Support The 8-Bit Guy on Patreon: / 8bitguy1 Visit my website: www.the8bitguy.com/ Watch the 8-Bit Keys episode from last month. • Intellivision ECS Keyb...
When I was a kid, my dad fixed our TV antenna with a bit of plasticine, "just for now". That temporary fix lasted few good years until the antenna broke completely.
I begged my parents for an intellivision and never got one. They said my Atari 2600 was good enough. I begged my parents for an NES and never got one. Our 2600 was good enough. So I gave up on consoles and went into PC gaming because my parents had no problems upgrading my computers when ever I asked. After all my PC was "educational" lmao
I never had a console or bedroom TV. My parents got me a cheap Compaq desktop in 1999 for my birthday and dialup internet. I saved up every summer and extensively upgraded it over the years to play newer games. I learned how a computer fundamentally works and how to manually repair broken parts. I threw in the towel and gave up last year when I just couldn’t get it to run Office 2019. It runs everything else just fine-Windows 7 games up until around 2013. I bought a new old stock MacBook Air that still has serviceable parts and it’s really nice to take with me to work and in the garage. I keep that old computer under my TV for streaming web radio and playing retro games.
Those2menoverthere . Thanks. If it weren’t for my parents making me learn how to understand and take care of my things, I’d be a completely different person nowadays. Same goes for my truck and my other little things. I love that old Compaq and I’ll keep it forever.
Looks incredible and the music sounds amazingly faithful too. I'd like to see a version for the Vic 20, but the lack of hardware sprites would probably make it less playable and attractive than the Intellivsions version which seems to play and look almost exactly like a low res version of the brilliant C64 version.
The passive RLC termination on the output of the video chip, and new additional composite circuit, has to keep the vertical and horizontal video blanking pulses clamped at a constant level for the TV to properly lock to it. Additionally, on the _back porch_ there will be the colour-burst that needs to be stable for a good locked chroma. Just above that is the black reference level that also must stay constant to maintain a constant brightness for the entire frame. This will take a bit of experimenting to get right and I imagine may be more complicated than just a resistor. Cheers,
Seems like David know nothing of the Intelli. Otherwise he would be floored. I myself was stunned. Those guys didn't push the Intelli to it's limits. They went past!
The answer: "... what others say." The noise on the screen and in the audio comes from the diode in the tank circuit used to demodulate the RF out of the signal. With no signal the diode voltage hovers right around threshold voltages and begins to leak random spikes of current. These spikes get amplified in the video signal pre-amp. Modern T.V.s from about the mid 90s to present, use an RF detector in the RF tank filter to trigger a screen blanker or substitute "blue screen" in the absence of an RF signal, ... *because semiconductors leak* . It's a fact of physics. The failed screen you show is typical of a video signal that "floats" above 1 volt. The "blacker than black" part of the signal which synchronizes the monitor's horizontal scan needs to be no more than or less than 1 volt. Occasionally the signal will nearly match the vertical timing in the monitor set by the line frequency and you get an edge "torn" image. Other times the line frequency and video timing are so far off the monitor never triggers the horizontal scan at all and you get a blank screen. The commented suggestions to add a 75Ω shunt resistor (to ground) to the composite video output draws the entire video signal down to or below the required 1 volt. It's a trick people used to bypass the very early VCR copy protection schemes where the recorded video on the tape was raised above the one volt "sync" threshold. The RF modulator sets this base voltage through the signal (usually the common) ground in the cable connection to the monitor.
I suspect that it's the input side that needs biasing fixes. I've made simple op-amp AV mods that use the 75-ohm series output resistor with a coupling cap, and had no sync problems. But the Astec RF modulator does have a characteristic input impedance (as shown on its datasheet). Really, I don't get why everybody has a different circuit for the same mod on different platforms. 90% of them can be simple op-amp circuits like the "official" Colecovision AV mod does. You can use a pot to adjust input gain if necessary. One thing I notice about the IV's mod is that it's two back-to-back common emitter amps which are not even impedance matched between them. Its likely purpose is to provide signal gain, but it needs 2 stages because each one inverts the signal. But there is no input coupling cap on the Astec, at least not that I've seen from actual inspections, so the Astec itself will be affecting the input DC bias voltage too. That is likely the missing part. Take a DC reading with the modulator installed, then with the modulator removed. Now you know what voltage to aim for with the replacement circuit, and whether it needs to be pulled towards power or ground. Connect that and the AV amplifier, then adjust until you get the desired DC voltage. *Edit: Looked at the IntvII schematic. The video in from the Astec only connects to 2 diodes, both in reverse bias. One goes to a video input from the cartridge connector (apparently the cartridge port also has expansion port capabilities), and the other goes to the internal graphics generation. Either way, you can only pull the voltage down, not push up. So the RF modulator is providing a DC bias that **_must_** be replaced if you remove it. A pull-up resistor to +5V would be all you need.*
I had a book on NTSC, and remember a lot of this. The two black bars were called “front porch“ and “back porch” because they were huge drops on each end of the signal.
