Atari XE Game System - Help with keyboard issue (not the mylar).

[Wyluli Wolf]

Since my original post is going on a year old (already? damn!) figured I would start a new one. I'm making one last ditch effort to fix my Atari XE game system (which was sold to me as fully working!).

The system (after cleaning, etc.) does work (it definitely wasn't tested as most of the games would not fire up until I thoroughly cleaned everything). Original game cartridges fire up and joysticks work fine.

When I fire up the system with just the keyboard plugged in, it boots to the basic blue screen. When I press buttons on the keyboard it makes a "boop" noise but no characters appear on the screen. If I fire the system up into diagnostic mode it passes all the tests fine. If I go into the keyboard test mode, none of the keys respond except the "Help" button which takes me out of the keyboard test mode.

 

I have replaced the Mylar with a new one.

I replaced both 4051 chips on the keyboard sub PCB.

I replaced the Pokey chip within the system.

I tested continuity from one end of the keyboard cable to the other end (seems fine).

 

None of the above has made any difference or shown any clues as to the issue.

 

Does anyone have any other idea's to offer? If it is not the pokey chip can I at least be certain the issue is something within the keyboard itself?

 

Thanks.

[Sugarland]

Pure guess here.. Try replacing the OS ROM. Sorry to hear this is happening.

Edited May 2, 2019 by Sugarland

[+Nezgar]

It could be the ROM.... But also the MMU is highly probable if BASIC and even the self test are erratic.

The OS, BASIC, and the Missile Command game are all banked into a single OS ROM on the XEGS. The 'self test' only tests the OS ROM 'portion' of the ROM, not BASIC or the Missile Command parts.

Does the system run the built-in Missile Command OK with no keyboard attached, and no cartridge inserted?

With the keyboard attached, no cartridge inserted, and 'SELECT' key pressed during powerup, do you get Missile Command?

With the keyboard attached, no cartridge inserted, and powered up with no function keys, it should bring up BASIC. You say it makes a "boop" noise -- will it do this at the press of any key on the keyboard, suggesting the keys are OK?

You're next two targets for replacement are the OS ROM, and the MMU. A programmed 27C256 EPROM is a pin compatible replacement for the original ROM chip. PM me I can mail you one. The MMU can also be replaced with an appropriately programmed GAL, but I have not done this myself yet, but I have a few on order to try. Maybe somone else here has some ready to go sooner. Otherwise, Best Electronics and B&C Computervisions will have OEM chips, but might have minimum order policies...

One more possibility is a tech tip posted by hardware guru tf_hh last year, although it describes symptoms only when the keyboard detached, which seems the opposite of yours.

http://atariage.com/forums/topic/284673-tech-tipp-strange-behavior-of-an-atari-xegs-and-solution/

[Wyluli Wolf]

It could be the ROM.... But also the MMU is highly probable if BASIC and even the self test are erratic.

 

The OS, BASIC, and the Missile Command game are all banked into a single OS ROM on the XEGS. The 'self test' only tests the OS ROM 'portion' of the ROM, not BASIC or the Missile Command parts.

 

Does the system run the built-in Missile Command OK with no keyboard attached, and no cartridge inserted?

 

With the keyboard attached, no cartridge inserted, and 'SELECT' key pressed during powerup, do you get Missile Command?

 

With the keyboard attached, no cartridge inserted, and powered up with no function keys, it should bring up BASIC. You say it makes a "boop" noise -- will it do this at the press of any key on the keyboard, suggesting the keys are OK?

 

 

Does the system run the built-in Missile Command OK with no keyboard attached, and no cartridge inserted? Yes, it boots into Missile Command with no keyboard attached.

 

With the keyboard attached, no cartridge inserted, and 'SELECT' key pressed during powerup, do you get Missile Command? Yes, if I have "select" pressed during powerup it boots to Missile Command.

 

With the keyboard attached, no cartridge inserted, and powered up with no function keys, it should bring up BASIC. You say it makes a "boop" noise -- will it do this at the press of any key on the keyboard, suggesting the keys are OK? With keyboard attached and no function keys it powers directly into the blue basic screen. While in basic every key makes a sound when pressed except SHIFT, CONTROL, BREAK AND A.

 

A programmed 27C256 EPROM is a pin compatible replacement for the original ROM chip. I have some 27C256 eproms. If you have the code and it's simple to burn, I can probably do this myself. Can you send the code to me? (I noticed you are in Canada so shipping will probably be high to the states..)

