it wont freak out), could this be way to go?
XJ4241 Scope from China. - Page 1
Forum section: electronics / repair

author: Anton2000
author_rank: Newbie
timestamp: May 19, 2020, 01:59:05 am
content: I'm trying to restore this scope . made in China in the 90, sadly after high voltage caps puffed out, and i made a full recap one channel does not work. I have manage to find the damage part a amplifier? IC named SG012 IB but I can't find anything on the net about it, i'm sure it is the problems as if I replace it with the one from the other channel it works... (kinda... as the positioning is not working at full range) I'm looking for any advice. a equivalent a datasheet anything at all.

author: fzabkar
author_rank: Super Contributor
timestamp: May 20, 2020, 02:01:13 am
content: I thought it may have been a Silicon General part, but I couldn't see it in their 1990 catalogue.http://www.bitsavers.org/components/siliconGeneral/_dataBooks/1990_Silicon_General_Product_Catalog.pdfA better photo might help me to recognise the logo.

author: Chris56000
author_rank: Frequent Contributor
timestamp: May 20, 2020, 09:58:40 am
content: Hi!That circuit diagram definitely needs one of my redrawing projects starting!I knew I've seen that pinout before – try an LM592 Differential Video Amplifier to replace it – the device's datasheet and the device itself are easily got – it has a Russian equivalent 1YO592P readily available cheaply!Chris Williams

author: jxjbsd
author_rank: Regular Contributor
timestamp: May 21, 2020, 03:51:06 pm
content: Someone discussed this IC in our forum. It should be similar to uA733 LM733

author: Neomys Sapiens
author_rank: Super Contributor
timestamp: May 25, 2020, 03:52:57 am
content: Quote from: Chris56000 on May 20, 2020, 09:58:40 amThat one is also known as SE592, TL592 is relatedDifferential Video Amp., adjustable Gains /Passband, 90MHz@100, 40MHz@400, 7.5ns, Rin4kOhm/5pF,Vs +/-3...8V. but Pinout may differ
XYH3606 Power Supply Died - Page 1
Forum section: electronics / repair

author: g3force7
author_rank: Newbie
timestamp: September 12, 2023, 02:18:24 pm
content: This power supply that I got from Taobao died after I anodised a piece of titanium (1 cm diameter). I set the voltage to 36V and current to 1 A and it worked for less than a minute before it shuts down by itself. If I turn on the main outlet power electricity will flow into the power supply, but it won't turn on. Even when it is not on heat was being generated and it can become too hot to touch. I dismantled the power supply and couldn't find anything wrong with it (no burnt mark).Imgur album of the power supply:https://imgur.com/a/PYULTj4

author: Stephen_Pejak
author_rank: Newbie
timestamp: September 14, 2023, 09:55:23 am
content: Power supplies are fairly simple devices. There could be many things causing this, but I will try explaining to you how to try and find the fault without using fancy tools. Firstly do another inspection and look for any tiny burn spots or cracked solder joints. If you find those, either the solder joint or the component that is on that joint is defective. If that is all fine, buy some alchohol(idealy 99% isopropyl, but ethanol should work as well). Apply it to the components on the board, turn the power on and try turning the power supply on(in case it has a switch). Once you do that look at the alchohol. Where it evaporates first is probably the fault. In case you can't find out anything like that, fault is more complex and definetly requires a good multimeter and perhaps an osciloscope to diagnose. But I believe you will find the fault with alchohol method. Good luck.

author: DavidAlfa
author_rank: Super Contributor
timestamp: September 14, 2023, 10:07:21 am
content: Which parts are heating burning hot?

author: g3force7
author_rank: Newbie
timestamp: October 04, 2023, 03:08:07 am
content: I think I got lucky (zero electronics engineering knowledge), identified the root cause of the problem (dead MOSFETs) and replaced them (had to buy from the power supply seller because the MOSFETs are from unknown source). The extremely hot components (MOSFETs) got my attention, so I Googled "How to test MOSFET" and found a YouTube video. Measured all 4 MOSFETS and found out that 3 of them are dead (low voltage reading between Drain and Source = dead MOSFET).(How to test MOSFET using a multimeter)https://youtu.be/8WfETwW6I9M(Before the repair)https://youtu.be/AxG9GmsTHOc(After the repair)
XYTronic LF-1600 Soldering Station with H-E error - Page 1
Forum section: electronics / repair

author: riscy00
author_rank: Contributor
timestamp: July 03, 2023, 07:06:07 pm
content: After a long absence (1 year or more in storage), I turn it on and it now show H-E, which mean heater fault. It is not S-E which is electrode replacement. What do I need to check before buying replacement iron, I have tested two iron and both show H-E.I open the unit and found no sign of burning or visual abnormality.Suggestion what to check?
Yaesu FRG-100 Clock Too Slow - Page 1
Forum section: electronics / repair

author: spongella
author_rank: Contributor
timestamp: April 06, 2020, 11:25:42 am
content: I've heard that there's a fix for the above radio with a slow clock, wondering if anyone knows what the solution is? Mine runs several minutes behind every month. Rumor is about using a variable cap instead of the original fixed one. Thank you.

