Help fixing my 65XE computer - Green Screen

[Jouster]

Hello all,

 

I am a frequent visitor to this forum as I have several Atari systems (7800, 2600 etc).

I've joined in the hope that someone can help me with a problem...

 

I decided to get an 8bit system, as I used to own one (Atari 800) back in the day. My PAL 65XE arrived last week and I eagerly powered it up to a green screen I could not complain to the seller as system was sold as untested.

 

Right here is what I have tried so far:

 

Changed all RAM - X8

Changed CPU - C014806-12

Changed ROM - C061598B

 

I even swapped the Pokey to see if that was the problem, but still no joy.

 

I suspect you guys have vast experience in getting these old systems working again, so I'm looking for some advice/guidance. I'm determined to get this going!

 

BTW, it looks like it's a 130XE motherboard inside this 65XE

 

Thanks in advance

[+Stephen]

1st of all - did you own an NTSC system back in the day, and now have a PAL? The colours are somewhat different. If not, there is a colour adjusting pot in the bottom of the machine. Be very careful - it's a super delicate pot, and it does not do a full rotation. There should be plenty of pictures on the forum showing the location.

[Guest]

Stephen just beat me to it with the pal/ntsc theory, the adjustment pot is a good place to start.

 

no joy?

try a different PSU, i'm sure i read somewhere that a bad psu can f*** things up.

 

have you tried via RF or monitor port?

[Jouster]

Let me clarify,

 

I'm in PAL land, so my previous A800 was a PAL system.

 

The green screen is a solid green screen (no prompt). It sometimes comes up brown, sometimes totally black. Sometimes it has lines down the screen also.

 

i.e. the system is not getting to the basic prompt at all

 

I thought it was the system ROM, but changing that didn't help. I haven't tried changing the Basic ROM as yet.

 

I have a logic probe but not really experienced in using it. So have changed the most of the 'common' problem chips in the hope that I got lucky.

 

The power supply is giving 5.02v under load.

 

What do you suggest I try next guys?

Edited March 8, 2017 by Jouster

[+Stephen]

Oh - sorry for the misunderstanding. If the screen is not being blacked out, I believe that is an indication that the machine is not even making it to the OS initialization routines. Could be many reasons for that - I'll defer to the more experienced hardware guys.

[electrotrains]

The green screen is a solid green screen (no prompt). It sometimes comes up brown, sometimes totally black. Sometimes it has lines down the screen also.

 

i.e. the system is not getting to the basic prompt at all

 

 

Hi Jouster,

 

I had a similar problems with my PAL 65XE (130XE board) after an ill-judged homebrew cartridge experiment went wrong.

 

In my case the MMU chip had got damaged - it produced symptoms similar to yours, so that might be worth a shot.

 

http://atariage.com/forums/topic/235824-i-thought-id-killed-my-65xe-now-im-not-so-sure-help/

 

Robin

Edited March 8, 2017 by electrotrains

[Jouster]

No problem, I should have explained it better

 

After 10 minutes or so, the only two 'hot' chips are the CPU and system ROM C014806 & C0615988

 

All other chips are cold to warm.

 

The screen is coming up brown mostly now, sometimes light blue...

[Jouster]

Hi electrotrains,

 

doesn't look like the MMU chips are readily available in the UK

 

Where did you get yours? How much with shipping?

 

Is there a way of testing the one I have to see if it is working? As I say I do have a logic probe..

 

 

Update:

 

Computer been on for 30 minutes, should freddie be stone cold??

Edited March 8, 2017 by Jouster

[Guest]

unfortunately, lots of possibilities

ram, OS Rom, Basic Rom, MMU, PIA

here's a checklist of stuff i typed up in a similar thread some time ago, hope it helps

 

1] if the board is socketed, rather than soldered you may have some "unseated" ICs.

check to see if:

ram, OS Rom, Antic, MMU, PIA (even CPU also) are fully in their sockets.

they can look "seated" but may not be. if your comfortable with doing so, you can remove them and reinsert.

2] if still a black screen try this (turn TV volume up):

power up using OPTION key, wait five seconds, press SELECT key once, press START

do you hear the musical notes? if so your computer is working

now press HELP, then SELECT, the START

press different keys randomly....do you hear the keyboard BEEPS?

these are good signs that your atari is fundamentally ok.

