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View Full Version : Atari400 wont power up....



ChiefRocka
November 29th, 2007, 03:36 AM
Hello there, my name is John and this is my first post.

When I was a kid, I received an Atari 400 for x-mas (in the early 80's)

Through the years I played that darn thing for ever and a day.


Well after being stored in my folks cellar for a little over 20 yrs, I decided to pull it out for my 6 yr old son to play with. "This thing was cool back in my day"...I told him

He looked at me and said...." http://i15.tinypic.com/72k1pom.gif"

Anyway, I found the power supply to be bad, and I had no joysticks...So I won the two stick, and a NOS power-supply still in the box from E-bay.

So, the new PS works (did the ol' 9volt batt tonge test...yaaooowww!)

Plug it in, flipped the switch....and.....nothing !!http://i16.tinypic.com/6ymhbg6.gif

I was so upset !!! I have tons of cool games my son would love.

I pulled the cover off..a little dusty, not to bad. The micro switch (cartridge door) seems ok....I can't find any loose solder connections....I just looked for the obvious...I dont have any computer test equipment.....all I have is car customizing/fabrication tools....I am a car nut...http://i5.tinypic.com/6l49e36.gif

Anyway, now what ??

What should I check....

Thanks in advance !!!!

John

barythrin
November 29th, 2007, 03:48 PM
Are you using an RF adapter for the TV connection? I can't recall for certain but I think the back of the unit has a "composite" video out, not an RCA video out and might be causing your lack of video if you just plugged it into your tv or vcr, etc without an adapter.

I could be wrong.. I'm not an Atari expert and haven't played with my 400 for a while, but it's thrown me off on several systems that I thought didn't work when I was just using an invalid video setup.

I wouldn't go testing a lot of electronics via the tongue test, it takes 1 amp to kill you and some of the Atari power supplies give a lot more than that.

- John

ChiefRocka
November 29th, 2007, 05:30 PM
No, what I meant was it doesn't power up....no power, the LED doesn't light, no sound from the internal speaker...you know, no power...dead !!

The rear of the 400 is just like the 2600/VCS...RCA cord coming out of the case...I guess I just need a RCA to 75 ohm connector to use on my TV, but I haven't got that far, because it doesn't power up

The funny thing is the power-supply was bad, so now I have a new one..but I guess it had more than one problem.

Your right, the old tongue test is not a good idea.

Anyway....now what ??

I really want to "Dig-dug" and "star raid" again !!!

John

Druid6900
November 29th, 2007, 07:34 PM
Well, as luck would have it, I have a couple of 400s sitting here with their little Atari guts hanging out (they both work, just haven't got around to putting them back together) and the first thing I would look at is the socket that the power supply jacks into. It'd be easy to crack the joints on that sucker with a good sideways yank on the cord or a little too much enthusiasm inserting and removing the connector,

After that, I'd check the 4 diodes (discrete bridge rectifier) right next to that connector, and there is a transistor on the outside of the metal shield right next to the top closed mechanism (which should give you a good, loud click when you push down on it to show that the micro-switch is working) that is probably a voltage regulator (I can't see the markings on it from it's mounted position) and it is probably either one or more of those components.

HTH.

ChiefRocka
November 30th, 2007, 04:18 AM
Well, as luck would have it, I have a couple of 400s sitting here with their little Atari guts hanging out (they both work, just haven't got around to putting them back together) and the first thing I would look at is the socket that the power supply jacks into. It'd be easy to crack the joints on that sucker with a good sideways yank on the cord or a little too much enthusiasm inserting and removing the connector,

After that, I'd check the 4 diodes (discrete bridge rectifier) right next to that connector, and there is a transistor on the outside of the metal shield right next to the top closed mechanism (which should give you a good, loud click when you push down on it to show that the micro-switch is working) that is probably a voltage regulator (I can't see the markings on it from it's mounted position) and it is probably either one or more of those components.

HTH.

Thank you very much...I will give that a try...

I know the diodes are like 'one-way' valves, right ??

How would I check the transistor ?? Is there a cheap tester available for Radio Shack or some thing ?

John

NobodyIsHere
November 30th, 2007, 05:03 AM
Hi,

I am no expert in Atari machines but were I facing your situation I would get either a VOM, logic probe, or oscilloscope and start chasing signals. I think Atari schematics are available online someplace. I don't know where but that would be invaluable information to help find the problem.

Ultimately, someplace the computer is not getting power or signal. I would literally start at the power plug and work my way through the guts of the computer. You know the power supply has to provide some level of power at its outputs, etc. It is just process of elimination until you find the problem.

Try carefully reseating all the components you can. You make need to clean connectors to blow off years of accumulated oxides. Follow Richard's advice (Druid). He certainly knows what he is talking about.

Failing all of that, I believe you can ask on these forums as there are some people who repair old computers for fun and/or profit. I know Richard does so you may want to look into that option if you can't fix it yourself.

Best of luck with your classic computer! Thanks!

