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Need help: Atari 800XL will not power on


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#1 Vyncynt OFFLINE  

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Posted Thu May 16, 2019 11:02 AM

What I have

I have two 800XL's (NTSC) which were both in storage for 10+ years. I only had one Atari power supply, which I learned was the "ingot". Both worked prior to insertion in storage.

 

I also have two 1050 drives, each with their own PSU. Both of those power up just fine. I did not have them connected when I tested the 800XLs.

 

Problem
Neither will power up. Power LEDs do not illuminate. Nothing on the screen.

 

What I tried
1. Initially tried connecting the PSU to the computer, but no power LED and nothing on the screen. No smoke, sparks, or explosions either. Had it connected about 10 seconds to each.
2. Tested a 5V ATX PSU (correctly jumpered and tested with a hard drive). Butchered the ingot PSU's DIN cable and wired it into a molex connector (black wire to red, black wire w/white stripe to black). Connected to the computer. Tested across the leads and read 5V DC. No power. Also tested with my Amiga's Bigfoot PSU w/molex connectors, but no luck either. Same results.
3. Connected to TV with RF and then to a monitor with monitor cable, nothing on the screen.
4. I wore a nerd bracelet and disassembled both. Caps are not visibly leaking. Chips are NOT socketed to the board.

 

Need Help

Does anyone know of a troubleshooting guide or tips to try to make them work? I have minimal electronics experience, but do have a pretty good voltmeter and am comfortable soldering. I realize I might need to replace components or the system outright (if I can find a working one for a reasonable price).

 

Thanks!


Edited by Vyncynt, Thu May 16, 2019 11:19 AM.


#2 DrVenkman OFFLINE  

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Posted Thu May 16, 2019 11:46 AM

Your ingot may have killed both systems in your tests but no way to be 100% sure yet. Have you verified that that your new-made PSU matches the correct XL power DIN is correct?

 

http://atariage.com/...ctor/?p=2323544

 

Once you've confirmed your pinout, get a multimeter and make sure the 5 volt line is putting out the correct voltage and it's nice and stable.

 

After that, it gets more complicated, especially if your boards are not socketed. The usual damage caused by an Ingot PSU going bad is memory, but really it could be any of the main IC's. But first thing's first: verify your DIN pinout with a meter.



#3 Vyncynt OFFLINE  

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Posted Thu May 16, 2019 1:01 PM

Your ingot may have killed both systems in your tests but no way to be 100% sure yet. Have you verified that that your new-made PSU matches the correct XL power DIN is correct?

 

http://atariage.com/...ctor/?p=2323544

 

Once you've confirmed your pinout, get a multimeter and make sure the 5 volt line is putting out the correct voltage and it's nice and stable.

 

After that, it gets more complicated, especially if your boards are not socketed. The usual damage caused by an Ingot PSU going bad is memory, but really it could be any of the main IC's. But first thing's first: verify your DIN pinout with a meter.

 

I appreciate the information.

 

That's what I was afraid of. I matched the 5V and GND connections correctly. Yes, 5V is very stable at the splice and the DIN pinout.

 

I read some older topics where people said Best Electronics sells a fully populated 800XL motherboard. I'm considering just buying one ($69) along with the repairable power supply ($27) so I don't have to deal with the hassle. Curious if http://www.best-electronics-ca.com is the correct address. The web page looks pretty dated. Wondering if anyone else has bought either of those items and if the boards are soldered or socketed.



#4 Forrest ONLINE  

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Posted Thu May 16, 2019 2:28 PM

As was recently discussed on this form, an ATX power supply requires a minimum load to operate correctly. I'm not sure the Atari draws enough current to operate with an ATX power supply. A 2-3 Amp 5V DC power supply designed for a Raspberry Pi should work better. You'll just need to splice in a DIN plug. These power supplies are widely available for $9-$14.



#5 _The Doctor__ OFFLINE  

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Posted Thu May 16, 2019 3:32 PM

D*mn it Jim, he's butcher not a physician!

Two dead usually means you've crossed something up...

maybe consider a different psu as some power supplies do not realize the Atari is even there to keep them switched on..


