hybridfree/eevblog-posts huggingface dataset:
Onkyo tuner repair - Page 1
Forum section: electronics / repair

author: Electrolitty
author_rank: Contributor
timestamp: December 19, 2023, 04:03:40 pm
content: Hello everybody,I am working on a 1980s Onkyo T-4015 tuner. The voltage regulator 78M12 has failed, probably because the voltage shown in the red rectangle on the diagram is not 18V as marked but nearly 29V. The mains transformer output AC2 to E is 21.5V AC. Unfortunately there is no indication in the service manual which voltages the transformer should deliver.What would be the least invasive way to get the input voltage for the regulator down to a reasonable level?

author: Fryguy
author_rank: Regular Contributor
timestamp: December 19, 2023, 04:12:21 pm
content: The voltage at the input of the 78m12 ist unregulated and will go up if there is no load behind the 78m12 - 18V is with load and @ 220V mains !Does the tuner work if you feed it 12 volts from a external psu ?

author: Electrolitty
author_rank: Contributor
timestamp: December 19, 2023, 06:15:11 pm
content: Quote from: Fryguy on December 19, 2023, 04:12:21 pmRight, but the 7812 cannot draw a lot of power, otherwise the 10 Ohm/1 Watt resistor will burn (-> schematics).By simulating a load of about 4W with a big resistor directly after the bridge rectifier, the voltage drops by 4.5V to 24V, much more as it would under load by the 7812.Therefore I want to lower the voltage at the 7812 input by some means.Quote from: Fryguy on December 19, 2023, 04:12:21 pmThe 7812 is not entirely dead. When I lower the mains input voltage (by variac) so that the voltage at the input of the 7812 is around 13V, the output then switches on again (at around 10.5V to 11V) and the tuner works. A bit odd I guess but that's what happens.

author: Fryguy
author_rank: Regular Contributor
timestamp: December 19, 2023, 08:10:03 pm
content: A standard fixed voltage regulator like a 78xxx needs a input voltage at least 3 volts above the output voltage to work properly .If the one from your tuner starts doing something at 13v input . . . something ist terribly wrong with it !The operating input range of this regulator is 15-30 V - throw this one out and put in a new one .
Onkyo tx-nr414 shutting off after few seconds - Page 1
Forum section: electronics / repair

author: Roberts
author_rank: Contributor
timestamp: May 24, 2022, 06:30:40 am
content: Hello again.I am struggling for long time now with finding fault on Onkyo tx-nr414.Unit shuts off after few seconds when turned on.Diagnostics mode works except for: It can not engage OPERATION CHECK 8 - Auto Measurement mode as it instantly shuts off.Voltage to ground from two bias channel points is high in my opinion (150 and 220mv).Checked preamplifier board and all seems ok to me, especially 220mv channel.Firmware is goodAny suggestions?

author: Roberts
author_rank: Contributor
timestamp: May 25, 2022, 10:04:46 pm
content: Let me correct myself.Diagnostics mode works except for: It can not engage "OPERATION CHECK 7" - (3-0~3-14) as it instantly shuts off.
Onkyo TX-NR686 no DTS Sound - Page 1
Forum section: electronics / repair

author: Gulftown
author_rank: Regular Contributor
timestamp: December 10, 2023, 09:43:53 pm
content: Hello,i got an Onkyo TX-NR686 which has no sound in DTS, TruHD and ATMOS modes.If i watch a movie with an ac3 track or YouTube, it works just fine and also music streaming works.The digital mainboard is relativelay straight forward and has an Cirrus Logic CS49844A-CQZ Dolby and DTS decoder chip, which i suspect as the culprit here.Has anyone ever attemted to replace one of those, or is there a flashed setting on these?Unfortunately its impossible to get the datasheet for this DSP.Do you think that reflow might help?

author: macboy
author_rank: Super Contributor
timestamp: December 11, 2023, 04:22:41 pm
content: Unfortunately those chips are often also marked as "no replacement supplied" or something similar. In other words, you can't buy one for repairs because they (the IP holders) are worried about the chips being used something else without paying the licencing fees.Most equipment that can output DTS, TrueHD, or Atmos can also be set to decode those internally and send multichannel PCM instead. Of course you lose Atmos object based audio, only an issue if you have more than 7.x speakers.

author: Gulftown
author_rank: Regular Contributor
timestamp: December 11, 2023, 07:09:39 pm
content: Quote from: macboy on December 11, 2023, 04:22:41 pmThere is an ebay listing for the chip from a seller with more or less good rating.https://www.ebay.com/itm/373119019318I mean its 11 Euros and i am capable to solder it using a hot air station, but do you think it would work?

author: Gulftown
author_rank: Regular Contributor
timestamp: January 19, 2024, 08:12:28 am
content: Okay i swapped the Cirrus Logic CS49844A-CQZ but now i get no sound at all.I am really confident, that everything is soldered correctly and i get data on the lines and the nessecary voltages.But the chip gets constantly resetted every half second.I bet the chip needs some kind of programming.Does anyone have the an TX-NR686 who can dump the memory?Or a datasheet for the chip maybe?
Onkyo TX-NR708 with defective DSP chip D830K013BZKB3 - Page 1
Forum section: electronics / repair

author: Geert
author_rank: Newbie
timestamp: May 25, 2021, 02:41:57 pm
content: Hi,I have an Onkyo TX-NR708 with a defective DSP chip D830K013BZKB3.However these chips are known of it's premature failure and are swapped out with a newer revision D830K013DZKB3.Because you can't buy the chips from TI because you need to own a Dolby-Digital licence I was wondering if there is a possebility to find them elswhere ?All information is welcome !

