Trying out RIGOL's new 12-bit DHO800 on a real vintage project. Is it any good?

Is the new Rigol DHO800/DHO900 $299 oscilloscope a game changer?
Trying it out on a VARTA battery bombed Commodore PC10-III
12-bit ADC, HDMI, VESA mount, and USB-C power.
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Tools I regularly use
DeoxIT D5 Contact Cleaner
Hanstar 861DW Rework Station
Pro'sKit SS-331 Desoldering Station
UNI-T UT61E Auto Ranging Multimeter
UNI-T UT890D Manual Ranging Multimeter
MESR-100 mk2 ESR meeter
PINECIL Soldering Iron
PinePowerPSU
TS-100 Soldering Iron
AMTECH NC-559-ASM Flux
Kester 951 Flux pen
MaAnt Grinding Pen
Multicore 60/40. 0.38mm and 0.5mm solder
TL866 II Plus Programmer
RIGOL DHO800 70MHz four-channel digital scope
Tektronix 2246A 100 MHz four-channel analog scope
PCBs from PCBWay.com :)
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Join me on Twitter: / epictronics1
Music by Karl Casey @ White Bat Audio

[@danmenes3143]

Use all 4 channels of your scope. You can view the oe, dir, in and out at the same time in single shot and see what combination causes the line to ramp. Probably it is oe high, putting the device into hi Z

[@Epictronics1]

I never thought of that. I'll give it a try, thanks

[@jerther_]

Dave Jones made a video on how to properly ground a scope probe. One thing I remember is that the closest the ground lead is to the point being probed, the better the probing is (less induction from long leads). He even showed a ground lead that is like an inch long. I'd say it would make quite a difference in the MHz range! :)

[@ErrorMessageNotFound]

You should tie that enable pin high to test it. Leaving it floating might have all kinds of odd results.

[@Epictronics1]

I'll give that a try, thanks

[@tenkowal]

4:55 If you want to have a fast booting scope, Rohde&Schwarz scopes are waaay faster than Rigol. They also have better, more intuitive interface, and with great sample memory the FFT functionality was oh so better than Rigols. But they also cost 4x as much for same amount of channels and bandwidth, so you see why I'd choose the Rigol myself.

[@tokin420nchokin]

Nice scope, been looking at these Rigols.

[@fagear]

I think that that "weirdness" on the ISA bus is normal, I've observed similar signals on other PC motherboards. It's the capacitance of the trace that charges up pulled by that resistor network to Vcc. The bus is just left in Z-state when not in use, that's why do you see those slow rises. Congrats on the scope though!

[@Epictronics1]

Oh, I'll check and compare it to the 5150, thanks

[@stevemcknelly5036]

Wow... LAN port, HDMI, USB-C... Web control (which may explain slow boot... It's spinning up a web server), which is reasonably snappy... Seems like a winner!

[@Epictronics1]

I think it is, I'm very happy with it so far

[@Okurka.]

USB-C is for power only, though.

[@FileFixer007]

@stevemcknelly5036 Slow boot was because of Android OS booting from SD card. DHO8xx also can be easy hacked and upgraded with bandwidth and memory depth.

[@Zelon500]

This is definitely my favorite project of yours, always a treat to when you put out a video on this board!

[@Epictronics1]

Glad you like it :) It's a challenge for sure but we'll get there. In the next video I'm going to focus on the Faraday chip

[@mysomervda]

Nice review, I like that the review was in the context doing real world tests.

[@Epictronics1]

Thanks

[@SteveM0732]

A few years ago Tektronix sales stopped by my work to demo their new scopes and answer questions. I made a big fuss about the time it took to power on their scopes. I explained how when I take a scope to one of our systems to debug it the first few minutes are spent simply waiting for the Tek scope to start up. These were just sales people, but I wanted them to leave with the impression that at least some customers wanted shorter start up times. I felt like they had the mindset that scopes sat on a bench in the lab and were powered on in the morning and off at the end of the day and the long start up time wasn't an issue for most people.

[@Epictronics1]

I don't know enough about scopes to know why they are so slow, but surely they can do better than this.

[@portblock]

I believe most new scopes are just some variant of a linux computer thus the reason for for the boot process, where some of the older more expensive scopes were all dedicated hardware for each function. its now like just a USB scope and PC all in one box.

[@MarianKeller]

@@portblock The concept to base the instrument on a PC platform with, usually Windows, actually comes from the high-end segment. I guess this is now the first sub-€1000 scope to run a general-purpose OS, with Android definitely being the more reasonable choice to run on the ARM-SoC.

[@petermikus2363]

​@@Epictronics1most scopea are running either linux or some weird form of android from some really cheap form of solid state memory thus the longer boot times.

[@Okurka.]

It takes long to boot because it runs Android from an SD card.

