Rigol DHO800 [814] failing to boot up - Page 1
Forum section: electronics / testgear

author: Hix
author_rank: Regular Contributor
timestamp: January 13, 2025, 08:41:56 pm
content: Does anyone know if there is a hard reboot sequence for the DHO814? I cannot get it to boot up. I've tried multiple power blocks including a MPB 130W jobbie.Once I hit the red power light, it turns green and that's as far as she goes. Absolutely nothing on the display. It hasn't been used for more than 10 minutes. Any ideas? I'm all ears.Here's the issuehttps://youtu.be/foNty4EBuQ0

author: Fungus
author_rank: Super Contributor
timestamp: January 13, 2025, 10:12:58 pm
content: If there's no Rigol logo then it's badly messed up. The only thing to try would be to open it up and reflash the SD card (or just reseat it).If it's new though, send it back. It could be a component failure, too.Quote from: Hix on January 13, 2025, 08:41:56 pmNo, there isn't. Not when things arethatbad.

author: Hix
author_rank: Regular Contributor
timestamp: January 14, 2025, 06:15:32 am
content: This is what I feared. No chance of reseating the uSD as the seal is in place. Time to discover how much they expect me to shell out on shipping it back....

author: eTobey
author_rank: Super Contributor
timestamp: January 14, 2025, 10:57:06 am
content: Quote from: Hix on January 14, 2025, 06:15:32 amWell, it is not your fault, is it?

author: Hix
author_rank: Regular Contributor
timestamp: January 14, 2025, 11:42:44 am
content: No, not my fault, but I still expect them to decide that I am liable for shipping costs. Will see how it goes. Fortunately it was bought on PayPal and I used their three months free credit, so I imagine that affords a little more protection, given there is an argument for it being sub-standard. The saga begins.

author: Fungus
author_rank: Super Contributor
timestamp: January 14, 2025, 03:25:03 pm
content: Quote from: Hix on January 14, 2025, 11:42:44 amI don't think so, but let's see.

author: NE666
author_rank: Frequent Contributor
timestamp: January 14, 2025, 06:48:04 pm
content: If you bought it through an official UK reseller, e.g. Telonic, then I would expect them to be reasonable about it. Perhaps you may have to pay carriage initially, on the basis that you will have that refunded to you if they agree that the unit was defective on supply and not damaged by you. Amazon UK offer free returns for Prime members, which includes instruments Rigol equipment store.On the other hand, if you bought from the likes of Aliexpress, then you need to pay more attention to the terms of supply. Interestingly, the store I bought my DG822 Pro through say they offer 90 day free returns. Of course, the proof of the cake is in the eating - I've been fortunate enough to have not yet had the need to test that contract.I hope it works out well for you.

author: Hix
author_rank: Regular Contributor
timestamp: January 14, 2025, 07:37:34 pm
content: Yeah, typically it was from Banggood. I've have very good experiences with them this far, but sod's law the most expensive thing I buy there has an issue. It was a tough decision, but given that they had an offer on it and they cover the VAT, it ended up over £185 cheaper, so not to be sniffed at. Providing it hasn't died. Will see how this evolves.Incidentally, is there anything that can be done with the 814 or is it maxed as it is?

author: norbert.kiszka
author_rank: Frequent Contributor
timestamp: January 14, 2025, 07:53:38 pm
content: Open the scope. Remove the SD card and put it back. Quite often there is a problem with connections and that two steps are good enough to fix it.

author: Hix
author_rank: Regular Contributor
timestamp: January 14, 2025, 08:22:53 pm
content: No can do. If I do that, the warranty foil sticker is borked and if it is a hardware failure then they will definitely not accept the item back. I have prodded the SD with a spudger, though a hole in the casing, to see if it was unseated, but it seemed sound. I'm in limbo until they come back to me and don't want to void any warranty that there is. Absolute worst case, if they wash their hands of it, I'll go through Paypal to try and get it refunded and then pull the card and check it isn't corrupt.

author: norbert.kiszka
author_rank: Frequent Contributor
timestamp: January 14, 2025, 08:27:57 pm
content: Poking it will not work. You have to push it (You should hear click) in order to remove. Push it again to make it back. Mine also had this problem, when I was working with my own firmware (made from scratch).

author: Hix
author_rank: Regular Contributor
timestamp: January 14, 2025, 09:03:50 pm
content: You can't access it properly without removing the rear cover, removing the rear cover invalidates the warranty. If it is a hardware issue, I'm screwed, so I will wait for the seller to come back to me.

author: Hix
author_rank: Regular Contributor
timestamp: January 23, 2025, 09:56:16 pm
content: Well the seller offered me 24.50 to get it repaired.... Not sure how they worked that one out. So I got PayPal involved and they have instructed me to send it back for a refund. At my expense.Off the back of that I decided that I'd open it up and check the uSD was seated. Which it appeared to be. But I removed it and rescued it, just to see. Still doing nothing on boot. So I can only assume it is a hardware failure. Is there much by way of empirical data for these failing? I'd rather try and do something with it before sending it back seeing as it's going to leave me about 40 out of pocket. They haven't even offered a replacement unit. Bit irked by it all.