author: perieanuo
author_rank: Frequent Contributor
timestamp: May 25, 2021, 03:48:34 pm
content: some said they replaced D830K013DZKB3 from aliexpress/ebay with succcess, someone said D830K013DZKB4 worked but without audio stream capability.imho the price+effort didn't justify, a replacement updated board is a better solution or just try some pioneer competition product

author: dc101
author_rank: Regular Contributor
timestamp: May 25, 2021, 07:44:01 pm
content: Wouldn't the replacement DSP also need to be programmed? Or is the firmware for it stored somewhere else on the board?

author: Geert
author_rank: Newbie
timestamp: May 25, 2021, 08:51:59 pm
content: Quote from: perieanuo on May 25, 2021, 03:48:34 pmYou are probably right about justifying the price, the effort means nothing to me since it's a max 15min job swapping the chip.Quote from: dc101 on May 25, 2021, 07:44:01 pmI believe there are two different firmwares, one is on the DSP itself and the other on the board.
Onkyo TX-NR818 Transistor Substitutes for TTA0001 TTC0001 - Page 1
Forum section: electronics / repair

author: kingswoods
author_rank: Newbie
timestamp: July 04, 2023, 12:31:38 pm
content: Hi guys I am a noob and I have read somewhere that 2SC5200 and 2SA1943 are suitable replacements for the TTA0001/TTC0001 as they are obsolete. Does this sound right and is it ok to just replace one pair of these transistors in my Onkyo TX-NR818? I can see the TTA/TTC on eBay but apparently they are all Chinese fakes.

author: m k
author_rank: Super Contributor
timestamp: July 08, 2023, 12:36:43 pm
content: Quick peek indicated yes.What you think?

author: kingswoods
author_rank: Newbie
timestamp: July 09, 2023, 02:49:34 am
content: Thanks MK, yes I think they look suitable but it looks like mine are actually ok and I'm having trouble what is making this thing go into protection mode. All those transistors and the emitter resistors look ok so Im a bit stuck now.

author: macboy
author_rank: Super Contributor
timestamp: July 09, 2023, 12:52:01 pm
content: Usually these receivers have multiple fault detection circuits. Usually they have over-current, DC on output. Sometimes temperature, power limit (simultaneous high-ish power on multiple channels). You need to determine which is tripping the protect, then work backwards from there to the fault. Remember that a fault detection circuit may itself be faulty, giving you a false positive fault detection.

author: kingswoods
author_rank: Newbie
timestamp: July 10, 2023, 03:58:09 am
content: Thanks Macboy I put it back together to test but left out the preamps but now it doesnt start at all. I saw a youtube where they did this with a different receiver to eliminate the preamps from the diagnosis but it hasnt worked for me. Do you think I screwed up the assembly or it needs them installed to go into standby?
Onkyo Tx-SV434 wont turn on, looking for service manual or tips - Page 1
Forum section: electronics / repair

author: cdev
author_rank: Super Contributor
timestamp: May 03, 2020, 12:30:19 pm
content: Hello, I recently acquired an old Onkyo TX-SV434 receiver, for free, the outside looks nice but very dusty inside.After a bit of an internal cleanup, it still hasn't worked, it is stuck in standby mode and does not come out of standby when I press the power button.It probably was sitting in a garage or basement for a long time from all the dust inside of it.It weighs quite a bit. These were quite nice receivers back in the day with decent audio specs. And quiet, when working.Also the power switch may be broken, its hard to tell if that is the problem, it may just be a soft power switch. It appears to have been worked on before. My first assumption which may be wrong is that a built in safety mechanism may be preventing it from turning on because of a problem like a blown audio output transistor or similar.Does anybody have a service manual for this specific receiver? I'd like to fix it and use it on my bench. Lacking the manual its hard to know what connections on the huge internal IC are the ones that could bring it up. So I figured I would ask if anybody has some experience with it first. It would be a nice receiver if it was working.. Apart from the huge control IC everything else looks fairly generic and easily replaceable.

author: SpecialK
author_rank: Regular Contributor
timestamp: May 03, 2020, 02:09:53 pm
content: https://www.manualslib.com/manual/698467/Onkyo-Tx-Sv434.html?page=9#manual

author: cdev
author_rank: Super Contributor
timestamp: May 03, 2020, 04:30:53 pm
content: Thank you, SpecialK.This is a good time to catch up on all my partially finished projects. It would be great to get this working. If not I can probably extract some decent parts out of it. (the transformer looks useful)I figure its worth putting a little bit of money into in the interests of having a nice tuner/amplifier next to my electronics area. Its going to be fun cleaning all that dust out, its nasty!Figure I will try 70% IPA first.
Onkyo TX8255 memory leak (Solved)  - Page 1
Forum section: electronics / repair

author: Remy
author_rank: Newbie
timestamp: January 16, 2023, 01:47:46 pm
content: Hi,I have an amplifier tuner onkyo TX that loses the memory of FM stations during a power cut.After looking at the diagram, I think it is the C704 capacitor (super capa) which must be in default.I attach below 3 extract from the schematics to view this capacitor.Before the amp is disassembled, I would like your opinion on this problem.Thanking you in advanceRemi

author: TERRA Operative
author_rank: Super Contributor
timestamp: January 17, 2023, 10:53:30 am
content: I have repaired Onkyo amps with leaky supercaps before, it is a rhing with them when they get older. Be sure to check for corrosion damage to the PCB!

author: Remy
author_rank: Newbie
timestamp: January 18, 2023, 08:39:33 am
content: Hi,Thanks for the advice. I will take time to clean the circuit when replacing the capacitor.After spending 1 hour on the amplifier, the modification is done and everything works correctlyBelow picture of location capacitor has replaced, and the picture of the defective capacitor.thanks for the feedback.
Onkyo's TX-NR626 HDMI switching issue? - Page 1
Forum section: electronics / repair

author: ttx450
author_rank: Regular Contributor
timestamp: October 25, 2023, 12:49:59 am
content: I take it the HDMI switching issue is on the HDMI board? My receiver just started not switching the HDMI inputs, some audio would switch but not video, most dont switch. I am guessing 15-20k hours on the unit. Whats the likelihood for repairing this? Is it caps on the HDMI board? thks..

