5200 console appears to have damaged the power supply

[+DamonicFury]

So I was trying to do someone a favor by taking a look at their dead 4-port 5200 console. Plugged it into my setup and nothing happened, as reported. But I then tested my power supply that Ive used for years and its only outputting 2 volts now! Anyone have any idea what might cause a 5200 console to wreck its power supply?

[atari-dna]

Probably just the 30 year old capacitors on the output side of the transformer. Completely dried up by now. The filter caps after the diode bridge. They smooth the DC rectified current. I have all the parts to rebuild if you want.

 

 

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Edited July 31, 2018 by atari-dna

[+DamonicFury]

Probably just the 30 year old capacitors on the output side of the transformer. Completely dried up by now. The filter caps after the diode bridge. They smooth the DC rectified current. I have all the parts to rebuild if you want.

 

Thank you for your reply! It does make sense that the caps are to blame given the low voltage being output. And I would indeed be interested in the rebuild parts, thanks! But Im still leery of the console... any idea if it might have some condition that would have possibly fried the caps that have been working well for years? Im really concerned that if I try another power supply with it that it will suffer the same fate.

[nick3092]

Other than a dead short in the console, I'm not sure what could happen in the console to fry a power supply. Should be easy enough to check on the console with a DMM.

 

As for the brick, it has two 3300uf 25v caps in it, and a 5A glass fuse. At least that's what we're in two of mine.

Edited August 1, 2018 by nick3092

[atari-dna]

I’d take off the hood, and look at the voltage regulators (and power filter cap) and check the small ceramics around the power section for shorts with your multimeter. Let me know what you find. Check the MJE210s and the 7805s on the heat sink. Also, with a 2 port make sure none of the power plug port pins on the PCB are shorting against a screw or trace, etc. the screw or strap holding the heat sink nearest the power port should be nylon—unless someone replaced it. Let me know what you find, and we will continue to diagnose.

 

 

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[+-^CrossBow^-]

You sure you didn't plug in a power supply for something else? I recall one of the 8-bit peripherals uses the same size barrel jack but is totally different and have heard of 5200s getting killed using the supply for the 8-bits in them before.

[+DamonicFury]

You sure you didn't plug in a power supply for something else? I recall one of the 8-bit peripherals uses the same size barrel jack but is totally different and have heard of 5200s getting killed using the supply for the 8-bits in them before.

Positive. Its the same power supply Ive used with my 5200 for years. But yeah, I could see how that might happen!

[+DamonicFury]

Id take off the hood, and look at the voltage regulators (and power filter cap) and check the small ceramics around the power section for shorts with your multimeter. Let me know what you find. Check the MJE210s and the 7805s on the heat sink. Also, with a 2 port make sure none of the power plug port pins on the PCB are shorting against a screw or trace, etc. the screw or strap holding the heat sink nearest the power port should be nylonunless someone replaced it. Let me know what you find, and we will continue to diagnose.

Its a 4-port so no worries about the power port. Nothing looks scorched or bulged on the board that I can see. My electronic skills are a bit rusty, not really sure which components I can test for continuity with my cheap ass multimeter. Will do some research and try to figure out what I need to do. Thanks for your kind offer to work through this - much appreciated!

[atari-dna]

Happy to help. Check this diode (lower left in photo) using your meter, on diode function. It should only read in one direction.

 

 

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Edited August 1, 2018 by atari-dna

[+DamonicFury]

Huh, the board on this 5200 looks A LOT different!

 

[+DamonicFury]

There are other diodes in the power section that are reading in both directions. :-(

[+DrVenkman]

There are other diodes in the power section that are reading in both directions. :-(BAAB2648-66DA-47B1-8CE2-06D98E4ADE8A.jpeg

Testing diodes in-circuit like that isn’t always reliable; there might be another current path through the system bus, especially if one end of the diode goes to the ground plane.

[+DamonicFury]

Testing diodes in-circuit like that isn’t always reliable; there might be another current path through the system bus, especially if one end of the diode goes to the ground plane.

 

Thank you for that information... I won't assume those diodes are at fault then.

[atari-dna]

That’s a glass passivated capacitor you’re testing in your photo, a 104 .1uF. It should beep both ways. The diode I showed in the other photo is my mistake, that’s from a two port board—my fault. Diodes will have a band on one end, designating the cathode.

 

Your capacitors look fine; there is no protection diode on the 4-port, again my mistake.

 

When you powered the unit on, when your power supply acted up, did the LED come on? Any picture at all (or solid black screen) or just snow?

 

If you have a second power supply, I’d be inclined to power up the unit again, to see if it will draw any type of picture.

 

Your power supply board will look like this, there’s a diode bridge and two caps (plus a fuse) which need to be populated. If it worked fine before and hasn’t been dropped or something, I suspect it is simply in need of a rebuild and the ravages of time just caught up with it.

 

Edited August 1, 2018 by atari-dna

[atari-dna]

True in some circumstances, though the protection diode in a 5200 two port will only read in one direction while in circuit (unless it’s faulty). Too bad that doesn’t apply in this case because the 4 port architecture is different. That’s my mistake, browsing the forum while a bit too tired.

 

Testing diodes in-circuit like that isn’t always reliable; there might be another current path through the system bus, especially if one end of the diode goes to the ground plane.

 

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Edited August 1, 2018 by atari-dna

[+DamonicFury]

That’s a glass passivated capacitor you’re testing in your photo, a 104 .1uF.

 

D'oh! It's been twenty years since my last electronics course, and obviously I haven't been putting those skills to use much since then. Thanks for the correction!

 

 

When you powered the unit on, when your power supply acted up, did the LED come on? Any picture at all (or solid black screen) or just snow?

