Modding a TV for RGB - Part 2
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- Опубликовано: 14 окт 2018
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For more information on this mod visit here:
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The absolute madman actually fixed the hot glue cable
He ain't no Drakon, thank Christ.
Now I hope he fixes the vga adapter cable.
hahahaha lol
What a Madlad lol
@@elephystry Probably easier to buy a VGA to SCART adapter and wire the colour lines to the phono leads he installed.
Aaaand.. now we have to include premade VGA to RGB cables with Planet X3.. dagnabbit, David! :D
Anders Enger Jensen video 30 seconds ago, comment, 2 hours ago, nice one youtube, nice one.
A Sandy Soldier that’s because he commented on patreon!!
how many people are actually going to mod their CRTs to take RGB tho? probably not many since not even 8bitguy knew exactly what he was doing when modding it so most viewers will probably know even less
lolz
Or, make it a +$3 add-on at checkout.
I just converted VGA to scart 😎, I'm European
Just saw your humorous Expo presentation tonight, I was never more happy and felt like I was giggling like a little kid the whole time. Stay awesome! Oh, and don't forget the cables next time! Be like that guy with all the cables he could ever need in a box in his car. Oh, and the guy with the portable power bank was like a cherry on the cake!
Man I love these videos. Cant get enough. Been watching since 2014.
Ever tried anything you learned from this channel?
I did, as a matter of fact
so true
Yes I have tried stuff. I tried a bunch of the LCD stuff from a couple years back. As well as Mac stuff.
@@driptopia nice!
Holy crap, part two of this awesome mod?! AND JUST FROM A FEW DAYS?!
I love you...~
I love you too.
I'm thinking it's because the Patreon supporters get to see the video a few days early, and that gives him time to incorporate the suggestions and get to the post-processing phase by the time the rest of us have seen the first one.
sus
8-bit guy is truely a genious, he has such a wide skill set. He could be anything from a carpenter to a phycisist.
IKR
I'd just like to say thanks for giving me the confidence and impetus to do fixes and mods on my own. Your channel is pure gold. Keep it up man!
I recently discovered your channel. I’ve been binge watching everything for the last week or so and I wanted to tell you I really like your content! They’re entertaining and informative and I look forward to watching all your upcoming videos! Best wishes!!!
If you want an "optimal" solution, you just need to add an I²C EEPROM to your connector and program in the NTSC timings.
"optimal"
I did once, and I'm still surprised it works even on Windows 10
i used to have a VGA to SCART adapter in the late 90s ! worked flawless , PAL res on windows !
Dude I just wanted to let you know I’ve seen almost all your videos in the past two months. You’ve got great content and you seem like a cool dude. Love your videos. Keep it up man
THIS update makes me feel much much better about the setup. Excellent work!
Planet X3 VGA transparency works. Nice to See.
nice catch!
@@The8BitGuy now it's time to make 4-direction movement sprites for the tanks. ;-)
Thanks for the the VGA bonus! 🙂
Wasn't expecting a part 2, and and certainly not this soon. It was really cool to see the VGA trick working at the end. Thanks for the update!
Fascinating. Electronics was my first love back in the late '70s before I knew much about computers. I love videos where you spark that interest again. I used to skip school and spend my days at the library reading radio electronics books. LOL
This is nice addendum to the previous video. Nice to see that you fixed the flaw with the RGB mod, and interesting to see VGA being displayed on that CRT TV. As always, great video 👍🏽
Personally, I wouldn't bother with the VGA, since we've all got loads of old VGA monitors kicking around.
some high end crt tvs actually had a vga mode that allowed them to work as a normal monitor, and it was as easy as switching inputs.
@@dcfuksurmom There are also some HDTVs that support VGA, especially early HDTVs made before HDMI was invented.
Good video thanks
This video is amazing a sequel to my 1st 8-bit guy video?Yes please! How haven't I seen this yet?!?!
The intro and the music are all flipping awesome!
I believe you can push RGB straight through from VGA to your new RGB connectors (0.7v peak-to-peak) and combine your HV to csync and pull off the same thing with the higher quality input. There are also fancier and more specific (S3, Matrox, etc) DOS TSRs to juggle frequency and compatibility. Of course there is also the issue of the lack of vertical stretch and improper aspect ratio. Hmm. Now I want to dive into it, myself.
I'm follower of your channel too, I would like to ask, do you know where does that "ntscneg" come from? I haven't found anything in Google (4:40).
I watched this 1080p video of a TV with RGB mod with a HD monitor connected via HDMi.