The MMU can also be replaced with an appropriately programmed GAL. I have some GAL20V8B chips on hand. If this is the appropriate chip, I can also burn the code if it is straight forward. Do you have the code?

 

Thank You!

[+Nezgar]

I didn't ask, does the "BASIC blue screen" show "READY" ?

 

It's odd 'A' doesn't respond...

 

Anyhow - an XEGS 32KB ROM file you can try programming is here: http://atariage.com/forums/topic/259483-xegs-game-rom/?p=3639787

 

Otherwise, basic postage from Canada for something small like a single chip is only a few dollars, but it takes 1-2 weeks to the US.

 

I have seen others post files for programming an XL/XE MMU to a GAL16V8, and I'm guessing a 20V8 isn't compatible. I haven't found a file for an XEGS MMU yet, but I'll do some more searching.

 

In the mean time maybe someone else knows more on the MMU/GAL front.

[Wyluli Wolf]

I didn't ask, does the "BASIC blue screen" show "READY" ?

 

The BASIC blue screen does show "READY".

Have you tested that 32kb ROM file by chance to make sure it works?

I guess I'll go ahead and de-solder the two chips and solder in IC sockets. I'll program a 32kb rom chip and see if that makes any difference. Please do let me know if you find anything on the MMU. I'll report back with the results.

 

Thanks again.

[+Nezgar]

The BASIC blue screen does show "READY".

Have you tested that 32kb ROM file by chance to make sure it works?

I guess I'll go ahead and de-solder the two chips and solder in IC sockets. I'll program a 32kb rom chip and see if that makes any difference. Please do let me know if you find anything on the MMU. I'll report back with the results.

 

Another thought.. If you by chance have a standalone BASIC cartridge handy, you could try plugging that in to see if it performs any better than internal BASIC...

 

The linked XEGS.ROM file has CRC32 D50260D1, which matches the CRC32 I believe is original. I have programmed EPROMS with that image for a number of people in the past who have reported it working. (And in some cases, replaced BASIC and Missile Command with other 8K games. )

[Wyluli Wolf]

I do not have a standalone Basic cartridge handy. I do have the Uno cart for the xegs which was my main motivation for getting this going since you sadly need the keyboard to use the cart.

As a side note I have several game carts which all work fine.

 

I programmed and socketed in the 27C256 EPROM using the code provided. She fires up ok but with the same results. In BASIC the keyboard keys still make the noise when keys are pressed. In the keyboard test mode there is no response at all except when the "HELP" button is pressed to exit the test screen.

 

Found THIS for the MMU code but I'm not sure what the difference is between the two. One, apparently, is incorrect.

[+Nezgar]

Alright, that's good we can at least rule out the OS ROM now.

So we're down to a suspect MMU, and trying soldering two 1nF capacitors between ground and the both KRx lines as per this topic:

http://atariage.com/forums/topic/284673-tech-tipp-strange-behavior-of-an-atari-xegs-and-solution/

I do not have a standalone Basic cartridge handy. I do have the Uno cart for the xegs which was my main motivation for getting this going since you sadly need the keyboard to use the cart.
As a side note I have several game carts which all work fine.

Hmm, I can't remember, does the UNO let you navigate the menu selections with the Joystick? If so, you could try putting a BASIC.CAR/ROM file on the UNO to emulate a real BASIC cartridge...

Found THIS for the MMU code but I'm not sure what the difference is between the two. One, apparently, is incorrect.

Yeah, that's the only one I've seen, to replace a CO61618 for 600XL, 800XL, 65XE, 130XE. (It won't be compatible with your XEGS) A stock 1200XL uses CO60609, and XEGS uses C101686. Those two I haven't seen GAL files for programming...

[+tf_hh]

Hi,

 

If I fire the system up into diagnostic mode it passes all the tests fine. If I go into the keyboard test mode, none of the keys respond except the "Help" button which takes me out of the keyboard test mode.None of the above has made any difference or shown any clues as to the issue.

.....

Does anyone have any other idea's to offer? If it is not the pokey chip can I at least be certain the issue is something within the keyboard itself?

 

Some good hints already were mentioned. It´s very improbably, but maybe worth a try: Check my post about XEGS keyboard issue

 

Here´s the code for the XEGS MMU, if you want to try it with a new GAL. You must take a 16V8 one. Speed rate 25ns or faster is fine.