author: norbert.kiszka
author_rank: Frequent Contributor
timestamp: January 23, 2025, 10:22:33 pm
content: Once I read somewhere on Rigol website, that we should buy those scopes from a authorized distributors, which I did twice without any significant issues (once I had problems with communications, because they didn't have it in their stock and I was in another country in remote area, so we had to synchronize time to send it to me. But in the end it reached my place at correct time.). I and other people had issues of not booting, just black screen. In my case it was, when I was makingmy own firmware from scratchon separate SD card, but I figured out that possibly it can be bad connection in SD card socket, so I removed it and put back and it worked - it happened me again maybe two times more. Others had same problem with original firmware and original SD card, but removing it and putting it back also helped.Quote from: Hix on January 23, 2025, 09:56:16 pmYou mean that You removed it and put it back? You should push it inside, and release after You hear click. After that push it again and also release after click - after that it should fit in by itself. If You done it and it didn't help, try second time in case of bad luck ("bloody Murphy"). I think, I don't need to remind You about ESD (at least touch the common ground before touching anything else on PCB).If that will not help, I and others did a huge reverse engineering of that series, so maybe we will be able to help You. If You still have warranty sticker, then maybe best solution will be to force seller to replace, fix or give Your money back. In some countries (If I remember correctly, in Poland, where I live), damaged warranty sticker doesn't mean that You have lost warranty (by law), but seller can see this differently...Right now, I don't have too much time right now (soon Im going aboard again). If nobody will answer here on this topic, try teardown or hacking topic - maybe it will increase mess in that topics, but more people have notifications enabled there.https://www.eevblog.com/forum/testgear/rigols-new-dho800-oscilloscope-unbox-teardown/https://www.eevblog.com/forum/testgear/hacking-the-rigol-dho800900-scope/

author: Hix
author_rank: Regular Contributor
timestamp: January 24, 2025, 08:06:41 pm
content: TL;DR So, does anyone know of the existence of a base firmware that I can copy to my SD to try to see if that works?Sorry, missed that typo. I meant to type re-seated it. I removed the uSD and reinserted it in the normal fashion. But this didn't work.I am wondering if the card may have become corrupted and this is what is causing it to fail to boot. I find it very strange that a new DHO814 should just stop working after less than a couple of hours use.I have seen a lot of people hacking the DHO800 series, so am wondering if there is a base vanilla card image I could try copying to the card and seeing if that works? I don't want to go down the route of trying to upgrade it, just to see if I can get it working.

author: norbert.kiszka
author_rank: Frequent Contributor
timestamp: January 25, 2025, 08:08:43 am
content: Personally I have image from my DHO924S with only one hack (literally just a game installed in Android), but Dave (owner of this forum, user EEVBlog) posted image of his DHO814 (or DHO804 - I don't remember, but it should work on all DHO800). For 99% it was on teardown topic and for 1% it was in hacking topic.If You have Linux, make a backup of what You have currently:Code:cp /dev/mmcblk0 path/to/sdcard_backup.binAnd wait about 15 minutes.Code:cp path/to/image_file_from_dave.bin /dev/mmcblk0And wait about 20-30 minutes.Image file from Dave was zipped, so You need to uncompress it before flashing. If You have Windows only, I can't help (Im not using this "rubbish" for about 20 years literally).

author: Fungus
author_rank: Super Contributor
timestamp: January 25, 2025, 11:40:22 am
content: Quote from: norbert.kiszka on January 25, 2025, 08:08:43 amIt's 100% in the first post of the hacking thread.

author: Hix
author_rank: Regular Contributor
timestamp: January 25, 2025, 02:40:35 pm
content: Do you mean this post?https://www.eevblog.com/forum/testgear/hacking-the-rigol-dho800900-scope/msg5074423/#msg5074423I have downloaded and flashed the image that is in this linkhttps://mega.nz/file/UjBC3KRY#Kqv1BCHNQdPcUGMfR8IqbuUwHUsUhU4GpO1keTAXqf8But still not seeing anything on boot. It is doing some kind of POST as the buttons light up on first powering.

author: norbert.kiszka
author_rank: Frequent Contributor
timestamp: January 25, 2025, 03:10:42 pm
content: Quote from: Hix on January 25, 2025, 02:40:35 pmEven if You cut power for CPU, those buttons will still light up for short while after powering up - there is a separate PCB with buttons and leds and some ICs.If You can listen UART, there is a port on top-right of PCB - with description of pins. If it tries to boot, You will see some text (ASCII) data from it.Also You can check voltages from RK808 according to datasheet.

author: Hix
author_rank: Regular Contributor
timestamp: January 25, 2025, 07:14:16 pm
content: The fact that I have tried another image and it still isn’t booting makes me think that there is a hardware failure. Annoyingly I don’t think I have any option but to return the item at my cost with no replacement. The gamble didn’t pay off.

author: norbert.kiszka
author_rank: Frequent Contributor
timestamp: January 25, 2025, 08:43:03 pm
content: Either way... did You try to listen data from UART port?

author: Hix
author_rank: Regular Contributor
timestamp: January 25, 2025, 09:08:27 pm
content: I haven't. It didn't seem like it was worth the effort of trying to find something that I could cobble together to try to use to sniff the UART. Do you think it would achieve much?

author: norbert.kiszka
author_rank: Frequent Contributor
timestamp: January 25, 2025, 09:19:00 pm
content: Most important thing to achieve is if it try to load bootloader and kernel or it's completely silent. In last case, it should be problem with some voltage powering CPU or SD card.If I remember correctly, there was two users on this forum with almost shorted two pins somewhere on PCB by too much solder, which was clearly visible to naked eye. If You found lack of one or more voltage in power lines, then You know where to look further.

author: Hix
author_rank: Regular Contributor
timestamp: February 14, 2025, 08:38:51 pm
content: Well, it was shipped back via UPS at my considerable expense. And now UPS are telling me that the address given to me by PayPal to send it to doesn't exist. So it is now sat in a UPS warehouse with another £50+ of customs fees and the owner is nowhere to be found. PayPal have stopped responding. Looks like I'll have to recall the package and argue the customs fees. Hopefully it is something that can be repaired, or I'm the owner of a very costly paperweight :/

author: norbert.kiszka
author_rank: Frequent Contributor
timestamp: February 15, 2025, 09:20:08 am
content: Currently Im back in my country for couple days, so I can help more. Please give me some photos of PCB at whole right side (when watching at back after removing back case). You can also measure voltages around capacitors and coils.Anyway, try to remove SD card and put it back. Check SD card connectors if they are ok and clean. Maybe some isopropyl alcohol. Also, You can make a backup and reflash it with image from somebody else backup - sometimes data can be corrupted, especially on cheap SD cards.For next shopping with expensive equipment - don't buy on Amazon or Ebay. Look for specialized and if possible, authorized distributors - it's more expensive, but IMHO savings on cheaper sites are not worth it. Even Rigol recommends to buy only from authorized distributors.