Edited by _The Doctor__, Thu May 16, 2019 3:33 PM.


#6 toddtmw OFFLINE  

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Posted Thu May 16, 2019 3:52 PM

One of my favorite exchanges in one of the Star Trek parodies posted on Usenet:

 

Kirk: Bones, help this man, he's injured!

McCoy: Damnit, Jim! I'm a doctor not a - oh, right.



#7 bob1200xl OFFLINE  

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Posted Thu May 16, 2019 4:19 PM

It would be useful to know if your 'ingot' power supply is bad or not. If the supply has failed, it should output 7 or 8 volts.

 

Measure your old ingot output (unloaded). If it is 5 volts, you may have some other problem. Hard to understand no LEDs. Not much has to work for them to come on.

 

Bob



#8 _The Doctor__ OFFLINE  

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Posted Thu May 16, 2019 4:24 PM

power switch stuck in off position internally? shorted and blown cap?



#9 Urchlay OFFLINE  

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Posted Fri May 17, 2019 2:08 AM

Hard to understand no LEDs. Not much has to work for them to come on.

I've got a 600XL that spent some years in storage... the power LED didn't
work, so I thought the whole machine was dead. It's connected via the
keyboard connector AFAIK, I somehow fixed the power LED by moving the
keyboard around: the option & reset buttons were getting stuck in the
down position, so I loosened the keyboard screws & wiggled the keyboard
a bit, then tightened the screws... now the power LED mostly works,
but occasionally will flicker a bit while I'm typing.

Also have a 1200XL with exactly the same problem: everything works fine,
but no power LED.

#10 Vyncynt OFFLINE  

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Posted Fri May 17, 2019 6:11 AM

As was recently discussed on this form, an ATX power supply requires a minimum load to operate correctly. I'm not sure the Atari draws enough current to operate with an ATX power supply. A 2-3 Amp 5V DC power supply designed for a Raspberry Pi should work better. You'll just need to splice in a DIN plug. These power supplies are widely available for $9-$14.

 

I had a couple of regular hard drives connected also and they powered up normally.



#11 Vyncynt OFFLINE  

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Posted Fri May 17, 2019 6:11 AM

It would be useful to know if your 'ingot' power supply is bad or not. If the supply has failed, it should output 7 or 8 volts.

 

Measure your old ingot output (unloaded). If it is 5 volts, you may have some other problem. Hard to understand no LEDs. Not much has to work for them to come on.

 

Bob

 

I didn't realize the need to test this, but already trashed the old ingot.



#12 DrVenkman OFFLINE  

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Posted Fri May 17, 2019 7:06 AM

Also have a 1200XL with exactly the same problem: everything works fine,
but no power LED.


The 1200XL has two connectors between the top half of the case assembly and the main board: one for the keyboard matrix and another smaller one for the LED board. Make sure the LED connector isn’t reversed or installed offset to one side.

#13 Nezgar OFFLINE  

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Posted Fri May 17, 2019 3:10 PM

I didn't realize the need to test this, but already trashed the old ingot.


You gave the Ingot the treatment it deservred regardless if it was good or bad. Testing it now would just help determine if it was indeed failing with a high voltage output, and may have contributed to damaging components in the computer.

#14 kheller2 OFFLINE  

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Posted Fri May 17, 2019 4:58 PM

The 1200XL has two connectors between the top half of the case assembly and the main board: one for the keyboard matrix and another smaller one for the LED board. Make sure the LED connector isn’t reversed or installed offset to one side.

 

I've also seen the LED solder broken and needed to be fixed.



#15 kheller2 OFFLINE  

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Posted Fri May 17, 2019 4:59 PM

Open the 800XL's up.  You have a multimeter so check to see if 5 volts is making it to any chips.  The power LED could be because of a bad keyboard connection.  But the likelihood of both being bad points to the killer ingot.



#16 bob1200xl OFFLINE  

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Posted Fri May 17, 2019 8:42 PM

Even if the ingot was putting out 10 volts or more (highly unlikely), the LEDs should be OK. The LED is forward biased thru a 220 ohm resistor, which limits the current in the diode.

