BBC Master mods and improvememts

[@adriansdigitalbasement]

Hi everyone, my patrons pointed a small error in my video with regards to color composite. In the video, I said connected the color signal between R118 and R130 (Effectively the base of Q12) and ran that to another resistor that was effectively the base of Q13. As I mentioned in the video, to do this mod, what you actually need to do is connect a capacitor between the emitter of Q12 to the base of Q13 using a capacitor. The capacitor I installed in the video was actually connected to R137 (the emitter of Q12) and went to R151 (base of Q13.) Both of these resistors are BROWN BLACK RED GOLD, which are 1K resistors, so if you replicate the resistor as shown in the video, it will work. Here's a picture of the mod: imgur.com/a/nVUQfdC

[@technerd9655]

I don't understand why this mod was necessary. Wouldn't the OSSC convert the PAL signal form the RF modulator to standard HDMI?

[@adriansdigitalbasement]

@@technerd9655 OSSC only has a SCART and VGA (RGB) input.

[@essemque]

Just paused @30:20 and scrolled down to the comments to point this out; glad you already caught it. :)

[@CandyGramForMongo_]

“If you’re watching this video in the future…” I’m not sure how I would watch it any other way, Adrian. ;)

[@nahumgardner]

Maybe somebody in the 16th century is watching this, like the haunted BBC in the Dodleston story

[@MattSiegel]

some of us retro enthusiasts are stuck in the past!

[@thewi2kbug]

perhaps the time jump features can allow people to watch and mod thier owns.

[@MrKurtHaeusler]

Dunno bout you but I’m watching it in the present 🤷‍♂️

[@paul_boddie]

@@nahumgardner Relax: he doesn't have Edword installed!

[@billraty14]

I am always impressed that Adrian laughs when he is frustrated by something instead of getting upset.

[@AOClaus]

If only the entire world could figure that out.

[@GDLarcade]

This might be my favorite non-Commodore Adrian's Digital Basement video to date. I can't really explain why. It just had everything I like about your videos in spades, passion for the hobby, solving technical puzzles and being able to relate what you are doing to the audience well. Thank you!

[@adriansdigitalbasement]

Thanks for the kind words! Yeah it's hard for us in North America to relate to this machine since none of us every used it (or even knew much about it.) It's just been really fun playing around with it and learning more about it and I hope to share some of that with my viewers.

[@sertacpamukcu]

I'm watching Adrian's videos for a long time but this was one of the best. I really appreciated. Thanks.

[@dr_jaymz]

I think I agree. I really don't know what it is, I love watching these videos and I love the BBC, always have, always will. Its one of the best thought out machines I think there has ever been. Part of the reason is that the BBC wanted functionality to triumph over the penny pinching.

[@jkdsteve]

I grew up on Model B :D My favorite mod was the aftermarket NVRAM board that you could flash BBC ROMs into or add additional, switchable physical ROMS.

[@raybarker]

If I recall correctly, although MOS 3.5 has several bugfixes, it is even less compatible with BBC Model B software than the standard version. For maximum compatibility, an OS downgrade to something like 1.20 is necessary. It's a relatively common mod to have a large EEPROM with several versions of the MOS which are switched out with a hardware toggle or rotary switch picking which banks get switched in and out.

[@zoid9969]

IIRC, the weird characters you see loading games (e.g. Arkanoid) occur because the Master has a different character set to the Model B, and the games were originally written for the Model B. The explanation of the parameters for the "TV" configuration now finally make sense after decades of me not knowing exactly how they work. It seems so simple now - it's a signed integer!

[@thewelder3538]

This is NOT correct at all. The weird characters are caused by the address space being different on the Master than the BBC B. For instance the expanded character set on the BBC B, with say a tape filling system lived at Page &C00. So code for the BBC B used to directly load into that page. The sound and envelopes were pages &800 and &A00 etc, so rather than defining the envelopes, you would directly load into those pages. On the Master, those pages don't contain the character definitions anymore, so code that directly loaded into those pages doesn't work and that's why you're seeing weird characters because the graphics are loaded there, but the Master isn't using those pages for graphics.

[@necro_ware]

Great video, as always! Thank you for mentioning and I'm glad to see that my project was useful. I guess, I can add the information you have found to the documentation. Thank you for the contribution ;)

[@jamesfmilne]

Instant upvote for working on a BBC Master. Thanks from London!