author: xrunner
author_rank: Super Contributor
timestamp: April 06, 2020, 11:43:19 am
content: Check out this thread. Probably the crystal is inaccurate now -https://forums.radioreference.com/threads/yaesu-frg-100-internal-clock-running-fast.384535/
Yaesu FRG-7 repair - Page 1
Forum section: electronics / repair

author: rhb
author_rank: Super Contributor
timestamp: August 03, 2020, 10:14:48 pm
content: I bought one which has some issues. The frequency is off by 10 kHz at the low end and 90 kHz at the high end. I suspect that it needs alignment as it appears to have been repaired. I've also encountered a birdie that suggests there is a squeg, an unstable spurious oscillation, somewhere.The user manual provides the alignment information and I have plenty of test gear. However, I've never undertaken this level of radio diagnosis, so if someone has experience with the FRG-7 at component level I'd appreciate a chance to discuss the problems and what the spectrum should look like at various test points.I'm using the spectrum analyzer feature of the Instek MDO-2000E series which has the major virtue of not putting my 8560A front end at risk from DC offsets as I don't yet have a DC block for it.Have Fun!RegEdit: I've determined that the 3rd LO range is too large. If I trim TC403 to set the LO at 3.445 with the dial at 0 it is at 2.35 at 1000. I can't see how to correct that except to put a large cap in series with the air variable. Comments? This unit has the fine tune cap which I have set at midrange when it's centered.

author: rhb
author_rank: Super Contributor
timestamp: August 04, 2020, 09:30:52 pm
content: After a much head scratching I sat down and did the algebra. Based on measurement of the main tuning cap I calculated I needed an additional 56 pF in parallel. After adding that across the fine tuning cap if is now exactly at 3.455 MHz at the 0 mark and 2.455 at the 1000 mark on the dial.Except for measuring the main cap and the fine tuning cap, I took the other caps at the schematic value when I calculated what the minimum capacitance needed to be to swing 1 MHz from the 19 pF position to the 348 pF position.That raises the question of whether it ever tuned correctly. Though perhaps the ceramics in the LC tank were close to 20% over nominal when it was built.All in all very strange. I'd expected just to be able to adjust the trimmer cap and coil.Have Fun!Reg

author: rhb
author_rank: Super Contributor
timestamp: August 06, 2020, 01:32:27 am
content: I finished doing the alignment per the instruction manual. Discovered an interesting cause for the squeggs.The multiturn dial mechanism uses a stack of disks with lugs. They had oxidized and were randomly introducint a large parallel capacitance which would drop the 3rd LO to 1/2 or less. Or worse yet, be unstable.A bit of Deoxit cured it.An easy test for the issue is to set the radio on AM with no antenna and spin the dial quickly. If you hear scratchy pot noise, put Deoxit on the dial stop plates and the rotor shaft bearings.Have Fun!Reg
Yaesu FT-900 service manual (technical suppliment) plea for help - Page 1
Forum section: electronics / repair

author: WastelandTek
author_rank: Frequent Contributor
timestamp: February 21, 2023, 06:04:31 pm
content: On the bench I have an FT-900 that is missing some 40dB of RX sensitivity. I want to poke around the first mixer and see what is going on but every instance of the "Technical Supplement" I can find online is the same illegible scan. The text circuit description and component lists are good enough and helpful, but the schematic is pretty much useless.Does anyone here possess a better scan or a physical copy of this document?This is an example of the scan I can findhttp://www.iw2nmx.it/Yaesu/FT-900/FT-900%20Service%20Manual.pdfavailable at several sites, pages 69 and 70 being of particular interest.Thanks.

author: CapLeaker
author_rank: Regular Contributor
timestamp: February 23, 2023, 11:51:15 am
content: Been in the same boat as you before fixing these FT-900.Its a nice looking rig for sure. Luckily I do have a better schematic for it, but you need to install a .djvu reader, something like WinDjView. This isn't perfect, but at least much better what you got.73!

author: WastelandTek
author_rank: Frequent Contributor
timestamp: February 23, 2023, 06:18:41 pm
content: Much, much better. Thank you so much!Being able to actually read the interconnection diagram was particularly helpful and got me going on this again. The fault ended up being an open 0.33uF inductor in the RX path on the LPF board, L5016, it appears to be, with C5058 and C5059, a low pass filter situated between the T/R relay RL5014 and the RX jumper to the RF unit J5004.I include all this detail because, interestingly, these components are not present in the schematic revision you posted and my fear is that some future searcher might be confused. I rolled up a coil out of magnet wire somewhat close to the 330nF called out and was able to hear a test carrier weaker than 140dBm, so success there, but the omission of these components on the other schematic revision suggests that Yaesu determined at some point that this filter was not needed and similar success might be had by simply deleting the capacitors and replacing L5016 with a jumper. All this is quite conveniently accessible under the bottom cover so if anyone would like to take a look I suspect later revisions of the radio might have shipped in that configuration.The DjVu format can be conveniently converted to PDF athttps://djvu2pdf.com/I would have uploaded the conversion, but the resulting file is too large even zipped.Thanks again for the upload. I believe this is the highest resolution Yaesu FT-900 schematic available on the internet at this time. Once again, the EEVBlog forum delivers.
Yaesu FT-991a head set jack problem - Page 1
Forum section: electronics / repair

author: jhormilla
author_rank: Contributor
timestamp: August 22, 2023, 12:56:48 am
content: Hi all, I have a Yaesu FT-991A with a head set jack problem, when I plug in my head set it's intermittent, i tried another head set and the same thing, I can't find anyone that sells this jack part# P1091426, for the mean time I swapped the head set jack with the key jack since it's the same part number but I now can't use the key jack. I looked in Digikey, Mouser, Newark etc. Any information would be appreciated.