author: Hix
author_rank: Regular Contributor
timestamp: February 15, 2025, 12:07:56 pm
content: Hi,Thanks for trying to help, currently the scope it sat in a warehouse in China, so I am unable to do anything. But it looks like I will have to recall the shipment as UPS have stated that it could be destroyed if not resolved in three days. Will let you know if I get it back into my hands.I had tried with a couple of different firmware versions. Card was correctly seated and the contacts cleaned with IPA. This is what led me to believe it was hardware related and return it due to the amount of time I had to do so before any warranty period expired.

author: Hix
author_rank: Regular Contributor
timestamp: February 25, 2025, 09:06:01 pm
content: Well, shes back in my hands. Am going to try flashing a few firmwares and see if that does anything. Some of the inductors were reading 1V but UART was 3v3 so that looks positive

author: Hix
author_rank: Regular Contributor
timestamp: February 25, 2025, 09:33:00 pm
content: Flashed the image fromhttps://mega.nz/file/UjBC3KRY#Kqv1BCHNQdPcUGMfR8IqbuUwHUsUhU4GpO1keTAXqf8but still doesn't show the Rigol screen on boot. The fan runs and the buttons do their thing. Tried HDMI just in case but notihng, but then again I'm 99.9999% sure it needs the OS to decode and port the HDMI out.Are there any more image files out there? I don't hold out much hope.Will see if I can jury rig something to try and probe UART, any things to look for if I do this, or am I just looking to see if it is spitting out bits?

author: Hix
author_rank: Regular Contributor
timestamp: February 25, 2025, 09:37:38 pm
content: This is the back of the PCB, I see nothing untoward, bar some crap in the solder on the upper mount peg of the USB header, lower right.

author: ptluis
author_rank: Frequent Contributor
timestamp: February 26, 2025, 01:35:33 am
content: Quote from: Hix on February 25, 2025, 09:37:38 pmTry flashing on a different SDcard

author: thm_w
author_rank: Super Contributor
timestamp: February 26, 2025, 02:06:26 am
content: Is there any difference in behavior with the SD card installed or with it removed?If the above suggestion doesn't work, maybe inspect the SD card slot for damage, and pins for solder. From the image it looks OK. But its really easy to damage those SD insertion detection tab things.

author: TurboTom
author_rank: Super Contributor
timestamp: February 26, 2025, 02:17:52 am
content: Did you remove the screw in the heat sink or has it been missing right from the start? If the latter is the case, I'ld disassemble the whole scope very carefully and look if the screw has been lodged in there somewhere, maybe causing the trouble you're observing.

author: Hix
author_rank: Regular Contributor
timestamp: February 26, 2025, 09:35:57 am
content: Same behaviour with and without the micro SD. I've flashed the firmware listed to no avail and tried another known working card too.I've looked at the solder joints with a loupe and they look sound.

author: Hix
author_rank: Regular Contributor
timestamp: February 26, 2025, 09:38:25 am
content: Yes, I detached the main board from the controls board and removed and reseated the ZIF for the display, in the hope that it could have just worked loose. I just placed the screws in easier holes to prevent loss whilst the case was removed.All screws are accounted for and not shorting the PCB.This error predates the removal of any screws.

author: FixyMixy
author_rank: Contributor
timestamp: February 26, 2025, 10:09:31 am
content: Quote from: Hix on January 13, 2025, 08:41:56 pmOscilloscope boots into adb early at boot sequence. You should try to backup your personal files. Download "minimal adb for windows".Try (from the adb folder):1) connect:adb devicesadb connect <your scope IP>:55555adb devices2) pull it:adb pull rigol/3) Download rigol dho800/900 sd card imagehttps://mega.nz/file/06VDFaBI#3pmlujrkarmJ63_5Vh9VDz-VOt_nxBVmmBv0GXrSxZoflash it to a (working) sd card.4) Push your personal files (but only from the /rigol/data/ folder not to owerwrite executable files) to the scope.

author: Hix
author_rank: Regular Contributor
timestamp: February 26, 2025, 10:18:02 am
content: I have no personal files, so is there any value in trying to pull anything via adb?I have already flashed that image and it is not working, have tried two known working as cards with that same image, to no avail.

author: ptluis
author_rank: Frequent Contributor
timestamp: February 26, 2025, 10:21:02 am
content: Quote from: Fungus on January 13, 2025, 10:12:58 pmFungus did you manage to know what failed in your scope?

author: FixyMixy
author_rank: Contributor
timestamp: February 26, 2025, 10:22:15 am
content: Quote from: Hix on January 25, 2025, 02:40:35 pmOh, I see you've already tried to flash fresh system image. And it kind of boots up. Try to download logs with the adb to see what's wrong.

author: FixyMixy
author_rank: Contributor
timestamp: February 26, 2025, 10:24:24 am
content: Quote from: Hix on February 26, 2025, 10:18:02 amWithout calibration files you lose some accuracy, but the scope should be usable anyway.

author: Hix
author_rank: Regular Contributor
timestamp: February 26, 2025, 10:28:03 am
content: That relies on getting it to boot, which is the primary point of failure. Calibration can be handled once it actually fires up, if it ever does.