Use display port noob
@@aidanstanding this is the internet I have no clue what you said it's too long, didnt read
@@ThomasFarquhar2 CORRECT!
I watched that same 1080p video on a 4K TV running as my monitor...
Last 8 minutes of my birthday and I'm watching The 8-Bit Guy modding his TV even more. Totally the best way to finish off my day :D
love the change thats a great way to manage the blanking line.
Additional to the comments on scart connectors on the last video. Yes, we in Europe were lucky to have the IDEA of scart... but the actual connector design was really REALLY bad. It'd have been better to use a D-sub of some kind
Yeah it's rather… chunky to say the least. And kinda awkward to get to on most TVs, I ended up getting a scart switch box just so I don't have to reach behind the TV in my bedroom (which currently has my Sega Saturn plugged into. It's got a really good RGB signal via scart too! First console released to come as standard with a scart lead, iirc. So much better than rf)
The problem was that with all that signals in the cable was bulky, because it contained in itself a lot of single coaxial cables, if you think about it, much more cables than VGA, as you had 3 coax for R, G, B, 2 coax for composite in and out, a coax for the RGB blanking signal, and audio L/R in and out, and a couple of single cables for functions like input selection, data pins for teletext, etc.
The connector wasn't that bad, it was fairly easy to take apart and mod, for example to add extra wires and other thing, a D-sub connector wouldn't had that flexibility. The only thing that I would have added was some kind of latch to keep the connector secured to the TV, especially if you had the TV on a rotating stand it was easy for the connector to unplug.
You had varying degrees of quality when it came to SCART cables too. Some as you said had several internal coaxial cables, some used twisted pair and some had just the foil wrapper around simple wires.
Some were worse, just single wires with no foil. For a good quality like the Amiga for example, 3 coax for RGB, 1 coax for Csync, 2 coax for audio, and 3 single wires for commutation, blanking and ground. That made a pretty big cable. I used many saved VGA cables cut away from dead monitors to tweak my own SCART cables and always had good results.
Your channels intro makes my day...
L. Alp M. Schiesser you want a 10 hour ver
Why not?
You are a man of many technical talents! Wish I had a steady enough hand to solder and things like that.
Thanks for the VGA demo, I was hoping you did this! :D
I was looking at the diagram for a old 20" tv I have and I can do the same mod, but there is other thing that would be very cool to do, the tuner is an i2c slave. So with an arduino, a analog multiplex and logic gate to overwrite the av/tunner selection pin of the jungle, a new mod could be made that you keep the av input free, make the rgb overwrite a tunner channel like 5 and you could use the remote.
Ah, to have had a true RGB monitor back in those days...
Thanks for the update David.
2 8-Bit Guy videos in 3 days? I'll take it! Great content as always!
That's what a lot of PC-based arcade machines (Golden Tee, Big Buck Hunter, etc..) do: they force a 15kHz scan rate.
They're typically Linux-based and use SDL for graphics. If you've ever seen one booting up, the BIOS and console are unreadable on the arcade monitor.
Have to say, the SCART connector does have a CEC-style implenentation which is simply a broadcast of +5V over a pin on the SCART socket (I think there are other meanings for other voltages on the same pin, but I can't be sure)
It isn't really a surprise that an American TV could be easily modded to display an RGB source. You're probably partly repopulating connections that American TVs already contain, because the same chassis is used for European TVs that do have a SCART socket and an RGB connection (as well as Japanese TVs with JP-21 connectors)
You might want to test this with a TV from the 1970s or earlier, TVs whose tube has a similar pattern to VGA monitors of the 1980s and 1990s rather than the pixel pattern that 1990s TVs have (which is the same pixel pattern that new TVs have for HD sources - and possibly even 4K sources)
Pin 8 pin is +9-12V for 4:3 aspect or 5-8V for 16:9, and its implementation varies considerably, some sets power up from standby (and also shut off when signal goes down), others just switch to AV if the set is turned on already, some do nothing. There are also pins for digital data bus which was originally rarely implemented at all and incompatible between manufacturers. In some cases the pins needed to be disconnected by cutting the wires on cable, as incompatible protocols connected together could cause really bizarre behavior. Since late 90's most manufacturers agreed on using AV.link which was a direct predecessor to HDMI-CEC and is supposed to be cross-compatible with it to some degree even now.
The Samsung TV modded on this and previous video actually has the composite video and audio input in SCART-connector shaped block and the cutout on the back case is for SCART. Can't see the bottom of the PCB on video, but if the chassis is same as on PAL model, the signals may have already been routed there and only thing needed to be done was to desolder the RCA connector block and replace it with SCART connector.