 

So, it may be the k/b connector or a loose solder joint. Regardless of the power LED, you should get some kind of screen flash or audio pop when you power on. If you have 5 volts reaching the power buss.

 

Bob



#17 Urchlay OFFLINE  

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Posted Sat May 18, 2019 12:01 AM

The 1200XL has two connectors between the top half of the case assembly and the main board: one for the keyboard matrix and another smaller one for the LED board. Make sure the LED connector isn’t reversed or installed offset to one side.

Probably a dirty/loose contact caused by age, it (the power LED) was
working when it went into storage, not working when it came out (but
the rest of the computer seems fine)... might start a new topic for this
1200XL when I get around to messing with it.

#18 Vyncynt OFFLINE  

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Posted Sun May 19, 2019 3:47 PM

power switch stuck in off position internally? shorted and blown cap?

 

Possibly. I checked both. Here's what I found.

 

Machine A appears to be older. No revision number or date on the board. RF shielding was screwed down. Chips are NOT socketed.

 

Machine B appears to be newer. Revision A2 (1983). RF shielding was crimped down. Chips ARE socketed (yay!). Found a detachable red lead running from the board at 13 to the cartridge bay dust cover/doors.

 

Just to be sure, I tested the both keyboard LEDs by running 3.3V and a 220 ohm resistor. Both work normally.

 

On both systems, I tested the lower leads from the power switch. They show 0 ohms when off, and machine A shows 1 ohm, machine B shows 0.8 ohms when on. I don't know what to check after that.



#19 Vyncynt OFFLINE  

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Posted Sun May 19, 2019 3:47 PM

Open the 800XL's up.  You have a multimeter so check to see if 5 volts is making it to any chips.  The power LED could be because of a bad keyboard connection.  But the likelihood of both being bad points to the killer ingot.

 

Checked both LEDs. They are good.



#20 Vyncynt OFFLINE  

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Posted Sun May 19, 2019 3:48 PM

Even if the ingot was putting out 10 volts or more (highly unlikely), the LEDs should be OK. The LED is forward biased thru a 220 ohm resistor, which limits the current in the diode.

 

So, it may be the k/b connector or a loose solder joint. Regardless of the power LED, you should get some kind of screen flash or audio pop when you power on. If you have 5 volts reaching the power buss.

 

Bob

 

Yep, verified. Used my Raspberry Pi breadboard kit to test. Put a 220 ohm resistor inline and tested with a dummy LED, then tested the keyboard LEDs. Both are ok.



#21 Vyncynt OFFLINE  

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Posted Sun May 19, 2019 3:49 PM

Open the 800XL's up.  You have a multimeter so check to see if 5 volts is making it to any chips.  The power LED could be because of a bad keyboard connection.  But the likelihood of both being bad points to the killer ingot.

 

I have no idea which pins to check on the chips.



#22 Geister OFFLINE  

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Posted Sun May 19, 2019 6:31 PM

Standard TTL logic chips generally have +5V on the upper tight pin and ground on the lower left.  In most cases you can determine the location of power and ground by observing the traces on the board.  Thin races are address/data lines, and thick lines are power and ground.



#23 RodLightning OFFLINE  

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Posted Sun May 19, 2019 6:58 PM

Since you are using just the one power cable on both, I would start by making absolutely sure that 5vdc is present at the DIN connector and power jack inside the computer. Both XLs completely dead suggests an issue with the power plug.

Wet the DIN pins with wd-40 or rubbing alcohol and then repeatedly insert and remove the plug into a power jack. Friction will help remove any tarnish.
Let the contacts air dry for a while, then power up a computer. If no joy, then try taking those measurements at the power jack and other points inside the computer.

#24 DrVenkman OFFLINE  

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Posted Mon May 20, 2019 5:52 AM

 
I have no idea which pins to check on the chips.

I’m on my phone or I’d post a direct link, but Atarimania has Atari field service manuals and/Sams Computerfacts service manuals for the 800XL. Chip pin outs for all the main ICs and logic chips are in those books. They can show you which pins to check for +5V and ground, logic pulse patterns to check if you have a logic probe or scope, etc.




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