author: FixyMixy
author_rank: Contributor
timestamp: February 26, 2025, 11:07:29 am
content: There is a special script on the scope to copy logs to the USB drive.adb shell /rigol/shell/copy_logs_to_udisk.sh

author: Fungus
author_rank: Super Contributor
timestamp: February 26, 2025, 11:32:57 am
content: Quote from: Hix on February 26, 2025, 09:35:57 amAt this point it's fairly clear that it'sNOTthe SD card or flash image.It's a hardware failure. Maybe a bad chip, maybe bad soldering, maybe bad power.Power supply is easy to check but there's lots of little voltage converters on the PCB. Look for voltage test points.

author: Hix
author_rank: Regular Contributor
timestamp: February 26, 2025, 11:49:05 am
content: ------Edited------Fungus, I'veprovedprobed a few points on the board seems to be legitSo, the UART to the right of the SD car on the upper edge of the board shows 3vThe six port header just below that reads 3v3Some of the pins on the SD reac 3v (well some 2.9xxx but deemed that good)Is there anywhere in particular that would be wise to probe?I've got a pi pico somewhere so will try and use that to see if there is any UART data when it tries to boot.I've tried the HDMI to another screen, but suspected it was a futile idea and was proven rightAny other ideas on how to unbrick this?

author: Hix
author_rank: Regular Contributor
timestamp: March 01, 2025, 06:29:44 pm
content: So, I've managed to dig out an old Saleae clone 8CH logic analyser. I've hooked it up to the GND TX RX on the uppermost header on the right hand side of the board. TX line shows as HIGH and RX shows as LOW but there don't appear to be any packets.Happy to listen to those wiser than I as to what data settings to use, or anything else to try to read any outputI am a rank amateur at UART so could be me getting things wrong.

author: norbert.kiszka
author_rank: Frequent Contributor
timestamp: March 01, 2025, 06:38:06 pm
content: 5 $ UART-USB converter and some terminal (Im using Linux with it and without problems). Even if You made wrong settings, You should be able to see early U-boot logs as some bad chars - at least. If not and voltages are ok, then next step will be to heat up all BGA chips with hot air, to the point of melting solder joints, because single bal can be a cause.And I repeat myself again: If You want to buy new expensive staff, buy it from certified reseller instead of Amazon, Ebay or something like that. It's more expensive, but much less problematic.

author: Hix
author_rank: Regular Contributor
timestamp: March 01, 2025, 06:56:59 pm
content: Connecting to another header on the PCBYields some results. There are strings that mention reboot, so something is working in there....It's all well and good reiterating about purchase selection Norbert, but without the ability to move time, it is a little fruitless. I'm stuck with what I'm stuck with so am trying to make the best of what I have. Anything that is going to resolve this is very gratefully received

author: norbert.kiszka
author_rank: Frequent Contributor
timestamp: March 01, 2025, 07:01:22 pm
content: I think, that UART is from FPGA (which have own CPU with two cores). Use UART which is located literally on top right. Even with broken FPGA, screen is connected to the CPU (via MIPI-DSI) and You need to boot CPU to make anything (including installing and playing games...) with this scope.

author: Hix
author_rank: Regular Contributor
timestamp: March 01, 2025, 07:20:32 pm
content: Yeah, there is no output from the UPPER RIGHT UART.Would this point to a failure of an IC in some way? Surely if there was a bad BGA it wouldn't have booted up all those times before?I'm trying to think what the last thing I was doing with it was. I have a feeling I was testing WiFi dongles using a USB hub plugged into the front USB port.

author: norbert.kiszka
author_rank: Frequent Contributor
timestamp: March 01, 2025, 10:18:05 pm
content: Check 5 V at USB socket and heat up those damn BGA chips. All of them, including memory around CPU. Check all voltages from RK808 (not only inductors, because it has also LDO), if You didn't already.

author: Hix
author_rank: Regular Contributor
timestamp: March 01, 2025, 10:22:12 pm
content: Do you have a diagram of where the BGA chips are? I don't really want to risk reflowing ICs that I don't need to.

author: norbert.kiszka
author_rank: Frequent Contributor
timestamp: March 01, 2025, 10:24:22 pm
content: CPU (RK3399) and RAM closest to CPU.

author: Hix
author_rank: Regular Contributor
timestamp: March 02, 2025, 12:01:43 am
content: Thank you.Can I ask, are these known to have hardware issues?I've been trying to scour the interwebs for any examples of DHO800 failing and not found anything.It just seems strange that it was working before it wasn't. I would have thought that if there was a solder issue it would have prevented it booting form the start.

author: norbert.kiszka
author_rank: Frequent Contributor
timestamp: March 02, 2025, 12:11:18 am
content: Quote from: Hix on March 02, 2025, 12:01:43 amCouple years ago, I was living from repairing mostly laptops. In older and newer ones, problems with balls are quite often.Anyway, malfunctions are pretty often caused by something simple, like shortened cap. But diagnosing it is a another story.

author: Fungus
author_rank: Super Contributor
timestamp: March 03, 2025, 07:28:06 am
content: Quote from: Hix on March 02, 2025, 12:01:43 amNo.Quote from: Hix on March 02, 2025, 12:01:43 amThere's your clue, right there.

author: Hix
author_rank: Regular Contributor
timestamp: March 03, 2025, 06:51:01 pm
content: Well, I've used a hot air station to try to reflow the ICs and memory chips, to no avail.adb is showing nothing.I've tried the image that has been recommended from the first post in the hacking the DHO800 thread, that hasn't worked. Though when I later tried to flash the SD with a different imaging tool  this tool flags that the archive may be corrupted. This could be an issue, but I cannot find any other images and trying to find on other threads is seemingly irksome to other users.I'm at a loss as to what to do.

author: Fungus
author_rank: Super Contributor
timestamp: March 03, 2025, 07:05:23 pm
content: Do these 'scopes flash any lights on the front panel or click any relays when you turn them on?