[@ukwebb]

glad to see you like my schematic re-drawing :)

[@kwanchan6745]

that is cool being able to replace the NVRAM chip, that has been a persistant pain for many bbc master owners (bbc micros don't have NVRAM)

[@adriansdigitalbasement]

Yeah I was frankly shocked when I saw everyone suggesting to replace the batteries and more AA batteries and then add a diode and resistor. I thought there had to be a better way!

[@kwanchan6745]

@@adriansdigitalbasement the original battery arrangement was definately handled by the B-team, as it didn't even have the diode/resistor arrangement, resulting in exploding battery packs

[@AlsGeekLab]

Loved this series. Beeb is such a great machine and the mods you made were great.

[@erinwiebe7026]

Your enthusiasm is so much fun to watch @Adrian!

[@stewartskardon7376]

Hi Adrian. The EPROM that you removed may contain NFS (network filing system) which is needed in order to use the Econet interface.

[@kwanchan6745]

doesn't the bbc master have a megarom that contained all the rom images, including ADFS and DFS ? wasn't NFS part of the DFS like the DNFS 1.20 ?

[@ukwebb]

@@kwanchan6745 no - its a separate chip. I never understood why they didnt include it , but they didn't

[@ukwebb]

You can see when he downloads the image from teh chip theres no actual code just gibberish/ random data.

[@andyjdhurley]

@@ukwebb correct, it certainly wasn't a language rom as, by design, they have to have an identifier at the top in readable text which gets displayed by *ROMS. The lack of any such identifier means it would not be recognised by the system. It could be some kind of game data but I doubt that. Most likey just a spare rom that was kept there for safe keeping.

[@ukwebb]

@@andyjdhurley same for service roms ;) it identifies a rom as being ' of interest' by looking for the copyright header '[null](C)' which must start at the offset position recorded in the 8th byte (x0007) in the rom.

[@frazzleface753]

It was great to see you learning this system and solving the challenges along the way. This is a very rare computer in the US, and to get it running natively with the best output for North America, is just awesome!

[@kdrum90]

In my opinion, this is one of the best Adrian’s videos so far. BBC machine is charming and looks very capable, it would be nice to see what it can do.

[@Soruk42]

For mass storage on my Master 128, I opted for the Pi1MHz solution, which interfaces a RPi Zero with the 1MHz Bus port under the keyboard through a level shifter board. The firmware on the SD card as part of this project emulates (amongst other things) the BeebSCSI add-on, which provides me with up to 4 hard disc images, each up to 512MB in size - so that's 2GB disc space. What's even better here is no ROMs (or ROM images) need loading to support this, as it's completely compatible with the built-in ADFS. (I also had a spare Pi Zero that was gathering dust from an earlier project that was no longer in use, so I gave it a new home here.) For video output I got a cable which connects the RGB socket to the RGB lines of a SCART plug which goes in the back of my TV. Good video series, I enjoyed watching it. I had considered MMFS, but ultimately decided on Pi1MHz as I don't have any EPROM programming kit (or any EPROMs to use).

[@NowInAus]

Your reaction to colour … awesome and such a testament to both your labours and the enthusiast community.

[@TonyHamlyn]

Awesome, I felt your joy when you pulled that Intel/Moto pin high and were able to store the CMOS settings. Love your vids.

[@exohio]

I'm 33 years old. I've been programming as a hobby since I was 9 years old. Even earlier if you count my C64 days (the first computer that I could call my own, not the family computer) copying code from a book at 6-7, lol. I never got into the hardware understanding of things. So watching you, I learned a lot, satisfying a different level of my hobby, I didn't know existed, building an even greater understanding of it all. It always felt like 'work' to me so I didn't enjoy it unless I was doing it for a hobby. If I had someone like you as a CE professor maybe I would have made a career out of it, you do a great job.

[@falksweden]

If you want to understand the hardware side of things I highly recommend Ben Eater's videos and especially the series where he builds an 8 bit computer from scratch and he has a really great tutorial on digital electronics. :)

[@exohio]

@falksweden I will absolutely check him out. Thanks for the recommendation. I stumbled upon Adrian for his diagnostics, working on my own C64, which I bought to relive my childhood 😅 this time with a deeper understanding, I managed to get it working again.

