Show me the Proper Way to Check An Atari AR Board

[mhanlen1]

Ok, I really apologize for the idiot question. I have a board coming back from repair from a KLOV'er. He told me that the AR may have fried my PCB at some point before I owned it, and before I put the PCB back in I need to test it. A lot of people take for granted that they know how and where to test boards on a machine. There are some a-holes like me that have no idea, so I'll try and make it easy. I need to check that this board is outputting the correct voltages, so I don't waste my money on a another board repair. I've done Bob Robert's Rebuild kit on the board, and it looks really clean, but I just want to make sure. I also know that the board should be plugged in when I'm doing this.

Ok here I have my AR board.

I have points labeled that I need to understand.

I take it point A&B are where I need to have my red leads attached to. Right? Each one is labeled with the voltage this point should measure at, Right? A @ 5 and B @ 10.3. C is the ground that my black lead should attach to when I'm testing either point, right?

What the hell is D? I know it's a pot but what does it adjust?

Also what should this multimeter be set on to do this correctly? Would this be the correct way to check the 10.3v (and then the 5v when I move the red lead to point A)?

Am I going about this the right way?

And one final question, about a solder joint on the heat sink. It looks to be from one of the two rivets holding the heatsink to the board. Should the solder point look like this? Should there be a pin sticking out, like on the other side? Does it even matter? Can anyone check a working one to compare it for me?

Thanks a lot. I hope I made this easy, and that it may help someone else in the future.

 

[Dokert]

Since this is an A/R I, your voltages will read high if it is not connected to the game board.

The 10.3vdc could read as high as 14vdc or so. (This voltage is unregulated)
The +5vdc will probably read almost 7vdc.

"D" adjusts the +5vdc, but will have little effect unless the A/R is hooked up to a game board.

The rivet on the heatsink is just that, and it is fine.

Meter setting 3 clicks left to 20vdc.

 

[mhanlen1]

Since this is an A/R I, your voltages will read high if it is not connected to the game board.

The 10.3vdc could read as high as 14vdc or so. (This voltage is unregulated)
The +5vdc will probably read almost 7vdc.

"D" adjusts the +5vdc, but will have little effect unless the A/R is hooked up to a game board.

The rivet on the heatsink is just that, and it is fine.

Meter setting 3 clicks left to 20vdc.

Thanks a bunch Dokert. Will it kill my board to have it hooked up a minute or two while I test this? And I take it I have my leads properly placed right?

 

[Dokert]

Test it without the board hooked up and see what you get first.

 

[mhanlen1]

Test it without the board hooked up and see what you get first.

OK, I wont have my board until next week, but my voltages are 13.6 and 6.3, which is about right, right? It should be safe to connect the board to then? When my PCB is connected what are tolerable variations in voltage?

 

[splattergatz]

your black probe for the multimeter could use the alligator clip attachment for tighter grippage and less dubious readings. red one too for that matter depending on what kinds of tests you are doing.

i like the nice new capacitors !

it would be fun to invent a "load rig" for testing the outputs of the power supply so you wouldnt have to hook it all up and be all hunched over trying to test voltages in the bottom of the cabinet.

 

[Dokert]

Looks fine. The 13.6 won't change with the game board hooked up. The +5vdc you will test on the game board itself and adjust as needed on the A/R I at R8 (D)

 

[mhanlen1]

Yeah, alligator clips would work better. I need to rig up two test wires for that- it was pretty awkward trying to hold the multimeter and the two test leads to stay in the loops.

 

[Dokert]

it would be fun to invent a "load rig" for testing the outputs of the power supply so you wouldnt have to hook it all up and be all hunched over trying to test voltages in the bottom of the cabinet.

No, no it wouldn't. They get really HOT!

 

[mhanlen1]

Looks fine. The 13.6 won't change with the game board hooked up. The +5vdc you will test on the game board itself and adjust as needed on the A/R I at R8 (D)

Thanks a lot Dokert, you've answered all my questions. I can't wait to get my PCB back and install my High Score save kit I ordered today. Next week can't come soon enough. Let's just hope my Asteroids will cooperate.

 

[DogP]

No, no it wouldn't. They get really HOT!

I'd highly recommend using a load... when I test power supplies I typically use a 10 ohm 10W resistor on the 5V line so I can verify at least that the regulation is working. That's only 0.5A, or 2.5W, so it doesn't really get that hot. But at least if I see some regulation, I can feel better about hooking a board to it, rather than assuming 7V w/ no load is normal. Plus, some switchers can be damaged by powering them up w/o a load on the +5V.

I also built a test load rig for a project at work... basically I just attached several large resistors to a heatsink. That worked really well, since the idea was to verify the power supplies performed normally with realistic loads before being connected to the real (expensive) devices. With loads on all the supplies, it drew about 50W. I used something like these: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=LT100J-1.0-ND .

DogP

 

[splattergatz]

10 ohm 10W resistor on the 5V line..........some switchers can be damaged by powering them up w/o a load on the +5V....just attached several large resistors to a heatsink........verify the power supplies performed normally with realistic loads before being connected to the real (expensive) devices. With loads on all the supplies, it drew about 50W

nice. want to try and make one.

think Bob Roberts' switchers has a label on them that says not to power them up without a load or they could be damaged.

use the right connectors, could use it for a few different power supplies.

 

[Dokert]

nice. want to try and make one.

think Bob Roberts' switchers has a label on them that says not to power them up without a load or they could be damaged.

use the right connectors, could use it for a few different power supplies.

Made one with a 10 ohm 10w resistor and it still got hot using a standard Atari A/R II on the +5vdc line

Bob does label the Happ switchers that he sells to say something to the effect of not powering them up without a load.

 

[splattergatz]

Made one with a 10 ohm 10w resistor and it still got hot

well, its probably enough to get a good reading and keep the power supply from getting damaged which is enough.

 

[DogP]

Made one with a 10 ohm 10w resistor and it still got hot using a standard Atari A/R II on the +5vdc line

Bob does label the Happ switchers that he sells to say something to the effect of not powering them up without a load.

It'll definitely get hot (2.5W worth), but not burn-anything-up hot... you could also wire up something more useful than a resistor that does more than generate heat... a light bulb would work, or on my test rig I made for work, the heatsink got kinda hot, so I cheated a little and added a 12V fan, but wired it as part of the load (since 12V was one of the voltages I was generating). It keeps the heatsink cool, as well as contributing to the test load. It should be easy to think of something to throw on as a test load that won't be damaged if the voltage is incorrect.

DogP