replay Posted February 28, 2015 Share Posted February 28, 2015 I guess i plugged a c64 power supply into my atari, yea i know it was a stupid thing to do but whats done is done now! Anyway i have no test screen just the old power light showing, I`ve read about the s-video test and i was wondering would the amiga s-video lead fix the atari 800 xl before i even try to test the machine like this! Thanks Quote Link to comment Share on other sites More sharing options...
Guest Posted February 28, 2015 Share Posted February 28, 2015 i think pins 5, 6 and 7 will have done the damage...you may have just blown the dc power port - if you're lucky Quote Link to comment Share on other sites More sharing options...
Mclaneinc Posted February 28, 2015 Share Posted February 28, 2015 You may want to say if you are able to change components and solder, that way people can make suggestions that could help you fix it. Its suffice to say that a lead change will not help and leave the machine off until you get help.. Quote Link to comment Share on other sites More sharing options...
baz67 Posted February 28, 2015 Share Posted February 28, 2015 Hard lines, fella. If it is totally kaput you might want to think about getting a 65XE. As it happens, I have one available and I could do you a deal through Amibay... Failing that, I've got a lovely Oric doing nowt right now. There's a moral here though...go steady with the power supplies from OTHER machines. It just aint worth it chancing it... and frying yer nostalgia. 8Bit Baz Quote Link to comment Share on other sites More sharing options...
replay Posted February 28, 2015 Author Share Posted February 28, 2015 Cheer for the replys When i power the machine on i do get a black screen but i cannot see anything else, it was working fine before i plugged the c64 power supply in, so i guess i`m wondering how to fix this and what to check first before i go any further with the fix. I do want to repair it, i was wondering if i should buy a pic programmer and if i do which pic programmer should i buy. I am also going to socket the complete boards for plug and play eproms, i already did that to the ram chips and that works fine when i finished fitting the ram sockets for the ram chips to fit in. Its just i thought my atari power supply was abit aged and that maybe i should try the c64 power supply, and thats what killed the machine. Quote Link to comment Share on other sites More sharing options...
replay Posted February 28, 2015 Author Share Posted February 28, 2015 Hard lines, fella. If it is totally kaput you might want to think about getting a 65XE. As it happens, I have one available and I could do you a deal through Amibay... Failing that, I've got a lovely Oric doing nowt right now. There's a moral here though...go steady with the power supplies from OTHER machines. It just aint worth it chancing it... and frying yer nostalgia. 8Bit Baz Thanks for that Bazz, but i`m quite the atari fan me, and an oric just wouldnt cut it for me. But thanks for your reply Quote Link to comment Share on other sites More sharing options...
Guest Posted February 28, 2015 Share Posted February 28, 2015 the fact that everything is "black" doesn't bode well. any red power LED power indicator? or is everything dead? Quote Link to comment Share on other sites More sharing options...
replay Posted February 28, 2015 Author Share Posted February 28, 2015 yes red power light is on but it just displays a black screen, if you power it off the black screen goes to the static screen, then power on displays the black screen again with the keyboard connected yes the red light displays, Now I cannot reset it i dont seem to have that option anymore, as all i see now is the black screen! Quote Link to comment Share on other sites More sharing options...
ClausB Posted February 28, 2015 Share Posted February 28, 2015 I've been preaching to you all for years that C64s are evil. But do you listen? No. 5 Quote Link to comment Share on other sites More sharing options...
Guest Posted February 28, 2015 Share Posted February 28, 2015 (edited) ok....perhaps some small tests are needed 1] is there any sound at all when you first power up? 2] try connecting a monitor cable to your TV if you have one 3] if cpu or mmu are working, then the next step is memory checking 4] on failure the hardware gets reset and you'll hear an audio click if you're not sure if you can "hear" anything - try this:- 1] turn your tv volume up 2] Power up Atari with OPTION key pressed (no devices attached) 3] Press SELECT key once only 4] Press START key once does it run the audio test? Edited February 28, 2015 by Guest Quote Link to comment Share on other sites More sharing options...
Bryan Posted February 28, 2015 Share Posted February 28, 2015 I had an 800XL which was connected to a C64 supply. I pretty much had to scrap it. Couldn't find a good chip in it. I'm sure there's a conspiracy in there somewhere. Atari supplies won't kill a C64! Quote Link to comment Share on other sites More sharing options...
chinnyhill10 Posted February 28, 2015 Share Posted February 28, 2015 I had an 800XL which was connected to a C64 supply. I pretty much had to scrap it. Couldn't find a good chip in it. I'm sure there's a conspiracy in there somewhere. Atari supplies won't kill a C64! C64 supply kicks out 5v DC and 9v AC. The Atari only wants 5v DC. Sticking 9v AC into it won't do anything any favours. It's odd what can work sometimes. The Acorn Electron requires 18v AC but you can run one happily on 9v DC without causing it any damage at all. Which is handy as 18v AC power supplies are rarer than hens teeth. Quote Link to comment Share on other sites More sharing options...
drac030 Posted February 28, 2015 Share Posted February 28, 2015 Once, by a stupid mistake, I connected a 12 V from a PC power supply to two computers: one 800XE and one 130XE. Only the FREDDIE chips were fried in both and were to be replaced, the rest survived. Quote Link to comment Share on other sites More sharing options...
Keatah Posted March 1, 2015 Share Posted March 1, 2015 (edited) It's odd what can work sometimes. The Acorn Electron requires 18v AC but you can run one happily on 9v DC without causing it any damage at all. Which is handy as 18v AC power supplies are rarer than hens teeth. Uncommon.. yes.. any trick circuitry or circumstances? Nope. The other half of the power supply rectifier is just using one side to pass 9VDC. The other half is never seeing the other half of the waveform. While it works. I'd be betting that something is under more strain than normal. Maybe, maybe not. They used this circuitry in Times Squared ST:NG and there was a 7th dimensional potentiometer that was turned throughout the incident.Thus moving the transitional point till the shuttle powered up. hahahahahahahaaaaaa!!! Edited March 1, 2015 by Keatah Quote Link to comment Share on other sites More sharing options...