[@GeorgeStyles]

8k roms worked fine in Beebs. Instead of being mapped from $8000-$C000 they showed up as 2 copies of the 8k at $8000 and $A000, and the software was written within the 8k, so ignored the address space above $A000. This is because on 27128's all 14 (i think) address lines were used to select which byte in the rom was accessed, whereas on 2764's the highest address line was not connected, making it repeat its contents into the 2nd 8k bank in the memory map. Some roms (Quest paint for example) even included a Nintendo NES style 'mapper' chip that detected activity on a 'magic' address, and switched between 2 27128's, giving a total of 32K of rom. ah, memories :) edit: would love to see you read that unknown 8k you pulled out - you seem to have the right kit to do so, or you can also use utilities on the machine itself to read it. Maybe its just been exposed to too much UV light over the years and has wiped itself?? Were you also aware that Masters had sideways ram, so you can load images of roms into it (using *SWLOAD I think) and they will behave like actual physical roms. Cant remember if the master had battery backup tho, so u did the right think blowing the eprom for your filesystem driver

[@thewelder3538]

It's not SWLOAD, it's *SRLOAD followed by the slot number and optional load and execution address. The Master did indeed have battery backup, but it wouldn't retain ROMs loaded into Sideways RAM. Also a full hard reset, so say a *FX200,2 and break would also clear out your sideways RAM.

[@AdamHougham]

Great video Adrian - thanks for the epic series finale! My neighbour used to have a Beeb Master when I was growing up, while I had to make do with the little 'Elk'! I also got to use them at school in our 'CDT' (Craft, Design & Technology) classes where we learned BBC basic, and LOGO while playing with a Turtle. Of course, the other MUST TRY piece of software is Elite as this was where it all started for Dave Braben's masterpiece. They're not cheap these days so having a Master, two Micros and the Elk is quite an acheivement, particularly as you're left of the pond. I make do with emulation and reminisce the old days while waiting for the simulated tape deck to load my software! If you get the chance to check out a Turtle, I'd recommend it and of course the ultimate Beeb addon - the Domesday Project!

[@mogwaay]

Great video, loved seeing you enjoy getting into your Acorn. They were such well designed technically excellent machines, wish they'd seen more success but the business side of Acorn wasn't always the sharpest I think. Really fun watching you mod this and get it working in a way that suited you, well done! Would love to see you jump to the littlest machine, the Electron as I've been working on that the most recently with a ULA replacement project. Cheers!

[@JuliaMono]

Seeing your honest, unfiltered joy in learning and tinkering is so so refreshing and cool. Thank you so much

[@button-puncher]

I love that someone got SPI working with this machine. Such a perfect solution. BTW, if you ever have a damaged SD card, using SPI is a good option to try to get the data off of it. It takes FOREVER but it works.

[@miscbits6399]

Fun fact: There are (were) 625-line 50Hz NTSC broadcast standards in some countries along with 525-line 60Hz PAL in others

[@Duddie82]

I programmed lots of programs in Basic. I created a learning program that covered Numbers, Colors. shapes sizes. My first child used my program and she got really good at it. When she got to school, they put her in first grade. She was too smart. And she excelled in first grade too. It was a powerful program. I know I should have put that program out. When I left my EX. She made sure she got rid of all my programming programs. It took me a long time to get that program finished. I would love to do it again. But I don't have a programing system anymore. And also no money to buy one. I Love the work you do. Big Time!!

[@BottIsNotABot]

Brilliant video as always, and still such a joy to see the BBC Master in action. Highlight of this video though is when you worked out the NVRAM around 59mins. I need to add a BBC to my collection, and think the Master is the way to go.

[@digitalarchaeologist5102]

I grew up in the UK so remember the BBC Micro and relatives being so ubiquitous in schools and around 6 months ago acquired a BBC Model B in Australia where I live now, unsurprisingly it originated from a school. Finally got round to renovating it after finishing other projects and this series just happened to coincide quite nicely. It's been quite a joy to discover how advanced they were for their time compared to their contemporaries although they would have cost a lot more than a Spectrum, C64 or Electron. In many ways it quite sad how progressive the UK was in the 80s and very early 90s with computing and then, well nothing... I guess ARM being an exception...

[@crashoverride328]

ARM being Acorn Risc Machine in the era of the Acorn Archimedes A3xx and A4xx first generation machines, then the name evolved and the processor became the heart of a majority of tech globally since from Apple to Arduino etc. But let's not forget the Raspberry Pi machines and the RP2040 as used in the Pi Pico...

