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1200XL Slow to Boot


gilsaluki
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Hooked up My 1200XL after a few years idle. With cart or disk, it takes awhile for anything to happen. Yeah, it powers up immediately (LED light on), but just sits there. After about 10 secs, takes longer when first powered up than subsequent power ups, it very quickly flashes red, then I get video and sound. Weird, never behaved this way before. I am using the RF cable hookup, not the monitor port. Any suggestions? Is my baby about to croak?

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Sounds like a power supply fault, in the 1200XLs case there's the 9V external and internal rectification and regulation down to 5V.

 

Try another Atari 9V AC supply. 1200XL is in common with 400/800 and the 810/1050 disk drives.

My guess though would be on it being something inside the machine though, and same symptoms with another external PS would just about confirm that.

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I have the motherboard exposed. I cannot find, or am ignorant to where the color adjust is on the MB. I can say the Giant Cap at the top is not bulged or swollen or leaking. I don't see any of the other bulging either. Can some point me to the power section on the MB and the caps to check? I do believe it is in the RESET circuit as I have to hit the RESET a few times to get it to load a cart. Now it takes about 30+ secs to load.

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Changing those Caps did not fix the slow boot. On first boot up (cold), it takes over 30 secs. Then I have to push the RESET button a couple of times to bring it to life. Any other ideas? I hate to see an almost pristine 1200XL go down for the count.

 

 

Query: have you tested to see if the machine can boot from anything on the SIO interface? The reason I ask is, one of my 1200XL's had some screwy boot problems a couple years ago - long boot times to BASIC or the self-test screen, and it absolutely wouldn't recognize anything on the SIO port (disk drive or even an SIO2USB device). Turned out to be a bad POKEY chip.

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The telling factor should be how long does it take to go from a brown/red to black, then to a text screen.

 

Brown/red isn't guaranteed but is often GTIA default and should revert to black about 3/4 of second after the OS starts up, ie on a normal machine a second after you give it power.

From then on, you should get a text screen with cursor and attempted disk boot about a second later.

 

That much so far should be regardless of good or bad Pokey. In theory a bad Pokey which still is able to partly function with serial operations might prolong the attempted boot process indefinitely.

 

 

But, the actual reset circuit - the relevant evidence there is delay from red/brown to black to text screen. Also you should hear the click sound over the TV which would be simultaneous with the brown to black change (and probably a better thing to monitor as it always occurs).

Edited by Rybags
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Hooked up My 1200XL after a few years idle. With cart or disk, it takes awhile for anything to happen. Yeah, it powers up immediately (LED light on), but just sits there. After about 10 secs, takes longer when first powered up than subsequent power ups, it very quickly flashes red, then I get video and sound. Weird, never behaved this way before. I am using the RF cable hookup, not the monitor port. Any suggestions? Is my baby about to croak?

You say it gets video and sound after several seconds. So, it is basically working? Does it boot to the rainbow Atari logo

with no cart in? It should, at power on, brief grey screen, then a solid blue screen for about 3 seconds then a brief black

screen and then the rainbow Atari logo comes up.

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Thanks for all the responses. Here is the sequence of events after I turn on the 1200XL (when cold). 1. Black screen for 90 seconds. 2. Blue screen. 3. Push RESET it does go to the ATARI screen. 4. Push HELP, run the ROM/RAM check, all ROM/RAM is Green/good. 5. All other system checks good. 6. Switch machine off (now warmed up). 7. Turn machine back on it goes almost immediately to Blue screen (only 2 or so seconds versus 90 secs for the first power up).

 

Additional information: The SIO works, load disk programs from 1050 drive. One more anomaly will happen from time to time. When starting a game such as Galaxian, some of space items are huge! I mean double the normal size. I push RESET and everything is back to normal.

 

As I said, I have replaced the two caps near the bottom of the MB to the left of the color pot and C39 (large cap at the top of the MB).

 

Do I have a chip going bad or do I need to do a complete recap? All caps look to be good, no bulging or leaking or swelling.

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Sort of... normal behaviour without a cartridge should be text screen/cursor after ~ 2 seconds, attempted boot from disk (assuming Start not held to boot tape). The disk boot attempt should timeout after a few seconds then go to the logo screen.

 

What happens on that initial powerup where 90 seconds of nothingness if you press Reset after a few seconds?

 

My suspicion is the reset ciruit going bad but I can't find much in the way of useful information anywhere about it.

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From what I gather it is not normal behavior to sit with black screen for over 90s. My 1200xl User's Manual said when the computer is turned on it should go to blue screen and to the Atari Logo screen within 2 to 3 secs. It never goes past the blue screen without pushing RESET. It will sit on blue screen all day, not normal. To answer your question Rybags. If I push REEST during the 90 secs, nothing happens. I too suspect the RESET circuit, but have no idea where to start troubleshooting. I have changed the CAPS recommended by Bob1200XL, that did not fix the issue. Dead-ended for now.

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Hi Bob,

I do have several multimeters, analog and digital (I was an aircraft electrician). Not sure how to measure a capacitor. The cap I used was a new one. Good name brand too. I got a large cap kit to recap my Lynx. That seems to work well. Are you suggesting I try another cap? Which cap? There are two caps to the left of the color pot, 1 inch above the bottom edge. I changed both because I wasn't sure which one you referred to earlier. Thanks.

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Yes - that's great, Kyle!

 

Use an analog meter set to 10v D.C. Measure pin 3 on the LS14. It should rise from ground up to 3-4 volts and then pin 4 (or 1) will go from 5v to 0v quickly.

 

Pin 2 will go plus when pin 1 goes to ground. If that happens a few seconds after you power on, the RESET circuits must be OK.

 

Bob

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From Bob1200XL "Use an analog meter set to 10v D.C. Measure pin 3 on the LS14. It should rise from ground up to 3-4 volts (Good, I get 3VDC) and then pin 4 (or 1) will go from 5v to 0v quickly (I get about 2.5VDC, then to 0V quickly, IS THAT AN ISSUE?).

 

Pin 2 will go plus ( It goes to about 4VDC) when pin 1 goes to ground(it does). If that happens a few seconds after you power on, the RESET circuits must be OK."

 

The system still has the same symptoms, slow to boot--black screen for the longest time (2 mins or more now). Eventually the blue screen comes on, but will not go to the Atari Logo screen without hitting reset. Note: pushing reset during black screen does nothing. Note: I tried another 47 uF C& cap from a different lot, same issue. Funny thing is, as the system warms up, the boots take less time. Odd. I also tried reseating all the main chips. I did not reseat the RAM as they have tested good with the built in memory test. Funny thing is, last night I thought it was good to go, it booted just fine, within a couple of seconds. Today, same problem--slow to boot.

 

Ideas?

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