According to the circuit at 4:36, the signal is only AC coupled... So when you remove the RF modulator, I suspect : - either a problem of DC bias of the previous stage. - or of input impedance. To get the same DC bias: 1- Measure the DC voltage value on the signal input when the RF modulator is present. 2- Replace the RF modulator with your circuit. 3- Add a big valued potentiometer between +5v and Gnd and connect the mid point to the your circuit input. 4- Turn the potentiometer until you measure the same DC voltage as in 1. To change the impedance, try as above with different valued potentiometers. (Or less experimentally: Ohm's law would give you R=R1//R2 if R1 and R2 are the two parts of the potentiometer). I hope this helps. Good luck!
My husband introduced me to your videos a while back and have been hooked ever since. I love watching you fix and clean things up. Watching you modify computers and such is pretty dang cool. Congrats on the million! 🥇🎉🎉🎉🎉🎉🎈🎈
The output impedance of a video circuit must be in series. The TV's input is in parallel to ground, so that its input is halved from your output. This guy's simple passthrough amplifier circuit shows the difference between input and output: www.labguysworld.com/VideoCookBook_002.htm
I remember my dad had his original-model Intellivision composite modded by one of his engineering friends. He just brought it over, his friend had the board already made up, and in 5 minutes he'd opened it up, mounted it, drilled the holes, and it works fine to this day. That said, I've never opened it up myself to see *how* they did it.
You're videos are always the best friend! Thank you so much! BTW, I always loved the Intellivision controller. The trick is not to treat it as a joypad, but a disk. It's more of a swipe than a press. Also, Defender of the Crown is mind blowing. I would never have imagined that would have been possible. That guy deserves a medal. He must have a made a deal with the Devil.
I always click on these videos thinking i'm just going to listen to the intro music and move on. Next thing you know its been 3 hours and on a separate tab i'm looking up the cost of a Commodore 64.
“Hover Bovver” talks with the Intellivoice module. Adds more humor. Only 4 official voice games were released, but there’s plenty of voice modules around.
I remember being impressed when I heard it as a child in the 80's when my brother played Space Spartans on our Intellvision! Nice someone went to the trouble to include speech in Hover Bovver!
There was a fifth official voice game, but it *ALSO* needed the ECS Computer Module - World Series Major League Baseball. A very impressive baseball game for the time, it used real player stats, but they couldn't get the rights to use the names, so the players all have made up names - but with the stats of real players of the early '80s. It's also ridiculously expensive to buy nowadays - I lucked out and got a boxed copy for under $75 a few months ago, usually it's $150+. But yeah, lots of ROM releases of era-unreleased voice games, plus many of the new games (like Hover Bovver) support voice. Hover Bovver's voice is great!
Hopefully someone makes an AVGN game that uses the module. "MATTEL ELECTRONICS PRESENTS: AY-ASS!" The screen would read "AVGN" or something similar, though.
This was amazing. The first console I ever played was the Intellivision and it's always great to see that fun system preserved and modernized so it can still be enjoyed. Sub +1 :)
I researched the composite mod a few years back, the circuit you built was designed as I recall to bring the video signal down a considerable amount in frequency levels to output as composite. It would also explain why the RF is still needed as without that there is no signal to alter. I think I might have still a made-up original board the guy sold for the original Intellivision, not sure but might still have it. I also recall he said the distances between the connections need to be as short as possible. As far as good games are concerned for the system, Tron was a favourite.
A lot of my life was spent playing Defender of the Crown on my Amiga 2000. Thanks for a fun and very useful mod on that Intelevision. It's absolutely something you can retrofix later and tweak.
Huge congratulations to David, the 8-Bit Guy for getting over a million subscribers! I watch the David's videos because they are so precise about every detail. Fascinating!