author: TERRA Operative
author_rank: Super Contributor
timestamp: October 25, 2023, 11:54:52 am
content: There was a service bulletin or ten put out years ago for many Onkyo recievers.The problem was indeed crappy capacitors on the HDMI board. I think they may have been 85degree rated caps too, possibly?I replaced the ALL the capacitors on the HDMI board in my brother's unit with high quality 105degree rated caps and all was well again.Attached is one of the service bulletins from Onkyo.

author: ttx450
author_rank: Regular Contributor
timestamp: October 25, 2023, 10:59:27 pm
content: Quote from: TERRA Operative on October 25, 2023, 11:54:52 amI might do that. I am restricted to not lifting more then 20lbs for 3 more weeks. I hate to pull out the receiver from my home theater 'hook-up' and leave a empty hole. All HDMI inputs ares used and I run a 7.1 speaker config. lot's of wires. Does me no good sitting there, just takes up so much room on the bench along with the void in my home theater cabinet. A cap switch out is much cheaper then a new unit.
Onnitronic XPA-1800 Part identification - Page 1
Forum section: electronics / repair

author: karlseN
author_rank: Newbie
timestamp: May 25, 2025, 02:08:38 pm
content: Haya! I recently got Gifted an Omnitronic XPA-1800 PA amplifier by a friend. He was a bit of a knob and blew up the input section by hooking it up to the output of another amp. I have already fixed all the blown SMD resistors and circuit board traces. After measuring all the resistnces again, I noticed what seems to be a Mosfet with 11Ohms between Gate and Source. I cant find anything on that specific part on the Internet! On the Positive section of the other channel there is a completely different part. I have already tried comparing the two individual channels on the Board. I thought they were identical. Appearently not:(.I have attached some pictures. Any help would be greatly appreciated! Any other tips on additional failures too! Thanks!

author: karlseN
author_rank: Newbie
timestamp: May 25, 2025, 02:09:51 pm
content: Here is another picture of the individual part. I cant upload multiple photos at once;(

author: Andy Watson
author_rank: Super Contributor
timestamp: May 25, 2025, 03:59:58 pm
content: 110between gate and source is not correct (assuming it was measured out of circuit). The two channels should be identical.https://www.alldatasheet.com/datasheet-pdf/download/775406/NCEPOWER/NCEP01T11.html

author: karlseN
author_rank: Newbie
timestamp: May 26, 2025, 12:27:39 pm
content: Thanks Andy! I also expected the two sections to be identical. They mostly are but that one shorted part is different. I am currently looking for a substitution of that mosfet. I rarely order from Digikey or Mouser because of the shipping costs. Once I found something, I will update you all. Just in case somebody else blows their Amp;)

author: karlseN
author_rank: Newbie
timestamp: May 26, 2025, 12:29:35 pm
content: Btw Yes it was measured out of circuit. I mistyped. It actually reads 11 Ohms between Gate and Source. And something like 400 ish ohms between Drain and source 🫣
Digital oscilloscope Owon 5032 E does not turn on - Page 1
Forum section: electronics / repair

author: Valera d
author_rank: Newbie
timestamp: July 02, 2023, 05:02:56 am
content: Hello, who faced such a problem. The digital oscilloscope Owon 5032 E does not turn on in advance. The voltages from the power supply look normal - 2 x 6 V and 2 x -8.4 V, 2 x ground. But at the same time, the xilinx spartan xc3s200a chip is heated, indicated by the photo with an arrow. Maybe someone has met with such a problem or in which direction to dig Thanks for the answer
Op Amp Saturation output - Page 1
Forum section: electronics / repair

author: cstiang
author_rank: Newbie
timestamp: September 29, 2019, 12:10:14 am
content: Hello I am doing board repairing with faulty current sensing circuit,The op amp have -12V saturate rail output with -1.73V measured on the inverting input of the op amp.I have tried to disconnect the non-inverting input of the op amp and it behave the same, tried replaced the op amp IC as well but no luck!

author: JFJ
author_rank: Regular Contributor
timestamp: September 29, 2019, 05:47:43 pm
content: Quote from: cstiang on September 29, 2019, 12:10:14 amA typical op-amp has an extremely high open-loop gain. Consequently, even a tiny difference between the voltages at an op-amp's inverting and non-inverting inputs will cause its output to saturate. The inputs are usually maintained at the same voltage by negative feedback.Presumably, the op-amp is monitoring the voltage drop across a low value current sense resistor, to determine the current flowing. If that sense resistor has gone high or open circuit, then the voltage drop could be too high for the negative feedback loop to handle. Hence, the op-amp's output saturates.
Opening M-Audio AV42 passive side - Page 1
Forum section: electronics / repair

author: Marsupilami
author_rank: Frequent Contributor
timestamp: March 12, 2022, 05:07:20 am
content: Hey folks!It's not a strictly electrical issue, but I'm guessing there are a lot of people here with quite some speaker experience so I'll try my luck.I have an M-Audio AV42 powered studio monitor set. The active side is clear but I can't figure out how -if at all possible- to take apart the passive side. The active side has a rear panel that's held in place by screws. If that's out of the way from the inside the screws holding on the front are accessible. However the passive side has no separate back panel, the whole rear of the speaker is one solid piece except for the bass port and the wire terminals.Has any one of you taken apart M-Audio speakers or something that's alike?Thanks!

author: Audiorepair
author_rank: Frequent Contributor
timestamp: March 12, 2022, 06:54:55 pm
content: Angle grinder.