author: xrunner
author_rank: Super Contributor
timestamp: August 22, 2023, 12:59:13 am
content: Did you call Yaesu for parts? They sell all the parts for the newer radios, I've used them many times and this part will not be expensive.

author: jhormilla
author_rank: Contributor
timestamp: August 22, 2023, 03:37:50 am
content: Yes, thank you. I did email them just before I posted here.

author: jhormilla
author_rank: Contributor
timestamp: September 02, 2023, 09:47:32 pm
content: UpdateContacted Yaesu and they replied with this.P1091426 Replaced by P1091686 NOT IN STOCKP1091686 Replaced by P1091749 CONNECTOR:PJ30460 NOT IN STOCKP1091749 CONNECTOR:HPJC30460-APB0AS003 Currently in StockOrdered two parts because there is a limit of 2, the new part has 9 pins the old has 6, cut the three pins that had no matching thru hole pads to go through on the PCB and all is good. I hope these hold up. The parts were under $4 for both. HTH
YAESU YC-355D Nixie display issue - Page 1
Forum section: electronics / repair

author: paronaram
author_rank: Regular Contributor
timestamp: November 09, 2024, 06:24:27 am
content: Hello Everybody,A few years ago, I purchased YC-355D. It's a massive "Frankenstein," but I still got it for the nixies.Right around the time I purchased this counter, I replaced the PS capacitors. (One was bad, so I replaced them all.) The device worked fine for a year or two, and then I stopped using it, and I had it on the shelf for some time.Purchased a late 1930's RF generator, restored and was hoping to measure output on nixie display, just to see how accurate analog dial is...I turned on YC-355D yesterday, and I got an error on the indicator.As you can see from the images middle indicator shows all symbols, instead of 0.Start troubleshooting, anode HV 226V comes to all 5 resistors R23-R27. On the other side of all these resistors, I get 147V except for the middle indicator, here I have 190V. I checked the resistor and it drifted from 22K to 31K so I replaced it, but the voltage did not drop to 147V.But I have a feeling that my issue is with SN74141N driver... I don't have TI IC, but I have Russian K155ID1... Do you know if I can I swap 74141 with this one-to-one?Thank you,Aram

author: factory
author_rank: Super Contributor
timestamp: November 09, 2024, 09:01:21 am
content: Yes the K155ID1 (they are actually made in Belarus) are the same function as the 74141, I've used lots to repair my old TE, the 74141 & 7441 ICs are a common failure, the 7490 isn't far behind.David

author: paronaram
author_rank: Regular Contributor
timestamp: November 10, 2024, 05:54:42 am
content: Replaced IC, same issue...Now this issue may be with SN7475N or SN7490NThank you,Aram
YAKO stepper motor driver YKA2811MA teardown and repair, Funny TRIAC ? - Page 1
Forum section: electronics / repair

author: oz2cpu
author_rank: Frequent Contributor
timestamp: March 04, 2022, 10:17:09 pm
content: in this video i talk a lot about a "pre-regulator" Triachttps://youtu.be/i97Hn7lG8qsany of you seen this type of usage before ?pre voltage regulator ?it is intended for AC use, but manual says it is also ok you use it with DC supply..in that case a triggered triac, will not the turned off again.the gate drive is made from optocoupler, and a few transistors, and a 4.5kHz oscilator opamp circuit,what the heck are they trying to create ?shorting the triac, repair the faulty units, so this confirms, no practical usage for this triac ?
Yamaha A-S500 Amplifier - Repair Log (Dim light - won't turn on) - Page 1
Forum section: electronics / repair

author: sammy3
author_rank: Newbie
timestamp: July 15, 2024, 06:22:49 pm
content: This is a repair log of a Yamaha A-S500 Amplifier - perhaps it will help someone in the future with a similar issueSymptomsDim power led like its in standby mode (but wont wake up)No relays activateNo error codes/blinking lightsWont enter diagnostic modeService manualhttps://www.manualslib.com/manual/1074982/Yamaha-A-S500.htmlTestingTest fuse 1 on OPERATION (1) P.C.B. (the power led can still come on if this fuse is blown)Fuse was found to be good.(Images of boards attached to post)Check voltages on CB2 connector coming of the same board.Found:PRY is 0v (should be 4.7v) - so power relay not activatedN_RST is .8v unstable (should be 5v)PWR_DET is 3v unstable (should be 5.1v)+5.5SUB and MG are correctIssue:After testing caps - c7 was found to be low (12nf instead of 47nf)Part number MPE 473K 400 Q2 C.POL.MTL 0.047uF 400V +/- 10% 10mm lead pitch (Polypropylene metallised)All other caps were healthy and after replacing this cap it now powers up fine.