Hover Bovver actually makes use of the Intellivoice. The voices add to the game's humor. Also, the original Intellivision has a way better controller than the Intellivision II. I have one of the only Intellivision composite mod videos on youtube, so you might have watched mine :) Cool to see some Intellivision love on your channel even though it wasn't your jam back in the day.
ONE MILLION SUBS!!! You deserve every single one! I love this channel, and have already learned SO much from watching your videos. Hope you have a nice trip out of town! Be safe!
David, when we met and were on the way to the auto show together, you were at just under 400,000 subscribers. I said it was gonna keep going and you were like, "Nahhhh it's slowing down and I don't think very many more people are interested in this kind of stuff." Now look! I knew you'd get there. Congrats on the million.
Why didn't you wait to figure out the issue with the RF Module before drilling holes into your console? Wouldn't it have been better to just put the wires through the back vents for the time being before drilling holes you cannot undo? Not criticizing I'm just wondering why you went this route.
Because it's an intellivision II so he's not worried cause he's keeping it for himself. You wouldn't do that to an original Intellivision due to value issues. Though to be honest they don't command high prices even though they were better than Atari's.
"It runs the same games". Well, almost all of them. Mattel modified the Intellivision II BIOS so that it would not run third party games like Donkey Kong. If you look at some game boxes they will have a sticker that says "Not for use with Intellivision II".
Except it probably wouldn't have because they're no doubt leveraging a large amount of ROM space (and probably extra components for bank switching) to make it look that good. Its doubtful even near the end of life of the console that they could have released it without having to charge an exorbitant amount of money for the game compared to normal game prices for the system.
@@JeremyLevi So when you consider the Starpath Supercharger cost $69 at the time and it had 6KB of RAM, they likely could have done a 50% upsale and still sold like gang busters.
@@WildkatPhoto Sure, but consider the Commodore 64 version (roughly comparable in quality) is over 160KB in size ... assume you're probably looking at something like 64KB-128KB of ROM, minimum, to fit the game. That's not small potatoes, cost wise in '86 (and not even thinkable in '79 when most cartridge games used 2-4KB of ROM).
Thanks for posting this. I've had this mid sitting around waiting to be installed. You motivated me to dig out my I2 and install it. It looks so much better. It also works with the 2600 add on plugged in. Thanks for the motivation and great videos!
Congrats for the Million! One blind suggestion, are there any termination resistors inside the RF modulator which reduce/remove any reflections of the image signal? If that is the case, all you'd need is to replicate that termination resistance in the composite circuit get it to remove the reflections.
Super happy to see the Intellivision getting some love, especially the II that I had when growing up. I always die a little inside when I see old plastic being cut up, though. Hah
I don't know if you are familiar with the British Sinclair ZX Spectrum 8-bit home computer, but once, many moons ago, someone wrote a game for that machine called Lawn Mower Simulator, which was so primitive that it sparked an annual Crap Games Competition. Ironically, some of the entries have been surprisingly un-crappy. ;)
@KoivuTheHab Have you not used a phone before? It's not a matter of your brain, it's the fact that the screen keyboards aren't really meant for precision stuff. Like. You know. Typing.
@KoivuTheHab My guess is you either have a phablet, small fingers, or enough time to spend ten minutes pecking on each message. Also, and, much more likely, a low enough self esteem that you feel the need to boost by convincing yourself that you're smarter than other people because of random false equivelents. :D
I wanted to sign up to be a Patreon but the only pledge you can do is $10. a month. I can't afford that. Please consider adding lower tiers, such as a $1 tier, and a $5 tier.
Can't say I've ever heard the term "Christmas Tree bit" but I can see where the name comes from.... Those are very very handy though. I call it a "stepper bit" or just "step bit"...
Most certainly, but I wasn't able to work it out. The mod that everyone is using is based on the load the RF modulator is drawing and modifying it is not as trivial as I thought. Long story short, we just don't have the time to work on it more at the moment. :-)
My first thought was that the modulator needed to present a 75-ohm load on the video signal. But as you say it sounds more like something else. That looks like a standard Astec RF modulator from that era, so opening one up to see what's inside should help. I understand it takes time and effort to do that; don't worry, we're enjoying the journey to get there! ☺👍 [ Edit ] If this helps, a link to a PDF doc with details: console5.com/techwiki/images/2/21/Astec_UM-1285-8.pdf Good luck!