[@ToumalRakesh]

Proper Review and Dave Jones in one sentence? "Your guess is as good as mine"...

[@TheRetroChannel]

I was eyeing the 1054z a few months ago, good thing I didn't pull the trigger before the DHO800 series pricing was announced. I also picked up the 804 and it's fantastic, except for those damn slow boot times and a few menu choices I think could be refined

[@Epictronics1]

Totally agree. It's great. Except for a few minor things

[@jclosed2516]

I guess the boot includes a internal calibration check. That calibration can only be made when a stable operating temperature is reached. As the DHO series have a huge heat sink (even then a fan cooling is needed), it will take some time to reach enough stability to present reliable measurements. This is all a result of integrating AD converters and compensation on a single high-speed chip. As said - It's only a guess, but it would not surprise me the boot itself is not that slow, but has a build-in wait cycle for the reasons mentioned above...

[@tigheklory]

I got the Hantek DSO2D10 and I like it a lot, but it is only 2 channels and this Rigol is obviously much better in that it has 4. The software on the Hantek is pretty good though. One of these days I hope you have the pleasure of working on a Coleco Adam computer.

[@BigBadBench]

“Different.. But still weird” I’ve experienced that a lot!

[@Epictronics1]

haha, story of my life ;)

[@kefler187]

I'd be curious to see the output in relation to the input for the data lines on the 74LS245. My guess is, once the input reaches ~2v(logic high for LS series chips) the output gets clocked in as a high and that's the oscillation you see on the output lines. If you replace the 74LS245's with the HC245, that ramp on the input side should go to somewhere around the 2.8-3.3v mark as that's the logic high for HC series chips. What shows up on the oscilloscope looks like the charging ramp for a capacitor which would make sense since the output side gets it's reference voltage and source from VCC and not the input and thus making the output side look normal. You can test this by rewiring the 74LS245 input and output pins in reverse and pulling the DIR pin to the respective 5v or GND to have data still flow in the correct direction. What @fagear said may be correct but the charge time would have to be significantly less than the setup time required by the 74LS245 for the address lines.

[@tony359]

now THAT is a scope! Congrats! I've struggled with 245 and those weird waveforms before. I thought it was a fault but was explained that this is due to TTL logic which can drive to ground very well but not so well to VCC - and never to full VCC - even with pull up resistors. So apparently the rising edge of those signals is supposed to be way worse than the falling ones. So bear that in mind, it could be a dead end!

[@Epictronics1]

Oh, that's very useful, thanks Tony! I'm learning something new with every project!

[@tony359]

@@Epictronics1 It was Vogons who put me on this track. Don't worry, I did exactly what you did, replaced all the 245 and checked the pull-ups... :) Learning is cool indeed!

[@Epictronics1]

@@tony359 Let's see what we will learn this week!

[@tommyovesen]

Looks great. What is the dim "shadow" curves on the scope that you get sometimes ?

[@Epictronics1]

There seem to be some occasional spikes that the scope doesn't trigger. Not sure why

[@Rubacava_]

The reason it takes so long to boot is that modern scopes use android. Scope frontend is just an android app. Also you can now hack it to have 250mhz bandwidth and 50 mpts memory thats 10x increase for 4 channel mode

[@Epictronics1]

That's awesome, thanks for sharing :)

[@Okurka.]

Try out the VESA mount. It blocks the vents making the scope overheat and shut off.

[@Epictronics1]

yeah, I thought about that. I'll put some spacers between the mount and the scope

[@tigheklory]

@@Epictronics1 Spacers are good and get a mount that has an X shape for more airflow.

[@Inject0r]

The pin you’re measuring has a weird output because it’s a transceiver. It’s used for directing data either way (DR pin pulled low or high should change its direction). If you pull the pin you’re measuring from the socket, you should be able to check the pulse on the socket pin, and on the 74LS245. If either of them has a non-TTL signal, you’ll know where to look. :)

[@Epictronics1]

Yes, the Faraday is up next! If that socket is crappy it wont direct the 74LS245 properly. And yes, I should have pulled pin 1 high and not just left it floating :)

[@Inject0r]

@@Epictronics1I meant pin 15 (B4). 21:32 If you bend it outwards, you’ll be able to check what the IC does with the signal it receives from the A side. It also allows you to check what the FE2010 does, measured from the socket.

[@Epictronics1]

@@Inject0r Ah, yes, that's the better way to do it, That way I won't get any interference from the bus on B pins if there is any, Good thinking! Thanks

[@andyh8239]

Can this behave as a spectrum analizer, or is that not possible with this particular scope?

[@BoredInNW6]

Did you ever try open source software (such as PulseView) for your 1054z?