Andrew Lynch

ChiefRocka
November 30th, 2007, 05:41 AM
Hi,

I am no expert in Atari machines but were I facing your situation I would get either a VOM, logic probe, or oscilloscope and start chasing signals. I think Atari schematics are available online someplace. I don't know where but that would be invaluable information to help find the problem.

Ultimately, someplace the computer is not getting power or signal. I would literally start at the power plug and work my way through the guts of the computer. You know the power supply has to provide some level of power at its outputs, etc. It is just process of elimination until you find the problem.

Try carefully reseating all the components you can. You make need to clean connectors to blow off years of accumulated oxides. Follow Richard's advice (Druid). He certainly knows what he is talking about.

Failing all of that, I believe you can ask on these forums as there are some people who repair old computers for fun and/or profit. I know Richard does so you may want to look into that option if you can't fix it yourself.

Best of luck with your classic computer! Thanks!

Andrew Lynch


Thanks Mr. Lynch...

WOW...so far this site has been a great help !!


Well, it's not a Classic Chevy, but I will give it a try !!http://i7.tinypic.com/7ypuasl.gif


John

NobodyIsHere
November 30th, 2007, 06:32 AM
Well, whether the broken system is a Chevy Malibu or an Atari 400, the technician's diagnostic and repair process is essentially the same. Identify what you know, research what you don't, check your assumptions, measure, document, and trace.

Using Google, I could not find a scan of the Atari 400 schematics but I did find where they are located. They are contained in a document called:

"Atari 400/800 Technical Reference Notes C016555"

Since Atari is still in business you may have to purchase it (it is probably copyrighted material) but it should not be too expensive. More thorough searching may reveal it hiding on the web some place. Be sure to check USENET as well as that is a classic place for this sort of information.

Best of luck with your project!

Andrew Lynch

Druid6900
November 30th, 2007, 08:34 PM
Well, whether the broken system is a Chevy Malibu or an Atari 400, the technician's diagnostic and repair process is essentially the same. Identify what you know, research what you don't, check your assumptions, measure, document, and trace.

And if all that doesn't work, get a pair of needle-nosed pliers and start crushing ceramic capacitors until it complies.

"Resistance is the opposition to current flow" :)

NobodyIsHere
December 1st, 2007, 06:28 AM
And if all that doesn't work, get a pair of needle-nosed pliers and start crushing ceramic capacitors until it complies.

"Resistance is the opposition to current flow" :)

Great Googly Moogly Richard! I had not heard of that one before! Are you serious?

It sounds like some sick form of torture. Wouldn't just checking continuity between Vcc and Gnd rails make more sense?

Thanks!

Andrew Lynch

Druid6900
December 1st, 2007, 11:59 AM
Nope, you have to teach this uppity old crap who's the boss.

Besides, after you make an example of one, you can always tack the caps back on to the leads that are left :)

BTW, did you notice that this is, appropriately, my 666th post (insert evil laughter here)

NobodyIsHere
December 1st, 2007, 12:17 PM
No kidding. Did someone get up on the wrong side of the bed this morning? Taking your aggressions out on some old defenseless computers?

;-)

Have a nice day, Mr. Evil.

Thanks!

Andrew Lynch

Micom 2000
December 3rd, 2007, 05:29 PM
On the other hand you could simply buy an 8-bit Atari on Ebay for $10 and shipping. The 400 was a cheap version of the 800. Even an 800XL or even better a 130XE rarely go for too much and your kids would consider you less lame. Most of your programs would also be compatible. Possibly $30 tops. An Atari XEGS with it's cute colored buttons on the keyboard and Laser-gun as well as it's built-in programs could possibly draw them away from Nintendo xx and make a common bond as well as reminding you of your youthful joy with the 400. Altho I haven't checked lately what GS's are going for they are likely the same. Oh, and IIRC, the XEGS will also work directly from cartridges and joysticks, no keyboard entry involved.

The upside is if they can discover they can actually write programs which will allow their computer to jump thru hoops. It's not much distance intellectually to understand that each computer language is similiar and can also be manipulated similarly.
Voila ! Your kid, stage by stage develops the killer app because he has a broader grasp than most limited MS$ programmers
and becomes a millionaire. He/she buys you a condominium in the Bahamas or Tahiti.

They're not about to discover it with Playstation ll nor pointing and clicking in Windows. You've got the right instincs.

Lawrence


Hi,

I am no expert in Atari machines but were I facing your situation I would get either a VOM, logic probe, or oscilloscope and start chasing signals. I think Atari schematics are available online someplace. I don't know where but that would be invaluable information to help find the problem.

Ultimately, someplace the computer is not getting power or signal. I would literally start at the power plug and work my way through the guts of the computer. You know the power supply has to provide some level of power at its outputs, etc. It is just process of elimination until you find the problem.

Try carefully reseating all the components you can. You make need to clean connectors to blow off years of accumulated oxides. Follow Richard's advice (Druid). He certainly knows what he is talking about.

Failing all of that, I believe you can ask on these forums as there are some people who repair old computers for fun and/or profit. I know Richard does so you may want to look into that option if you can't fix it yourself.

Best of luck with your classic computer! Thanks!

Andrew Lynch