 

Logic equations: MMU_XEGS.TXT

JEDEC file for GAL burning: MMU_XEGS.JED

 

Good luck!

 

 

[Wyluli Wolf]

Hi,

 

 

Some good hints already were mentioned. It´s very improbably, but maybe worth a try: Check my post about XEGS keyboard issue

 

Here´s the code for the XEGS MMU, if you want to try it with a new GAL. You must take a 16V8 one. Speed rate 25ns or faster is fine.

 

Logic equations: MMU_XEGS.TXT

JEDEC file for GAL burning: MMU_XEGS.JED

Thank you for the files. Looks like other folks are jumping in and downloading them as well. I have ordered some GAL chips and sockets so I can give this a try. Unfortunately, it will take a month or so for them to arrive.

In the meantime, if anyone thinks of anything else to try, please let me know!

 

NEZGAR - The Uno cart requires the use of the keyboard. You can not select anything with the joystick. I guess I did not make that clear in my post

 

Thanks again.

[+DrVenkman]

NEZGAR - The Uno cart requires the use of the keyboard. You can not select anything with the joystick. I guess I did not make that clear in my post

Flash the microSD card with one file ...

 

EDIT: Eh, never mind. Youll still need to press ENTER to load the file.

Edited May 9, 2019 by DrVenkman

[+kheller2]

Is there a way to get a program to autoload in basic and run w/o keyboard interaction.. just wondering if we can get a printout of the keyboard scan codes.

Its interesting the the A key doesn't make a noise when pressed, but the other keys do. hmmm.

[+Nezgar]

It should in theory still boot a disk if a drive is attached. I recall DOS 2.5 has a tool to make an autorun.sys to start a BASIC program.

 

Wyluli Wolf, do you have a drive, or some means to boot an ATR? If so I could construct a self boot disk image...

[Wyluli Wolf]

It should in theory still boot a disk if a drive is attached. I recall DOS 2.5 has a tool to make an autorun.sys to start a BASIC program.

 

Wyluli Wolf, do you have a drive, or some means to boot an ATR? If so I could construct a self boot disk image...

No disk drive. Just the system, keyboard and xe light gun with a few game cartridges and the UnoCart.

[+Nezgar]

Well it was an idea I guess... an SIO2PC adapter would be the cheapest/most useful runner up. (And man, joystick control for UNO would have been great in hindsight!)

 

Well, it made me curious to verify my memory anyway... Indeed the DOS 2.5 SETUP.COM has an option to create an AUTORUN.SYS that loads a specified BASIC program file.

 

[+kheller2]

what voltage does pin 16 of Pokey show when the shift + another key is pressed vs not pressed?

[Wyluli Wolf]

what voltage does pin 16 of Pokey show when the shift + another key is pressed vs not pressed?

Took a whack at this. Using a multimeter in DC voltage mode, I used pin 1 for ground and pin 16. I set the multimeter to "2" and tried to measure. You need at least 4 hands to do this. I didn't see any reaction at all. I tried again at the lowest setting (200m) and 20 just to be sure. Nothing as far as I can tell. This was while holding SHIFT down (no reaction) and holding SHIFT+other keys (tried numbers and letters)..no reaction.

[+kheller2]

Took a whack at this. Using a multimeter in DC voltage mode, I used pin 1 for ground and pin 16. I set the multimeter to "2" and tried to measure. You need at least 4 hands to do this. I didn't see any reaction at all. I tried again at the lowest setting (200m) and 20 just to be sure. Nothing as far as I can tell. This was while holding SHIFT down (no reaction) and holding SHIFT+other keys (tried numbers and letters)..no reaction.

 

I'll have to try this on one of mine. I would think you would see a voltage change. I was looking at the schematics and since you've basically replaced everything but passive components I was wondering if this pin was shorted high or low. KR2 is run through pin 1 one of the DB15 and runs through the CR1 and R18 on the keyboard circuit. That is pin 20 on the actual keyboard which maps to BRK CTL SHFT. Your multimeter should have read 0 or close to 5 depending.

 

Again, I'm just looking at probably inaccurate schematics but the thought came to me because your A key wasn't responding which makes me wonder if something is shorted -- hence wanting a program to dump the keyscan that is being sent.

 

I could be drinking too much as well.

[Sugarland]

Or maybe it's the keyboard end of things...? As in the pcb, other than the 4051's which you replaced. Take a close look at both sides under a magnifying glass?