[@jkdsteve]

My Model B was 349 UKP (from memory).....though I may have received a 50 discount. Add 49 quid for an old TV, how I lusted after a Microvitec CUB :D

[@crashoverride328]

@@jkdsteve I'm guessing it was later than 1984 or didn't have the Disk Interface...

[@me_fault]

In the first evaluation boards ARM1 ran as a co-processor in a BBC Micro.

[@jkdsteve]

@@crashoverride328 Yes, I was on tape for quite a while, so relieved when I added a (Cumana?) drive some time later.

[@andysimpson8974]

Guy from Northern England here. My school had a suite of these in use well in to the nineties. Some thought they were rubbish because PCs were appearing in homes by then and the graphics weren't as good as my Sega Megadrive 😂😂

[@EdgyNumber1]

BBC BASIC was in my opinion the best, and switching between this language or the assembler in line, made this system sooooooo efficient to work with. I so would sorely love to see BBC BASIC V on Raspberry Pi.

[@tcpnetworks]

Fantastic video Adrian. We had these machines for about 5 years in Australia - and they were fantastic. We did computer science at high school level on these very machines. I had one at home until 1992, when i upgraded to an Archimedes.

[@Pink404]

It great to see your joy exploring the BBC Master computer. Being from the UK this was one of the systems I had fairly regular access to.

[@paulomigueldias1111]

I was the proud owner of a BBC B in 1983 after having a ZX Spectrum and I was worried to come down from 48K to 32K but this machine and it's BASIC and in-line assembly simply made the best ever 8bit machine. That how I learned about I/O a Analog to Digital conversion and finally was able to connect the BBC to my electronics, LED's, servos, the works. Take good care of that machine my friend, I am also going to use some parts I have to make a SD card upgrade like you. Great work !

[@UpLateGeek]

I never saw a BBC Micro or Master at school here in Australia, at least towards the end of the 80s. My school (primary school years 1-6) had Microbees until the early 90s, when we upgraded to windows 3.1 machines, I'm guessing in 1993. It is really cool to see what we missed out on. The BBC Master does seem a lot more powerful than the Microbees we had. Although I'm pretty sure it was much more expensive than the Microbee, so our school wouldn't have been able to afford to buy as many computers. I remember we had one Microbee per student, but when we upgraded to the Windows machines there were fewer so we had to share. If we had BBC machines instead of the Microbees, we probably would've had to share those too. Mind you, from what Perifractic described of his school years, they shared computers at his school anyway, and the UK government was funding the purchase of those BBC machines for schools too.

[@aw34565]

Great video. I have a BBC Master here in Massachusetts. I use an RGB -> SCART cable from fleabay and a SCART to HDMI upscaler to view the video signal on an HDMI monitor. This solution works very well for me.

[@adriansdigitalbasement]

Yeah that's how I first hooked up my BBC Model B ... those upscalers are quite laggy unless it's something like the RetroTink or OSSC, but those are so costly.

[@AnthonyRBlacker]

Very nice work on this ne Adrian. Superb find on the battery hack with pin one. Very very nice. Great content!

[@Broken-Silencer]

The BBC Micro's were very capable machines. The cost of owning one was substantial, so most homes had Sinclair ZX Spectum's (in the UK, that is). I think some judgement is based on how many games were available for machines, but it's clear that it makes financial sense for bedroom coders to make games for the more popular, widely used home computers. The games (not that games should be what defines a machine's capabilities, but that's what home computers mostly got used for in the end) that were developed for the BBC, particularly arcade clones, were pretty impresssive. When Acornsoft released 'Elite', it was a game changer. The port to the Spectrum was good, but the C64 couldn't plot lines as fast as the BBC, because the 6502 processor in the C64 wasn't clocked as fast. Saying that, the 64 was an incredible bit of kit too. So much innovation in those days. This video may be of interest to American viewers: kzbin.info/www/bejne/faG6oHlrqruamKM

[@OtterlyInsane]

Be interesting to do a PiTube on it to explore all the coprocessor options

[@MrRobbiepee]

I was thinking that. One of the options is an 80186 DOS compatible, which looks pretty interesting

[@MrUSFT]

Such a great machine. Really well designed. I wish it had been more available in north america

[@Beany2007FTW]

Well, goodness, this takes me back to primary school in the north of scotland. That said, we didn't do anything quite as fancy - we played a gardening simulator (who can grow the highest sunflower) and Rocket Raid, and Chuckie Egg. Got a few of us hooked though; I'm head of IT for an IT services company, a mate is the IT teacher at our old high school, and another mate went to uni to do robotics!

