Troubleshooting the beautiful Atari 800

well hello everyone and welcome back to adrian's digital basement on today's video we actually have a first we're gonna be repairing this atari 800. i've never actually shown an atari 800 on the channel while other than a couple unboxings on mail call episodes but never repair so today is time to break that bad habit and work on an atari 8-bit machine so without further ado let's get right to it [Music] it's a really really nice looking machine i gotta admit this machine along with the 400 which was the cheaper lower cost counterpart to this came out in 1979 so a number of years before the commodore 64 which i think is around the very end of 1982. these machines also came out before the vic-20 e-mail so they really did beat commodore the punch with a color home 8-bit computer now as far as consumer-oriented 8-bit computers obviously the apple 2 was already out well i mean and the pet and the trc but if we're talking about ones that had sort of sound and color well the apple ii was a competitor but unlike the apple ii the atari 800 and the 400 twin really have very capable color graphics multi-channel sound output as well while it doesn't have expansion slots as the apple ii does it's a very expandable system it's really quite an impressive machine i have to say now from a build quality this thing is built really really well and i think it was shown in the price it was pretty expensive of a machine i think commodore was setting out to undercut atari with this machine when we take a look inside we'll see a little bit about how well this machine is built but even from the outside the case is really thick and sturdy the keyboard feels very nice to type on at least this particular one aesthetically i think it looks pretty cool we have four joystick ports on the front on the side of the machine here we have the video audio output it uses a dim connector but different than the commodore 64. and this may be the very first machine ever that i'm aware of that has luma chroma video output so it's the equivalent of s-video for that really sharp image that the later commodore 64s ended up adding as well but atari was doing it here in 1979. this multi-pin connector here is the expansion connector and i think it's called sio serial i o now i apologize in advance to all the atari fans i really don't know a whole lot about the atari 8-bit line so i'll surely make mistakes as i go through this repair so please just bear with me so anyways back to this sio or serial i o port it's very much like commodore's iec port and it allows you to daisy chain external peripherals modems cassette drives use this as well as did the floppy drives and unlike the iec port on the commodore this was designed for pretty high speed operation right from the get-go so disk drive performance on the atari is far far better than a non-fast loader equipped c64 we have a slider switch here which is just a channel selector i think is two and three for the rf output we have a power switch and then 2.1 millimeter barrel power input now it's ac on this particular machine i think it uses nine volts ac and that's because there's an internal power supply in here to generate the various voltage rails that are needed on the back of the machine there is a fixed rf cable now this is very much like the 2600 before it why is this permanently attached when all the other connections on the side of the machine and the front of the machine are removable this seems really silly and i have to admit when i take this computer apart i'm going to be removing this cable entirely or if there's room inside i'm just going to tuck this away in there i'm never going to use the rf and i find this wire hanging out the back is just ridiculous and on the bottom we have a couple labels here i'm not sure what these two accepted stickers are this one says august 17 1985 and this one was used as a little bit of a warranty sticker and someone obviously has been inside this machine looking at the atari label itself though atari 800 number 063 maybe that's the plant number and then i guess this is a serial number here so if anyone recognizes where the sequence or what factor this was made in uh definitely put a comment down below we'll look inside to look at the chips to see when they were actually made so that will give us an idea of the time period now looking at the keyboard here it's got a pretty decent layout like the 64 and pretty much all machines at the time you know they didn't really have a standard so things are a little strange what you would think is a normal delete key is actually a break key with the delete key being next to it and possibly an even worse move than on the 64. the arrow keys are actually alternative functions on these keys here and i think you need to push control to hit them or something i'm not 100 sure on that but you have up down up here and then left and right on the second row below also a little bit strange the caps lock is on the same row as the asdf and the enter key or return is on the row above where it normally is on the qwerty row this would normally be like the backslash on a standard keyboard so when you're initially trying to use this computer just the fact that the enter key is up here is this kind of throws you for a loop and then the break key is in the spot where you should be pushing the delete key in a very 70s fashion here we have these buttons as well so this bottom one here is a fixed button that doesn't actually push that is the power led we have a start a select an option and then a system reset button and what's cool is the reset button it's sort of recessed in these little um i don't know plastic things here so if you bump the keyboard like that you're not going to push the reset key you have to push that down with your finger i think overall the aesthetics of the machine and the keyboard and everything about this thing just it just screams late 70s and i love it i absolutely love it but wait there's a little bit more coolness about this machine up here on the top above the numbers it says pull down and when you do that this actually has this flip