[@Epictronics1]

No, I just sent it off as quickly as possible. Glad I did though, I'm super happy with the new DHO800. I'm not saying the 1054z is a bad scope, but I'm very happy with the swap

[@neverendingstudent]

On boot time: it's the result of building the scope programming / application on top of an existing (in this case, Android) operating system - on the one hand, it's WAY easier and cheaper to develop if you use a pre-existing OS/HW-architecture combo, on the other hand it does mean that the OS/HW-architecture combo is not an efficient, lean, special-purpose design meant only to do what it was built for. Pros and cons. Personally, I'm OK with it, largely because it makes it correspondingly easier to modify and hack. But, yeah, my 40+ year old Tektronix TDS744A does boot up in less than a tenth of the time as my Rigol DHO914.

[@petermikus2363]

Even expensive top ebd scopes nowadays run on some form of Linux or Android that whole thing actually came from the high end sector. As far as i know modern Tek scopes are a tad notorius for the slow boot times.

[@portblock]

First let me say, Im sure the scope is a great value for what it is, but let me explain why I would never buy this scope: #1: No EXT trigger on the front, so much of my design work depends on it #2: There is no separate verticals for each channel - so many times I need to quickly adjust and if I am on the channel and I hit channel button again, it turns off the channel, so I need to press it again, see so much time fiddling than getting my work done.

[@thedopplereffect00]

Are you happy with the bandwidth? I guess for retro hardware you don't need much. Have you ever used a scope with digital break out cables, for example if you want to decode an 8 bit data bus?

[@Epictronics1]

I just switched to digital actually. I have no experience in decoding a data bus. From my understanding 70MHz should be enough for me. Although, I think the hacker community is probably going to figure out a 100MHz hack for these scopes. If they haven't already :)

[@petermikus2363]

​@@Epictronics1the dho800 can be hacked up to 100Mhz i think and the Siglent SDS800 series can be hacked up to 200Mhz from the 70Mhz model, plus it has a logic analyzer attachment.

[@snaplash]

What about the outputs on U105 and U106? If they look good, then maybe it's the terminator resistor pack for the uppermost LS373.

[@Epictronics1]

I'll check!

[@ovalteen4404]

It looks like my MSO1104Z also has that web page view. I haven't tried it yet, but it claims to support the same LXI 2011 interface. It also has the same command interface that the Ultra-Obsolete software uses, and you can download a manual for sending commands. I'm guessing that the old interface is intended primarily for remote control though, not for screen-sharing.

[@Epictronics1]

It seems like they just abandoned the Ultra scope software back in 2019. I don't understand why they stil have it as an option for new products. The web interface is great though!

[@ovalteen4404]

Apparently you can communicate with it through other means (probably serial) and just send and receive commands. There's a huge selection of commands that look as if they can do anything that the front panel buttons can do, possibly more, and with less knob-turning. So it's possible that with the right software you could use one program to manage settings while the web interface shows the results.

[@j-fharbec379]

How’s the signal without that bis transceiver installed? Something might be shorted to that trace and causing a bus conflict.

[@Epictronics1]

I'm not sure if I ever checked. I'll make sure to do that, thanks

[@electronash]

27:58 Could try hooking up the Enable signal to one probe, then test the B1 side of the chip with another probe. It looks like maybe the Enable signal is going High at the wrong time? Possibly a clock divider issue on one of the main ASICs? (or as you say, one of the PLCC sockets has a bad connection.) The weird signals you are seeing are on the ISA slot side, no? It could just be that the bus tranceivers are just expecting data *from* an ISA card during the times when Enable is low. So what you are seeing are the remnants of data from the A1 side of the bus. Could again be that the Enable pulses are shifted in phase slightly, which is causing the whole problem with the board booting. I would look to see if there are any clock divider ICs. It might be that they are supposed to generate two or more clocks which pulse on alternate phases. (ie. on some machines, you might see one clock pulse that goes high to output an address, then a separate clock pulse high to latch the data. It could be that one clock is missing, or both are pulsing at the same time when they shouldn't be.)

[@electronash]

I just checked the schematic for the PC-10, and it doesn't have any TTL clock divider stuff. It's so highly integrated into the ASICs, there isn't a huge amount of supporting logic around them. There's a hand-drawn note in the PC-10 Technical Manual, which just shows a few XOR gates buffering the 28.636 MHz osc. It looks like that 28.6 MHz clock goes to the CLOCK0 pin on the graphics chip. The graphics chip then also has it's own 16.257 MHz clock going to both the CLOCK1 and CLOCK2 pins. But it's not like the gfx chip is outputting a clock to other stuff. It just has the ISA interface and a '245 buffer. It looks like U602 is the ASIC for basic address decoding and IRQs. It has "16 MHz" and "CLOCK" inputs. Not sure where those come from atm.