[@ThaVoodoo1]

Great Video Adrian, as an Amstrad CPC 464 owner this is so cool to see the BBC Master.

[@oldboy5001]

Great mods. I wish I'd had your skills when I owned a BBC back in the day.

[@nickblackburn1903]

Shift and Escape should launch the menu I think? I love watching you, an American experiencing this amazing UK computer. :) Nick, UK :)

[@skonkfactory]

The Commodore 1084 is actually a Philips CM8833, which was sold by Acorn as the AKF12

[@firstsurname9893]

Although the Philips versions are more common Daewoo and Likom also made 1084 monitors.

[@idio-syncrasy]

I can tell you really liked the bbc master. Thank you for this series.

[@garyjohnson4608]

I've enjoyed the videos about the Acorn. This is the first time I've ever seen one. Very interesting machine.

[@petesapwell]

Really enjoyed this one Adrian, I did briefly encounter the BBC computer here in the U.K. nice machine, I live the font they use.

[@TheEulerID]

BBC basic was largely written by the same person responsible for the original ARM instruction set.

[@marillionuk]

Roger (Sophie) Wilson wrote BBC Basic and with Steve Furber, both developed ARM. Credit to these two individuals.

[@TheEulerID]

@@marillionuk I was very specific in referring only the to the design of the ISA, not the design of the processor overall.

[@stevewhitcher6719]

In the 1990's in the UK most TVs could display NTSC 4.43 which is the oposite of what you have created here 60hz but with pal colour this was used by people that had american VHSs or DVDs because there was a wider range of titles avialble in the uS and japan.Because i wanted to record my US sourced VHS to DVD i ended up buying a US DVD recorder ( which was very cheap because it didnt work in the UK) and an analgue TV standards converter so that i could convert my NTSC 4.43 that was coming out of my UK sources VCR to NTSC 3.58. Previously i had, had a Uk sourced VCR that had a switch on it so that it could either output pure NTSC or 4.43 they were sold in the UK by panasonic and all anime fans had one, but mine had broken before i had sourced the NTSC DVD recorder hence why i used the standards converter! I aslso discovered that my analogue converter also removed macrovision!

[@kaitlyn__L]

I remember saving up for a DVD player with the same output switch option, always wanted the fancier VCRs but by the time I had my own money there was less of an impetus to get one.

[@AntneeUK]

What a great series. Have watched all 3 videos this morning

[@kevywevvy8833]

I'm pleased to see you have the opportunity to appreciate a stalwart of 80's british microcomputing, in a country where it's pretty obscure. My UK college days were spent on a mixture of PDP11 and BBC 'B' but the classroom had a couple of Masters for good measure. The B and the master had a colour-co-ordinated monitor stand available that went over the back end of the computer making the thing look a bit like a PET. The standard colour monitors supplied in educational establishments were the uk-built Microvitec 14in RGB metal-cased monitor, (in a matching cream-beige) later ones being called the 'cub' monitor. For mono monitors, the Philips green or amber 12in plastic deal were the popular choice on composite.

[@Codeaholic1]

Very cool. It would be fun to see some of the later riscos systems.

[@AlastairMontgomery]

Yes it would be good to see what he thought of those systems.

[@adriansdigitalbasement]

Sadly they are completely unobtanium here in the US. The best I could do is show off Risc OS running on bare metal on a Raspberry Pi. It'll be insanely fast compared to the original machines, but it's a pretty nice experience. www.riscosopen.org/content/

[@geoffcollins6601]

Awesome video - many thanks. There is so much more the BBC B & the Master can do. Try a RPI as a co-pro on the tube interface.

[@JamsterJules]

Absolutely brilliant. You get the same buzz from fixing stuff as i do from coding still (am im 55!)

[@simonro9168]

14:17 Reminds me of my old math teacher who said at the beginning of the year "I'm not gonna make you guys do (graded) math up at the blackboard. I already get things wrong when I need to write here and talk at the same time, I know if the pressure of a grade were added nothing productive would come out of it." She was great :)

[@trickysoft]

If you look at my SD card adapters, it is just a board to move the wires around and an arduino adapter soldered together with a 20pin plug. I sell them with an SD card with my menu on it and an EPROM with MMFS but only in person, usually at shows to people who I think would otherwise put their beebs back in the loft or get rid of it. This isn't an advert, so please don't try to buy one from me. You may have noticed the white triangles near the IDC connectors, all the original BBC add-ons have matching triangles on their connectors to help get them plugged in the right way around. I put them on my boards, but tipex (snow pake or whatever over there) or a piece of white tape can save you from embarrassing mistakes ;)

[@LibertyWarrior68]

The 68 Ohm output video resistor is probably correct because you also need to account for Collector Emitter resistance of the transistor which is probably 7 Ohms to make a total of 75 Ohm appearing at the output.

