atari 800 xl troubleshooting

[Denl0]

Hi recently I've tried to start an atari 800 xl (pal) . I keep getting a blank screen on it.

 

I've read other threads concerning this problem.

 

Things I've tried so far:

 

-Measure output. I got 3 times 5 volt inside the computer.

-Refit all microships.

-Using star raiders cartridge also didn't work.

-None of the parts get's really hot.

 

 

Things I've noticed:

 

Sometimes I get yelow screen flash but then it turns black.

Sometimes with star raiders I have very thin blue lines. And sometimes a nice beeeeep sound.

 

When I press reset the blue thin lines or the sound goes away.

 

If I use UHF it finds the atari at 62 Mhz here there are blue dots around 1 cm appart from each other moving.

 

I do remember that it was broken when we put it away 10 years ago. It was broken suddenly 1 day it was working , the day after it diden't boot.

 

Are there any other things I might have to try?

 

I can't really swap ic's since we only have one atari 800xl

 

Are there any other common bugs on the pc. I think it's not damage from being old.

 

My dad suspects that cartridge bay is somehow stopping the system from booting?

 

Thank you for you're help!

[Denl0]

I havn't looked at the back of the pcb are there any chips there?

[russg]

I havn't looked at the back of the pcb are there any chips there?

There are no chips or anything on the bottom of an 800xl mb except solder spots and board traces.

[Roydea6]

There are no chips or anything on the bottom of an 800xl mb except solder spots and board traces.

Unless there has been one of the modern upgrades done to it like VBXE that sometimes requires the need to mount something in the way of the upgrade board go on backside.

[Denl0]

We own the computer for then 30 years so I don't think it has modern mods

 

Any Ideas of what I could try next?

 

Ooh I also have another question.

 

Has anyone tried this:

 

http://www.abbuc.de/...rechner-service

 

to get his atari fixxed?

Edited January 22, 2013 by Denl0

[mimo]

just the usual replace ram,os,cpu,pokey,mmu. easier if you have a spare working xl with all chips socketed to swap parts with

[Denl0]

Wouldn't it still show a screen if the ram was broken? + It was broken suddenly not because its old.

[russg]

Wouldn't it still show a screen if the ram was broken? + It was broken suddenly not because its old.

Long time, no response.

 

From the 800XL Field Service Manual:

 

Black or Grey screen (not just a dead screen, it comes up with a black or grey screen).

 

Clock circuit:

Y1 (a crystal), transistors Q8, Q9, capacitor C109

 

Other circuits:

U2, U7 to U20, U22, U23, U26 to U30

 

U2 a 74LS138 decoder 14 pin LS chip 2nd chip down from cart port

U7-Antic bottom second from left

U17- GTIA left most bottom

U8 - CPU 3rd from left bottom large chip

Drams on the left

U18 IC 74LS08

U19 74LS14 Hex inverter

U 20 Hex buffer CMOS

U 22 Pokey second up on fourth row from left

U23 PIA rightmost bottom Large chip

OS ROM U5 there are two smaller chips up the middle, it is the bottom, slightly bigger one

the BASIC ROM U4 is the smaller chip just up from OS ROM

 

All this does you no good, since you don't have a working board to try swapping with.

If you really knew what you're doing, an oscilloscope.

Edited February 27, 2016 by russg

[sparkplug.0128]

new to atari 800xl. i plug in my basic cart and get this screen. any help?

 

[Beeblebrox]

8 minutes ago, sparkplug.0128 said:

new to atari 800xl. i plug in my basic cart and get this screen. any help?

 

Hi. 

 

Firstly if this is an 800xl then Atari Basic is already built in so you don't need a basic cart.

 

We'll also need a bit more info. 

 

Without the cart plugged in what do you get. (Upload a pic). You should have a blue screen ready prompt. 

 

What cable are you using to connect to the TV also btw?

 

Where are you based also? Ntsc or pal computer? 

 

 

Edited September 20, 2023 by Beeblebrox

[+Stephen]

Also - what power supply are you using?  That looks suspiciously like a bad ingot style power supply over-volting.  I would not turn the machine on again until you can verify the power supply is outputting 5VDC.  They are regulated, so you should definitely not see anything over 5.2VDC and there should be no AC ripple / noise on the output.

[sparkplug.0128]

20 hours ago, Beeblebrox said:

Hi. 

 

Firstly if this is an 800xl then Atari Basic is already built in so you don't need a basic cart.

 

We'll also need a bit more info. 

 

Without the cart plugged in what do you get. (Upload a pic). You should have a blue screen ready prompt. 

