The massive speaker made this the perfect machine for sneaking into the computer shop, and writing a large for-next loop, followed by the EXPLODE keyboard and running away. Not that I ever did that.
Awesome video, bad luck indeed! You might be helped a lot by the Romulator when working on 6592 systems like this, it’s very much worth the $35 USD price.
HAHA Adrian, I was thinking of that while watching this, and am glad you chimed in. Because the 6502 is so difficult to diagnose a system for (due to it being register anemic), the Romulator makes it so much easier.
I've played the Blake's 7 game! It's really good, and the characters are even really good likenesses of the actual actors! I used to watch the TV series when I was a small boy, so this made the game extra-special. 😄
Wow, you just transported me back about 35 years when one of the members of my local computer club had an Atmos and I remember thinking it was really cool! The aesthetic was quite unique in it’s day. Thanks.
I remember a guy in our town had an Oric Club at his house. I only went once because he charged everyone a £1 each for using his electricity at what was then about £0.06 per KW/hour that was quite a markup!
I really like the way you fault find. logical and concise! I run a small workshop in Derbyshire UK repairing vintage studio and musical equipment. I hope you don't mind but I have used a few of your videos to show to my apprentices. It helps to have a second voice of reason when trying to get the youngsters to do things in a logical way and not jump in all guns blazing, assuming they've seen the fault before, and not just the ramblings of some crazy 60 year old ex BBC engineer just doing it the old BBC way. Anyway Thank you.
Oric reminds me of ORAC, the insuperable supercomputer from Blake's 7. That's a fond memory from my youth. This computer looks interesting, and the designers made some interesting choices in the product's design phases. Thanks!
I've seen other youtubers with RAM chips that pass tests but still fail in the machine. I think it's more common than people think as most haven't had access to a decent chip tester until recently.
To test proper, you need to be able to monitor timings with precision, and more precision requires better components and design. Just like oscilliscopes.
The biggest problem with most RAM testers, and even chip testers, is that they tend to be forgiving about the timing values. For RAM testing especially, though, you need a tester that knows the minimum required RAS time, minimum required CAS time, and minimum data in/out times, and it needs to test according to those timings. TTL chips should also be tested against their datasheet timing specs.
Wow! I don't remember ever hearing about the Oric! Man, I would have practically cut off my left foot for a system like that in 1983. It's so small and compact, yet so much packed onto that tiny little MB! Hell, I want one now! Can you get them on ebay? Imma go look, but I bet you can't. ;)
I built a tester for the SRAM modules on the TRS-80 Model 100 which have four 2K SRAM chips on a ceramic carrier. On one module my tester said it was fine, but it would fail in the machine. Fortunately, my friend made an awesome test harness for the M100/T102 machines, and it was able to report the failure as in A10. Looking at A10 and nearby address lines on the scope, when the module was in the M100, there was a very obvious RC curve to A10 when it changed states. In my tester this curve was not apparent. My friend said, "The bus drivers on the M100 are right at their maximum rating for driving the capacitance on the address bus." My Arduino based tester had much stronger outputs, so a little extra capacitance did not make a difference. You can have other issues where a gate draws a bit too much current and the chip will test OK on a tester but fail in circuit as the chip driving it and possibly other chips does not have the fanout to drive that load. Interestingly I was able to soak that module in alcohol for hours and fix it. I suspect it was contaminated with the awful flux they used on the M100 which can turn slightly conductive.
DRAM can be very touchy about timing delay, especially with the timing of RAS and CAS, and how much time you must have them both selected, and how much time the bus must be held on the trailing edge of the pulse for the chip to latch the address in, and then the amount of time it needs to be inactive before the other pulse. Likely the timing here is just on the edge of acceptable on that chip, and the driving from the ULA is a little weak, so the edge is slow, and thus the latches do not get the correct address latched before it starts to change to the other, or the ULA is writing or reading the data lines before the chip has finished decoding the address, so the written data or read data is not always correct. Seeing as screen data, also from the ULA, is mostly correct, with no bad single bit errors to show consistent failure, it must be only the CPU ram read and write timing that is off spec, at least for that chip, though likely the others are close to it as well. Likely the original design is very picky about the manufacturer of the DRAM, as they relied on the timing of a specific chip being better than the specification, and this finally has drifted with age. Would be interesting to know who made that DRAM, and if the others you tried were the same manufacturer, and probably the same fab as well, from the number imprinted under the chip in the ejector pin marks. Crystal failing is common enough, though you could simply have turned it around in circuit and it likely would have worked again, TTL crystal oscillators do that. Yes I have also experienced the IC working, just not in this unit, but it works in another, because the timings are just different enough, and also it works cold, but not hot, or vice versa.