Those old delta gun TV's are probably impossible to converge satisfactorily to whole screen area for RGB use. Also when working with older sets which did not have any baseband video input from factory, one has to keep in mind that they may actually have live chassis, and it would be very dangerous to add any inputs without adding isolation transformer, which would need to be rather large and expensive, as these sets were power hungry. There have also been some live chassis sets that used optocouplers for composite video input, but those are rare.
"You're probably partly repopulating connections that American TVs already contain, because the same chassis is used for European TVs that do have a SCART socket and an RGB connection (as well as Japanese TVs with JP-21 connectors)"
Not quite. While very few sets can be modded that way, the vast majority of modeable sets(such as the one featured here) take the RGB from the Microcontroller's signal on it's way to the JUNGLE chip for OSD purpose. Not from an unpopulated part of the board like you alluded to. A set could be a NA exclusive and still be modeable.
"You might want to test this with a TV from the 1970s or earlier"
Unfortunately that won't be possible : ( Only TVs with JUNGLE chips can be modded, and these didn't show up until the '90s. I frequently check the list of confirmed models that can be modded, and so far it's only mid '90s sets and newer. We'll see how it goes
@@FinalBaton "You're probably partly repopulating connections that American TVs already contain, because the same chassis is used for European TVs that do have a SCART socket and an RGB connection (as well as Japanese TVs with JP-21 connectors)" Not quite. While very few sets can be modded that way, the vast majority of modeable sets(such as the one featured here) take the RGB from the Microcontroller's signal on it's way to the JUNGLE chip for OSD purpose."
Meaning that the set already has at least one RGB input that could be used not only for an OSD but also connected connected to a Teletext decoder or passed through to a SCART socket. It wouldn't surprise me that cheaper TVs sold in Europe would have done just that.
"Not from an unpopulated part of the board like you alluded to."
But if the Jungle chip is so useful for European and Japanese TVs and adds features that are useful to TVs across the world, why not add it? Especially when Japan uses NTSC too. 8-Bit Guy didn't use an unpopulated part of the board, he used the existing RGB input the TV already has.
"A set could be a NA exclusive and still be modeable."
Because it would already have an RGB input.
""You might want to test this with a TV from the 1970s or earlier"
Unfortunately that won't be possible : ( Only TVs with JUNGLE chips can be modded, and these didn't show up until the '90s. I frequently check the list of confirmed models that can be modded, and so far it's only mid '90s sets and newer. We'll see how it goes"
I was working on the assumption that all TVs take the RF signal through a demodulator which would then output a composite signal (take out the demodulator and you have a composite input even on the oldest TVs) which the set would then convert to RGB to power the guns on the tube, of course, these inputs on the tube could be massively high voltage and require a fair bit of work.
Of course, I could be wrong, the composite input could be decoded to component video rather than RGB. American TVs only had to deal with NTSC, European TVs had to potentially deal with PAL and SECAM, PAL being similar to NTSC but SECAM being very different AFAIK.
@@GeoNeilUK On sets of that era, by the time it is an RGB signal, it is in a very high voltage state whether the set is a chassis tube set or solid state.
Awesome work. Thanks for the VGA follow-up! Back in the day I had a nice NEC multi-sync monitor connected to my Amiga which could sync down to 15khz.
thanks so much, ive been hoping someone would post some videos like this that i can replicate, keep up the mod videos! loving em
So much easier just to use the Scart port ;-)
Greetings from Europe!
Salutations from Poland!
Saluti from Italy :-)
Sveikinimai from Lithuania
Greetings from braSil 😉
All the best from the Netherlands ;-)
David, am so sorry about your cat. I hope she is in a better place now.
Ugh, animals don't have a soul and won't go to heaven if such a place existed.
@@Okurka. I liek to be meaningless meen it nut mattar if I rape baby while murder a cripple old lady an den rob bank and keel al dare wit bio chemikal weepon den gu tu local polike sation wit flamtrower an burn al dem an loot der bodeez wile tee bag tem
Corrupted Reptile what? Please translate I can’t ready anything on what you said
Okurka your heartless. Animals do have souls unlike you. YOUR SOULESS.
Nice work getting the sprites to be transparent at 6:14 David! Quite an upgrade from the old pink color from your demonstration in the third video about Planet X3! I would also like to say that I've finally gotten my channel (this one that I'm writing from) up and running and your music from 8 Bit Keys works great with my channel! Can't wait for the next video! :-)
Cool!!! I'm glad you went ahead and demonstrated this! How I am just now seeing it two weeks later is beyond me, though!
Why wouldn't a diode work?