[@a4000t]

you can run tape around the edge card connector leave it sticking up above the pin side,stand it on end and fill with hot glue to encapsulate the connections. embed a wire loop in the glue as a pull tab

[@rictecilder]

Great group of mods for an old computer, now I want to fix up my CoCo collection with SD cards and mode there video outputs. Thanks for all the great videos. Even if it is just reseating chips like a few have been.

[@CobraTheSpacePirate]

Haha! I think it is hilarious when you mention people complaining about covering the UV erasable PROM. I have them sitting all over the place and in machines with no stickers. I it just a pain to take the sticker off every time a new update comes out. LOL!

[@adriansdigitalbasement]

Yeah I normally don't cover them because it's just a non issue. I don't leave them sitting exposed to sunlight :-)

[@michaelcarey]

Great video Adrian. Even though I was a die hard C64 teenager in the 1980s, I had a lot of respect for the BBC machines. Toward the end of my school life my High School (in South Australia) set up a computer room with a dozen BBC B machines, all connected to each other, a shared printer and floppy drives with Econet. Loads of fun sending messages between machines using Econet 🙂

[@parrottm76262]

So many 'freaking' nuggets in this vid. This makes me want a BBC Master. Love what I have seen of that basic.

[@amyworrall9246]

Glad you noticed the colour jumper for composite! I was shouting at the screen :)

[@paulsaunders5555]

O my God. it's like seeing my cradle agen. Enjoyed the series. Xxx

[@roboftherock]

Thanks, Adrian. That was an excellent triptych. I really enjoyed them.

[@Renville80]

Just make sure the clock battery is over 3 volts before buttoning up the computer and putting it away. A coworker came across a situation with one particular SRAM / clock chip (can’t recall the part number, will try and find it) that when the battery voltage is just under 3 volts when it is powered down, that chip begins actively draining the battery! Changing the battery to a fresh one fixed the ‘problem’.

[@rager1969]

Very cool. I can see your very stoked and emotionally satisfied by what you did here, and I don't blame you. It feels great when you achieve the elusive/ultimate (insert thing) on your own rather than following someone's guide.

[@jayfowler4747]

I recalled the name chuckie egg but when I saw the screen it brought back memories of playing it on my acorn electron ( which I pulled to bits 😅) one other thing that you reminded me of was getting a BBC B with a sideways ram/rom board that I never did much with but I seem to recall it having a varta bomb 😮 I think I need to dig it up and check.... thanks for the trip down memory lane, keep the videos coming.....

[@AntneeUK]

Everyone I know in the UK who used these when they were current are used to the Micro Vitec Cub monitors. The memories!

[@MarianoLu]

Love the BBC videos. Never had one but it looks like a great platform, they are had to come by here I’m the US.

[@nickolaswilliams935]

“Love the BBC” I stopped reading and laughed 😂

[@cdl0]

Adrian should be nice and warm this winter with all those jumpers that he has. :-)

[@falken_gt4]

Really enjoyed this short series, brought me back to school and early IT work days

[@peteregan9750]

it was used in schools in australia - really enjoyed its functionality in 1988 as moving to other systems was easier Because of its functionality and econet and seeing the phillips laser disk software. it gave a great insight of a lot of functions we use today. bought an amiga in 91 .....

[@EnglishMike]

Note: the schematics came with the original manual. Edit: as my fading memory comes back, I remember it was included with my BBC Model B manual as a fold out in the back of the manual. It's been a while since the days when everything came with a comprehensive manual... :)

[@kwanchan6745]

not the standard manual, a bbc micro foldout circuit schematic came with the advanced user guide which had to be purchased separately there is a newer online version with the original errors corrected

[@kwanchan6745]

the original manual had some schematics at the back, but they were not foldout and not A3 size like that of the AUG

[@deadreaver666]

Parts bin for the win! Well played sir

[@RayBellis]

If you enjoyed those mods the one that uses a Raspberry Pi Zero to emulate a whole range of second processors will blow your mind!

