Repairing a 1979 Atari Asteroids Arcade PCB
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- čas přidán 7. 11. 2019
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Glad I went back and watched an older video. Being a electronic hobbyist trying to learn more old digital stuff, I really enjoyed your troubleshooting. Good stuff!
Hey! I actually bought an original 1979 Asteroids cabinet from a nice guy in my area & your videos have been extremely educational on helping me repair mine. Unfortunately the cabinet I have has been gutted & trying hard to track down all the missing parts
You can get pretty much anything for it from ebay, or on the forums on KLOV.com , go check it out!
thanks Joe, I like how you just plow thru all the systems and you have a good way of explaining the way the machine works. Props!
It amazes me, to see how large the components are in these old machines. I'm willing to bet, that's why they survive the test of time. I can't imagine a modern board lasting this long. Thanks for sharing this.
ThomasGrillo it makes them repairable too, the newer stuff if you’re not a robot you don’t have the precision to solder! It can be done but it’s tough.
Indeed. The only way to do board level work on new stuff, is to use a microscope, and electromechanically guided soldering, with hand controls. LOL ;)
You see folks like Rossmann and IPad Rehab do it. Quite the skill.
I've done a couple things with a heat gun but I don't have the right equipment and I'm not really even that interested in getting into it :)
I'm not an electronics geek. I'm not a video game nerd...
But, these videos are still fascinating.
I guess it's that I like to see dead things brought back to life.
Yeah I think that's what I like about them too :)
Thanks love the ordinary Joe repair tips lol love all the repairs and nice job with the High Speed pinball my absolute favorite game.
Thanks Major, we loved the High Speed too!
41:52 I am an expert on this stuff, but enjoy troubleshooting videos anyway.
Glad to have you watching!
Learning a lot! Thank you man
Thanks Brewers Arcade, see you on the next video!
loads of great info. Thanks!!
Joe, I am working on an asteroids at the moment. Once the board get warm I start seeing lines jumping all over the screen. The board was repaired by an outside source, as well as the power supply. I just finished a cap kit on the monitor, but when it warms up the lines start jumping all over the screen.
I’m in the middle of fixing an asteroids myself at the moment and this is helpful. The memory test is all screwy. Game resets at weird times. And I had no Point of reference for the beeps. I need to go back and write
It down!!
Sometimes if it's doing different things each time it's the 'big blue' in the bottom of the game allowing ac voltage ripple onto the dc voltage. Good luck with it Bob!
@@LyonsArcade Thanks - I tested for AC ripple.. its good (less than .2v).. I may turn the board up to 5.1v like you do., at 5.03 now.. even on the far end of the board.. I'll fix the other obvious stuff first (ship fire sound broken)... leds not blinking right.. maybe fix the reset issue along the way as part of it.. thx sir
@@LyonsArcade I turned the voltage up to 5.1v and no resets for 18 hours.. I think this is solved.. Still others to fix. Thanks ;)
So satisfying 😩
It really is!
Great video!
Thanks Michael!
Maybe DMAGO stands for Direct Memory Access Graphics Output?
DMA is a way to access memory independent from the main CPU. There are multiple ways to accomplish this. For legacy CPU platforms, a common problem was how to use 2 processors with the same memory. Video is inherently a "client-server" type of situation. You have user code writing to the RAM and the video or video coprocessor reads it.
For the Atari 800, they used a modified 6502 which added a halt line (/halt, or drawn with the line over it, active low). It works much like the /RDY line on the CPU, as that is used to suspend processing, such as when you need to provide wait states for ROM or slow RAM. The halt line differs in that it also disconnects the memory from the CPU. ANTIC is the video coprocessor. So the halt line suspends the CPU and disconnects the CPU from the memory. That allows another processor or device to use the memory without competition for the bus.
And the video controller can even be a "dumb" device, like just a state machine that just keeps looping. All it needs to do at minimum is to read X amount of memory, send X amount of pixels, disable the video signal for about 1/4 that time or whatever at the end of each line, do all of that X number of times, then blank it for the equivalent of a scanline, then start over (at least for a raster monitor).
37:57 all that's missing is some ICs on a stick and we'd have ourselves a pretty good puppet show 👍
I might have to consider that in the future
I'm curious and going to try and see how many Arcade Asteroid consoles were sold since you mentioned it. I'm still a relative newbie to this channel. But this arcade game repair appears to be the most challenging one I've seen so far. But I enjoy watching how you're working through it.
Great video very interesting
Thanks Arcade Crusaders, we appreciate you watching!