[Edit: this comment is, as SEVERAL have told me, despite my already being corrected a few comments down]
Due to the way diodes work, it would unavoidably lower the 5V from the micro controller to like 3.6V, which might be out of the circuit's tolerance. Plus, doing that thing with that switch is easier and cheaper
Cuz you need a FULL BRIDGE RECTIFIYAH!!
@@Crusher29 I see what you did there!
the problem is a FULL BRIDGE RECTIFIYAH!! would drop the voltage by double the amount ;)
Yes, I AM fun at parties. I seek out the pets
Bengineer8 You are right about the lower voltage, however, a typical silicon diode only has a voltage drop of around 0.65 volts, so the output would be ~4.35 volts which is very close to the range of a TTL-level IC (4.5v to 5.5v approximately). A germanium diode has a voltage drop of ~0.2 volt
2 uploads in one week !!! Woah i must be dreaming ♥♥
Using the VGA cable on an interlaced TV is very cool stuff and I do like the interlaced Amiga look...another great video.
I've found myself being hooked onto these videos. Heck, I can't change a 3-pin plug (UK) without blowing up the house but this is fascinating.
@1:59 for a brief moment I thought it was the sound of a short-circuit then the whole area was on fire 🤣
a more elegant solution would be to just add a diode (maybe schottky) between mcu output pin and your +5v switch, so that current could never sink into the mcu. leaving a dangling ic pin is ungood, and with a long wire connected to it, doubleplusungood. it can lead to all sorts of erratic and weird behavior.
I don't think I agree here. You can normally safely leave an output pin unconnected. For inputs it is a different story, but that is not the case here.
a TV has high-voltage parts that produce powerful noise, and does the processor really need any more trash in its power and ground rails (in the simplest case) than it already has? why not prevent a potential problem before it has a chance to arise??
on the other hand, if it hangs once in a blue moon it's not really a big issue.
You need a hell of a lot of inductance to confuse chips running at TTL voltages, don't worry.
Oh wow! i expected this part 2 to come in a few weeks, its kinda weird to get a part 2 so fast here ^^
I never thought you would go back and finish that cable! Well done, sir!!
The solution is to have a resident program that will keep the vga registers set to whatever you want so that even if apps change them they go back to the correct frecuency in say half a second?
Otherwise youd need a loader or to patch the games so they dont change the registers
Eternal love!
that wouldnt work if game messes with geometry, "changing them back" would distort custom mode game planned to use, like 320x240, 320x400, etc. What could work would be periodically (lets say every 1-2 seconds) reading CRTC, detecting change and adapting to new values.
The solution is to add an EEPROM that describes the NTSC video mode.
you'd need to rewrite the registers at least every 60th of a second, CRT's refresh crazy fast, from 60hz up to 200hz (maybe even further, but nobody knows yet)
MARIO nobody changes timings every frame, you do that only when changing modes, 1-2 seconds without picture is not the end of the world
Hey, David, you can add a diode between +5v and blanking signal to add an extra layer of protection.
yeah just in case the switch gets stuck in the middle so the microprocessor can output 5 volts to the jungle chip but no voltage can go into the mcu.
Definitely something worth looking into to revitalize these CRT based TVs from...not so long ago.
awesome video :) Cheers David! won't be used here in the UK but it does make you wonder about a lot of things!
I feel like there should be a TSRs that will sit between the game and the real hardware (hook the int) and just make it pass through timing things that work, and block register settings that will cause it to drop into an unsupported mode.... or at least watch for a keypress that will drop the video card into a working resolution/timing set. I made one back in the day for my Gateway Handbook... press a key sequence and it toggled through a few video modes/screen stretch values to fill the screen better for a few different games. :D
Sounds interresting
Lemmings Cracked by Fabulous Furlough, eh? 5:47
I just found Planet X2 +3D by Faayd/Excess.
I guess David won't mind us using it as he uses pirated software himself.
Can you buy Lemmings today?
+Morgan Feldon Probably not. It's likely abandon-wear. I meant it more as a joke then to accuse of piracy. Plus, I'm sure Dave bought Lemmings back in the day, and since it was a floppy, it's likely to have stopped working by now, so he probably just needed the files for the game he already bought.
Morgan, that doesn't matter.
You can't buy most NES or SNES games today, but that doesn't stop Nintendo going after pirates.