author: norbert.kiszka
author_rank: Frequent Contributor
timestamp: March 03, 2025, 07:08:41 pm
content: Are You using Windows and Windows tools? For a company known as Microsoft (or maybe Microsh*t), everything not designed by them (including disk format) is corrupted.My advise is, change Your OS for something better, like BSD or Linux. On that two, You can use disks from almost all other operating systems.

author: norbert.kiszka
author_rank: Frequent Contributor
timestamp: March 03, 2025, 07:13:28 pm
content: Quote from: Fungus on March 03, 2025, 07:05:23 pmI can't understand why You are trolling this forum for so long. Those questions are dumb as hell.Buttons are driven by a separate IC and after powering it up, it will always flash them for couple seconds. Relays are driven by CPU GPIO and AFE (I2S communication based on CPU GPIO). Both will be silent, when CPU can't boot.

author: Hix
author_rank: Regular Contributor
timestamp: March 03, 2025, 07:55:20 pm
content: I've just used dd on mac terminal, no errors flagged, but the image doesn't boot.Are there any specific points on the board that I can probe with a DMM to ascertain if voltage is present where it should be? I've measured random points and found 3 and 3v3 present, but am wondering if there is somewhere that would flag dead or alive more quickly?Quote from: norbert.kiszka on March 03, 2025, 07:08:41 pm

author: Fungus
author_rank: Super Contributor
timestamp: March 03, 2025, 08:04:56 pm
content: Quote from: norbert.kiszka on March 03, 2025, 07:13:28 pmRight, so this is a test for...?

author: norbert.kiszka
author_rank: Frequent Contributor
timestamp: March 03, 2025, 08:15:48 pm
content: Quote from: Fungus on March 03, 2025, 08:04:56 pmThis is a test for something that we know already.

author: thm_w
author_rank: Super Contributor
timestamp: March 03, 2025, 11:19:33 pm
content: There should be many more rails for the CPU/FPGA. 1V, 1.2V, 1.6V something like that. Any inductor you see would likely be a rail. They will lead to a large ceramic cap. Who knows if all rails are on on boot though.If it does end up unrepairable, sell it to someone here so they can use the ADCs to attempt to upgrade the DHO1000.Hopefully OP didn't reflow those, and only tried on the CPU.

author: Hix
author_rank: Regular Contributor
timestamp: March 04, 2025, 01:40:40 am
content: Nope didn't reflow anything else other than the CPU and memory chips immediately adjacent.I've measured voltages at many points on the board. There are lots of points around 1v. a few 3v and 3v3 there was also one point at 8v?!?When I have time outside of work, I'll photograph the board and document what I have measured and where. I'm living in hope I can resurrect it.Failing that I would sell it to someone wishing to develop something from it. Think of it as a kidney donor

author: ptluis
author_rank: Frequent Contributor
timestamp: March 04, 2025, 02:44:26 pm
content: UPDATE! UPDATE! i received a message stating that this model doesn't have a HELP button! but the model i recovered does in fact has this button located on the place where the QUICK button exists! My customer bought it directly from china it was one of the first units to be released, could this be a counterfeit unit? demo?In this case I don't know if it will apply to other scopes without this key. Anyway I leave this post and my experience on this------------------------------I was able to revive a non working Rigol DHO814 from acustomer. This customer tried to hack this device and he told me when he was trying hack through adb there's a power failure when he was sending data. After that the scope stop working.I tried other SD cards with different firmwares and no luck.Symptoms: lights turn on, relays don't click, Rigol logo not displayed, fan working, nothing more work, no adb access.I leave the original sd card on scope before I try the following:Somehow I was able to enter booloader mode of the scope, but logo isn't displayed, I read on other post that logo is controlled by bootloader, but honestly i can't explain why it worked.I tried entering bootloader mode 5 times, keep reading.This is how I did it, if you have a broken scope you don't have nothing to loose, maybe it also work for you. The only negative point is that the Rigol logo stop being displayed!1. I used a 16GB usb flash drive formatted in FAT162. Download the latest firmware file for the DHO814 from the official RIGOL website. Extract the GEL file from the zip and place it in the root directory of the USB drive.3. Insert the USB drive into the USB HOST port on the front panel of the DHO814.4. DHO814, From power off state, press and hold the HELP button and power it back on, and release the power button BUT don't release the HELP button until you see the led on the flash drive blinking, it must be continuous blinking, if it just blinks briefly and stops, it won't work!I HAD TO REPEAT THIS 5 TIMES, i was almost quitting and suddenly it worked.5. there's no information displayed on screen, when the flash drive led stops blinking, I waited another minute and then power off the scope.6. I remove the usb-c power cable and the flash drive and wait a minute7. i turn the scope on, nothing happened, but i decided to leave it on because i remember i recovered some smartphones waiting longer at the beginning and after around 1 minute the scope become alive and boot almost perfectly it took a total of around 3 minutes.8. I rebooted the scope several times BUT The RIGOL LOGO is NOT displayed!Calibration took around 45 minutesMy customer accepted the scope the way it is and took it back. At the moment of writing this text he didn't complain.I hope this helps those who have similar problem and could recover you units, you have nothing to loose, just a little of your time.

author: Hix
author_rank: Regular Contributor
timestamp: March 04, 2025, 03:37:13 pm
content: That sounds very positive Luis. It isn't working on my scope, but that could possible be that the GEL file I have is already installed. I wonder if I try and older firmware, will that flash? I'll have to see if I can download a previous GEL file and try that. A d it is the Quick button on the upper right, below Clear that you held down until the flash drive stopped flashing?As luck would have it the only drive I have that lights up is the very one I was using for the DHO814. There's serendipity there for sure.