author: GLouie
author_rank: Regular Contributor
timestamp: March 12, 2022, 06:55:22 pm
content: I don't have an answer, but it is curious. Do you have a photo of the active side inside screws of the front panel?My guess would be that the passive side has the entire front decorative panel glued on after the woofer is installed.

author: commongrounder
author_rank: Frequent Contributor
timestamp: March 13, 2022, 05:30:58 pm
content: Have you checked to see if you can remove the terminal strip and port, then reach inside with a long screwdriver to access the front panel screws? Surely they gave some means to service these?

author: Marsupilami
author_rank: Frequent Contributor
timestamp: March 13, 2022, 07:13:11 pm
content: Quote from: GLouie on March 12, 2022, 06:55:22 pmThis is my guess as well unfortunately. It makes sense to make it as cheap as possible and just glue it on. The screws holding the front in the powered side would not be accessible from the back on the passive.Thanks!

author: Marsupilami
author_rank: Frequent Contributor
timestamp: March 13, 2022, 07:15:47 pm
content: Quote from: commongrounder on March 13, 2022, 05:30:58 pmMaybe they did not. It's a cheap unit. There isn't an obvious way to remove the port or the terminals and I don't want to force them. I lean towards what GLouie wrote, that the front is glued on.Thanks!

author: GLouie
author_rank: Regular Contributor
timestamp: March 13, 2022, 07:57:21 pm
content: My feeling is that serviceability isn't a factor for products at this price point, but I look at it as something that was assembled somehow, and therefore must be able to be disassembled! Maybe with a few scratches.I could also envision that the speaker was coated or vinyl/plastic wrapped and it covers all of the seams and any fasteners. Maybe no screws on the box as gluing would be faster and cheaper, or perhaps it is an all plastic box, but I would still bet on 2 molded pieces and that the woofer has screws, and they are hidden by the decorative front panel. I'd try looking around the front panel, maybe after some hair dryer work.
Opgal therm app hz - Page 1
Forum section: electronics / repair

author: Pyro
author_rank: Newbie
timestamp: September 02, 2021, 10:33:06 am
content: Hi everyone, I have two opgal thermal cameras, one is completely dead, and the other also failed, but last night, I was checking the caps and ic's in diode mode, and for some reason the camera started working.One component T1210B GHDF G4, gets so hot, as in when measured with my multimeter, hit 100 degrees, but I found it whilst holding the pcb and burnt my finger.When I was checking the caps for continuity, I had 4 caps beep at both ends and the other 100 or so caps only beeped at one end.The company I purchased these cameras off, will not help at all now, as I have sent back 5 other's that did the same thing, and at $3000 each, I would have thought they would find the problem, and fix it.I dont have much in the way of test equipment, just a multimeter, but looking to purchase an occiliscope etc and set up as best I can, now that I'm single 😉Please throw questions at me, or possible answers, but I know I haven't given much info, as im not exactly sure, what you need to know. I do have many pictures of the pcb and most of them decent close ups.The camera runs off an Android phone at 5v then gets reduced to the run the ic'sAny help would be appreciated, as for me, this was the biggest purchase I have made ($6000 for 2 of them) other that car and house.Glenn
Opinion about this solder job from supplier - Page 1
Forum section: electronics / repair

author: john2k
author_rank: Newbie
timestamp: November 28, 2022, 06:58:28 pm
content: I purchased a PCB from china which is for my car head unit. A modification is required where 4 SMD resistors (0805 size) need to be moved around (2 from each side) this allows it to work as RHD. The supplier in china that I purchased it from said they can do the modification. Having just taken delivery of the PCB boards and looking at the area where they did the resistor move, it looks a little bit messy but mainly what looks like flux residue. But what is worrying me a little is trying to zoom in to the resistor to take a pic, the writing on the resistors seem a little burnt out or maybe they are covered with flux. I'm not sure. So i'm a little concerned if those resistors they de-soldered and re-soldered are still ok. So wanted some opinions based on the pics below, do the resistors look like they will be ok? is there a way to clean this without risking anything on the PCB?

author: ataradov
author_rank: Super Contributor
timestamp: November 28, 2022, 07:12:09 pm
content: Hard to tell. Given the presence of flux, it looks about as expected. Clean up the flux and see if it looks any better.

author: john2k
author_rank: Newbie
timestamp: November 29, 2022, 10:28:23 am
content: What's the best way to clean it without risking any damage to the board?

author: coromonadalix
author_rank: Super Contributor
timestamp: November 29, 2022, 11:12:19 am
content: IPA isopropilic alcohol .... for me, i'm more aggessive with acetone loll, but never touch plastic and dont smell itsloppy job and use a nail finger to gently scrape off some solder left overs on the pcb

author: Microdoser
author_rank: Frequent Contributor
timestamp: November 29, 2022, 11:18:45 am
content: Hard to tell, is it possible to get clearer pictures?Seems to me that adding a little flux and reflowing them would make it look neater, but from the look of things it's electrically and mechanically sound.It looks as though what was required has happened, they moved some resistors by hand. Personally, I would have done the modification myself if I were concerned about aesthetics post-modification.

author: Gyro
author_rank: Super Contributor
timestamp: November 29, 2022, 11:56:36 am
content: It's a good example of things to consider when asking a vendor to do such modifications. Hand rework with an iron is never going to be as neat as reflow - and you don't want them to reflow the board twice. They're also going be doing such reworks at speed. More specifically, if you want them to clean the flux off, you have to explicitely state it, otherwise they won't bother.
Optikinetics K4 Projector Repair - Page 1
Forum section: electronics / repair

author: saxicola
author_rank: Newbie
timestamp: July 10, 2021, 08:32:39 pm
content: I have one of these in for repair. The HID lamp driver mosfets are blown (all over the board. Well two of them). The manufacturer have helpfully sanded all the chips so I have no idea what these are and it's unlikely they'll send me a schematic, even though this was made in 1998. I suspect they'll be something like STP9NK50Z, four in total. Just guessing though, based on various reference designs on-line.Does anyone have any information on these?If it doesn't get repaired it'll be landfill, for sake of a couple of components. Of course I still need to find why they exploded.The board is silkscreened as PCB BRIDGE ISS.2RegardsMike Evans

author: Audiorepair
author_rank: Frequent Contributor
timestamp: July 10, 2021, 08:41:00 pm
content: Have you talked to Optikinetics yet?