up latch here flip up liz so to speak and inside here you have cartridge ports so we have two cartridge slots left cartridge right cartridge and this one here is the basic cartridge so without this the computer doesn't have basic i'm not sure if atari ever released replacement or updated basic cartridges or maybe third parties did for this thing but at least on these early machines it was easily swappable now on later ataris i know they actually integrated the basic onto the motherboard and there was there was no way to replace it one thing though when we have this cover open take a look at this die cast metal thing inside here it's really substantial looking and it goes all the way down to the cartridge slot which looks a little bit like what you'd see on a 2600 but i'm pretty sure that this chunky metal here had to have been expensive to make and clearly if you've ever seen inside a commodore 64 or vic-20 which of course you have if you watch my channel there is nothing like this in those there's actually a little bit more we can do without taking the entire computer apart when it comes to accessing what's inside now once you pop the lid open there are two screws right here and here and i've already taken these out because i've already been poking around a little bit because i've never actually poked around this machine at all so i had to kind of figure out how things worked but with those screws out then this i think comes off this whole like plastic piece there we go and take a look at that we actually have four expansion slots in this machine and look at this metal this all continues under there like that's just amazing so i'm operating completely from memory but i think what these are are ram boards and i think this front one is a rom board and indeed this rather nice looking card i just pulled out which is in really nice shape does actually have four 116 drams on here i think it's pretty funny that what looks like a serial number here is kind of only half stuck on and there's a little bit of uh that sticky tape here i don't know what the deal is with that maybe you peel that off and you're supposed to stick this underneath the machine to to show the serial number of this card i don't know anyhow these chips seem to have date codes from very early 1982 well actually no this one here is from the 31st week of 1982. and actually the dram chips here are from the 41st week of 1982. the thing is this machine might have been bought with a lesser amount of memory and these added later although i think i read that early on the 800 came out with say only 16k of ram but later they were all sold fully maxed out with 48k which is three of these boards installed we'll just quickly take a look at the other ones look it's got the same thing going on with that sticker and yes it's the 42nd week of 1982. it is odd that they have a different color pcb here the one on my right hand is a little more green darker kind of greeny blue either way they're both 16k ram boards and they seem about the same vintage i find this a little unusual look at this trace here zigzagging back and forth i wonder what the deal is with that i couldn't have possibly done anything for timing you see stuff like this nowadays when you're having matched length traces but that matters for differential pairs on like very high speed devices not a computer like this which i think runs at like 1.7 megahertz or something there abouts all right let's check out this uh the last board in here and look it's that darker color pcb again look someone did tear off that sticker or it's floating around inside and these ram chips say 45th week of 1982 so this is slightly younger than all the other boards and there's a look down into the machine you see those three slots and all that plastic and metal and everything like i said again very nicely built all right and then the last one this looks like rom chips but we have 1982 dates here on these rom chips as well okay let me repopulate these cards so we can take a look at what this machine is doing because as i said this was a repair because there's something wrong with this thing so let's see and i'm noticing here actually that you can put these cards in either direction i think yeah they seem symmetrical and that would be bad obviously because i think that would cause damage i also find it a little bit strange that while these cards are in here they just sort of wobble around in the slots is it possible that the lid somehow holds them down but i mean there doesn't seem like there is anything on here maybe it just pushes down onto the cards i don't know there's these little notches on the top here what i think is really cool about this setup is expanding your ram on the atari 800 is clearly something that a regular consumer could do and it's low risk i guess other than plugging the cards in backwards because it's very easy to get this cover off and just stick these cards in in addition did you notice that all of the ram chips were socketed so ram diagnostics should be pretty easy especially because you can just pull cards out while you're doing ram tests whatever those ram tests are and on that rom board these were also socketed as well so if you had to do say a rom replacement that would be doable as well or they could just send you an entire new rom board potentially all right for reattachment looks like this metal cover notches in right there and actually slots in here so that's a really good fit and look it just sort of clips down there and it doesn't move around at all so even without those screws in there this is not really going to fall out very easily especially if you have that lid closed all right so obviously we're not going to be using my commodore 64 power supply what i have here on the bench is this data byte power supply it's a 9 volts ac output 42 watts i have no idea if this was the actual atari factory power supply but i got this machine and an atari disk drive like an 810 and they both use the same power supply so i have two of these which i've labeled atari 800 or 810 right there as i had mentioned before just has a normal 2.1 millimeter barrel jack