 

What cable are you using to connect to the TV also btw?

 

Where are you based also? Ntsc or pal computer? 

 

 

Thanks for responding. I am in the NTSC region. i get the same result whether the cart is plugged in or not. I am currently using coaxial port (1st party cord)

[Overange]

12 minutes ago, sparkplug.0128 said:

Thanks for responding. I am in the NTSC region. i get the same result whether the cart is plugged in or not. I am currently using coaxial port (1st party cord)

What video connector ports are you using on the back of the Atari and on the TV?

 

Sound like you are using the RF co-axial Phono to Aerial connector, it could be the TV is not tuned in correctly.

 

However, if you are using old school RF Aerial Connections, best to move away from that way and I would advise you get a 5 pin Din to Composite Video Connection cable and try that method.

 

Can you show a photo of your set up?

 

Back of TV and Back of Atari.

Edited September 21, 2023 by Overange

[sparkplug.0128]

here’s the setup 

[Overange]

1 hour ago, sparkplug.0128 said:

here’s the setup 

Oh, yeah that’s an old school rf tuner setup.

 

looking at the front of your tv you have the yellow composite phono connection, if I was you I would get the Atari 5 pin din video to phono connection cable. 
it will save a lot of time and trouble and give you a better picture.

[ivop]

2 hours ago, sparkplug.0128 said:

 

If I'm not mistaken, that looks like the dreaded ingot power supply.

 

 

It is known to overvolt when failing and fry several chips on your main board.

[+Stephen]

1 hour ago, ivop said:

 

If I'm not mistaken, that looks like the dreaded ingot power supply.

 

 

It is known to overvolt when failing and fry several chips on your main board.

I mentioned this earlier.  And I will bet double down, after seeing this, that he is frying (or has already ruined) the system because of it.  I begged, PLEASE CHECK THE VOLTAGE before turning on the machine.

[sparkplug.0128]

how should i go about checking the voltage?

[sparkplug.0128]

also what replacement power and video cables do y’all recommend?

[Geister]

Do you have a digital volt/ohm meter?  You should see around 5 volts between the ground and power pins.  

 

Search for USB power supplies on the Brewing Academy website. https://thebrewingacademy.com/search?q=power+supply

They also carry a composite video cable for the Atari and TI computers.  The cost isabout $18 each.

[+scorpio_ny]

One thing @sparkplug.0128,

 

I see you using the RF connection. Did you check to make sure sure that the TV is set for “antenna”, not “cable”?Next, check which channel you are using on the TV and which  channel you have set on the computer (channel select switch). They should both match.

 

 

Edited September 22, 2023 by scorpio_ny

[ivop]

18 hours ago, sparkplug.0128 said:

how should i go about checking the voltage?

As previously said, with a voltmeter. But no matter what it says, it could be 5V now, but 7V ten minutes later. Do not ever use it again if you do not want to do any (more?) damage to your Atari. Cut off the cable and bin it.

 

[+Stephen]

6 hours ago, scorpio_ny said:

One thing @sparkplug.0128,

 

I see you using the RF connection. Did you check to make sure sure that the TV is set for “antenna”, not “cable”?Next, check which channel you are using on the TV and which  channel you have set on the computer (channel select switch). They should both match.

 

 

Antenna and cable are the same for the VHF band (channels 2-13).  That's why non cable ready TVs back in the day needed the external tuner box to get anything channel 14 and above.  I still contend that the picture looks like the computer is trying to make video but is being overvolted and that is messing with the sync.

[+Stephen]

On 9/20/2023 at 6:11 PM, sparkplug.0128 said:

new to atari 800xl. i plug in my basic cart and get this screen. any help?

 

 

Just now, Stephen said:

Antenna and cable are the same for the VHF band (channels 2-13).  That's why non cable ready TVs back in the day needed the external tuner box to get anything channel 14 and above.  I still contend that the picture looks like the computer is trying to make video but is being overvolted and that is messing with the sync.

So - look dead center of that picture.  You will see a horizontal band, with dark line in the center, followed by a bright line, then the start of another dark band.  That is the classic VBLANK signal these machines generate.  Back in the ancient days when these machines were new, CRTs had a vertical hold knob and if you misadjusted it and rolled the picture, you would see that.

[_The Doctor__]

PAL computer on an NTSC TV will do some of these anomalies, add humm bars from a bad PSU to the mix and you get a dance party of devious and torturous video showing your Atari dying. Are you in the USA using an NTSC TV with a PAL computer and ingot boat anchor of death hummm bar fry your machine power supply? Get a GOOD PSU and a display capable of PAL system video.