@@Okurka. You now can buy NES Games
In 90s (around 1992) I had actively used a clone of 8bit 6502 based computer: Oric Atmos, called Pravetz 8D. I paid a good amount to get a custom mod to use my PAL TV trough the din connector on Oric. Now I'm not a tech savvy person, but the comment the technician made popped up while watching the video: "o its simply R, G, B and sync" so they probably made something similar to this mod :D
Thanks to this, picture was clear and gave me the pleasure of many hours of assembly developing. Thank you for bringing back these lovely memories ... I wish I have a way to import the code I had written then to see on an emulator now ...
David is a genius with electronics. Kudos to create this video to turn a standard television to a monitor.
For anyone who don't have this tri-state switch you can add a diode between the switch and the mcu that will works the same
It actually depends on what diode you put in there. One wich drops down only about 0.2-0.4v, it may work. A more common 0.7-1.5v drop diode? Probably it would be out of the chip's tolerance and wont work.
Nice hack. But i have loads of vga monitors. What i am missing is cga and ega monitors.. And even hercules monochrome. Been googling for specs on MDA and found nothing. Still will find something eventually. Have you covered hercules monochome adapters?
I have not covered Hercules yet. But I'll be mentioning it soon enough.
Hercules... you could probably get into a vga monitor with some work, with resistors etc., but why not use something like mce2vga?
LGR did a good review of a Hercules card
Robeight MDA is like CGA, but only one color and different H/V frequencies. Original Hercules is literally MDA but with a graphics mode in same resolution and frequency. MDA, Herc, CGA and EGA can all be configured to arbitrary H/V frequency as long as you keep the pixel clock the same, since they all use or emulate the classic Motorola/OnSemi 6845 chip.
The nice thing about this mod is that by using a 9-pin D-Sub connector, you could turn your composite CRT TV into a CGA monitor!
HOLY SNIPPLES 2 WHOLE 8 BIT GUY VIDEOS IN 1 DAY.
Love seeing the Planet X3 stuff in your videos, that's the exact reason I backed!
It would probably be cleaner to just put the new circuit inside of an adapter box that the RGB and VGA cables plug into. Either way, since you have to change the output from the VGA card for this to work at all, meaning it no longer works with any other VGA monitor, this strikes me as more of a "FOR SCIENCE!" thing.
To be fair, that's exactly what he did it for - he outright says at the beginning he did it because people asked him to demonstrate it. He originally just wanted RGB video.
@@ThePageofCups Of course, I didn't mean to imply that "FOR SCIENCE" wasn't a great reason to do something.
He literally said it was a dirty way of doing it, just for a quick demonstration.
And now, everybody disassembles his tv and add this mod.
Xidexs my TV has Scart.
Welll my samsung ips tv awready haves hdmi, vga, and rgb composite. I would like to do the reverse mod to some old devices wich i can't seem to find the rgb cable, and add the component input.
@@CaptainDangeax The biggest issue is the lack of scart cables ouside europe. I dont even know if, for example there is a scart cable, for example, for a ps2.
@@eduardoavila646As far as I know PS2 has an HDMI output, so is not in the scope of this video. The playstation classic has an analog output and then, you can choose between composite or s-video, with a 4MHz bandwidth, and RGB, with a 20 MHz bandwidth
@@CaptainDangeax No i hadnt. The hdmi cable that exists for the ps2 from what i know is a third party cable wich actually has a circuit inside to convert the signal. So a rgb composite cable usually looks as good as the hdmi option or even better. And it would also be way better to record directly from a capture card (i think), because it would have one less converting circuit to drop the quality.
The xbox 360 had a hdmi cable nativelly without any conversion circuits.
love your videos, My first experience with multimedia was actually an AST Advantage! at 133MHz, 16MB ram and windows 95... some great memories...
It's great. The best content on RUclips.
I seem to remember years ago there was a range of ATI video cards which had modified VGA BIOS ROMs to support 15KHz mode so they'd work with an RGB monitor. Really interesting video, being in the UK I'm spoilt with SCART but years ago I had a TV which only had Composite Video input, made it awkward playing US import consoles in black and white :-D
I wonder too if it's possible to get a board to convert from the VGA frequencies to RGB?
You need a downscaler, VGA and NTSC are very close, 31.4kHz vs 15.7kHz horizontal scan and 60 Hz vertical for both, but with PAL, 50Hz it's a heavy problem, causing flickering or artifacts
I think Matrox G200 TV series also had a specific BIOS, able to output in 480i or 576i at 15khz.
That was fast! And it’s still unlisted! 😂
101ToonLink lmao
This RUclips section is bliss compared to other corners of the internet. Quality content AND viewers!
Lol, epic addendum David, you never leave a stone unturned 👍👍
According to all known laws
of aviation,
there is no way a bee
should be able to fly.
