Mega ST2 overheating?

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CopperCAT
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Mega ST2 overheating?

Postby CopperCAT » Mon Jul 07, 2008 5:10 pm

I have some weird issue with my mega2.
First after about 15-20 minutes, now after a few minutes already (of gaming or using a program), it just spontanously reboots. The screen flickers white and it starts reading from the floppy again, then it flickers again and it keeps doing so until you turn it off for a while. The longer you wait before turning it on, the longer it takes to happen again. Sometimes it doesn't just reboot but stays flickering between blank white screen and noise or previous windows.

Any help on this? This is the only ST-compatible I have so i'd really like to fix it... :(

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PaulB
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Re: Mega ST2 overheating?

Postby PaulB » Mon Jul 07, 2008 5:30 pm

Sorry I can't point you to a specific fix but it sounds like a classic case of heat=expansion=disconnection. As in when the computer is a bit warmer from being on for a while, the heat is making parts expand and eventually disconnect. Hence the reboot.

Try removing your power supply, Put it on some plastic sheet, plug it in and put a voltage meter on different earth and live pins and see if the voltage jumps up and down after the same amount of time as in the Atari. At least that way you can determine if the power supply is at fault or whether it's further on in the Atari itself.

Also remove the pcb and check both sides for bad traces or dry solder joints.

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Re: Mega ST2 overheating?

Postby bullis1 » Mon Jul 07, 2008 5:40 pm

PaulB wrote:...removing your power supply, Put it on some plastic sheet, plug it in and put a voltage meter on different earth and live pins and see if the voltage jumps up and down after the same amount of time as in the Atari...


Well, maybe not on a plastic sheet. If it has an overheating problem you wouldn't want to have to scrape melty plastic off the bottom of your PSU. A desk/workbench will probably be fine. PSUs don't seem to be all that ESD-sensitive anyway.
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Re: Mega ST2 overheating?

Postby Chandler » Mon Jul 07, 2008 6:01 pm

power supply

take it out, remove it from it's base and resolder all the solders, but before look at them through a magnifying glass and see if you can spot any dodgy ones

bet you there are loads!

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Re: Mega ST2 overheating?

Postby CopperCAT » Mon Jul 07, 2008 6:30 pm

It seems that when I put off the (plastic+metal) casing and put the PSU away from the motherboard, it keeps going :s ? I have been playing "chuckie egg" for 15min now and still completely stable :)

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Re: Mega ST2 overheating?

Postby ppera » Mon Jul 07, 2008 6:33 pm

In Mega ST PSU really overheats (many people confirmed). Some fan is recommended.

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Re: Mega ST2 overheating?

Postby CopperCAT » Mon Jul 07, 2008 6:40 pm

ppera wrote:In Mega ST PSU really overheats (many people confirmed). Some fan is recommended.


But it does have that little whiny 4cm fan? And I never had any heating problems with it before.
Maybe the cause is somewhere else? Could the metal cover have something to do with it?

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Re: Mega ST2 overheating?

Postby Chandler » Mon Jul 07, 2008 8:44 pm

yeah the mega st psu has a fan

the psu get's VERY hot and with bad solders it causes the joints to "flex" hence the switching on/off

i've seen it in normal ST's

confirm the psu is ok before looking at anything else - you WILL need to use a magnifying glass (don't care how good your eyes are 8O ) and look at the solders closely

could also be a dodgy component on the PSU

while you've got the magnifying glass out :wink: give it the once over looking carefully

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Re: Mega ST2 overheating?

Postby Greenious » Mon Jul 07, 2008 10:45 pm

I pretty much agre with everyone here, the PSU is your best bet. I've seen PSUs overheat, but I don't think I've ever seen anything else in an Atari do it, so...

And a bad solder can work for years before it fails.
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Re: Mega ST2 overheating?

Postby ppera » Tue Jul 08, 2008 8:43 am

Chandler wrote:yeah the mega st psu has a fan...


Mine has not - so, someone removed it earlier... But it is opened by me all time :D

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Re: Mega ST2 overheating?

Postby mrnukem » Tue Jul 08, 2008 9:32 am

My Mega ST2 will scramble Hi Res Graphics when it has been on for a long time. It's strange but thats the only thing that seems to be affected by the heat. I leave picture slide shows on a lot (Not sure why I do this but I think it's neat). Anyhow after it has been on for an hour or more it will display the Hi res Pictures as distorted, lots of lines ect..But Low Res NEO pictures chug along with no problem. I turn it off and 30 minutes later it's back to normal.
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Re: Mega ST2 overheating?

Postby CopperCAT » Tue Jul 08, 2008 3:27 pm

Thanks for the tips, I'll check it thouroughly :)


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