author: wasedadoc
author_rank: Super Contributor
timestamp: July 15, 2024, 08:47:28 pm
content: Yep. Another case of the capacitor in a capacitor dropper losing a lot of its capacitance.
Yamaha A-S500 Power problem - Page 1
Forum section: electronics / repair

author: Ajuztam
author_rank: Newbie
timestamp: December 17, 2023, 09:57:55 pm
content: Hi. I have a Yamaha A-s500 amp with a powering problem. When I turn it on a CD Input and Pure direct lights come on for a second and then go off and power led flashes constantly. Anyone familiar with such problem? Thanks

author: m k
author_rank: Super Contributor
timestamp: December 21, 2023, 06:20:29 am
content: Something is overloading and protection is activated.You must start measuring.

author: RFDx
author_rank: Regular Contributor
timestamp: December 21, 2023, 10:45:33 am
content: The amplifier has a self diagnostic function where the flashing of the power LED tells you what the problem (power supply, abnormal current or voltage in the power amp, high temperature etc.). The service manual has all thenecessary details.
Yamaha AV receiver htr-6250  weird issues  - Page 1
Forum section: electronics / repair

author: oolloo
author_rank: Contributor
timestamp: May 11, 2020, 11:31:53 am
content: Hi I've had weird issues with AV hdmi ampSome are solved by unplug replug.It's a 2009 I bought from someone.2 friends have newer 2013 models one is 7.1 like mine . They don't habe tge following issues.1 with cisco iptv 4k boxes the video will after months of use draft to tear up, then goto fine grain light snow. Power cycle from front fixes it either for minutes, hours or months.I'm thinking that's a hdcp hand shake issue.It does have latest fw.The real issue is that when switching from program to program or ch to ch. Or program playing to adverts then back to program.The sound changes, it will be eithermuffled vocals ,more bass,lowered dialogue volumeFrom channel to channel I have to select different effects , or speaker setups or modes to get the center vocals pnly and bright clear.My friends and i all use the same TV provider and cisco stb .The above is year round all tempsCould it be that dust has built up inside receiver ?On 30deg centigrade days it does seem to overheat and act up.Please help

author: oolloo
author_rank: Contributor
timestamp: May 11, 2020, 11:34:48 am
content: My friends simply leave theirs on straight Dolby digital and everything sounds great on their Yamaha av receivers , I do too but I suffer the above issues. All my hdmi cables are new and high speed rated for 4k.One more thing firetv 4k stick , 2020 mfg date has only the sound issue same for fta satellite unit, nothing else has the video issue.
Yamaha AVENTAGE RX-A1080 - Dead - need Service Manual/wire diagrams - Page 1
Forum section: electronics / repair

author: mgoodmaster
author_rank: Newbie
timestamp: January 12, 2021, 02:01:04 am
content: HiMy Yamaha AVENTAGE RX-A1080 took a lightning hit and is dead - no power, no standby. Does anyone know where I can obtain the service manual?thanks!Mark

author: SpecialK
author_rank: Regular Contributor
timestamp: January 13, 2021, 12:10:01 am
content: That's a current model I think. Crutchfield shows earliest reviews from the fall of 2018 and advertises a 3-year warranty. It should still be under warranty. Also, if you bought it with a credit card, some cards extend warranty coverage,

author: jjd
author_rank: Contributor
timestamp: January 14, 2021, 12:09:06 am
content: I'd check over at AVSFourm, if anyone has one someone there will.
Yamaha AVR RX-V677 No response - Page 1
Forum section: electronics / repair

author: MALE20
author_rank: Contributor
timestamp: February 12, 2022, 08:16:51 pm
content: Hi, I got a Yamaha RX-V677 unit which I am trying to troubleshoot. Long story short there is no chance to start the unit. Power board seems to be OK however enabling signal that goes to DC-DC converters is not there which means other necessary voltages are not present on digital board (page 93 in service manual). 3.3V and 5.6V from power board are present. I am now puzzled as I don't know where to go from here. If anybody can help please let me know.https://elektrotanya.com/yamaha_rx-v677_htr-6067_rx-a740_sm.pdf/download.html
Yamaha CDC-585 lens assembly - Page 1
Forum section: electronics / repair

author: abhi1981
author_rank: Regular Contributor
timestamp: May 01, 2023, 02:24:05 pm
content: Hello everyone,I have a Yamaha CDC-585 with a bad laser. Got a new laser assembly from AliExpress.AliExpress instructions* The components replaced must be completely the same models as the origanl &Professional operation only .*The laser head have anti-static point to prevent static burn laser tube as a security measure. It's better to wear an antistatic wrist strap or wash your handsbefore welding and installation.When using a high-grade anti-static soldering iron,you can remove the anti-static point directly,ordinary iron requires special attention, heat iron to reached soldering temperature,then remember to turn off the iron's power,prevent static of iron burn laser tube, if you need,we can do it before ship.*Recommedation tool: soldering ironApart from this, should the laser assembly be connected directly to the player or it will have to be adjusted first with an oscilloscope?? Please advise.

author: shakalnokturn
author_rank: Super Contributor
timestamp: May 01, 2023, 03:10:16 pm
content: If possible first connect the FFC (ribon cable) linking the pickup to the electronics, then remove the solder blob on left of FFC on pickup.Ideally you would adjust eye pattern amplitude with an oscilloscope and confirm laser diode current is correct for specified amplitude.Another approach could be to measure laser current with a DMM and adjust it as low as possible still being good enough for reliable playback.If things don't go as planned keep in mind that AliExpress sell a lot of junk.