Correct. According Noel's problem: a memory cycle ends when both RAS and CAS go high again. Usually this doesn't happen exactly at the same time, sometimes CAS is triggered slightly before RAS (e.g. shown in Am9064 datasheet), sometimes RAS is triggered slightly before CAS (e.g. shown in HM4864 datasheet). Noel's defect DRAM still works when CAS is raised before RAS but not vice versa, so there is most likely a defect in the column/row drivers. Hard to find this problem since a tester usually provides only one method.
@@HappyBeezerStudios I am assuming you were not changing anything on the DDR2 module itself? In which case, isn't likely to be a clock skew problem. If you were dealing with a problem affecting the timing of multiple signals going to the DDR2 module then it is likely to be a setup/hold time issue. Clock skew is to do with only the clock line going to multiple registers/flipflops.
I used to sell the Oric-1 in Iceland, working for Bókabúð Braga back in the time (of course along with all the other 8-bit computers available at the time... ) There were suprisingly many buyers...
Great job! I had my friends Korg EX8000 synthesiser on and off the bench for almost a year. Ended up being the crystal!!!! I took one out of an old STM Nucleo board and the thing fired back up to life. I think it is getting 'that' time for old crystals.
Love your video's, but it's Not a Laser thermometer. You can rip out that laser and it'll still work. It's an IR thermometer or IR gun thermometer to be more exact.
Ha! I had no idea. I assumed it was measuring some variation of the laser reflected back or something. Goes to show it's outside my area of expertise! 😃
@@bradnelson3595 You are possibly thinking of Adric as Peter Davidson's TARDIS companion. Coincidentally a closer match would be Orac, the advanced computer in the Blakes 7 TV show that the game shown was based on. Also of interest, the show actually featured an Acorn System 1 computer in the prop used as the visual representation of the Slave computer. Not forgetting that Blakes 7 was written by Terry Nation, the creator of Doctor Who!
@@MikePerigo Yes, Mike. I think that's it. Funny how those syllables stick in the brain although recall can scramble them a bit. And, oh, perhaps I was thinking of Blake's 7. I haven't watched that in years. I bet that's the one. Wow. Your recall mechanism seems to be functioning properly.
I still have the one I bought in the 80s. Still in its (now tatty) polystyrene box (but missing the outer card sleeve). Best of all, the peelable paper scratch protector on the shiny detail above the keys is still unpeeled! Great computer, probably better keys than any I've ever used since.
My first experience of a computer was my friend's dad's Oric-1, I was absolutely amazed by it. My friend then got an Atmos himself, so fond memories, especially of Zorgons Revenge, an awesome game. More Oric videos please!!!
Always loved the look of the Atmos, very cute little machine. Brilliant video as always Noel, glad you got it working and nice job tracking down that really bizarre memory timing issue.
Thanks for the very interesting video. It brings back fond memories. Yes, Orics were very very popular in France. I've owned both an Oric 1 and and Atmos. I still have the Atmos stored somwhere, this makes me wanting to dig it out. It's a specially modded one, a hack I did myself, piggy-backed Oric 1 and Atmos ROMs with a switch to select one. This because they weren't 100% compatible really. Some games worked only on either machine. I did add a reset button too. Hope it still works because I don't have your skills and equipment to fix it if it doesn't.
@@paulscottrobson I don't think it had a SECAM encoder. But at that time in France pretty much all TVs had a SCART (Peritel) connector, which was fed with separate RGB and sync signals. It was just a great machine, affordable, with great graphics, good sound (who didn't love the SHOOT, ZAP etc.Basic commands?) and a reasonably reliable cassette interface. Way better than what the local brand was trying to push (Thomson TO7) for the home computer market.
One note about the use of 4164: the Oric allows the ROM to be disabled, and then you have a full 64K of accessible RAM. The bizarre decision is that there's no way to do this without external hardware! Disk drive controller interfaces did this to put the OS in the upper 16K of RAM and complete the bank switching circuitry. This trick was at the centre of many Oric Atmos ads claiming you didn't lose RAM if you used additional peripherals. It was because you lost RAM if you *didn't* have any.
its not a common problem but they can and do go bad, i had a colour decoder crystal fail in a 1970s colour tv in the early 90s , it was still oscillating but must've gone enough off frequency to stop the decoder working, new crystal cured it
@@andygozzo72 I literally in 35 years of electronics have never had had that happen. I would really find it as a last resort. It’s such a passive robust component.