When I need to lift a bug leg I put the chip into a spare socket then lift the leg on the socket then plug the socket with the lifted leg onto the board, as you do not bend the legs on the chip no broken impossible to find IC,s !
That's a good idea!
5:45
The Hyperspace button can be found at a random location out in space
Again with the mystery music XD
Haha we try to keep it entertaining
Hi Joe great set of videos you have made, I have been binge watching since I decovered them. I was a repair engineer for 30 years untill my health stopped me, your videos have brought it all back for me thanks. I must mention my understanding of a Watch Dog circuit. It is just a circuit that loops periodically and resets the processor, unless the code the cpu is running interupts the WD it will constantly reset the cpu. This is so if the cpu was to crash it would automatically restart the code because the cpu did not stop th WD in time.
the WD circuit is usally only controled by the cpu and needs properly running code to function correctly. so if the reset is polling its is most likely because of the cpu not correctly telling the WD to sleep, either bad code or bad signal from the cpu.
I think you're right, when I explained that in the video I talked about it backwards :) Like you said I believe it runs over and over again if the code isn't working correctly, you can go into the schematics and kind of figure out where it's going wrong usually... Thank you for watching Retro Man Dan I appreciate the comments! See you on the next video!
Scares the poo out of me when you go 'numbers station' on me like that.
And oscilloscope is definitely a good tool for troubleshooting when it comes to electronics just not video games you may spend a few bucks but you’ll save your time and you won’t bend any needles like with the old Votto meters so have a good day bye-bye
Thank you Clark for watching!
24:10 the CPU has a few registers, so you could say it has like three bytes of RAM.
(TL;DR)
But you can test RAM even without that, all you need is ROM. Like, the code could say write 0x55 to the first address, read the address, test if it's 0x55 (so this test will fail if the ROM is corrupted because the value 0x55 is stored twice), if not goto error, then do the same with 0xAA. If the tests pass, you can use the first byte of RAM to store the counter for iterating over the rest of the RAM. But even the simplest CPUs have at least two registers plus accumulator, so you'll only ever need this knowledge if you decide to build your own CPU without registers and then write a RAM test for it...
O.K. thanks that makes sense to me. I was wondering about that, because the manual clearly suggests that yes it can detect any of them as bad, I suppose that means if i'm not getting a ram test program running, it won't typically be the first two 'scratch' ram because even without them it would still run the test? In the future I'll ignore the ram until the test is running, in this instance it ended up being the roms in the wrong locations, leaving the first two ram alone would have helped me find that quicker :)
@@LyonsArcade On Asteroids and Asteroids alone (I think): If it's watchdogging in Test mode, then it's something severe. Like the CPU itself or glue logic. Probably not the RAM. Unless it has outputs shorted which you can find easily with the logic probe (like all data bits are pulsing but one).
About vector RAM: I once had a bank of bad LS157s (between vector ROM and CPU) preventing the CPU from accessing the vector RAM, flagging these chips as bad as well.
You can read the story somewhere in here: tempect.de/senil/ARCFIXEN.TXT
I assume the three bytes of RAM in the 6502 you are referring to the A, X and Y register. Everything you say is correct but you need at least the A register to work for the 6502 to read and write from memory. Everything goes through the Accumulator. Also don't forget the flags register - a few more bits of memory in the 6502 that you'll need. There's also the S register just to be complete.
@@djmips exactly!
Hopefully not to be annoying but whose logic probe do you use? Mine bought the farm and I'm looking to replace 😉
I don't even remember what brand it is, the little label on it fell off! It was a cheap $10 one, I'd like to get a little newer one soon.
How do you verify the contents of the ROM's? Are 'images' of the contents available somewhere to compare against?
Yes, the MAME roms are the exact same ones, that's the whole purpose of MAME is to preserve the original roms and software of the original games. So if you download the MAME rom it matches up.
JOE, If an arcade game board doesn't have a DMAGO to separate the video section from the CPU section, what signal do you disconnect the cut the board troubleshooting in half? Can you explain more what this DMAGO signal does or how it controls the watchdog circuit?
It's only on this one board, only on Asteroids. I think there's similar signals on other vector games but I'm not sure the names.... the reason it's a problem on Vectors is because the 'vector state' part of the board works different than a regular pcb that creates a raster signal. If it's a regular raster game depending on the title, the watchdog circuit is a little more easy to troubleshoot... you basically look through the watchdog circuit and see which area of the board is causing the issue, on a vector often nothing will display on the screen if there's a problem in the vector state area.