Its wings are too small to get
its fat little body off the ground.
The bee, of course, flies anyway
because bees don't care
what humans think is impossible.
Yellow, black. Yellow, black.
Yellow, black. Yellow, black.
Ooh, black and yellow!
Let's shake it up a little.
Barry! Breakfast is ready!
Ooming!
Hang on a second.
Hello?
- Barry?
- Adam?
- Oan you believe this is happening?
- I can't. I'll pick you up.
Looking sharp.
Use the stairs. Your father
paid good money for those.
Sorry. I'm excited.
Here's the graduate.
We're very proud of you, son.
A perfect report card, all B's.
Very proud.
Ma! I got a thing going here.
- You got lint on your fuzz.
- Ow! That's me!
- Wave to us! We'll be in row 118,000.
- Bye!
Barry, I told you,
stop flying in the house!
- Hey, Adam.
- Hey, Barry.
- Is that fuzz gel?
- A little. Special day, graduation.
Never thought I'd make it.
Three days grade school,
three days high school.
Those were awkward.
Three days college. I'm glad I took
a day and hitchhiked around the hive.
You did come back different.
- Hi, Barry.
- Artie, growing a mustache? Looks good.
- Hear about Frankie?
- Yeah.
- You going to the funeral?
@@roberte2945 what did I do?
@@roberte2945 BEE-leave me I wasn't trying to
I love the intro its cool only thing I live for lol
That little peak of Planet X3 running on VGA was a fun surprise. Thank you to the teams work on it.
Very big thanks for your videos! Funny, I also was looking at similar Samsung my father bought very long time ago, but, fortunately, it had SCART :D
The only recommendation I'd make is adding a current limiting resistor as pull-up resistor in switching circuit.
Never clicked so fast!
Can you reverse the vga to composite part to hook a composite computer up to an vga/ega monitor?
No, because the composite output will be at 15khz horizontal sync and the VGA monitor expects 31khz. You'll need something like a GBS-8220 which adapts a 15khz signal for use with VGA.
not to mention that you'd also need to split the composite signal back to R+G+B+Sync
The RetroTink 2x and a VGA to HDMI cable might be a good bet too
For a digital solution like the RetroTink or OSSC you need some kinda box to convert that digital signal back to analog, can't just do it with a cable and it's most likely going to be blurry.
@@Nukle0n Well maybe not, 640 x 480 31khz is what they both output in line double mode, so it might look pretty OK on a VGA monitor with a simple adapter.
great video. Thanks for the follow up.
one of his best videos.
That was fast! Question, instead of the double throw switch, can't use a diode to prevent the 5v returning to the microcontroller?
there is a lot of comments discussing diodes, different types and the like.
You could also just use a resistor so it just sinks much less current.
@@russdill Problem with that is that it's still back feeding into the microcontroller, plus it would also affect the level of the signal going from the microcontroller to the jungle chip when the switch is off. A diode would have a small effect on the signal level as well, but not as much as a resistor would.
The double throw switch is an elegant solution that minimizes the change to the blanking signal. Yes, there is still some extra resistance due to the longer wire, but it's nothing compared to using a resistor or diode for this.
The switch solution is clearly preferable. I'm just saying I've seen similar problems solved in a very similar way. You're connecting an open-source to a totem-pole in a configuration where if the open-source (switch) is driving high, you don't care about the totem pole. Just put it behind a 4.7k. It'll have a negligible effect on the voltage if it's driving low, and will only be sinking about 1mA. The thing to watch out for here is it has an effect on the microcontroller's rise time. Back of napkin says it'll be fine though.
I'm still in the learning phase here, but I was wondering...
Would you be able to solve the problem with a diode between the microcontroller and the +5v supply?
Possibly. but it was easier just to add the extra wire for the switch.
@@The8BitGuy True. Less parts to buy.
Thanks
Yep a diode would work. A switch works fine too as long as you don't get any issues with "bouncing"
I'm really surprised it worked. TTL gates only work by draining current to the ground and assume a 5v input when unconnected. The jungle chip is obviously not TTL.
I have a semi-digital Brother typewriter with a digital dictionary and word correction that I was thinking of restoring, since a few parts are broken. Thanks for inspiring me, and greetings from the East coast.
Hey, that small form factor 486 I sent you that got banged around in shipping is up and running! Good to know you're actually getting some use out of it after all!
lol you're running a cracked version of Lemmings. 👍
Looks like you have to attenuate most of those RGB sources. That’s why your black levels are so bad in RGB mode. Also, you can fry some RGB equipment like that. RetroRGB recently made a good video series about using an oscilloscope to get proper RGB levels from your devices so that you don’t fry the display or video hardware you connect it to.