[@ChrisStedham]

Great video. If you have a couple of spare Raspberry PIs there are a couple of things you can do... Coprocessor emulation through the Tube interface (pitubedirect) and 1MHz bus device emulator (Pi1Mhz). Also... Have you figured out the significance of the StarDot forum's name? 🤔

[@londonbobby]

yes the Coprocessor mod would be fun to play with, especially the 80186 where you can run old DOS programs.

[@adriansdigitalbasement]

Hah yeah ... *. for directory listing on the Beeb :-)

[@grahameida7163]

I wrote a program on this micro to calibrate reference grade accelerators for national standards in the UK, using laser inferometer techniques and IEEE controls … BBC basic was so powerful back in the day.

[@truckerallikatuk]

Yep, I wrote a full on database in BBC basic for my exams back in the day. It was clunky and did things the slow and long way, but it worked fine. BBC basic is insanely powerful, and encouraged structured programming. And the built in assembler was fun too.

[@Error6503]

My final year university project was to build a satellite tracker using a Beeb. Orbital calculations were in BASIC talking to the Real Time hardware controller written in assembler ... I absolutely loved that project.

[@makermatthew]

The BBC Micro Model B issue 7 boards had the same jumper to add chroma signal to composite. I put a small switch like you did, colour/mono.

[@graffaelv]

Adrian, at 30:18 you mention R130 and R118 as connection points however I think you meant R137. R130 and R118 connect to the Base of Q12 whereas R137 connects to the emitter of Q12 which I believe is the correct spot based on your description. Did I miss something?

[@leesmithsworkshop]

Ozretrocomp Tony is one of the nicest guys, we both made Electron videos so got talking over that at the start of the covid times.

[@fattomandeibu]

I used these things at school as a primary schooler, but I have more C64 memories for games, but its always really cool to see them. Great to see running, and fun to see your solution to certain... I guess you'd say regional problems. I remember using PAL60 on the Dreamcast and A1200 just to be able to get a colour picture on my RF only bedroom TV. For downstairs when me mum was out or in bed, I could use SCART for RGB. With the Dreamcast it's sorta surprising, as it was inbuilt into most games to ask if you want to play in PAL60 on startup, it's odd for such a hacky mode to be almost system standard. I only ever had 1 TV it didn't work on and it was an expensive JVC set from the early '90s. Even cheap crap '80s portables managed it after a quick fiddle with the vertical hold.

[@mwk1]

59:20 - przekozak jesteś Adrianku 🍻

[@sweh]

The corrupted text is likely due to a compatibility difference between the original BBC and the Master; in particular how they handled soft-defined characters. The memory map changed between OS1.20 (the B) and MOS 3.2/3.5 (Master). So it's not uncommon for B games to show corrupted characters on the Master, especially if they cheat and load directly into RAM rather than using the official "define character" routines. You can get a "multi-OS" ROM for the Master that lets you have MOS3.2, MOS3.5 _and_ a modified OS1.2; just switch between them with a toggle switch. The OS1.2 mode normally solves these problems.

[@antonyshipley7552]

If you look at how we in the UK do a "ZX Spectrum Comp Mod" we do just connect the V1 signal to the comp output using a 100 micro farad capacitor to remove the DC.

[@twocvbloke]

All you need now is the tin box Microvitec Cub monitor for the full experience, only big issue would be the voltage (and I've no idea if they can be switched or modded for 120v), although shipping one of them across the pond and having it arrive intact, that's another problem... :P

[@Pest789]

Wow, this machine is really slick.

[@DarkVain]

Great Vid Adrian!! Still love the 1702 had the best picture.

[@delmonti]

brilliant! ...and excellent machine in every way.

[@melkiorwiseman5234]

I noticed that link on IC40 the first time you showed that area of the circuit diagram. I was waiting to see if you spotted it too before commenting, but I thought immediately that there must be a way to reconfigure the hardware to use NTSC instead of PAL. It's fun to see that you noticed it too, and that it worked.

[@chrisyboy219]

BBC Master Compact on my shelf here in N America (Canada). Didn't make any NTSC mods though, cause I have a PAL RGB Scart TV. I installed an SD interface internally with the exact same games image it looks like you have, and I also installed a little RGB to S-Video board inside that brings S-Video out to the back of the system which is handy when I use it with a projector! Even though most North American TV's are absolute shite when it comes to handling PAL, projectors sold here can be quite good so I use them a lot!