so that's all pretty standard if you've lost your power supply and you have one of these you just need a beefy 9v power supply and that's all you really need to worry about no polarity obviously because it's ac all right for connecting to the retro tank i've gone ahead let's see it focuses i made this little pigtail it's a din there and it goes to luma chroma and audio now there's one extra pin on here so it's possible that there's also composite video on that din jack although i'm not totally sure and i made this a while ago because i've had this computer for multiple years now and i tested it out with this figured out it wasn't working and i never did more so these rca jacks go to the retro tank which you see flashing periodically that one goes to my speaker up there and we're ready to turn this on there it is we have a ready prompt the image looks amazing it's really sharp it's really clear no interference or anything like that but the problem with this machine appears right now when you first power it on when i try to type anything on the keyboard nobody's home no key does anything at all except for system reset actually resets the machine so this is the problem that i want to troubleshoot now perhaps this keyboard has bad key switches they're dirty or there's a membrane underneath that's not working i've never been inside an 800 i know nothing about how the keyboard even works is it connected to the motherboard i mean i think so because the reset button works but maybe that signal is carried over a separate set of wires to a different place on the motherboard perhaps on the motherboard there's a problem with one of the ics that reads the keyboard what i want to do before i open this up is i want to test some software on this machine now remember how i talked about the sio port on the side of this thing being for disk drives and whatnot it's a very standard 5 volt ttl serial signal so this right here is an old android phone it's like a motorola g moto g i think and this is something i made quite a long time ago for testing this exact thing what you see here is a 3d printed sio connector that plugs into that serial port and i stole the pins that are in here off of an old at power supply if i recall obviously if i had a regular spare sio cable i could have cut that and just made that but uh either way it goes into this which is a ttl serial board that plugs into usb this is pretty standard stuff got this from china for like a dollar or whatever ages ago i use these all the time for programming microcontrollers and stuff like that has a mini usb that goes to what is a usb to the micro usb on the go cable and the reason for that is of course i can plug this contraption into this android phone here and with some software on here this can emulate disk drives and even with no working keyboard that doesn't mean that this machine won't work and that is simply because it actually supports auto booting which is something that commodore does not support not until the commodore 128. so if i wake up the moto g here and i plug this cable into it like so it's actually going to pop up with the program that's on here called aspect or aspe qt and actually have pac-man loaded right there but that's all it takes this is now ready to go to emulate disk drive if i turn on the computer that beeping is actually loading the software so this machine is actually working so normally it loads basic from the rom it's very quick and look there it is pac-man it just loaded so it says press select for two-player game if i push select hey that is actually working look at that and then it says press option to change difficulty and look the fruit is actually changing as well so that is interesting and then press start to play game well i'm going to plug in my modified nes gamepad here which has a regular atari slash commodore port on there let's plug that into this front joystick port here and we'll hit start to play game well the start button on the keyboard works and this machine is clearly working because i'm able to play pac-man sound is working graphics is working as much as i love playing with a game pad i must say that pac-man really is better with a proper joystick just maybe that feels a little bit more authentic i don't know look at that i actually finished the level without dying amazing oh look a little cut scene here that's kind of cool [Music] all right seems that the computer is working quite well we know the joystick port works sio port works these buttons on the side of the keyboard work so we'll have to look at how those are connected and it just seems like all the keys on the on the main part of the keyboard don't work alright so i'm going to turn off the computer here and i think it's time to open this thing up take a look on the inside all right i still have this top cover somewhat disconnected so i'm just going to remove that while we take the bottom off or at least i attempt i don't think there's any screws on the top side at all i think everything is on the bottom i don't think there's even a screw in this middle one someone never reinstalled that one all right i don't know what i'm doing here so does the top come off here i flipped it back over i think maybe the bottom comes off aha there we go okay check it out this metal cover it's like super solid all that die-cast metal we saw on the top all extends to the bottom here so the motherboard clearly is underneath most of this cover it's rf shielding a really substantial type of rf shielding some of the motherboard sticks through here nope uh maybe yep i think some of the motherboard sticks out and this is like for the i o connections to that board whatever it is and also the main joystick ports and there's a speaker in this machine i thought i heard it click when i turned on the computer but it's weird because i don't think i heard the pacman music coming out of it and the speaker is just sort of sitting there but all right obviously it's held in by the case we see here the rf cable and you notice there's tons of room inside this computer over here so i can just kind of unwind this once i get this apart and leave this