Yes, even the Sega Genesis needs components in the cable. The RGB is non-standard, from a time before there was an RGB SCART standard. It’s really more in line with what you might connect to an arcade machine’s CRT.
Ehm.... the Sega Mega Drive was released in 1988 in Japan, then in 1989 in the US as Genesis and in 1990 in Europe as Mega Drive. SCART was introduced in 1984 and by 1988, most televisions had it.
There were official SCART cables for the Mega Drive:
segaretro.org/SCART_Cable_(Mega_Drive_2)
The black level is bad because the resistor values need to be tweaked some. I thought about mentioning this, but decided not to.
Daniël Mantione You misunderstand. It was a regional standard when the Genesis was engineered, not an international one that was broadly required for TVs across Europe and other PAL regions. Even when it became an international standard it wasn’t standard in Japan.
In Japan the Genesis multi-out pinout was actually developed for the Sega Mark III/Master System before its release in 1985. Though the pinout is the exact same, strangely, it requires amplification to reach proper SCART RGB levels where a SEGA Genesis needs the exact opposite (attenuation resistors). They also require capacitors.
Perhaps most televisions *in stores* in 1989 may have had it by that point, but it would be years before enough people replaced their TVs that “most” in people’s homes would have them. Obviously, Japan was only concerned with the NTSC launch in the ‘80s where it was not standardized for consumers so the output was not made to conform to any European standard. Obviously. Just like Neo Geo, the RGB coming out of a Sega Genesis model 1 is more akin to what you would use with an arcade machine, which makes sense because SEGA was a member of JAMMA (Japan Amusement Machine Manufacturer’s Alliance, IIRC). The JAMMA standard for RGB was intended for arcade machines and the coin-op industry. “Standard?” Yes. Consumer/end-user standard? No. Industrial.
What’s even more relevant than how ubiquitous it was in new TVs or how prevalent it was in homes at the time is when it became mandatory for all TV manufacturers to get European certifications, but that’s proving hard to pin down. It was only made mandatory in Eastern Europe in 1989 and was only mandatory in France before that.
The EuroSCART guidelines also dictate that the device outputs the proper levels already so that a straight-cable with no resistors or capacitors can be used. This makes SEGA’s official RGB SCART cables in violation of the standards. I actually don’t think it should apply to devices with a proprietary multi-out (not standard to begin with) but high-profile RGB engineers like Voultar insist that the required components absolutely should be inside the console and not inside the cable.
Japan never really settled on a physical standard. Some TVs accepted a weird D-Sub-like connector, others used RCA Cinch, some used a SCART-like JP21 with a different pinout, and still others used 15-pin VGA-style connector. Even the lauded XRGB Mini Framemeister opts for Mini-DIN instead of any of those (Mini-DIN), and their standard 21-pin adapter cable is wired for JP21, not SCART.
Japan couldn’t even decide on an electrical standard, which is why the PlayStation doesn’t have CSYNC, the PlayStation 2 uses Sync on Green, and different Neo Geo AES systems output wildly different RGB levels (even more like arcade boards where they were adjusted by a technician, considering the pedigree), and even Japanese-produced North American TVs with 15-pin “RGB” ports don’t work with RGBS (RGBHV-only, AKA VGA). This is why RGB for consumer electronics remained niche, even in Japan.
I think I’ve got a pretty good handle on this. ;)
The 8-Bit Guy Yeah, but you also generally need to add capacitance and sometimes need to do more for proper sync (not with Genesis, IIRC).
Can you elaborate on this? I performed the exact same mod on an identical CRT and the black level was atrocious. Lowering the brightness on the flyback transformer helped but of course, this dims the overall picture.
seriously awesome videos! wouldn't mind more CRTs vids. i learned a lot from these videos. might tr to mod my small crt too.
Your knowledge of electronics is impressive
Where can I get that God tier T-shirt?
Where do you get NTSCPOS.COM?
web.archive.org/web/20160304020057/www.ccs.neu.edu/home/bchafy/tvFiles.tar.gz
Such an awesome episode/mini-series.
I'm not certain whether I'd have the skill to actually open up a CRT TV. The CRT Tube makes me nervous without being with my cousin who has the electrical experience from his engineering career. :) Still, awesome!
I love the music in these videos
You could have just connected the switch to the Jungle chip side of the resistor
That would limit the power coming back to the MCU chip, but not remove it altogether. Besides, the resistor probably brings the signal from the MCU down to the level the Jungle chip needs, so bypassing this directly to +5v could damage the Jungle chip. David's method is effective and has fewer potential problems in the long run.