For sure! I didn't even talk about how there's a random character that appears on screen half the time you turn it on. That could be a fun deep dive to figure out why that's happening 😃
It's always great to see an Oric get some love, I had an Oric-1 48k back in the early 80's, it was a solid little machine - I loved mine. I even ended up reviewing a few Oric games for a magazine.
Had a problem with a faulty pc. Did hard disc test, DRAM test etc and found no problems. In the end I removed one DRAM module and it started working ok.
That's a sh.t RAM test. A comprehensive RAM test does take time. But if the entire chip was dead rather than just a few addresses with in it, then a simple stuck at 1 and stuck at 0 test on each bit in the word at an address in that chip should have detected it.
Crikey, you can even recognise Blake in your friend's game - lol -. And I though my brother was the only one that made a Blake's 7 game - lol -. His was older and kind-of based on the old Basic text/graphical Star Trek game, ie , a much more fancy version.
Still have my Oric-1. I liked how you could type "beep, "explode" and others and it would play those sounds out the speaker. It was a nice little touch. Although it made a lot of games sound alike.
Wow, an Oric! I started my micro journey with a home-build Microtan 65, which got expanded over time, I even made a DIY RAM expansion for it. Of course, as soon as the Oric appeared my Tangerine loyalty won and I got one. Never had any problems with it and got a lot of use from it for a number of years. Moved on to the Amiga family eventually.
The Oric 1 was my first personal computer. I was a poor student, and I loved the opportunity to finally be able to have my own programable computer in BASIC.
I know the computer is called an "Oric", but if you're playing Blakes7 on it, wouldn't that make it "ORAC"? (after all, I hear the name "Oric" for a computer, and I automatically think of Blakes7 anyway)
As you've experienced, sticking a DRAM into a simple tester or POST is often not sufficient. In the good ole S100 Bus days, the CP/M MEMR Rasmussen RAM test (the vintage equivalent of Memtest86) was the best assurance for DRAM to be operating properly. This program runs through a series of comprehensive tests such as walking bit tests to make sure the DRAM will operate as expected. These older machines often had no parity RAM error checking so when things went awry, they went totally awry!
Great video. I had exactly the same issue with mine. It was faulty with multiple failed ram chips so I did a complete swap with some 4164’s from China. Wouldn’t work. I swapped the multiplexers, inverter, tried a different ULA. I fell short of swapping the CPU. Turned out that although the ram worked, the timing was not as advertised. Finally found a set that worked!
A minor quibble: you keep calling them "demultiplexers", but those chips are actually _multiplexers_ (they take the full range of address lines and multiplex them onto a smaller set). A demultiplexer would go the other direction (input the column and row addresses and output the full 16-bit address).
Grew up in France and can confirm. I had an Atmos and it was popular (albeit quite briefly and less so than the original Oric 1). I remember drooling over the Stratos announcement...
Its called the murphy law. Bad luck that can happen to the best IT geek. Congratulations for the resilient enfort to solve the problem. Best regards from Portugal.
Oh WoW. 🤯 I remember seeing the Oric 1 in the shops in the early 80`s and thought it was just a Spectrum clone also remember seeing poke being replaced by doke. So thought yep its a copy not interested. But now seeing the AY chip and the color graphic maybe I should have given it a second look. As I guess back then many others would of passed it by too.
Great episode Noel! I greatly enjoy these videos which resemble mystery stories, Sherlock Holmes for detective mysteries, House M.D for medical mysteries, Noel's Retro Lab for retrocomputing mysteries ;-)
In a previous video here, I mentioned doing the replacements and doing them one at a time into another machine for people who don't have the chip tester, but was poo-poo'ed saying mass chip replacements isn't the way to do it. I like the fact you used a known good working Oric to test the RAM and discovered that _was_ the issue, even though the other test with the chip tester said they were all good. It's be interesting if you posted a follow up (pinned) message that you tested the other batch of RAM with the new firmware, and whether or not it found a bad chip.