Keatah Posted March 1, 2015 Share Posted March 1, 2015 I guess i plugged a c64 power supply into my atari, yea i know it was a stupid thing to do but whats done is done now! Yes you really are an ass for doing that. Reminds me when I took apart my girlfriend's zip drive to unstick the locking level, and I borked the heads out of rushing and carelessness. At the time I didn't have the skill to repair it. 20 years later I do, I fixed it recently! So if you don't get it fixed right away, make notes, and set it aside for the future. Quote Link to comment Share on other sites More sharing options...
chinnyhill10 Posted March 1, 2015 Share Posted March 1, 2015 Uncommon.. yes.. any trick circuitry or circumstances? Nope. The other half of the power supply rectifier is just using one side to pass 9VDC. The other half is never seeing the other half of the waveform. While it works. I'd be betting that something is under more strain than normal. Maybe, maybe not. I spoke to someone at the time about it. As 9V DC is half the voltage expected, nothing should be running under strain as the energy level is exactly the amount needed. The only "gotcha" is that the AC supply voltage is also passed to the expansion bus although seemingly peripherals that actually use the 18v AC are few and far between. There are people out there who claim to have used a 18v DC supply for years without issues although I'd be very wary. At 9v DC the Elk doesn't get warm and seems perfectly happy. Quote Link to comment Share on other sites More sharing options...
Keatah Posted March 1, 2015 Share Posted March 1, 2015 I was thinking that one side of the AC/DC rectifier would be working full-duty as opposed to having some downtime while the other side does its thing. I suppose if it's DC it's just passing right through. On another note: Did the early VCS units work on 9VAC and later VCS/2600's work on 9VDC? It's been years since I looked at that circuit. Quote Link to comment Share on other sites More sharing options...
replay Posted March 2, 2015 Author Share Posted March 2, 2015 Well today i have free time, so i`m going to check the complete board on the atari, i have some spare ram chips ready even though i know they are not the problem here, So i`m going to check all the resistors around the board then change every chip i see on the board, i`m putting each chip on eprom sockets so i can change them all easy. I think this should be interesting because when we have all finished this thread anyone else with this problem will have all the answers to what i did and tested to correct this problem, even if it means the board cannot be fixed. We should have all the answers soon, i`ll take pics of each step i do! Quote Link to comment Share on other sites More sharing options...
replay Posted March 2, 2015 Author Share Posted March 2, 2015 (edited) Just on another note i am also going to re-program or burn some epoms that i have here, that are from a spare working atari 800 xl mainboard so i will have all eproms and ram chips and resistors, the works. when i do find the fault it will be posted with the fix. Edited March 2, 2015 by replay Quote Link to comment Share on other sites More sharing options...
replay Posted March 2, 2015 Author Share Posted March 2, 2015 By the way if any of you know of anywhere i can download the eprom chip data for each eprom on the 800 xl mainboard that would help. Thanks Quote Link to comment Share on other sites More sharing options...
replay Posted March 6, 2015 Author Share Posted March 6, 2015 Update I have replaced all the 8 ram chips and its changed nothing still have the black screen, plus I have tested voltages though out the board from boot up to stand alone no power, I have tested all the resistors , diodes , capacitors. So now we are up against the eprom chips , Yesterday I removed the cpu from the board and already have a Ginny pig on its way from eBay a fully working 800 xl with every chip I could ever need. So the next step is to remove all the eproms from the board like I've done with the cpu and put them all on dil sockets so I can then plug and play with all the new eproms on the Atari 800 xl. I`m thinking it's going to be the cpu eprom but I'm also guessing it could be the Freddy eprom first left on the board. But as I say I'm going to change one by one until it comes back to life and I'm guessing after I've tested everything this old classic will come back to life next week. Quote Link to comment Share on other sites More sharing options...
Keatah Posted March 6, 2015 Share Posted March 6, 2015 Murphy's law states it will be the in the last 25% you find the problem. Quote Link to comment Share on other sites More sharing options...
replay Posted March 8, 2015 Author Share Posted March 8, 2015 (edited) Ok I have my GQ-4X USB Eprom Programmer and have a nice condition xl 800 Ginny pig unit that i have removed the eproms and read the data on them and also written the data to a new blank eprom and they all work fine. I have also removed freddy and cpu and verious other chips on my broken xl 800 and replaced one by one eproms with the new coded chips and wait for it....... IT TOOK OUT FREDDY AND ALSO THE MAIN CPU THAT I HAVE NOW PUT ON SOCKETS. SO THATS IT GUYS! IT WAS THE FREDDY CHIP AND ALSO THE CPU EPROMS, THATS WHY IT DIDNT GO INTO SELF TEST ON MAIN BOOT UP ON ROMS AS IT TOOK OUT THE FREDDY CHIP AND THE CPU CHIP FIRST, THE RAM WAS OK AS I COULD READ THE DATA AND VERIFY IT, I would have liked to add step by step pictures on this but i dont know how its done on here, that would have shown you how and what i did from start to end to fix the atari xl 800 Edited March 8, 2015 by replay 1 Quote Link to comment Share on other sites More sharing options...
replay Posted March 10, 2015 Author Share Posted March 10, 2015 I found this link which could be very helpful to some with Atari problems. http://www.atarimania.com/documents-atari-400-800-xl-xe-technical-documents_3_8.html 1 Quote Link to comment Share on other sites More sharing options...
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