@TexElec Sorry for suggesting obvious things, but have you tried just sticking potentiometer between video-in and ground, and another between audio-in and ground and just fumbling with those? If 75R resistor didn't work, try a pot - trust me, it's worth trying. You can also try to dig up a datasheet/schematic of a similar RF modulator - they are probably designed to be more or less interchangeable - and see what its inputs are supposed to be. A datasheet for console's videochip (if it exists) could also be of use. Measuring current/voltage with a multimeter is useless here, you need to get a datasheet and/or just guess the value. If you can find nothing, it is probably around 50-75 ohms, so start with a 150 ohm pot and slowly move it down. If nothing is overheating then it's most likely ok - just don't leave it powered for more than a few seconds. If possible, hook a scope to the line while moving the pot. I'm sure you'll see what's going on. If that didn't work, I'd try a stupid thing - connect the modulator to the video output through another pot and slowly move it up until picture starts deteriorating, then attempt to counter this with pot to ground, and repeat. Another thing to try is modify the new amplification circuit - hook up pots instead of resistors and look at the scope, comparing with how it should look like with modulator attached. Probably combine with previous method That being said, I still don't understand why remove the thing in the first place? Isn't having two output options better than one? I don't think signal quality suffers all that much from an attached RF modulator - it's most likely not that great to begin with, crispy clear consumer TVs did not really exist back then so I doubt anyone put too much thought there.
@@jwhite5008 I had about 4 of them going, and just could never get it to look 100% correct on the scope. I tried tacking on several loading caps / resistors of various values, etc. The fact is, video signals are fairly picky. I was able to get unstable images, but never really as refined as the original circuit. I'm working on a ton of stuff right now, including the X16 and there are a ton of INTV mods out there just like the one I built on the perf board for $20 or so. I was hoping to replace the modulator as I personally always remove them to prevent interference, but honestly, I think an FPGA->HDMI approach would be better so I don't even know how much more time I would spend here.
@@TexElec Analog video signals and RF in general feel a bit like voodoo at times don't they? There are fully documented specs and waveforms for NTSC timing out there, but modeling high frequency circuits and working out precise timing with passive components is an unforgiving art. Especially when you consider the host devices are tuned and tweaked as assemblies based on the inductance, capacitance/impedance/reactance of the all the components in the signal chain from the power supply to the casement. The most reliable way to do it today is as you suggest, put an ADC at the video chip's output and generate the right signals using modern electronics with some isolation from the dodgy retro circuits.
Congratulations on more than a million subscribers and while I wasn't a huge Intellivision fan either, I admin, that Defender of the Crown look amazing, if you keep in mind what this system is capable of.
First time I ever heard a step drill called a "Christmas tree bit". I love it, so I'm gonna nick it! Henceforth all my step drills shall be known this way.
Great video, David! Congratulations on 1 Million Subs! You should do something special. Like maybe a Livestream and play some of your favorite Retro games.
The gain gets turned to maximum and it's just amplified noise. It's not the cosmic big bang background noise or radio astronomy cosmic rays or pulsars and supernovae. That noise is at UHF channel 37, from 608 to 614 Megahertz. Also important to radio astronomy are 410 MHz and 1.4 GHz, but not the source of this noise. Edit: Well, *some* of it is cosmic big bang background noise. en.wikipedia.org/wiki/Noise_(video)
Getting better pictures out of old computers is always a fun challenge, I recently used an Amiga A520 RF adaptor to gut & use the DB23 connector to connect a SCART cable (Smug Mode Enabled) to connect my A600 up to my TV, and the picture quality over Composite is absolutely amazing on my LCDTV... :D I put all the wiring back inside the shell of the A520 so it looks sort of original, aside from the big black cable poking out the back where the RF connector used to be and the audio wires sticking out through the "Audio In" hole... :P
I don't know if this is a recent development but congrats on making 1 million subs! I love your videos they are fun and educational and I know I've learned a few things that have helped me over the last few years.
Well, red for video is period correct, at least. The video cable for my VIC-20 is red for video and white for audio. This was before TVs had RCA connectors, mind you, so that would have been for a monitor back then.
@@stevethepocket maybe but still... red is much more common as audio out than the opposite, it's way harder to get things backwards and fry one input by accident
the modulator on the intellivision has parts inside of it that help create the composite signal so it has to stay or you wont get any composite out at all.