cable inside the case i don't have to cut it or anything all right let's keep digging in here i'm going to remove this very chonky rf shield here now i had always read about the atari 800 and i think the 400 having this very substantial shielding and it was around this time in the late 70s that the fcc in the us started kind of cracking down on these computer manufacturers like you know apple with their original one in their early vic 20s and the trc and that stuff during the late 70s really had no rf shielding at all so emissions you know could have been problematic for interfering with radios and tvs and stuff that were nearby so with this machine made by atari i think they were owned by warner media at the time which was like a tv studio and they obviously had a relationship with the fcc so unlike with apple i think that they had to make sure that they they were not skirting these new fcc part c part b whatever the rules were at the time hence all this very crazy shielding and you have to imagine that back then maybe the testing techniques for testing for our missions weren't that sophisticated so they didn't really know what to do other than just like throw everything with the kitchen sink at it and this is what the engineers came up with this this very substantial shielding i mean i've already removed uh there's gonna be eight screws i'm not even sure that's that's all of them well i'm just gonna keep taking screws out all right so this thing seems to be somewhat loose although i don't know not sure here okay well there is one thing i am noticing while i'm taking this out and it's that the keyboard under here is connected to this board but the buttons on the side the orange buttons the led the reset are connected to this board here so they are two separate things entirely i think we're there almost i'm going to take the speaker off and the keyboard connection which is right here goes to this pcb where the joystick ports are and is this me making a good connection yeah i think it's on there properly looks like it's sort of a bent type of connection it's hard to tell what's happening here until we get this flipped over the keyboard connection is extremely stuck on here it's coming off there it is okay i think i have freed the computer it's unbelievably heavy and let's put that down and move this keyboard okay so there it is this is what i was talking about here so there's the uh these reset buttons option start they go on this little pcb over on the side here keyboard connection is here so we'll be able to give this thing a little test because we first need to see if these keys are making contact now check it out it's a mitsumi keyboard same manufacturer is on the 64. so i'm presuming if we take this pcb off with all these little tiny screws it'll have a very similar setup to the 64 with those little plungers or the little contacts that contact the pcb and certainly on the commodore pet um i've had more than one pet through the basement here none of the keys worked at all and it was all entirely a problem in here so i'm kind of thinking that's almost certainly what's going to be the case here all right and there there is the atari 800 on the inside just look at this look at this insanity here it is so built amazing just simply amazing so luckily for the rf cable here it just simply connects to this sideboard right here with this internal rf rca cable because there's the rf modulator what we have here is the bridge rectifier with discrete diodes we have a couple capacitors here to create the dc and then on this heatsink here we have some voltage regulators it feels like there's perhaps one back there which i can't easily see although maybe not there's definitely one right here right here there's a little kind of micro switch of some kind when i push that down it does something i have to kind of wonder if it's something to do with this top cover perhaps this pushes down on that switch all right and here it is right here it's this little black plunger it does move and that is pushed down when you have this closed so obviously if you open this up maybe it shuts off the computer maybe it resets it or something like that or keeps it in reset so when you plug a cartridge in it won't potentially damage anything or maybe when you close the lid it resets the computer or something like that but very high quality feeling switch this whole computer just seems to be really really well constructed we have two pcbs in here this huge die cast cage this complicated case assembly atari just was not messing around with this machine there is quite a bit of dust on this shield in here and i know it obviously doesn't really mean anything but i'm just gonna clean that dust off i'm gonna remove this rf cable here take a look at this wire management vacuum or strain relief for this rf cable that is so chunky and substantial but there it is there's the rf cable for the 800 so if you want to remove it easy peasy just take it apart take it off there cut these uh zip ties off and you can just stash it inside the case when you put it back together all right i am noticing here that this top cover is now disconnected from the motherboard so what i'm going to do is just turn this around here i think i need to remove these expansion cards and this should allow us access to the motherboard underneath maybe okay i see what's going on this is still screwed together on the side right here and with those screws out i should be able to pull this off the board to board interconnect here there we go and now i think this should lift off there it is i mean just look at this oh i'm sorry i know i've talked about this a lot but this is just funny to see in person i'm all right we get our first glimpse at this machine so one thing i'm noticing is there's another card back here look at that it's just hidden out of view in um behind the other slots so this one here says atmc and i assume this is the brains of the operation there's the 6502 processor and then we have an atari branded chip from 1979 here looks like it's c014805-22 and then we have the co122 96 d-03 a little bit of ttl logic we have potentiometer