[@timothyp8947]

When I was at school, oh so long ago, I used to think the BBC was quite clunky compared to my VIC-20 (and the PET that had been donated to the school because the screen editor built into commodore machines was just streets ahead of anything else in terms of usability. I think the (much later) Master may have had alternatives, but the standard 'copy key' method of editing is a bit horrid - half a step above a paper terminal. HOWEVER, as a now semi retired software engineer, I now appreciate how clever the software architecture of Acorn MOS is; the Sideways ROM idea, for example, allowing lots of alternative file systems, programming languages etc. all within the confines of the 64K address space is something I think no other (non Acorn) 8-but got close to. Then add in concepts like the Tube.

[@adriansdigitalbasement]

Yeah the Commodore editor is a shining star in late 70s system honestly ... And indeed, if you had a BBC and were doing any serious editing, it looks like you really needed to get that Basic Editor ROM I've seen some people use. It's quite amazing that the 1977 PET had that wonderful editor that everyone loves from the VIC-20 and C64. But yeah, the computers are just so smartly designed, and the rest of the basic interpreter is pretty damn great.

[@jorgelotr3752]

39:13 originally called NTSC-N; it seems that some NTSC machines, like the Atari ST use this mode when running PAL software (similar to how PAL home video systems from the 90s play back NTSC tapes in PAL-60, which is just an image with NTSC resolution and frequency but colour translated to PAL).

[@Bob3519]

Another great one! Thank you Adrian!

[@michaelhaardt5988]

The Dallas Chips with the internal battery and crystal have a battery and crystal in their larger case and the IC pins for those are bent upwards and connected to those. You can revive any old Dallas chip by removing some potty to uncover those pins, disconnect the way to the internal battery and connect an external coin cell. Some other RTC chips of that type have the IC pins for crystal and battery at their head sides and need those uncovered, but basically there is no need to throw any of those chips away.

[@billfruge25]

The BBC Micro is, IMHO, the best 8-bit machine I've ever used. The BASIC supports in-line assembly, and it can be expanded from the basic cassette tape model all the way up to running Digital Research DOS and the GEM Desktop GUI off a SCSI HD simply by installing/swapping out the primary and secondary CPU's and a file system ROM. I really wish this machine had caught on better in North America back in the day as it was/is so much better than anything that was out at the time.

[@perinoid]

@1:1:39 Did you consider, that incorrect characters may be somehow related to that small ROM chip that you'd removed? I know, probably a wrong idea but... who knows ;-)

[@MikePerigo]

37:57 I can’t be sure without seeing more of the chips on that schematic but I think you’ll find that the N on the NPAL (and NBLK) pins stands for NOT and not NTSC. This would indicate that this is an Active Low signal in the same way as other conventions use a bar above the signal name or a negating circle on the pin. This would appear to be confirmed by the link connecting the pin to ground on PAL machines.

[@adriansdigitalbasement]

That's extremely unusual, especially given the fact the other IC's on the schematic have a bar/line over the text to indicate active low. Also conventionally written with a preceding slash. (ie. /CE)

[@MikePerigo]

@@adriansdigitalbasement Not sure what happened to my follow up reply but in case it is KZbin objecting to my inclusion of supporting links but to summarise not only is it not unusual but early manufacturers data sheets used that convention. My favourite example is the National Semiconductor INS8060 SC/MP processor.

[@MD4564]

I think you are correct Adrian regarding BBC Master being sold to Australia, especially in schools, I think it was rebranded as Proton...? "BBC Proton" microcomputer, made by Acorn in UK but modified in Australia in 1981. This model was widely used in Australian schools. The donor states that he assembled the machine in the UK while working for Barston Computers.The circuitry is hand soldered. This unit is serial no. 2. It is the third one made as the count started with 0. (Also known as BBC Micro Model B).

[@paul_boddie]

The Proton was Acorn's planned successor to the Atom before the BBC contract came along. The design was then adapted to meet the BBC's needs and became the BBC Micro, available in Model A and B variants. The BBC Master followed the Model B+ which was itself an updated version of the Model B, also being the common element in Acorn's largely unreleased Business Computer (ABC) range.

[@JonoHalle]

When I was at school we had these. There was a ROM you could install that gave the BBC speech. We used to mess about with it a lot.

[@danp3653]

Yes I remember that. *speech and it had some interesting pronunciation