author: Hix
author_rank: Regular Contributor
timestamp: March 04, 2025, 03:39:57 pm
content: Damnit. Rigol only lists the latest GEL file to download. I don't suppose anyone has anything previous they could share do they?I have 00.01.04.00.02 so anything previous to that would be great. Assuming that is, that you can 'downgrade'

author: norbert.kiszka
author_rank: Frequent Contributor
timestamp: March 04, 2025, 06:43:41 pm
content: I think I have all firmware versions, starting from 00.01.00.00.00. But I have mess on a laptop disk, Im tired and that will not work, since this recovery method works with bash scripts. Bash will not works If You don't have at least Linux kernel (Android kernel is basically Linux) booted. If there is complete silence on UART, and You tried other SD card with other image (assuming that was correct - on Windows You can't be sure for anything - that's why Im not using Windows), then this will not help, because You have hardware issue, not with software.Quote from: Hix on March 04, 2025, 01:40:40 amHow much?Quote from: Hix on March 04, 2025, 01:40:40 amI don't know if there is a 8 V somewhere (Im aboard and far from my scope, so I can't check), but two things. There is AFE IC, which has opamps - Im preety sure, it use negative rail also. Second thing, AFG uses +12 and -12, but I don't remember where was source of that voltages (maybe that AFG board has own converters, but Im not sure).

author: ptluis
author_rank: Frequent Contributor
timestamp: March 04, 2025, 07:39:20 pm
content: Quote from: Hix on March 04, 2025, 03:37:13 pmHi i tried with the latest firmware 00.01.04.00.02I add an update note at the beginning of my post. look like the unit I recovered is not the same sold right now. the one I recovered had an HELP button in the place of the QUICK button. Ive been searching for pictures all around but can't find one with the help key. I wonder if it was a prototype? demo? fake? I discovered this by trial and error maybe on the new units some other key does the same? can't help you more because i don't have the scope anymore.

author: Hix
author_rank: Regular Contributor
timestamp: March 04, 2025, 07:46:24 pm
content: I've tried pretty much all of the other buttons but no success. I already had that version of the firmware, so it likely wouldn't do anything anyway.But it is looking increasingly like hardware failure.Annoying as reading your post, it sounded like a carbon copy of what I am faced with.Running out of hopes and dreams 😂

author: Hix
author_rank: Regular Contributor
timestamp: March 07, 2025, 10:10:27 pm
content: Are there schematics available for this model?Given it looks like there is a hardware failure I might as well learn some fault finding skills. If I have half an idea where to look I stand some chance of possibly finding something that isn't as it should be.The fact that one CPU is seemingly working and spitting out data via its UART, then something down chain from there is seemingly the issue?What would those wiser than me say about it being a passive that has failed rather than the main CPU? Are there lines from the CPU which would indicate that it is alive, other than its UART?Ita an expensive paperweight so I may as well use it as a learning tool at least.

author: thm_w
author_rank: Super Contributor
timestamp: March 07, 2025, 10:48:26 pm
content: Quote from: Hix on March 07, 2025, 10:10:27 pmNo, schematics aren't available.I thought it was the FPGA UART that was working, and the CPU UART was not outputting anything?There are common failures you can always look for:- shorted ceramic capacitors- shorted FETs (though these are more likely only after device is running for a while)- hiccuping/dead rails (may require an oscilloscope)- Oscillators not oscillating (look for an EN pin, see where that leads you)- maybe stuck buttons or issues on the front panel board?Then beyond that its tracing things around and figuring out the design for yourself.Would start from voltage input, follow it down through the converters.

author: Hix
author_rank: Regular Contributor
timestamp: April 08, 2025, 07:51:59 pm
content: Are there any differences between any of the PCBs?I’m just wondering about a hypothetical scenario whereby I were to purchase a unit from an EU supplier that strangely developed the same fault.

author: Fungus
author_rank: Super Contributor
timestamp: April 08, 2025, 08:22:17 pm
content: Quote from: Hix on April 08, 2025, 07:51:59 pmNot in theory.Maybe there's revisions where they changed components for price/supply reasons but they should be functionally the same.

author: Hix
author_rank: Regular Contributor
timestamp: May 05, 2025, 01:02:15 am
content: I managed to log the output of the FPGA UART. I have attached this to the post as a txt file.The CPU UART remains silent.

author: Hix
author_rank: Regular Contributor
timestamp: May 05, 2025, 01:16:49 am
content: Having finally found Dave's logs of what his 814 was doing when he did the teardown, it seems that my FPGA is stopping a few lines short of his. Apart from his boot log being seemingly duplicated, mine is missing the following lines towards the end of the boot. I am guessing that this is the handover to the CPU?My bootlog finishes here:Code:DMA Done !Handoff Address: 0xFFFF0000In FsblHookBeforeHandoff functionSUCCESSFUL_HANDOFFFSBL Status = 0x1This is MultiBoot Image 3!!!FlashID=0xEF 0x40 0x18Whereas Dave's bootlog finishes with these additional linesCode:Recv Command Boot!!!Target Addr: 0x00400000Running Command Prog!!!Try MultiBootSend Software Reset!!!

author: norbert.kiszka
author_rank: Frequent Contributor
timestamp: May 05, 2025, 07:28:45 am
content: FPGA is connected with CPU via PCI-E. You can desolder FPGA entirely and still CPU should be able to boot.

author: Hix
author_rank: Regular Contributor
timestamp: May 05, 2025, 12:28:15 pm
content: I was hoping that the missing part of the logs may help to hone in on a specific area to focus on. I don't have the skills to reverse engineer the circuit without a schematic to help me fault finding. So I'm just left with randomly probing components for voltage. I'm stuck way out of pocket on this and am just using it as a project to try and learn, with a vain hope that it can magically be brought back to life.