I have fond memories of Oric 1. It was the second machine I used after C64. We typed a few programs from the manual and also played some games. The Atmos was also well known here and on display at local shops. I almost bought one! (But in the end I got a CPC464)
The coolest thing about the Oric is that the ROM is copied into RAM on power on (that's where the other 16k 'goes'). You can then *overwrite the copy in RAM*, thus patching the ROM! For example, want to change the font in text mode? Overwrite the sprites!
Oh interesting! I didn't realize that. I assumed the ROM was simply mapped in that space. But wait, how does that work? The copying must be done by the ROM code itself, so there has to be a way in software to select either reading from ROM or from RAM for that addressing space, right?
@@NoelsRetroLab I don't remember the exact details (this was about 40 years ago!) but I got this from a book that I ordered from the local library. I guess the test is to see if you can POKE above C000!
I'd like to know where you read that :) My understanding is that no matter what you do, on a stock machine you always access the ROM part. When you plug a floppy disk drive (Microdisc, Cumana or Jasmin), you get additional electronic circuitry which allows to switch between the ROM, the overlay RAM, and the onboard eprom on the disk drive, which allows the DOS to be in memory (in overlay ram) without using any additional memory - with the exception of the $400-$4FF which is used to swap between ROM and RAM depending if you are executing BASIC commands or doing disk accesses. So yes, with a disk drive plugged, you can indeed do what you mentioned (copy the ROM to RAM and patch it), it's actually exactly what I did for my "The Hobbit improved" which was in video ("Oriclopedia: Let's improve the Hobbit") just a few days ago.
This is exactly what a PC does when you have the 'Shadow Video ROM' selected in the BIOS - it copies the contents of the ROM to RAM for slightly faster execution. As you say it allows the user to POKE new values into the character definitions now held in RAM to create your own custom fonts. :)
@@aCivilServant The Oric ULA always fetch the font from B400/B800 in TEXT mode and 9800/9C00 in HIRES mode, there's no need to patch the ROM font to have custom fonts.
I'm actually amazed that there is still so much interest in this machine. It had a fantastic keyboard and I loved it, and wrote several bits of software myself
If the manufacturer had used a Z80 cpu instead of the 6502 that has a ridiculous low number of registers and instructions this could probably be a serious contender for the Speccy...
Yes the Z80 can run as a minimal system with no RAM, just executing ROM code quite well, and also you can simplify things a lot, as you also have separate IO read and write, so your ROM can simply be connected to the memory read only, having multiple images of it in the memory space if it is not 64k, allowing some fancy tricks with code wrapping around in a block or jumping. Enough resisters to at least store a little state, and an alternate set to use with a subroutine, though passing data back and forth could be hairy.
It's pretty much impossible for a general-purpose chip tester to test the timing limits of a DRAM chip. Especially since every different speed grade of static or dynamic RAM chip would have different timing specs. The same problem exists with pretty much any chip. Testers test the logic of the chip, not the timing. Even something like a 74LS74 has a setup time for the data relative to the clock, for instance. If the chip fails in some odd way that makes this required time much longer, but that's the only change, it will still pass in a chip tester, because it's being tested at a much slower speed.
Another fantastic deep dive into a problem. My own mental checklist of “maybe it’s this” or “hmm, maybe it’s that” as you went along and I was getting increasingly confused along with you. I love the follow through and not simply leaving it as “it’s fixed somehow”.
The Oric was awesome. I have owned one since a teen and still have it in it's boxed. Shortly afterwards I got an Atmos, love the keyboard, that too is still boxed. Since then I have four more from various places and even managed to get hold of the official printer, okay it was a rebadged MCP40.
Great video Noel! a false positive until you updated the firmware, I think your final ram test using a working machine should have been used before you got sent down a rabbit hole.
Thanks! Yes, I wonder what it was that made the Spectrum beat it by a landslide. I wonder if it was price, marketing, or just being out 6 months earlier.
I didn't quite like how extremely unclean a lot of those signals were.. I would've suspected that the error would've been a capacitor failing, ESPECIALLY after the ram-chips passed the test.. That said; This computer was made while it was still a bit of a "Wild West" approach to design, and everyone wanted to make money, and everyone wanted to make it cheap, so.. It's possible that they just used a bread-board and trial and error, and assumed that if it worked.. it worked.. but differences in the analogue properties of digital circuits matter, so they may (f.ex.) try to read the ram slightly faster than specs, BUT it works on pretty much all chips out of factory.. but some of SLIGHTLY lesser quality "Just barely", so it doesn't take much wear and tear, or possible damage from transients, static electricity, or whatever.. for the chip to degrade the slight bit it has to degrade to make one specific computer not work any longer.. .. Whereas most testers have GOOD electronics (clean signals/clocks) and therefore can't fully appreciate the lower quality merchandise that is out there.