author: Haenk
author_rank: Super Contributor
timestamp: May 01, 2023, 04:21:34 pm
content: Yep, this will only work (hopefully) when the protection blob is removed.In general, the Aliexpress pickups are not that bad, if it's a commonly used type. Usually they are just drop-in replacement and don't need adjustment (to my experience).However shipping/packaging leaves a lot of room for improvement, that's why I almost always order 2 of them. However they are quite robust it seems.Be careful when it's an uncommon, old or rare part - I would not trust those.

author: abhi1981
author_rank: Regular Contributor
timestamp: May 04, 2023, 04:48:20 pm
content: Installed it as per your instructions and its working fine.Initially I used the original PCB with the motors because the connector was different in the new one. But, it was skipping badly, so I desoldered the old motors out and put the new ones in. The skipping problem was fixed and its working perfectly now. Thank you shakalnokturn and Haenk for your help
Yamaha dsp-az1 dead AV amp  - Page 1
Forum section: electronics / repair

author: jamarjan
author_rank: Contributor
timestamp: November 23, 2020, 11:49:51 am
content: Im struggling with Yamaha DSP-AZ1 (aka RX-Z1) amplituner.Its not coming on, cant force the DIAG mode - nothing.All voltages are there but the standby supply is quite low 9V instead of 13V, there is oscillation on the main chip, and also the signal from the on-off switch is there.There is a significant voltage drop on the +5V rail for the CPU.Under thermal cam only the main CPU and the voltage reg are getting hot.After taking the chip out everything cools down.My assumption is - faulty main chip.The main chip is M30624FGAFP 16bit µ-COM - it has rs232 communication, but i cannot find any roms for it or even flashing soft.I've recently acquired an second identical fully working unit.Is there a possibility to duplicate the main chip software?Or maybe someone has access to the Yamaha software:Z1Flash.exe and Z1_MainI33IC.mot

author: ambrosia heart
author_rank: Regular Contributor
timestamp: November 23, 2020, 12:32:55 pm
content: The main chip is M30624FGAFP 16bit µ-COM - it has rs232 communication, but i cannot find any roms for it or even flashing soft.The Main microprocessor has a flash rom embedded inside.If it is getting hot, you can still read the programme. Theflash rom may be not damaged.
Yamaha dxs15 active subwoofer  - Page 1
Forum section: electronics / repair

author: superdota2
author_rank: Newbie
timestamp: November 26, 2024, 01:42:06 pm
content: Hello to everyone..Protect mode is on, no sign of burned parts, mosfet all good, no dc out, supply is good,Any suggestions

author: suntime
author_rank: Contributor
timestamp: November 26, 2024, 07:45:52 pm
content: Hi,Check the speaker.

author: superdota2
author_rank: Newbie
timestamp: November 26, 2024, 11:36:14 pm
content: Speaker is fine,
Yamaha EMX512SC - Page 1
Forum section: electronics / repair

author: raginnoob
author_rank: Newbie
timestamp: January 31, 2020, 06:11:00 pm
content: Hi,I'm an absolute noob and just signed up today. I have pretty much no electronics experience (although I have used a soldering iron once or twice in the past...) but am looking to learn.The mixer will not turn on.I have tried different power cables and checked the continuity of the internal fuse.Apparently this is a common problem with this particular model. What component needs to be replaced to solve the issue please? Here is a link to a youtube video with someone having the same issue:Also here are other links on the internet with other people trying to resolve the same issue:https://www.ifixit.com/Answers/View/321645/No+Power,+it+shut+off+one+day+and+hasn%27t+worked+since.https://www.soundonsound.com/forum/viewtopic.php?f=26&t=25891https://music-electronics-forum.com/showthread.php?t=26867Please please help me solve this issue. Any help would be greatly appreciated.PS Here are some pics and I also have the service manual.
Yamaha HTR-2067 don't power up - Page 1
Forum section: electronics / repair

author: mikelino
author_rank: Newbie
timestamp: May 08, 2019, 02:06:16 pm
content: Hello everybody!!I have a problem with my Amplifier Yamaha HTR-2067.After a stormy evening with a lot of thunder, my amp, don't power up. I heard a click trying to switch it on and then nothing. I read something about a protection function, and I try to reset it by pressing "Power on + Info + Tone control". After I did that I tryed to switch it on, I heard a click and nothing happend.Can you tell me how to repair and fix the problem?Thank youMike

author: Andy Watson
author_rank: Super Contributor
timestamp: May 08, 2019, 03:48:40 pm
content: Start with the easy stuff - check fuse F1501 that supplies the power transformer.https://elektrotanya.com/yamaha_htr-2067_yht-1810_ns-b20_ns-c20_ns-swp20_sm.pdf/download.html

author: mzacharias
author_rank: Frequent Contributor
timestamp: May 09, 2019, 02:17:59 pm
content: Yamaha AVR's almost NEVER blow the main fuse. The high current trigger for the protection circuit is faster than the fuse.Blown outputs - shorted bridge rectifier or shorted large filter cap - no matter. The protection circuit will shut the receiver off so fast you never even really see it come on.

author: mikelino
author_rank: Newbie
timestamp: May 10, 2019, 12:17:11 pm
content: I saw in this video Yamaha RX-V557 Receiver Fix (https://www.youtube.com/watch?v=MwvjAtSr5t8&feature=youtu.be), and in some other website that i read that many people solve the problem with the substituion of a Capacitor.Could this be also my problem?Where can i find the broken capacitor?thank you!!