author: norbert.kiszka
author_rank: Frequent Contributor
timestamp: May 05, 2025, 12:37:09 pm
content: In cheap products like a Rigol ones (especially not from authorized resellers), often You can find cold solder joints, shorts in ceramic capacitor or damaged coils. This scope has some LC filters at power supply lines (probably not on the CPU lines). If all CPU and CPU RAM voltages are present, then my next suspicion will be soldering joint(s). If I remember correctly, I already advised to do reflow of CPU and RAM with hot air and a lot of flux. If that doesn't help and there is no sign of life on HDMI output, then probably some of those chips are dead. Some people had problems with contacts on SD card socket, but removing card and placing it back always helped.

author: Hix
author_rank: Regular Contributor
timestamp: May 05, 2025, 01:48:49 pm
content: Does anyone know if there are there any of the test points present on the board that relate to CPU or RAM voltages?

author: norbert.kiszka
author_rank: Frequent Contributor
timestamp: May 05, 2025, 01:57:27 pm
content: Back converters are very easy to measure if they have correct output voltage or if any. Multimeters usually are immune to fast ripples, so You can measure it from any side on the coil. Coils usually are quite big, so mostly it's easiest place to put probe. So there is no need to waste time to look up for test points or even capacitors.RK3399 has recommended DC-DC converter which is RK808 and that one is actually used. It's placed on the top right corner and there are big coils around it. With quite big solder joints on two sides.

author: Hix
author_rank: Regular Contributor
timestamp: May 05, 2025, 02:46:40 pm
content: So I have measured the coils around the RK808.Starting from the upper left going clockwise.2R2 0.88v test points to the left of it 0.9v2R2 1.85v test point to upper right 1.85v2R2 1.13v test point to right 1.13v2R2 0v test point to lower left 0.91vWhich indicates that the lower left coil is not getting the voltage that I assume the test point indicates it should be having.

author: norbert.kiszka
author_rank: Frequent Contributor
timestamp: May 05, 2025, 02:50:14 pm
content: Sometimes there are poor connection between multimeter probe and unleaded tin from china. Also there is a documentation of this RK808. Anyway, You can try to resolder this chip. Desolder it, remove old tin and put it with new leaded tin.

author: Kean
author_rank: Unknown
timestamp: May 05, 2025, 03:53:48 pm
content: The RK808 datasheet is readily available and gives some example application schematics.Note that it has 4 buck regulators, but also a bunch of additional low-current linear regulators (which may not be used).Before trying to reflow or swap the IC, I'd suggest checking that rail reading 0V for a shorted capacitor.Shorted multi-layer ceramic caps are one of the more common failures these days.

author: norbert.kiszka
author_rank: Frequent Contributor
timestamp: May 05, 2025, 03:56:22 pm
content: Quote from: Kean on May 05, 2025, 03:53:48 pmThat's what she (the most people) said. Personally I experienced this only once in one small and simple device.

author: Kean
author_rank: Unknown
timestamp: May 05, 2025, 04:09:37 pm
content: Quote from: norbert.kiszka on May 05, 2025, 03:56:22 pmI've seen quite a few (estimate 20<N<100) on brand new equipment coming from CMs, both local in Australia and from China.I actually had to repair 3 devices for a client in the last month all with a shorted MLCC, all new stock from their CM. Passed final inspection at the CM, but failed on install. The CM now says they have improved processes to avoid this. In this case it was 100nF 100V 0805 caps with no visible damage (ESD?), but in previous cases it was typically higher value and larger footprint caps (cracked).

author: Hix
author_rank: Regular Contributor
timestamp: May 05, 2025, 05:32:19 pm
content: I applied hot air to the inductor that was not reading the TP voltage and now it does so.The FPGA UART still reads the same and the CPU UART is still blank.Going back over things however, Dave's FPGA log doesn't appear to be duplicated. It seems there are two boot cycles of the FPGA. Mine halts at line 107 but his goes on for 5 more lines before the apparent second boot, whereby it terminates with the same string as I see.I understand that Norbert believes that the FPGA and CPU operate exclusively, however, the fact that there is a difference in the FPGA logs surely points to something?May I ask what the function of the FPGA is in this application?I have discovered that Telonic have a 10% discount on the DHO804 at the moment, so am considering just accepting my losses and purchasing from there. Thery also have a Siglent SDS804X-HD for very similar money, which additionally supports CAN and LIN, which intrigues me as I am an automotive design engineer in the real world and CAN coupled with an oscilloscope could be very useful.

author: norbert.kiszka
author_rank: Frequent Contributor
timestamp: May 05, 2025, 06:05:18 pm
content: FPGA does acquisition from ADC and sends that data over PCI-E bus to the CPU (also AFG and LA in 9xx models). Displays (MIPI-DSI and HDMI), both USB ports and managing everything is done by Android app working on CPU.

author: Hix
author_rank: Regular Contributor
timestamp: May 05, 2025, 06:18:21 pm
content: Thanks for the explanation. At least I have a little more understanding of the system architecture now.On the bright side, I've increased my UART skills and am gaining exposure to real world fault finding. If nothing else the DHO814 is a learning tool, even when it isn't working.Maybe at some point I'll have learned enough to get the old girl going again...

author: Hix
author_rank: Regular Contributor
timestamp: May 09, 2025, 12:21:11 am
content: I ordered a replacement DHO804 as it seemed that the 814 wasn't coming to life any time soon. One interesting thing I noticed is that on connecting the PSU to the 804 the power button blinked green then went to red.On the broken 814 when you attach the PSU the unit instantly tries to power on. I'm wondering if this could be a clue as to what may be going on.I also fed Gemini the datasheet for the RK3399 [all 1100+ pages of it, and it came back in less than 5 seconds, which amazed me]It offered some pretty useful sounding advice. I'll list the more pertinent points below. It may help someone else, or may be interesting for others wiser than me.QuoteBut there is a decent list of things to go hunting for now, and I have a DHO804 to fault find the DHO814 with

author: Hix
author_rank: Regular Contributor
timestamp: May 09, 2025, 01:12:51 am
content: Well, quick play and pin 1 on the crystal on the DHO814 is showing 23.8MHz which seems to be about what it should be doing.I'll have a more in-depth look tomorrow evening and see what else can be unearthed.