@@LyonsArcade Thanks, I just don't know how a raster game and a Vector game is able to draw the images on the arcade CRT screen. There is Vertical and Horizontal sync signals that are the coordinate locations & positions of the CRT screen. The arcade games Color PROM chips is a look up table of the colors you can to choose from. So I'm confused on the differences between a raster game and a vector games because vector games don't use Vertical & Horizontal sync signals they use Vertical & Horizontal deflection signals so I'm confused how a raster game works and a vector game works to draw images. Can you maybe explain how they work
@@LyonsArcade , I just confused if H&V deflection signals are the same thing as H&V sync signals. I'm not sure what the differences are between H&V signal signals in raster arcade games compared to H&V deflection signals in Vector games, what are the differences?
7:11 I wonder what happened that would cause the game to beep when you were using the multimeter.
I probably touched two things at the same time and shorted something together!
One question: On a working asteroids board, what should pin 37 (watchdog) be doing? Toggling hi/lo? stay pegged hi? Stay pegged low?
It should stay high
@@LyonsArcade thanks
Nice repair great job now move on monitor next ☺
Monitor is coming next Friday, i'll see you then Danijel!
Hey Joe, I have been watching all your videos in hope to figure out an issue that i am having with my asteroids arcade. My issue is that the PCB and the A/R are only reading about 2 volts. Definitely not enough power to operate. These reading were tested at the ROM chips, the attached grounds and +5's. I checked the original power supply as well and it appears to be working fine with appropriate levels. In the J5 wiring harness i am getting about 12-13 volts in 1, 2, and 3. Roughly 37 volts in 6 and 7, and about 7 volts in 8 and 9. Any help or expertise would be greatly appreciated.
Check the lug on the A/R and see if you're getting your 12-13 volts there too, then check the 5v on the A/R to see if it's only 2, if it is your 2n3055 that's mounted to the heat sink on the A/R is probably bad. It's pretty common for those to fail and usually it'll cut the voltage in half like that.
@@LyonsArcade yes i am getting the 12-13 volts there. So i will try replacing the part you recommended. Thank you.
@@LoveLazyKeto Sounds good, let me know if it fixes it!
@@LyonsArcade The A/R voltage is able to be adjusted now. Still no audio or video. Solid red light on player 1 start. Voltage on A/R was set to 5volts and the pcb was reading 4.75volts. I have to watch more videos to find out my next step. Unless you have a suggestion.
I was testing the cpu C3 chip and it was getting fluctuating voltage readings and then stopped. Once it stopped i was getting a thrust noise until i reset. The it was a single beep on start up and the game play buttons would make the same beep when pressed. Also i have a single vertical line on the screen. She is trying.
37:24 I didn't know that you spoke a second language
I am fluent in all the latins
precisely at 38:00 auto gen captions think you're saying Frankie something
It made sense to me!
BTW, it could be possible that if the crystal got knocked loose, it could be damaged internally. Just thinking.
I have know idea why I had the two games confused.
So my bad.
No problem brother
21:00 uh-oh, LSD flashback
Trippy!
Every come across a star trek arcade game?
Unfortunately i've never had one, I do get a couple of the Star Trek pinballs in from time to time, though!
Dmago = “Direct Memory Access” go ????
That could be!
The GO part could be Graphics Output.
Interesting, but for the love of Mike stop talking about how much easier it would be if you knew how to use an oscilloscope and spend a little time finding out how. It’s not like you have to spend a vast amount of $ these days in buying one, and once you have the basics down (which aren’t all that complicated, it’s basically voltage vs time, and when to start recording) then half the job is done. The other piece of (very cheap) kit to consider is the logic analyser. These can be had for not much more than your logic probe, and will tell you things like what is coming out of a chip vs what is going in, what frequency the clock is running at, what data is on the data bus, what addresses are being generated on the address bus etc. Basically much of the time you can find out which chips are bad without desoldering and replacing them.
Thank you for your criticism and negativity
You seem to have convinced yourself that ‘scopes are some kind of witchcraft. Far from being negative I’m telling you that they are not, that they are not expensive (you should be able to pick a used CRT based 20MHz twin channel model for sub $100) and they will start telling you useful things with only basic knowledge. I’m also telling you about an even cheaper piece of kit that will tell you whether a section of a board is doing what the schematic says it should. One or both of these will make your life easier, IF you have a little faith that they are not beyond you (and you are clearly smart enough to coax these old boards back to life).
@@stevetodd7383 -- I don't think so. I think he hasn't really had the need to use one. That is just how more conservative and insular sorts of folks think. You just learn to make do with what you have.