Fully seeing you here, Mike. David could have also used a diode between the Jungle chip and the micro, with the switch in the center.
Would there be implications for the jungle chip if it sinks 5v without a resistor?
@@beware_the_moose Could be, depending on what the input voltage tolerances are on that particular model of chip. From the datasheet I found, it probably wouldn't be a problem on this particular set, but it could on other TVs with different Jungle chips.
@@remyrattner6399 I was thinking that a diode would have been effective as well
This is one of those videos where I click Like in the first 5 seconds.
Thank you for fixing that. I may mod a few TVs this way in the future.
Great Video!
Just a small note on SCART connectors. Theoretically it was pretty cool, but in practice it was quite a mess. It had lots of options, including the RGB, but not every TV implemented it. Most did not, as much as I know. Even if a TV did so, it did usually just for one of its SCART inputs. Cables were not the same, either, some had just the most important wires, some had more… If everything worked well, it could do some nice tricks, like a VCR downloading the TV channel frequencies from the TV via SCART or, which was more common, switching on and off a VCR or a DVD player could switch the TV on and off. With my first DVD player it did not work very well: a signal from the TV on one of the pins simply disabled the DVD. I had to use a little tape on the corresponding pin to have picture at all. The idea was nice, and actually it was pretty usable, but definitely could have been better.
RGB was almost always implemented on SCART due to French legislation, the would have been rejected from the French market otherwise. But indeed, TVs with just a single SCART port that is RGB enabled are relatively common.
I didn't know that, thanks for the fix.
RGB as far that I know was supported by most the TVs on the market. On one TV only the primary SCART connector supported RGB, as the second one typically supported S-VIDEO (and since they share pins it was not possible to have both on a single SCART). But it was not a problem since you could daisy chain your devices, back in the days I had my SKY receiver plugged into the TV, and my VCR plugged into the SKY box, and then a DVD player into the VCR.
Most of the problem you had with SCART where due to using cheap cables, the good cables were bulky because they contained in themselves single coaxial cables, the cheapest one only contained single cables not individually shielded, so a lot of the times a signal would interfere with others, and produce ghosting (for example, the video return signal from TV interfering with the feed signal from a VCR, very annoying. For fixing that problem you would have needed to open the SCART cable at the TV side and cut pin 19, making the cable unidirectional in practice)
SCART had feature that neither HDMI this day has:
- ability to daisy chain devices
- video return, so you could have recorded from a set top box with a single cable
- automatic input selection on the TV (there is HDMI CEC but doesn't work most of the times)
- passing teletex data to the TV, useful if you wanted to see teletext from a set top box
The reason that in France RGB was required was that in France they used SECAM to encode color information, where in most other european countries PAL was used, so the only way to get compatibility with other european equipment such as VCR was to use RGB (that was always compatible since RGB is universal and the sync was compatible with PAL)
Again, thanks for the info. About the daisy chaining: I pretty much hated it. In order to watch DVD, I had to turn on the VCR, and select the AV input. It was much better when I finally had a TV with two SCART ports :)
DAMN! Man, I don't really understand, how You could live without SCART (or something simillar) in US...
And the rest of the world (except europe and japan)
Not to mention 120V and the NTSC standard.
NTSC - Not The Smartest Choice with 29.97fps :D And imperial scales in general... I am pretty sure, that if I buy dozen of eggs in US, there will be 11.876 of them...
@@vapno92 If i buy eggs in europe i'm pretty sure they will come all sliced up (interlaced).
I thought I got another notification late, but it turned out to be something even better!
Absolutely great improved mod, i congrat you for the fact that that crt tv still works after 21 years.
Obviously, a vga signal can only work on a tv if the signal is not greater than 320p,.
👌
EpicLPer video, 30 seconds ago, comment, one hour ago, nice one youtube.
@@asandysoldier3164 Patrons ftw
Yeah, i know now, ive been corrected 4 times now.
Wait, is he actually gonna fix that cable? I thought he’d never bother to fix it like a normal person! *EDIT:* Wow! He actually fixed the connector!
I thought it was more normal not to fix it.
Cavey Möth Yeah I agree!
Awesome video! I'm working on modifying my 1980s Sony Trinitron for this RGB mode! :D
man thats awesome. i did that wiring job but didn't know why it wouldnt work. i got the same whizzly whizzly frequency wrongness. didnt know about that msdos tool to change the frequency. man thats amazing seeing VGA go out to a TV. it goes against everything you'd be told traditionally