author: saxicola
author_rank: Newbie
timestamp: July 10, 2021, 08:48:56 pm
content: I've emailed, but it's the weekend and there's some sort of football thing on.The driver looks "a bit" like:https://www.st.com/resource/en/application_note/cd00211534-70-w-hid-lamp-ballast-based-on-the-l6569-l6385e-and-l6562a-stmicroelectronics.pdfAt least the hot end does.

author: themadhippy
author_rank: Super Contributor
timestamp: July 10, 2021, 08:54:40 pm
content: Quoteif its got the motor and lens ive got plenty of bin space you can use

author: Audiorepair
author_rank: Frequent Contributor
timestamp: July 10, 2021, 09:00:56 pm
content: I would wait to hear from Opti.Clearly it has value.Phone them, they are people.
Option hack for Tek RSA6114A?? - Page 1
Forum section: electronics / repair

author: CrazyTiger
author_rank: Regular Contributor
timestamp: June 07, 2025, 03:29:02 am
content: I managed to get hold of a Tektronix Real-Time Spectrum Analyzer RSA6114A. It was purchased as a defective unit that was unable to power on. Fortunately, the issue turned out to be the front foil switch, which was faulty. The good news is that the foil is exactly the same as the one used in the Tektronix 7000 series scopes, making it relatively easy to source and replace.The unit now boots up normally and passes all diagnostic tests. However, I noticed an amplitude reading loss of around 6 dB at frequencies above 6 GHz. My guess is that one of the LO amplifier stages might be faulty.Also, I’m wondering—has anyone managed to hack or unlock the options for this series?

author: squadchannel
author_rank: Frequent Contributor
timestamp: June 07, 2025, 03:43:06 am
content: Ask them about this topic.https://www.eevblog.com/forum/testgear/tektronix-rsa5100-rsa6100-series-calibration
Opto Part number - Page 1
Forum section: electronics / repair

author: Faringdon
author_rank: Super Contributor
timestamp: July 19, 2023, 08:04:46 am
content: Hi,We have an opto on a PCB which we believe is of the Sharp "PC357" family.P357https://uk.rs-online.com/web/p/optocouplers/8264684?cm_mmc=UK-PPC-DS3A-_-google-_-DSA_UK_EN_Displays+%26+Optoelectronics_Index-_-Optocouplers%7C+Products-_-DYNAMIC+SEARCH+ADS&matchtype=&dsa-1592138831419&cq_src=google_ads&cq_cmp=15904458467&cq_term=&cq_plac=&cq_net=g&cq_plt=gp&gclid=Cj0KCQjwk96lBhDHARIsAEKO4xaAvdlPVsiNkrnlzPJnbfOpRnNYW8enH4kkC8z3DiLcqd0WSUzyBIMaAr2-EALw_wcB&gclsrc=aw.dsIt is marked....QUOTE...S B8357D....UNQUOTEAccording to the above datasheet, this means the CTR could be either....300-600%200-600%160-600%80-600%...from looking at page 5 of the datasheet.Do you know which one it might be?

author: ace1903
author_rank: Regular Contributor
timestamp: July 19, 2023, 08:24:03 am
content: Maybe TLP357 also very common opto?

author: CosteC
author_rank: Regular Contributor
timestamp: July 19, 2023, 08:51:45 am
content: Page 2 tells you where "RANK MARK" isPage 5 tells you what "rank mark" translates to CTR @ I.F = 5 mA

author: Faringdon
author_rank: Super Contributor
timestamp: July 19, 2023, 09:17:13 am
content: Yes, thanks, but a Rank Mark of "D" corresponds to many different CTRs, as page 5 says

author: wasedadoc
author_rank: Super Contributor
timestamp: July 19, 2023, 09:56:35 am
content: Not many different CTRs, but the range between 80% and 600%.If you want to know the CTR of your device you will need to measure it. Not difficult to do and does not require any elaborate setup or exotic equipment.

author: CosteC
author_rank: Regular Contributor
timestamp: July 19, 2023, 10:22:53 am
content: Quote from: Faringdon on July 19, 2023, 09:17:13 amTo the range of CTRs to be precise.Parts are measured and marked per bin/rank to narrow down spread of CTR for your project. Relying on exact CTR value is bad practice. CTR drops with age and varies with temperature anyway..
Oricom UHF050 uhf cb schematic? - Page 1
Forum section: electronics / repair

author: zzsteve
author_rank: Newbie
timestamp: December 10, 2014, 09:49:20 am
content: Hi,Have pulled the reverse polarity protection diode and receiver comes to life, but no transmit. Does a schematic or manual exist?Anybody had a go at this unit before?TIASteve

author: GEuser
author_rank: Frequent Contributor
timestamp: December 10, 2014, 12:31:59 pm
content: I doubt there would be a schemmy , too cheap and too new a radio .If you have another uhf pull the final or disconnect the drive to the pa transistor and see if one can rx it on the other radio , then it might be the pa transistor or module if one can rx a signal even if it measures ok with a DMM or AMM .

author: Flashman
author_rank: Newbie
timestamp: November 03, 2022, 05:54:25 am
content: Hi, do you still want a schematic? Pressing the PTT sends a signal to the CPU which in turn puts a low (TxEnable) on the base of Q4. This in turn switches Q201 on and also Q35 the main DC switch for the PA.