 

Nothing from the LED, no picture at all, just the snow.

 

 

If you have a second power supply, I’d be inclined to power up the unit again, to see if it will draw any type of picture.

 

Your power supply board will look like this, there’s a diode bridge and two caps (plus a fuse) which need to be populated. If it worked fine before and hasn’t been dropped or something, I suspect it is simply in need of a rebuild and the ravages of time just caught up with it.

 

 

Boy I sure hate the idea of potentially sacrificing another power supply to this machine without making any kind of repair to the 5200 first. Especially since its original power supply is also in the same condition (I don't think I mentioned that before.) Yes, the power supplies can be rebuilt, but the outer casing takes a lot of damage getting into it.

 

(I freely admit I may be a bit paranoid about losing another power supply to testing this 5200, but I used that thing A LOT over the past eight years or so. If it could be killed by using it with this known defective console, it sure feels likely that another old PS might die as well.)

[atari-dna]

 

Nothing from the LED, no picture at all, just the snow.

 

Interesting. I’m thinking no power is getting to the unit. Is your switch box working normally?

 

Hrm, no you hadn’t mentioned a second power supply problem before, I withdraw the suggestion to hook another one up then—too risky. Do you have an adjustable benchtop supply or a variac? That’s the safe way to go.

Without any power entering the unit, assuming switchbox is good, the voltage regulators or the 4013B flip flop are good candidates to check. Is the flip flop (located near the LED pipe) chip socketed?

 

 

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[+DamonicFury]

Interesting. I’m thinking no power is getting to the unit. Is your switch box working normally?

 

Hrm, no you hadn’t mentioned a second power supply problem before, I withdraw the suggestion to hook another one up then—too risky. Do you have an adjustable benchtop supply or a variac? That’s the safe way to go.

Without any power entering the unit, assuming switchbox is good, the voltage regulators or the 4013B flip flop are good candidates to check. Is the flip flop (located near the LED pipe) chip socketed?

 

Yes, the switchbox is fine, thank goodness. Tested that after the incident, along with my original 5200 that I plugged into the now-dead power supply, using my backup PS.

 

No, as you might guess, I don't have anything that sophisticated (hell, my 15$ Radio Shack multi-meter doesn't even beep like a multi-meter should!) The 4013 is indeed socketed.

[atari-dna]

That chip toggles power to the unit’s circuitry, effectively the on/off switch. If you have another 4013 to swap in there, it’s hazarding a guess but these have a reputation for failure. It might be the culprit. It’s a good place to start.

 

With your power supply disconnected from the atari, and simply plugged into the wall, what is your DC rating at the tip? Should be around 13-16V with no load. What do you get in the two dead units? They’re center positive I believe so the red lead goes in the barrel and the black lead touches the metal sleeve. Confirmed, center positive. Let me know your D/C readings when just plugged into the wall. No harm there.

 

 

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Edited August 1, 2018 by atari-dna

[+DamonicFury]

That chip toggles power to the unit’s circuitry, effectively the on/off switch. If you have another 4013 to swap in there, it’s hazarding a guess but these have a reputation for failure. It might be the culprit. It’s a good place to start.

 

With your power supply disconnected from the atari, and simply plugged into the wall, what is your DC rating at the tip? Should be around 13-16V with no load. What do you get in the two dead units? They’re center positive I believe so the red lead goes in the barrel and the black lead touches the metal sleeve.

 

I had seen that IC was often the cause of 5200 power issues in doing my Google research. I don't mind swapping it with a known good 4013 for testing (other than risking the backup PS of course!)

 

That's exactly how I've been testing these power supplies (thanks, YouTube and RetroGam3Nerd!) The two dead units have been getting 2V-5V, while the good one gets aroung 15V. (I also have another unit with a suspected dead fuse, that gets 0V. Going to try replacing the fuse soon on that one once I get some in the mail next week.)

[atari-dna]

Try swapping it. Also break out your meter and test the voltage regulators on the heat sink. Use continuity mode. Do any of the legs on either 7805 register as in continuity with one another?

When viewing the regulator, straight on, pin 1 (left) is input, pin 2 (middle) ground and pin 3 (right) is output.

 

 

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[+DamonicFury]

Try swapping it. Also break out your meter and test the voltage regulators on the heat sink. Use continuity mode. Do any of the legs on either 7805 register as in continuity with one another?

When viewing the regulator, straight on, pin 1 (left) is input, pin 2 (middle) ground and pin 3 (right) is output.

 

Will give your suggestions a try when I can get to the machine again in a few hours, and will report back. Thanks!!!

[atari-dna]

Great! We will get it working, hang in there.

 

 

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[smbaker]

Another option may be to test the 5200 with a plain ordinary 12V wall wart. Check the wall wart with the DMM to make sure it is in fact 12V, and that the polarity is as expected before using it. A modern regulated wall wart should be close to dead on 12V, but older unregulated wall warts could be all over the place. Everyone has spare wall warts laying around.

 

My suspicion is that your 5200 is pulling too much current, though not enough to blow the 5A fuse (I've never looked inside the power supply, but I'm assuming what nick says about the fuse is correct). Too much current could eventually cause the diodes inside the power supply to overheat and fail. Or it could have damaged the transformer windings.

 

Diagnosing the 5200 under power might get you to the diagnosis quicker (just look for something getting really hot and go from there), but is not without its risks. As others have mentioned, a current-limited bench supply is the way to go, though pointing this out doesn't do much good if you don't have access to one.

Edited August 1, 2018 by smbaker

[zylon]

Some common dead short items I've seen on 4-port consoles include the video cable, and also dings in the shielding on underside of the board contacting solder joints.