author: CJay
author_rank: Super Contributor
timestamp: May 10, 2019, 01:14:25 pm
content: Quote from: mzacharias on May 09, 2019, 02:17:59 pmFast enough to protect against a nearby lightning strike on a stormy evening with lots of thunder?Thought not.Check the fuse.

author: Andy Watson
author_rank: Super Contributor
timestamp: May 10, 2019, 03:16:28 pm
content: Quote from: mikelino on May 10, 2019, 12:17:11 pmHighly unlikely. That is a RX-V557, you claim to have a HTR-2067. As far as I can see your HTR-2067 does not have a SMPS.QuoteI would imagine that Dave has thrown it awayP.S. What state was the fuse in ?

author: mzacharias
author_rank: Frequent Contributor
timestamp: May 10, 2019, 04:36:05 pm
content: Quote from: CJay on May 10, 2019, 01:14:25 pmI did say "almost", but yes I was in fact thinking of faults that originate in the unit itself, like I said. Blown outputs, shorted filter cap or rectifiers, etc.Still doesn't hurt to check the main fuse. Only takes a second, once eliminated it's on to more fertile ground.

author: CJay
author_rank: Super Contributor
timestamp: May 13, 2019, 08:21:46 am
content: Exactly, always check the obvious, it saves a lot of pain and self flagellation later.

author: mikelino
author_rank: Newbie
timestamp: May 13, 2019, 10:48:53 am
content: Unfortunately it's not the fuse.... Any other suggestion?

author: Andy Watson
author_rank: Super Contributor
timestamp: May 13, 2019, 01:47:03 pm
content: Check that the power supply voltages are present and correct.
Yamaha HTR-5760 Receiver Repair - Page 1
Forum section: electronics / repair

author: Helblind
author_rank: Newbie
timestamp: December 24, 2020, 06:13:59 pm
content: Hey all!I am looking for some guidance in repairing a Yamaha HTR-5760 receiver that I took out of storage. I am a relative newb but I do have some experience replacing boards and soldering, and I do have a multimeter and the service manual. However, the electronic diagrams are gibberish to me and I am unsure where to start. I am hoping there is a blown capacitor or something similarly easy I can replace.Anyways, here is what is happening:The unit turns on for a second then turns off. There is a small click when it turns on and off coming from the board behind the power supply, but I believe I remember those clicks as normal. It turns off with speakers connected or not.I am able to access DIAG mode, but only in protection cancel mode. In DIAG, there are a few findings with potentially various levels of significance. When I switch into menu number 8: VFD Check, there is a louder click coming from a Omron G5PA-28 power relay(?) at the back on the unit. It clicks again when I move out of menu 8. As well, in menu number 9: TEST ALL, when I scroll through the individual tests, the relay clicks when I reach TEST PRES L or R, but not when scrolling between the two of them. I have no idea if this is normal behaviour.The last noteworthy finding is on menu item 11: AD DATA. The DC is listed at 7, well within the parameters of 1-13. However, the PS constantly switches between 21 and 22, 21 being out of the parameters of 22-47. This, along with the error on entering the DIAG mode of PS PRT : 022 E, seem to point to a potential problem with the power supply or something which triggers the protection function.So, I am wonder what my next steps might be and/or recommendations to further understand the issue. I can take some voltmeter readings but I am unsure were to take them and what I should be looking for. Any assistance would be appreciate!Thanks!Helblind

author: mzacharias
author_rank: Frequent Contributor
timestamp: December 24, 2020, 07:44:59 pm
content: Check the various voltage regulators for low output.

author: KevinA
author_rank: Regular Contributor
timestamp: December 24, 2020, 10:54:17 pm
content: Sounds more like a shorted output stage, or d.c. offset on one (or more) outputs.Locate the 0.22R wirewound emitter resistors (3 pin resistors). Measure the voltage on any pin with reference to ground. Anything more than a few mV, and you have a fault on that output channel.

author: mzacharias
author_rank: Frequent Contributor
timestamp: December 25, 2020, 03:06:10 pm
content: Quote from: KevinA on December 24, 2020, 10:54:17 pmYamaha's don't behave that way with a shorted channel. The high current protect shuts the thing down before the display can even come on, and the diagnostics cannot be accessed until the short is cleared.One channel DC offset is certainly possible, and in Protect Cancel mode would be easy to find; I suggested checking the regulators first because that is what I would do, having done Yamaha warranty service for over twenty years.
Yamaha HTR-5835 C405 Capacitor Replacement 437k 400el - Page 1
Forum section: electronics / repair

author: mjrodg3n8
author_rank: Newbie
timestamp: August 04, 2021, 03:22:17 am
content: I have a Yamaha HTR-5835 Receiver that has power issues.The other day it was on, but then shut off. Hit the power button, heard a click, then it wouldn't do anything. That was 2 week ago. I unplugged it today, plugged it back it in, it clicks, but nothing... this happens about 3 times before nothing. Unplug, plug, repeat, same thing. I did some research and saw that there is a common capacitor problem with that at C405.1. Does that sound like the issue?2. If so, the capacitor says473K 400eIDoes anyone know of an exactreplacementfor that?Thank you.Mike
Yamaha HTR-5990 Screen/Diag Mode issue - Page 1
Forum section: electronics / repair

author: ALearningLad
author_rank: Contributor
timestamp: January 30, 2022, 03:12:53 am
content: All segments of the display come on and stay on, nothing on the HDMI output. This is in Diag Mode, fixed all issues I can humanely find. Any thoughts?Name a few test points if you want me to probe them, I'm just lost at this point.https://manualzz.com/doc/22983407/yamaha-htr-5990-service-manual< Service Manual

author: ALearningLad
author_rank: Contributor
timestamp: January 30, 2022, 03:32:42 am
content: Also some segments are brighter then others. I'm assuming the displays attempting to boot but stopping. Also it gets darker over time.