author: wasedadoc
author_rank: Super Contributor
timestamp: November 03, 2022, 10:29:59 am
content: @FlashmanThe OP last logged in here 8 years ago.
OS for the Tektronix TDS5054 - Page 1
Forum section: electronics / repair

author: BrunoGelli
author_rank: Contributor
timestamp: May 31, 2022, 02:52:49 am
content: Hi guys!I'm trying to revive one 500 MHz - 5 GS/s TDS 5054 oscilloscope. Someone did a favor on it and installed a new OS on it without backing up the old one. Long story short, the new OS is not working and we don't have access to a recover CD.Does anyone have a recovery image for this oscilloscope? I can buy a coffee for youThanks a lot!P.S.: I have access to the recovery CD for the TDS5000B series. I've tryied and it does not work!

author: langlv
author_rank: Contributor
timestamp: January 28, 2023, 02:59:26 pm
content: Do you still need it?, I have the recovery CD, can manage to make ISO for U.

author: elantra
author_rank: Newbie
timestamp: February 17, 2023, 02:17:27 pm
content: Quote from: langlv on January 28, 2023, 02:59:26 pmCan u share it? I do need it while i just got a tds5054 with hard disk error...Thanks in advance..

author: mkl262
author_rank: Newbie
timestamp: June 12, 2024, 06:23:46 pm
content: Hello, Is it possible to get the ISO files? Thanks.

author: coromonadalix
author_rank: Super Contributor
timestamp: June 12, 2024, 08:13:13 pm
content: send a pm to @langlv ...files are around 600mb and one at 40 mb, but one seem corrupted 061-3509-01 TDS5K_OS_RESTORE.isoand free registration on Xdev's you can grab some ghost backup and disk install
Oscillating Fan Motor - 2 Broken Copper Windings to Capacitor and Thermal Fuse - Page 1
Forum section: electronics / repair

author: Colombian Roast
author_rank: Newbie
timestamp: August 09, 2020, 09:54:58 pm
content: Hello to everyone! Happy Sunday Afternooooon!!I should first say that I broke these wires intentionally, but I forgot exactly what they were attached to.I was able to determine that there is no connectivity across the Capacitor, but as a result of not eating anything all day, my mind became forgetful, and here I am, unable to remember where things went. I am assuming I can solder them back into their correct places.Could someone please help me recall where these two copper windings and Capacitor wires are supposed to go?The two copper windings I broke were attached to the Thermal Fuse and to the Capacitor. I also removed the Capacitor, and do not recall what its Black and Pink wires were attached to. I also disconnected one of the Thermal Fuse's wires and do not recall where it goes.(I thought I needed to isolate these two pieces completely in order to test their resistance and connectivity.)The "Loom" from the fan motor has Black, Blue, Red, and White wires. Each is connected to a thin, copper winding wire that appears to have been twisted onto the ends of these four wiresThe Blue wire only has One copper wire attached to it. (I may have unknowingly broken its second copper wire, as there is a small, centimeter-long copper wire that appears to be the other side of the copper wire that was twisted onto the end of the Loom's Blue wire.)There is a second Black wire that comes down from the Synchro Motor. The second Black wire is connected to the end of the Loom's Black wire and is soldered to it there.One of the two wires from the Thermal Fuse connects at the union of the two Black wires.

author: sebouh
author_rank: Newbie
timestamp: August 10, 2020, 07:44:52 am
content: Colombian Roast,Difficult to understand your problem only by reading. In order to help you photos or a schematic diagram might be useful.

author: Colombian Roast
author_rank: Newbie
timestamp: August 10, 2020, 06:34:41 pm
content: Ok, I will see if I can snap a few good photos. Those winding wires are so thin.
Oscilloscop Matrix MOS640 - Page 1
Forum section: electronics / repair

author: nemo64
author_rank: Newbie
timestamp: April 02, 2021, 08:21:26 am
content: Hello! Can anyone help me with the service manual or an electronic diagram for the Matrix MOS640 oscilloscope? Thank you in advance!

author: JFJ
author_rank: Regular Contributor
timestamp: April 02, 2021, 05:04:18 pm
content: If you can identify other brand names, under which your oscilloscope was sold, then it could increase your chances of finding a service manual or circuit diagrams.For example, the Matrix MOS-640 looks very similar to the GW-Instek GOS-620:Schematics for the GOS-620/GOS-630 are available from here:https://elektrotanya.com/gw-instek_gos-620_gos-630.pdf/download.html

author: coromonadalix
author_rank: Super Contributor
timestamp: April 02, 2021, 06:47:00 pm
content: yup seems the same lolll another rebranded puppy

author: nemo64
author_rank: Newbie
timestamp: April 03, 2021, 08:46:37 am
content: Thanke you, but mos640 have not the same diagram with 620, not the same HV
Oscilloscope BWD 539d - Page 1
Forum section: electronics / repair

author: djuma89
author_rank: Newbie
timestamp: February 09, 2022, 09:37:37 pm
content: Greetings from Serbia,I came into possession of the Australian oscilloscope BWD from 1987, serial number: 41649. The oscilloscope was faulty but I partially enabled it. My first step was to replace all the electrolytic capacitors. Then I fixed the faulty intensity potentiometer after which I got the picture actually a trace. I adjusted all positions according to the instructions for the first start. I got a pale and flickering dot on the screen.https://manual-hub.com/manuals/bwd-539d-01-pdf-manual/Then turned on the X-Y button and brought the X wire to the input with my finger😊 In the attached picture you can see that the oscilloscope reacted which means that the X amplifier is good.Then I inspected the TB / X-Y switch and it seems ok to me. Focus changes sharpness also. Switch s201 works ok as far as I could measure.I reviewed the Q253 Q255 bi- stabile trigger, Q257 miller saw generator and Q256. The component test says they are good after I took them off the PCB.I would ask you if anyone has any advice? Thanks.Djuma

author: tautech
author_rank: Super Contributor
timestamp: February 10, 2022, 10:26:36 am
content: Welcome to the forum.Connect a channel to the Cal output which although not a precise signal source serves just fine for rudimentary tests.