here of some kind and then when we look at the motherboard probably underneath here which is clipped on i feel like i'm clipping it it just has all the slots in the cartridge slots we have a 65 20 right here so this would be the i o controller right here is a 90 42 i don't even know what that is a c012294 dash so that's some kind of a custom atari chip all right actually this socketed chip here is the pokey chip which stands for pot keyboard integrated circuit which is the digital i o chip designed for the 8-bit family of computers and it's also found in atari arcade machines it samples the potentiometers such as the paddles scans the matrices of switches for a computer keyboard as well as the sound generation has four voices of distinctive square wave sound either as clear tones or a modified number of distortion settings all right so that implies that the 6520 here probably only is handling the joysticks and potentially some of the i o from this board here like these uh front panel or these keyboard buttons here maybe that switch stuff like that so as far as the keyboard not working let's hope that's not the pokey that's the problem because i don't have a replacement pokey on hand although i'm sure it's a sort of obtainable chip i mean i don't really know if it's hard to find or whatever but it also is in a socket it looks really clean in here i don't see corrosion so i'm not going to jump to any conclusions that the problem is corrosion in here i think what i'm going to do for testing is i'm going to reinstall these boards here remember these all go with the chips facing away oh i'm also noticing on the back of the motherboard pcb looks like an expansion header there it is right there maybe atari thought about designing some kind of a rear expansion thing that gave more cards or something like that i want to test to see if the keyboard routine or scanning is working if we go right off the keyboard connector here and that will completely validate for me that it's just the keyboard that's dirty i'm going to plug the basic cartridge in and i will need something to prop up under this how about this roll of tape here is that going to be the right height oh yeah that totally works there we go and let's see if this thing is still working no what did i do wrong here oh this button needs to be pushed i think it kind of confirms my hunch that this little micro switch here cuts power to the entire system okay a little tape over there now let's see what happens there we go we got the ready prompt so i'm just going to do a quick google for atari 800 keyboard matrix and here it is atari 800xl i don't know if that's the same thing and so as you can see in this matrix when you push the m it shorts together pin 7 and pin 12 and that's what makes the computer actually register that key press aha take a look at this so there's the pokey and it doesn't read the keyboard directly it goes through these cd4051s here which is actually potentially a good thing these are the two ics right there they are socketed that means that if something bad were to happen on the input here then those ics would probably go first before the pokey does and those are easily replaced for testing i'm just going to clip this clip lead onto pin one here which on the schematic is right there and now i can uh just short to these pins over here and we should start seeing key presses all right we have the ready prompt i'm just going to clip this onto a little screwdriver here so i can poke uh see 14 15 16 17. so this is 14 and look i'm getting a key press uh it's the other one so yeah this is kind of showing us there's the nine and there is the zero that i was expecting so that tells us right off the bat that we have no problem with the circuitry that's scanning the keyboard and the problem simply lies in the keyboard itself so i gotta say that's pretty pleasing because uh that means that this atari here is fully operational at least from the circuitry standpoint and well it's from what does it say 1982 is what we see on these ics here that is a nice reliable machine clearly whoever is manufacturing these ics like this is a national semiconductor that made the pokey was a better fab than moss with their flaky flaky chips and on that bombshell i'm going to end this video here i'm really happy to know that the pokey inside the 800 is working fine and really the problem lies completely with the keyboard here so i'll have to be attacking that in the next video which i'm not really looking forward to because fixing mechanical problems in keyboards can sometimes be really tricky as you can see here on the bench there is lots more atari 8-bit stuff to come in the future most of this stuff i don't even know if it works except for the 800xl that sits on the top here this is one that i've had for quite a long time i got this before i was really making videos and it never needed any repairs it just worked and it's running ball blazer right here but this other stuff on the other hand i have a feeling there's gonna be some good troubleshooting videos coming out of that stuff so that's gonna be it for this video as you can see here i'm wearing an adrian's digital basement t-shirt if you'd like to order one i have them in various colors and men's and women cuts there's a link in the description below to my merch store next up i'd like to thank my patrons their names are scrolling up the side of the screen they knew about the fact i was repairing this atari well not this atari this atari before the video was published and have made some good recommendations for me to try some games including ball blazer which was one of them so if you'd like to become a patreon and get early access videos and whatnot there's a description the link below as well thumbs up this video if you liked it thumbs down if you didn't comment down below all the usual youtube stuff subscribe second channel etc etc and that is going to be that so stay healthy stay safe and i will see you next time bye [Music] you

Channel: Adrian's Digital Basement

Views: 103,690

Keywords:

Id: -X-IMg5yMQA

Length: 32min 3sec (1923 seconds)

Published: Sat May 21 2022