3] power supply may be a problem - it may not be supplying 5v. you'll need to try another PSU.

4] are you using RF/monitor output?

if RF, do you have a little channel switch next to the RF output lead? try repeatedly moving it back and forth - it can get dirt inside and cause bad contact.

try a monitor cable - these are fairly standard these days and are monitor to scart/RCA/S-video cables

5] try booting with a cartridge in the slot -

Star Raiders cart runs a diag on Antic, CPU and GTIA - so if Star Raiders works then ALL three should be good

which narrows your fault down to PIA, OS Rom, MMU or Ram

5] leave machine on for ten minutes....are any ram chips "overheating"?

there's some stuff to try there...good luck

Edited March 8, 2017 by Guest

[Jouster]

unfortunately, lots of possibilities

ram, OS Rom, Basic Rom, MMU, PIA

here's a checklist of stuff i typed up in a similar thread some time ago, hope it helps

 

1] if the board is socketed, rather than soldered you may have some "unseated" ICs.

check to see if:

ram, OS Rom, Antic, MMU, PIA (even CPU also) are fully in their sockets.

they can look "seated" but may not be. if your comfortable with doing so, you can remove them and reinsert.

2] if still a black screen try this (turn TV volume up):

power up using OPTION key, wait five seconds, press SELECT key once, press START

do you hear the musical notes? if so your computer is working

now press HELP, then SELECT, the START

press different keys randomly....do you hear the keyboard BEEPS?

these are good signs that your atari is fundamentally ok.

3] power supply may be a problem - it may not be supplying 5v. you'll need to try another PSU.

4] are you using RF/monitor output?

if RF, do you have a little channel switch next to the RF output lead? try repeatedly moving it back and forth - it can get dirt inside and cause bad contact.

try a monitor cable - these are fairly standard these days and are monitor to scart/RCA/S-video cables

5] try booting with a cartridge in the slot -

Star Raiders cart runs a diag on Antic, CPU and GTIA - so if Star Raiders works then ALL three should be good

which narrows your fault down to PIA, OS Rom, MMU or Ram

5] leave machine on for ten minutes....are any ram chips "overheating"?

there's some stuff to try there...good luck

 

Thanks for this!

 

1) The only socketed chip is Freddie (C061991), I'm socketing more as I try changing chips;

I've swapped all RAM for NOS 4164B-12

Swapped CPU

System ROM

Pokey

All seated ok

2) No luck with this, still boots with random screen colours, sometimes lines down screen

3) PSU giving 5.02v under load

4) Yes, I'm using RF. Crappy picture but I can see what the computer is outputting. And it's not the normal boot screen... No Prompt, just the aforementioned randomly coloured screens

5) I don't own any carts unfortunately. The only two IC's that get 'Hot' are the CPU and System ROM C014806 & C061598B

 

As in my previous post, should Freddie be stone cold?

[Jouster]

I guess I'll just keep replacing random IC's until it starts working.

 

I was hoping to avoid having to do this but it seems unavoidable.

 

I'll leave the MMU till last since it's the most difficult to come by over here.

 

I'll post how I get on for anyone interested.

 

Thanks very much for the help anyway guys

[Kyle22]

If the MMU is costly, find someone with a programmer and burn one.

 

PAL16L8 or GAL16V8.

 

I couldn't find a jed file for the MMU, so you'll need to use PALASM (included).

 

The EMMU is also included if you need that.

 

 

AtariPALs.zip

 

Edit: 16L8 PALs for sale here: http://www.ebay.com/itm/like/251186019869?lpid=82&chn=ps&ul_noapp=true

Edited March 15, 2017 by Kyle22

[shoestring]

I have a few spare gal16v8s and the equipment to program them.

 

I am based in Australia though so maybe you can get a better offer closer to you.

Edited March 15, 2017 by shoestring

[xrbrevin]

Hi ppl,

Sorry to butt in on this post but im having similar issues with a 65xe that i modded to 128k. i used a genuine EMMU and thus no 74LS device was needed at U35

It ran fine for a week or so, just as a 130xe should. i left it running in 'attract mode' (zone ranger) and after a while it i noticed it had frozen

on booting i now get a stable black screen - slightly lighter shade than the black border, if i plug in star raiders i get a browny-red screen. occasionally with a vertical cream-coloured stripe on the left side.