I had the exact same issue with RAM "looking" fine, but failing in circuit.. My issue was due to timing parameters not being met I believe.. anyway... it can be checked out here ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-ERGIMThCqYI.html
Uh. Oric Atmos. I happen to have a dead one in the basement as well. Among with some Spectrums. Guess after this video I'll consider to bring it back up and retest it. Maybe I get it to work again as well ... Thanks for sharing !
@@NoelsRetroLab Thanks for encouraging me. I also have an Elan Enterprise Sixty-Four with a totally broken keyboard membrane in stock ("Worked when parked" - 30 years ago ...) :-) The usual stuff. Same with the Spectrums I guess.
Great troubleshooting tour video! It's wonderful to hear your reasoning for the different steps. Although I don't have an Oric, I'm pretty sure, I can bring some bits (sic!) of knowledge learned from this video to good use on other computers.
I had the Oric 1, then upgraded to the Atmos and then to the full suit - printer, disc drive and their power supply etc. I built an assembler and EEPROM programmer to make a moving message (another 6502) LED display - I sold a few :) Finally, I sold the whole (dust-gathering, but working) package about 5 years ago for a healthy price. Great memories and a smashing video, thank you - Beamer, from the UK.
I have an Oric1 16K, which can be expanded to 48K with the right RAM xx464. You can use an Erebus if you don't want to do much. There is no saving, only loading. So more about the presentation of this interesting home computer with a 6502 CPU and AY sound.
I had an Oric Atmos. The extra 16k between 48k and 64K was used for the disk drive commands. If you used a '!' before certain commands, it would switch out the ROM and take you to RAM address space, where, if the disk drive was installed, all the disk drive commands were. If I've remembered and understood this correctly.
As long as we learn something than it's always fun when tech throws us for a loop. I have a ram stick that works only in specific slots. It's an 8 GB DDR 3 and it won't work in DIMM slot 1 on any motherboard that I currently have for DDR 3, but it does run in DIMM 2 and has no issues that I can find. I'm not using it not sure I should use it and it just doesn't make any sense to me right now.
Although I know better now, back in the day I actually used to think ORIC was French, rather than British because it saw reasonable success there but was completely eclipsed in the UK. It still has the feel of a 6502 based "spectrum" though :-)
The paint on your spare RAM chips look faded. Moreover, they have a datecode of 2015 (or 2011, I'm not sure). I wonder if they're authentical TI chips or if they're faked chinese chips
do you have the original amstrad demo and an amstrad colour monitor the cpc was bundled with, because one thing that puzzled me in the 80's was the demo animation of the flying yellow duck, it was a brighter yellow than what you could generate in basic, and i never did understand how they achived this, i spent some time on the issue but back then i wasnt a 6502 guy. or i maybe had a faulty monitor, but everything else seemed normal on it
Owned Atmos, back at the day... Looks was beautiful, machine itself... Well... Still, now I hope, that I'd still owned it... I don't and most probably never will again...
LOVE the 6502, HATE dynamic ram.. When the negative rail of my Table top Defender game died, it popped a lot of the 4116 ram chips. Because they were stupid expensive and I needed a shed pile of them, RGB banks of screen memory plus storage and workspace, I wrote a test program on the BBC Micro using a PIA to waggle the ram pins and found about half had died. The ones that got red hot were easy to find... PLA, TAX, PLA, TAY, PLA......
Hi, I was happy to see ORIC-1 & ATMOS again. I bought my first ORIC-1 (48k) in 1983 and two years later one with 16k RAM. Still original packt in my storage. Learned 6502 assembler and a lot About Hardware. A Real Flash back. Thanks for the Video!! Regards - Henry
Ah, the Oric Atmos, such a lovely looking machine. Not to really mention other channels but IIRC, the Oric-1/Atmos is currently the only 6502 system (or one of the very few) to not have a port of The 8-Bit Guy's PETSCII Robots game so I'm looking forward to your video on the graphics capabilities of the Oric and see if that might be why. Or well, the inaccessibility of disk drives for the Oric is also probably a reason.