author: ALearningLad
author_rank: Contributor
timestamp: January 31, 2022, 04:48:17 am
content: What i would really appreciate it a test point/data line/whatever the hell you want to call it to the display. Hook my scope up and see if it's working. Any ideas on where that test point would be?

author: mzacharias
author_rank: Frequent Contributor
timestamp: February 01, 2022, 11:19:22 am
content: If it does this whenever power is applied, and not just in Diag mode, I'd be suspecting the display driver IC itself.You obviously have the -30V and +5V supplies.
Yamaha HTR-5990 Transistor Issue - Page 1
Forum section: electronics / repair

author: ALearningLad
author_rank: Contributor
timestamp: May 21, 2021, 03:43:28 pm
content: A little back story...One day I decided to switch speakers, only issue is one was shorted. That blew a set of output transistors out, fixed it. All that is good no other shorts or problems so I decide to plug it back in.10 seconds go by just fine then these 2 tiny components started releasing a magic smoke. Could've mistaken this reciever for a fog machine it was that bad.Now your all caught up in my journey I have found nothing else wrong with the reciever except those 2 components. One was a capacitor, 16 volt .1 uf (board number is C408).The other was a transistor (board number is Q306). I just want to see if there is anything I have missed before I replace them.(I don't really want to have to keep ordering these from amazon or digikey.Just to create magic smoke)

author: BrokenYugo
author_rank: Super Contributor
timestamp: May 22, 2021, 04:35:49 pm
content: Sounds like stuff upstream of the blown transistors got damaged, or perhaps you made some mistake, but part numbers mean nothing without a schematic to refer to. You're going to need to provide schematics, or trace out the relevant bits yourself, or at least pics of the board (both sides, multiple angles), to get any help.

author: ambrosia heart
author_rank: Regular Contributor
timestamp: May 23, 2021, 04:33:47 am
content: Download RXV1600 and print out schematics.See pm and photos.Tell me your result if you want.Don‘T write too long, no time to read.I must finish the game.Tonight will be Ada Wong party time.
Yamaha HTR2067 repair help required please. - Page 1
Forum section: electronics / repair

author: SteveC
author_rank: Newbie
timestamp: November 03, 2019, 11:17:28 am
content: Hi,I have an HTR2067 that appears to have a blown subwoofer channel. I found the subwoofer connectors disconnected, not sure how long they were like that. Also not sure if they ever got shorted. I suspect when my wife moved some furniture that was when the wires got disconnected.Does this model have output protection of some sort? Anyone konw where I can get a service manual? I am a qualified tech.Regards,Steve

author: mzacharias
author_rank: Frequent Contributor
timestamp: November 03, 2019, 06:46:36 pm
content: There's no protection circuit for the subwoofer pre-amp level output, and no need for any. Most likely a broken solder pad or damaged eyelet at the jack itself, or disabled in the setup software. (There would be one or more muting transistors involved, as with all channels in a modern receiver.)

author: SteveC
author_rank: Newbie
timestamp: November 03, 2019, 08:41:12 pm
content: Thanks,I'm not using a powered subwoofer, the s/w speaker is connected to the o/p jacks on the rear of the unit. I haven't tested the cable yet as I only discovered the fault late yesterday. I plan to swap the s/w o/p with one of the surround o/p to see if it definitely the s/w channel after I test the cables.In my early days as a tech (I am now retired) I was taught not to leave speakers disconnected as that would blow the o/p chips, hence my thinking that as the leads had become disconnected, the o/p stage might have blown. Modern gear might be more robust though.RegardsSteve

author: SteveC
author_rank: Newbie
timestamp: November 03, 2019, 10:49:22 pm
content: An update.Not sure what happened, after entering diagnostic mode and testing all channels, it came good. Maybe yesterday for some reason my ears weren't hearing the bass as I was recovering from a bad cold.Strange.RegardsSteve

author: mzacharias
author_rank: Frequent Contributor
timestamp: November 04, 2019, 08:05:40 pm
content: Quote from: SteveC on November 03, 2019, 08:41:12 pmSolid state amps don't care about an open speaker load, but obviously speakers wires left unconnected at the free end is asking for trouble, shorting out especially.
Yamaha KX-360 cassette deck power transformer - Page 1
Forum section: electronics / repair

author: abhi1981
author_rank: Regular Contributor
timestamp: July 29, 2021, 05:45:40 pm
content: Hello,I'm planning to replace the power transformer of my Yamaha KX-360 cassette deck. Originally it was a 120v unit, but the dealer had recently replaced the transformer to 220v (Indian std.). It is running fine, but the quality of the transformer is terrible, and so is the quality of solder. I'm worried that this transformer may cause damage in the long run.The output of this transformer is aprox. 13v AC. I don't know whether it is correct. I have attached the circuit diagram.Please help me with correct tansformer specs, so that I can get a new transformer accordingly.