author: ahmedfotoh
author_rank: Contributor
timestamp: May 12, 2025, 09:20:20 pm
content: Hi Hex, I have the similar case as you post "Rigol DHO800  failing to boot up" I just bought a new Rigol DHO804 scope, when I turn it on the display stays appears Rigol logo and still appear to 5 minutes until a message appears to reopen application, I thought it is faulty SD card I open the cover and get out the SD card and reinsert and turn it on but the screen still black and no Rigol logo appears As it was before and no booting to operating system and no something occurs until I turn off, I use the original power adapter came with scope, , How can I install Rigol android operating system in a new SD card? Do you have backup of original firmware IMGC file to try to flash it at a new SD card ?

author: norbert.kiszka
author_rank: Frequent Contributor
timestamp: May 12, 2025, 09:24:46 pm
content: Quote from: ahmedfotoh on May 12, 2025, 09:20:20 pmSD card image was posted on this forum several times. Installing Android (or any other system) manually is not easy task - however there are some scripts. Personally I did one (but for Debian instead of Android) especially for this scope, but it took several months of work.

author: ahmedfotoh
author_rank: Contributor
timestamp: May 12, 2025, 09:33:43 pm
content: @norbert.kiszka Many thanks for reply I will try to install "Debian GNU/Linux for DHO800/DHO900 (Orange Rigol)"

author: norbert.kiszka
author_rank: Frequent Contributor
timestamp: May 12, 2025, 09:35:16 pm
content: Quote from: ahmedfotoh on May 12, 2025, 09:33:43 pmThis is a system without oscilloscope app. I didn't made app yet.

author: ahmedfotoh
author_rank: Contributor
timestamp: May 12, 2025, 09:46:51 pm
content: Can I flash it in SD card and using it as alternatively to the original scope system and I can use the scope functions?

author: norbert.kiszka
author_rank: Frequent Contributor
timestamp: May 12, 2025, 10:01:32 pm
content: You can flash image on a any separate SD card with almost any size. But scope app wasn't recreated yet.

author: ahmedfotoh
author_rank: Contributor
timestamp: May 12, 2025, 10:57:11 pm
content: Is there anyone can help me to find the original backup image for Rigol DHO804 scope?

author: norbert.kiszka
author_rank: Frequent Contributor
timestamp: May 12, 2025, 11:13:49 pm
content: Look up in the hacking and teardown topics.

author: Fungus
author_rank: Super Contributor
timestamp: May 13, 2025, 02:35:55 am
content: Quote from: ahmedfotoh on May 12, 2025, 09:46:51 pmNo.But you can play DOOM.

author: ahmedfotoh
author_rank: Contributor
timestamp: May 13, 2025, 02:46:05 am
content: @Fungus I don't like playing DOOM, But like playing PWM.

author: norbert.kiszka
author_rank: Frequent Contributor
timestamp: May 13, 2025, 09:24:25 pm
content: Quote from: ahmedfotoh on May 13, 2025, 02:46:05 amHeroes III of Might and Measurements is much better...

author: norbert.kiszka
author_rank: Frequent Contributor
timestamp: May 17, 2025, 09:03:41 am
content: Any updates?

author: reyv_perez
author_rank: Newbie
timestamp: June 06, 2025, 07:47:22 pm
content: I do not know if this is the right topic, but I have a Rigol DHO804 and I tried to connect to LXI on Windows 11 (the scope is connected via wired LAN) I tried connecting my laptop both on Wired and Wireless on the provided IP Address but I cannot seem to connect to the LXI Web Interface. I also tried doing the ADB via USB both on Windows 11 and Linux and came empty handed as when I try ./adb devices it doesn't show anything. Using the Ultra Sigma Software I can connect normally with the scope and can send SCPI commands normally, but I plan to pull the License and Key File from my scope and also do some backups.I am happy with the scope and it is running normally (firmware ver 01.03) but I want to upgrade the Bandwidth and Meg Points.

author: Fungus
author_rank: Super Contributor
timestamp: June 06, 2025, 08:24:56 pm
content: Quote from: reyv_perez on June 06, 2025, 07:47:22 pmGet that firmware upgraded. 1.03 can brick itself.

author: dzebrys
author_rank: Newbie
timestamp: June 24, 2025, 10:58:59 am
content: hi,Quote from: reyv_perez on June 06, 2025, 07:47:22 pmstart with simpleCode:ping -t <IP address>as provided in options->interface menuthen if there is a contact with scope, find a relevant guide for windows how to setup adb(android debug bridge), download adb portable and setup it according to guide.if all set try to connect to scope usingCode:adb connect <ip>:55555if the result is succ connected then you are in good situation, likely OS boot up correctlybut there are some minor problems with rigol frontend/application.otherwise claim warranty or if that's too much hassle for you and u like to hack, use/buy ttl level usb-uartadapter [PL2303 or so] and connect to uart port [GND,RX,TX] pins just on the right side of uSD card.https://live.staticflickr.com/65535/53165327816_f331d2b630_b.jpghttps://www.openvario.org/doku.php?id=projects:series_00:electrical_tests:serial_console_boot_logthat would allow you to dump boot log from OS. share it in this thread and maybe we can help find what's the issue.br/Piotr

author: MDA!85
author_rank: Newbie
timestamp: August 05, 2025, 03:45:31 am
content: I sent my DHO814 back to Rigol under warranty when it failed to boot after 60 days. I had to pay shipping. Turn around time was 2 weeks and it still would not boot when they returned it to me. Terrible reliability and equally poor customer service.