Keep your money guys, use it to buy needed stuff with.
Like a voltmeter. Be sure to test it without the computer connected first. You are looking for 5 volts where 7 or so means the power supply is a RAM killing machine. Check both power supplies or all you have for that matter. Connect good 5 volt supply to computer and turn it on to measure again, you still need 5 volts and if you don't have it then the computer is drawing too many amps. To be continued...
Move your #3 coil to an easy to work on spot and move that coil to #3 spot. Start it up, if the miss follows the coil, buy a new coil. If it stays on #3 buy a spark plug and spark plugs wires if that is applicable in your particular case. Still no joy you need to do a compression test on #3, today's engines should be over 100 PSI with 185 being near new condition. To be continued...
GTIA pin 17 will make 12 volt (IIRC) so if that's it then nothing to really worry about there. Phase 1 clock is voltage doubler pumped to provide that signal and it is required. You sure you are not on AC voltage setting?
Doesn't that indicate that they're working?
You are certainly assuming wrong, logic probe tells us there is activity but not if that is going in or coming out or what it should be. If you had a dead ROM I would hope all the support chips would be trying to talk to it in an effort to wake it up. Dead doesn't mean all signals enter the twilight zone and cease to exist, it means instead they are mostly ignored by the vacant party of concern.
These XEGS ROMs are known to lay right down and die. You can only prove a positive by swapping with a known good ROM and that doesn't fix it outright.
I don't believe STELLA is a chip found here. Please call it GTIA if you meant GTIA instead.
XL/XE schematics are almost identical as to device number. C42 is circled but I can't find it in XL/XE nor do I know if XEGS schematic number match XL/XE scheme as tightly as does XL to XE. Atarimania does not have XEGS in SAMS which means all we have is Sobola Schematic, is that correct?
Very much better but still in error due to repeated segments of same information. BUT the emulator is not prepared for a 2K file at all and it's very likely this form is the only one that would fly there anyway.
Here is the 2K version for those wanting to duplicate it exactly. I already tested it by adding it to itself three more times and then testing that file against your file for no differences encountered report from MS-DOS file compare program. Nicely done.
Except you haven't fully tested it yet grasshopper...
I thought so too, until I started a complex printing project and where I have done it before and knew it like the back of my hand, it would not start with the GAL MMU in place. Suspicious, this might be the issue a swap showed it was the case and the printing began.
They do work is the take away, but there can be timing issues even with the best effort to match original and exactly why my GAL failed to function in only this mode is beyond my capabilities to find out about. Just because it doesn't immediately take you to the self test doesn't mean all is perfect. Wish I had a conclusion to this story too but I don't.
Every time I see FTDI I think of the clone chip troubles.
Just over a year ago, FTDI, manufacturers of the most popular USB to serial conversion chip on the market, released an update to their drivers that bricked FTDI clones. Copies of FTDI chips abound in the world of cheap consumer electronics, and if youve bought an Arduino for $3 from a random online seller from China, you probably have one of these fake chips somewhere in your personal stash of electronics.
After a year, we have the latest update to FTDI gate. Instead of bricking fake chips, the latest FTDI drivers will inject garbage data into a circuit. Connecting a fake FTDI serial chip to a computer running the latest Windows driver will output NON GENUINE DEVICE FOUND!, an undocumented functionality that may break some products.
The above dated 2016 and found in the wild with a simple search on FTDI clone. Unless you use a linux box there still appears to be no resolution to the issue. Windows plus FTDI cloned chips is a brick.
Since your symptom is a brick and this issue is still alive, I have no hopes of a solution. I also see no solutions anytime I look this issue up online. Just a lot of hate and hot air.
Glad you took the roughing up as well as you did, no harm no foul, I now know what DOS is being used, thanks.
Ok, the repeating busy light is supposed to be a bad 6532 RIOT chip but often they are changed out and the symptom remains. Best if you had a working donor to supply the 6532, but they are on eBay as R6532P.
Looking like you'll be a year before we can beat enough info out of you to provide any help at all. Error numbers come from the DOS installed so it's important to know the DOS used. Especially useful for odd error numbers like 174 first reported.
Error 138 is Device Does Not Respond, that means DOS can't see it, nor can the OS. First thing to do is buy some DeOxit contact cleaner and wet the drive select switches from the side with the cover off. Then work both of them at least twenty times while still wet. Let it dry and work them again twenty times.
How about swapping around U26 and U27 for a test to see if the pattern changes in the self test? Might need to replace these if we can get it to change by doing this. At this point it could still be CPU, MMU and a host of others too, but hey what fun!
There must be a bug in the self test code as usually three rows is all I've seen. And this could bad ROM itself or the bug acting only with the particular defect. At any rate BASIC occupies the last half of the last row of three.
So your first screenshot if it were all green squares is what we want to see if it was booted with BASIC ON. Last screenshot is not possible, but there it is anyway. I'm leaning towards a failing ROM chip U5 at the moment.
My guess would be that somebody needed the ROM card so they took it.
Layout you report is NOT right by the Bit 3 diagram. I'm thinking the directions on the 'jump back board' are too open to improper interpretations?
S.C.S.D. appears to have owned CSS at one time. Probably before Bob Puff took over CSS at least that is what I can gather from an ad for the "Pill" in a Compute magazine that google hit on. page 60 http://nleaudio.com/css/
Back in those days I couldn't even afford a baloney sandwich for lunch let alone an issue of Compute.
Would be nice to know the numbers off those ram chips on the 16K S.C.S.D. board, can't read from the picture. Have my suspicions that the 16K board might be axlon type ramdisk and the switch on those typically turned the extended memory off. Never understood really why, unless they just did that because they could.
You should maybe buy a lottery ticket? I thought I was lucky when I found a Happy in a $25 goodwill 1050.
That's the commutator end for all those motors, there would be brushes inside making interference and according to the FCC you can't do that way back then. So the disc puts them in compliance mainly would be my guess. I doubt any TV viewers were affected in any case, prime time has been dead so long now it doesn't even stink anymore.
Ah, a programmer! Positively no good then, resume with Vyper68 in post #14 and change out U24 and U25 for new 4051 chips as a last ditch effort before moving on to keyboard jack connection problems or mylar issues. It could be any of those, possibly more, but we are getting there and trying the most often to fail points to hopefully get to the real issue asap.
Can I vote 4x for 576k RAM ?!? Somehow we must beat those 1088k Atari owners, heck the poll shows even more 1088k owners than 64k owners...
Ahah! I kinda figured that attitude would show up and even be the underlying reason for such a poll in the first place. Rumor has it that ramdisks are useless above x size and not much is done with them anyway. And x varies according to non ramdisk user in the first place. And not much is done with them anyway. Did I mention that not much is done with them anyway?
People can say similar as much as they want, but without a full meg available to me, my hands are tied behind my back. Like typing with the nose, it's not happening here. Give me meg or give me death.