author: djuma89
author_rank: Newbie
timestamp: February 10, 2022, 10:57:59 am
content: When I connect to the CAL only the point rises a little up. I don't see a horizontal line, just a dimly lit point, although the focus is set and the intensity is almost full turn. This is on both channels same. What do I check next?

author: tautech
author_rank: Super Contributor
timestamp: February 10, 2022, 11:18:51 am
content: Quote from: djuma89 on February 10, 2022, 10:57:59 amIt might be the Cal output is not working. Check its output with a DMM in ACV.

author: djuma89
author_rank: Newbie
timestamp: February 10, 2022, 01:26:54 pm
content: 2.14 VAC measurements Sanwa DCL1200R

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: February 11, 2022, 12:17:22 am
content: If you have a signal or function generator you can put the Same signal into both channels. In X/Y mode it should be a line at about 45 degrees.This will check both your channel amps.Maybe you have no Time Base (Horizontal) in your scope.If you are applying a small DC voltage to the inputs. Put the scope in DC mode. DC will not make it through the input if the scope is in AC mode as in your nice picture.
Oscilloscope Gould OS300 horizontal trace problem - Page 1
Forum section: electronics / repair

author: jpwm
author_rank: Newbie
timestamp: September 21, 2019, 07:50:22 am
content: Hi,I recently purchased this oscilloscope on Ebay, unfortunately the seller packed it badly so that some plastic parts of the case broke and the CRT came loose. I pulled it back into position and fastened it with cable ties. Unfortunately the horizontal axis doesn't work properly anymore.The trace of both channels can only be moved horizontally in an area between the left edge and the middle. Both traces can be moved vertically over the complete height up to outside the CRT.I have the manual for the oscilloscope, but so far I have only worked with considerably newer devices and therefore I can't really understand which setting could solve this problem. Online I found some similar questions, but there were never satisfactory answers. I would be happy if anyone had an idea what the problem is.(I also uploaded a video of the problem:https://streamable.com/z8c7c)

author: shakalnokturn
author_rank: Super Contributor
timestamp: September 22, 2019, 09:03:50 am
content: If CRT came loose first look for broken wires / connections to the X plates. (Between CRT and PCB)Other than that the X output stage is symmetrical (one output does the opposite to the other) if you have damage on 1/2 you'll lack X amplitude and offset on one side.

author: jdragoset
author_rank: Frequent Contributor
timestamp: September 22, 2019, 04:28:56 pm
content: Had a similar problem in the vertical channels on a tek 2215.Turned out to be an open resistor in one side of the vertical output stage.Check components on both sides of the horizontal output stage.
oscilloscope GWinstek GDS-2064 - Page 1
Forum section: electronics / repair

author: levnav1975
author_rank: Newbie
timestamp: October 28, 2020, 03:42:25 am
content: Please help ! In my oscilloscope GDS-2064 FPGA configuration fail. Colleagues if you know how is made FlashROM Fixture this firmware installed .Does anyone have a firmware for the GDS 2064.

author: whipaway
author_rank: Contributor
timestamp: March 22, 2024, 10:00:39 pm
content: Firmware version 1.11
Oscilloscope Hameg HM507 help in identifying the damaged element. - Page 1
Forum section: electronics / repair

author: rubennss
author_rank: Contributor
timestamp: October 14, 2021, 04:20:51 am
content: I have a Hameg HM507 oscilloscope in which one of the channels has been damaged.The 602I241R1U integrated circuit located on the AT-C50 board is damaged (there are two same such integrated circuits on the board).I am unable to decipher its full name and thus find a store where I could buy it and repair the oscilloscope.Could you please provide me with a full name?I am attaching photos of what integrated circuit I mean.Greetings from Poland.

author: Manul
author_rank: Super Contributor
timestamp: October 14, 2021, 10:20:30 am
content: It must be MCP602 in 8-TSSOP package. Good luck.

author: rubennss
author_rank: Contributor
timestamp: October 14, 2021, 04:56:05 pm
content: Thanks a lot for your answer, you are right.Just got a service manual from R & SCH from Germany.It is as you wrote.Regards.

author: fzabkar
author_rank: Super Contributor
timestamp: October 14, 2021, 06:15:15 pm
content: http://www.smdmark.com/en-US/search/code?id=602

author: rubennss
author_rank: Contributor
timestamp: October 14, 2021, 06:19:20 pm
content: thanks, it will be useful in the future :-)

author: Wegoe
author_rank: Newbie
timestamp: December 18, 2024, 10:57:11 am
content: Busy to find shematic diagrams for my damaged HM507. Seems you received those from R&S Germany? Can you a send me a copy of those? Would be of great help for me.KInd regards

author: rubennss
author_rank: Contributor
timestamp: December 18, 2024, 11:12:46 am
content: I do not know if I can post the service manual on the forum, send me an email, rafalparzyszek@poczta.onet.pl then I will send the service manual.

author: Andy Watson
author_rank: Super Contributor
timestamp: December 18, 2024, 11:55:47 am
content: Quote from: rubennss on December 18, 2024, 11:12:46 amProbably better to use the personal message facility rather that putting your email on the open web.
Oscilloscope Hantek DSO2D10 ,  help in identifying faulty ICs  - Page 1
Forum section: electronics / repair

author: rubennss
author_rank: Contributor
timestamp: May 27, 2022, 04:48:06 am
content: I got an oscilloscope Hantek DSO2D10 for repair.According to the owner, the damage occurred after applying too high voltage to the trigger input.The diode on this input was damaged + one channel completely, the other gives signs of life.After opening the shield covering the input circuits, it turned out that some of the ICs are very hot (up to 90 degrees C).After soldering them out, the time base line appeared on the screen (in the second channel these chips are practically cold - the channel gives signs of life).I have a problem with identifying damaged components to order new ones.All the catalogs I know didn't give an answer as to what these circuits are.If you can help me identify these ICs I would appreciate it.