author: floobydust
author_rank: Super Contributor
timestamp: July 29, 2021, 08:48:08 pm
content: Welcome to the forumsThe schematic shows a 11-0-11VAC secondary, and an extra winding for the dial lamps 300mA which is usually 6V. The guy just jumpered them to 11VAC and if they are way too bright, add a resistor or put the lamps in series.I would estimate 15-20VA, it's not much current, mostly for the motor. If mains voltage is high then 13-0-13 might be too much voltage and IC11 etc will run hot.The big problem is the tape head will pick up AC hum from the transformer, so it is customarily located far away and oriented at an angle for the least hum.Best to get a transformer that fits on the PC board? The new one looks a bit big and the laminations seem to have a lot of air gap between them. I wonder if it's handmade.

author: abhi1981
author_rank: Regular Contributor
timestamp: July 29, 2021, 09:13:11 pm
content: Thanks for your help floobydust.The transformer is indeed handmade. I think it is 12-0-12 2amp. Even after dipping in varnish, it is humming. The display bulbs have been changed to leds. They were too bright, so I covered them with masking tape. Now they are perfect.Can I use a 10 volt transformer? I believe a 11 volt one will be difficult to get locally. The mains voltage fluctuates between 220-240 volts, even after using a voltage stabilizer.

author: floobydust
author_rank: Super Contributor
timestamp: July 30, 2021, 05:08:31 am
content: A 10V part would be OK, the voltages are above what the regulators need i.e. +15V reg Q28 gets 27VDC in.
Yamaha M-70 massive damage - Page 1
Forum section: electronics / repair

author: czarlz
author_rank: Newbie
timestamp: October 23, 2024, 07:05:59 pm
content: Not quite sure what happened here! For sure the fuse did not have a chance to say a word.Have you ever seen parts (PCBs) for M-70? Those PCBs are so damaged that I would have to make them from scratch.

author: Swake
author_rank: Frequent Contributor
timestamp: October 24, 2024, 04:30:13 pm
content: Well.... thanks to some material regulations the house did not burn down. The other good news is that the PCB's still seem to be in a good enough shape that you can copy them. Hope you have a schematic, because whatever that black blob was before it is not going to be easy to identify.

author: amyk
author_rank: Super Contributor
timestamp: October 25, 2024, 02:58:07 am
content: Lightning strike?Schematics, service manual are easily found online. It's not a complex circuit. Whether it's worth repairing (restoring?) and parts availability is a different question.

author: Gyro
author_rank: Super Contributor
timestamp: October 25, 2024, 09:13:30 am
content: It looks as if it's a big PIO (Paper In Oil) capacitor in the power supply mains filter... and they have a reputation for blowing up in 230/240V supply regions...https://www.audiokarma.org/forums/index.php?threads/yamaha-a-760-a-760ii-a-960-a-960ii-a-1060-m-50-m-70-and-b-6-220-240v-warning.154682/It sounds a bit like a massive Rifa PME on steroids - with added oil and probably not hermetic.EDIT: From the service manual, it looks like C607, 470nF 250V, across the line, maybe it is an ordinary Rifa PME X Cap, difficult to judge the size and shape now. It looks as if that whole assembly is a Triac phase control regulator feeding the mains transformer primary. Yuk!
Yamaha Motifxs6 digital keyboard doing weird things. - Page 1
Forum section: electronics / repair

author: Yamin
author_rank: Frequent Contributor
timestamp: September 24, 2019, 01:28:58 pm
content: Hi everyone,Recently I got a Motif xs6 in for repair. The customer complained about some of the notes sustaining even after the key has been released. When it starts to happen it effects all the keys in all the octaves. For eg: All the C's and F#'s all octaves. It needed some other work done so I completed all of that and then powered it on to check it out.The first night I tired it was working perfectly fine. Then I went into service the keybed as the whole thing was in pretty bad condition. The keybed was exceptionally bad the solder joints were crummy and black in colour. I cleaned the whole board with Isopropyl alcohol. Put everything back together and powered it on. The problem started. Keys sustaining and the effected keys sound very loud. I took some voltage measurements and it clearly showed that the keyboard "thinks" that notes are pressed even after the key was released. I measured at the diodes and it normally should show 5V not pressed and something below that when it is pressed.Any way my thinking was 'bad connections!'. So I RE-SOLDERED all the connections (more than 200!). It almost looks new now.Again I put everything back together. Now the voltage measurements looks fine, but now what has started to happen after sometime only one key starts to go mad. There is a delay in registering the key press sound comes way too late when the key is pressed. It might get loud all of a sudden.I was hoping that some one could help me figure this out. I have downloaded the service manual but it only shows how disassemble the unit and names of the IC used etc. It doesn't show any test point measurement details or anything like that. There are two VR on the keybed circuit board named 'Gain' and 'Offset' the manual doesn't specify what it is and how it should be set.Here is the link for the service manual.https://www.synthxl.com/yahama-motif-xs-6/This is quite an important project for me. Hope you guys could help me out.Thanks in advance.