 

i have tried using a sys-check II cartridge in diagnostic mode but i get the same results as star raiders. this would imply the RAM is not the issue

 

i got a PAL16L8 with a view to programming a new MMU on my TL866CS EPROM programmer but i cannot convert the .src file to .jed (why isnt it available as a .jed has frustrated me... ) i had already socketed the MMU in readiness too :/

 

its tricky because the XEs have very few sockets, i cant do the swap test so easily!

 

i have previously mended an 800xl and 130xe that would not boot but they had visible PCB issues - this unit is visibly intact

 

any help would be much appreciated

[+DrVenkman]

If it froze while running, it could be anything - assuming the PSU didn't fail "hot" and take the system down with it, one of the IC's simply failed due to age. Last time I had a system doing that, it was the GTIA. However, the system would boot when cold; it simply failed after a few minutes when the chip heated up.

 

The colored image with Star Raiders indicates that ANTIC is probably okay. My first thought would be the CPU since SYSCHECK can't even run.

[xrbrevin]

Hi,

Thanks for the advice

 

I realised i had to bite the bullet and get the soldering iron out - XEs have so few chip sockets... I found a leftover MMU from a 1200XL U1MB mod so I didnt need to program the PAL18L8 after all - i tried it in but it made no change

 

I rooted further and the only 40pin Atari chip I could find was a CPU so I "socketed it" in and the 128kb 65xe now lives, again!!

 

Youre gut feeling is spot on I am a little cautious tho - i'm not going to work it too hard for now. im just relieved to see it running and passing tests

 

Sweet relief!

 

All the best & muchas gracias

Nick

[flashjazzcat]

Note the 1200XL (CO60609) is different from a regular XL/XE MMU (CO61618). 1200XL has no internal BASIC so pin 13 (BASIC on the XL/XE MMU) is a chip select signal for the low 1200XL OS ROM. That said, I'm interested to know how the 65XE behaves with the 1200XL MMU fitted.

[+DrVenkman]

Hi,

Thanks for the advice

 

I realised i had to bite the bullet and get the soldering iron out - XEs have so few chip sockets... I found a leftover MMU from a 1200XL U1MB mod so I didnt need to program the PAL18L8 after all - i tried it in but it made no change

 

I rooted further and the only 40pin Atari chip I could find was a CPU so I "socketed it" in and the 128kb 65xe now lives, again!!

 

Youre gut feeling is spot on I am a little cautious tho - i'm not going to work it too hard for now. im just relieved to see it running and passing tests

 

Sweet relief!

 

All the best & muchas gracias

Nick

 

Glad my instinct was correct!

 

Yeah, after my adventures this year with my two 1200XL's, I'm kind of developing a pretty good gut instinct for what's likely to be wrong with an A8-type machine.

[xrbrevin]

Note the 1200XL (CO60609) is different from a regular XL/XE MMU (CO61618). 1200XL has no internal BASIC so pin 13 (BASIC on the XL/XE MMU) is a chip select signal for the low 1200XL OS ROM. That said, I'm interested to know how the 65XE behaves with the 1200XL MMU fitted.

 

i noticed the 1200XL MMU is labelled a bit differently but i didnt check the numbers... i'll dig it back out, give it a go and let you know what it does. Do you know why in-built basic would require a different RAM logic? just curious... i ought to study the 1200XL differences because it is an oddity model

 

Dr.V - i think "gut feeling" is a secret ingredient in solving these puzzles, stubborn determination can help too lol. i had similar saga with 2x 1050s recently that taught me this. thanks to the kind folk on here they are no longer bricks, they are now: Happy and Mini-Speedy! (homebrew USD next)

 

All the best

Nick

Edited July 29, 2017 by xrbrevin

[xrbrevin]

Hi,

FYI, I just tried the 1200XL MMU in the 65XE and it would not work

The screen is yellow with a white vertical stripe to the left

 

I also tried the 1200XL OS ROMs but it wouldnt boot with either

 

have a good one!

[flashjazzcat]

Thanks for trying it!

[xrbrevin]

Oon another note, do you know if I can burn my own OS ROM for the 65XE?

I have found a dump file on the pigwa archives but I dont know if it is possible, let alone which blank IC to use

Cheers

Nick

[flashjazzcat]

Good topic on it here: http://atariage.com/forums/topic/249357-customizing-the-os-rom/

[xrbrevin]

Nice one - much appreciated!