author: Microcheap
author_rank: Frequent Contributor
timestamp: May 27, 2022, 05:50:14 am
content: First one is a OPA197:https://www.ti.com/lit/ds/symlink/opa4197.pdfsecond is easy LMH6702MA:https://www.ti.com/lit/ds/symlink/lmh6702.pdfand the third is LMH6551MM:https://www.ti.com/lit/ds/symlink/lmh6551.pdf

author: rubennss
author_rank: Contributor
timestamp: May 27, 2022, 06:05:09 am
content: Thank you very much for the information, can you please answer me how you deciphered these markings?I would like to avoid asking such questions in the future......

author: Microcheap
author_rank: Frequent Contributor
timestamp: May 28, 2022, 01:16:20 am
content: I normally try searching the marking codes on this site:http://www.smdmark.com/en-US, most o the time it will give me some useful results.For the opa197 I just used the TI website's search to look for the marking code.Then, some datasheets will have a table listing the part number with the corresponded marking code.

author: fzabkar
author_rank: Super Contributor
timestamp: May 28, 2022, 02:20:04 am
content: https://www.ti.com/packaging/docs/partlookup.tsp
OSCILLOSCOPE HANTEK DSO5072 PROBLEM - Page 1
Forum section: electronics / repair

author: illias28
author_rank: Newbie
timestamp: December 14, 2021, 02:07:21 pm
content: Dear sir ,i have a DSO 5072 oscilloscope it was working fine,but since yesterday it wont boot anymore it hangs on boot page with hantek logo, it shows me 3 options :F1 F2 and F3 but none of them works.could you please help me to resolve that problem.Best regards

author: shakalnokturn
author_rank: Super Contributor
timestamp: December 14, 2021, 07:02:49 pm
content: Any detail on what the 3 options are?If you have options to choose from the bootloader is likely working, possibly you could reload the firmware (if file is available) from USB drive, or over serial link USB or RS232.

author: illias28
author_rank: Newbie
timestamp: December 14, 2021, 07:09:46 pm
content: Hi,thank you for your help, F1:rebootF2: recover the systemF3: update the recover partitioni have tried F2 and then F3 but they didn't work

author: illias28
author_rank: Newbie
timestamp: December 14, 2021, 07:28:02 pm
content: i did contact HANTEK and they sended me the following files(see attachement).but the problem is that works only on win XP,and i have win10 on my PC.i have installed xp in virtualbox but the problem it doesn't access my usb drives nor sdcard reader.remarque:the files are too large for attachement i don't know how to send them

author: Traceless
author_rank: Frequent Contributor
timestamp: December 14, 2021, 09:51:20 pm
content: Hello illias,if you have Windows XP running in Virtual Box and want to use USB devices inside your VM you need to manually forward them as shown in this screenshot:Depending on your Virtual box settings and what type of USB device it is you may need to adjust the the virtual box USB settings to support EHCI or even xHCI as shown here:Note that for xHCI to work you need to have theVirtual Box Extension Packinstalled. Hope this helps.

author: illias28
author_rank: Newbie
timestamp: December 15, 2021, 10:20:31 pm
content: thank you very much for your help TRACELESS,i dont have the same interface in virtualbox(see attachement),but you showed how to activate usb.now i can access my usb drives but not my sdcard reader.Could you please help me

author: Traceless
author_rank: Frequent Contributor
timestamp: December 18, 2021, 08:47:09 am
content: Hello illias,if your card reader is not a USB device you can use the VBoxManage command line tool to link a virtual box disk image to a physical disk (SD card) on your system, by following the instructionsin section 9.7.1.1 here. For that you will need determine the device id of your SD Card. You should be able to look up the device id by opening the CMD shell in windows and entering:Code:wmic diskdrive list briefCheck the caption and model columns in the output to find your SD card. The columnDeviceIDwill show an id that usually has the form\\.\PhysicalDriveX, with "X" being an integer.However I think it would be much easier for you if you created a shared folder between your host and guest operating system and copy the files that way. Linked below is a short tutorial that shows you how to set up shared folders.
Oscilloscope Hitachi V212 Repair - Page 1
Forum section: electronics / repair

author: alpuy
author_rank: Newbie
timestamp: October 23, 2024, 05:35:17 pm
content: Hi, i was using the oscilloscope without problems until a whining noise started and after a few seconds the screen stopped showing any signal. I opened the oscilloscope and saw that the diode D1012 was physically cut but after replacing it with a 2CL70 diode it didn't fix the issue.Any tips about what could be the issue and what i can test?See the attached service manual page 69

author: George Edmonds
author_rank: Frequent Contributor
timestamp: October 25, 2024, 08:55:45 am
content: HiHave you checked F1001 a 0.25A fuse?G Edmonds

author: alpuy
author_rank: Newbie
timestamp: October 25, 2024, 02:13:13 pm
content: The fuse is fine
Oscilloscope HP 1703 under repair - Page 1
Forum section: electronics / repair

author: fant
author_rank: Contributor
timestamp: August 24, 2024, 01:52:47 pm
content: I have this oscilloscope that has an odd problem:the luminosity of the screen in normal operation is very low, at the limit to be seen.Instead if I use the memory function the luminosity is normal and the trace remains till one week even if switched off.All the other functions are fine.The luminosity in normal operations dropped from normal level in about one month (I use it not very often, say once a week).What could be?Thank you in advance

author: m k
author_rank: Super Contributor
timestamp: August 30, 2024, 05:18:52 am
content: Maybe a contact problem.