[@electronash]

I do have a feeling the onboard graphics chip might be fried, but then it doesn't seem to output clocks etc. to other stuff, so I don't know. The HDD header uses '245 buffer U204, which looks like it can be disabled with jumper JMP288? U203 (9268) is the floppy controller, and has its own 16 MHz clock which isn't used elsewhere. But it does have a '245 buffer U205 to the main data bus. Could be worth checking both of those buffers, socketing them, and temporarily leaving them out of the sockets? U401 (RTC), U402 (UART), U403 (Parallel port?) probably wouldn't prevent booting, unless they are mashing stuff on the main bus, or the ROM isn't reading the correct register value from one of them. Honestly, I think I would try bending the pins inwards on the PLCC sockets, lightly scraping the pins of the PLCC chips, then cleaning everything with IPA. oic, U101 is the Big Daddy chip. lol It handles the 8088 interface, address decoding, IRQs, DMA, speaker, keyboard, and drives the ISA (main) bus via some '244 and '245 chips. U101 gets the main 28.636 MHz osc, and outputs both CLOCK and OSC. But CLOCK and OSC both go through a 244 buffer, which is always-on. With CLOCK being the lower 8.0 - 8.33 MHz ISA clock. And OSC often being 14.31818 MHz (NTSC colour carrier multiple). I would have a look at both of those clocks on the o'scope at the same time, whilst squishing the PLCC chips into the sockets. lol

[@Epictronics1]

Yes, the socket of the Faraday chip is at the top of the list of suspects. If there is a bad connection, we would likely get a fault like we have right now

[@Epictronics1]

@@electronash Yeah, that graphics chip is very likely fried for sure. I can't quite see how it could cause the weird signals though. But if I get stuck, I'll pull it off the board and check. I'll make sure to get U204 in a socket if it isn't already, thanks

[@andrew1977au]

Was it me or did you put the chip in around the other way at the end ?

[@Epictronics1]

I had to check. It was correctly installed

[@wiwingmargahayu6831]

wow

[@mark12358]

Try to replace those PLCC sockets. Please do it!

[@Epictronics1]

Ok, I'll order some this week :)

[@asanjuas]

The clock on the intel 8088 must be expected as a square signal instead of the scope shows. I am an ignorant but it need to be square signal on the processor.

[@Epictronics1]

I'll check, thanks

[@xero110]

The scope boot time is likely because it runs Android. Some of the really high-end ones run windows on PC hardware. I would love a cheaper version of this scope with no screen and either HDMI (Which this has?) or that web remote view.

[@Epictronics1]

Yes, it has HDMI too. It's probably the better option but I need my mouse cursor to be recorded that's why I went with web control

[@Farull]

@@Epictronics1 It has mouse support. You can just plug in a USB mouse.

[@Epictronics1]

@@Farull Interesting. Is the mouse cursor recorded if I record from HDMI? This could be the better option

[@Farull]

@@Epictronics1 Yes, Dave of EEVblog tested it in his review of the scope!

[@Epictronics1]

@@Farull Great, I'll give it a try, thanks

[@kittyztigerz]

have you watched electricboom channel if not i have know he talking about few better tech test machine i havent used any this beside test light leds and just watch it flash fast or slow them can tell if there is issues which it old way before new test machine came out and i know they so expensive plus they were slow when it was cold and once it warm up it start speeding up if i were to work on one thing first thing i do is remove all other chip start with cpu and ram and 45ls245 and test to see if still same it lead me to think there is way spot it and all i could tell it from drag down resister and first start with one of chip at time until you find where trace is dropped from and alot time chip tester may or may not tell if bad or good it best just grass hopper chip until start to change

[@stefanegger]

would be easier to make a complete new commodore PC rather than fixing that one. At some point you will have replaced all the parts anyway :) Not sure about the signals, but new sockets, especially when they are already corroded, are a good idea. Cleaning them never worked for me.

[@Epictronics1]

You are absolutely right :) There is actually an ongoing project out there to recreate the PC 10 board. I will quite likely replace the board if the project ends up getting finished. That being said, I'm having a great time learning and finding faults on this board :)

[@rimmersbryggeri]

If yu want something that is actuall great for youtubing I think probably a picoscope is the way to go.

[@Epictronics1]

I'm super happy with the DHO800, It's great, thanks

[@rimmersbryggeri]

@@Epictronics1 Ok Im from the automotive industry and the pico is very popular there. You can set templates and alot of other cool stuff in the software. Maybe it's more relevant to auto applications though sine there are so many weird and wonderfulscope add-ons that are auto speific.

[@joshj88]

To be honest the PC featured here should never be totally fixed. If it is the channel might die rofl

[@Epictronics1]

😅

[@alanhightower976]

The 245 you are probing is the data transceiver to the ISA bus slots. You have nothing in the ISA bus slots. So you are just seeing the passive pulls on the end of the ISA traces as every read is also forwarded to the bus with no cards.