Star Wars AR-02 not getting +5V

gregbl

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My Star Wars upright (w/19" Amp) went down on New Year's Eve. It has been rock solid for some time, so this surprised me. Red LED on the Amp deflection board is lit. Deflection and High Voltage boards have been rebuilt fairly recently.

After some sleuthing, I found that the AR-02 board isn't showing +5v on the +SENSE test point. The other voltage test points are pretty darned close to what they should be (example: -5v is -5.1).

I've got multiple rebuilt and tested good AR-02 boards that I've tried, and they're all showing nothing on +5v.

Ideas on where to check next? Is there a way to test voltage going into the AR-02?

Thanks,
Greg
 
Check your fuses on the power brick. F2 4A slowblow. +5V is supplied by unreg 10.3VDC.
(-5V is supplied by different winding [36VAC] so has no relevance to the +5V).
 
What are you measuring on the 10.3V test point on the AR?

That is the main input. If you don' t have around 13.5-14.5V there, then the brick is your problem, and you should check the bridge rectifier first. (Google how to test a bridge rectifier with a DMM).
 
The fuses all checked out fine...did those first.

The 10.3v test point is showing nothing as well...that's the one I forgot to check.

So, you guys think the bridge rectifier is the problem? I'll look into testing that. I believe I have a replacement one from a Bob Roberts Atari power brick rebuild kit.
 
Check the bridge first. It's basically 4 diodes in a square, so you can verify it with a DMM, using the diode test function. If any of the links show a short or an open, it's bad. (You should normally get a 0.6-0.7V drop for each link, using the diode test function on your DMM, in the forward direction.)

The Bob Roberts replacement should do you fine.

Also, while you're poking around the brick, look for any burned wires, for any of the slide-on connectors. They sometimes get corroded and heat up as their resistance increases, and can start to melt. If you find any like this, replace them.
 
Usually if the bridge fails, it will take out the fuse.

Needless, use the schematic and work backwards to find the issue. Might be bad connection of fuse block / fuse holder or on the MOLEX connector.

At least you "know" the other voltages which are derived from 36VAC are OK. Just need to debug the 10.3Vunreg circuit.
 
OK, got the old bridge rectifier out and it is testing bad.

It is labeled + and - and the other 2 points are unlabeled (I assume they're AC then).

The new bridge rectifier from the Bob Roberts kit has AC and + labels and the other two are unlabeled. It is #7 in the picture on his page: http://www.therealbobroberts.net/bridge.html.
Based on that picture the bottom left is labeled + and the upper left is labeled AC.

The + connection is easy. Based on the description on his site, I would then assume that the - is the bottom right. And then the AC ones are the upper left and upper right. Am I correct?

Apologies, I've not changed out a bridge rectifier before.
 
typically I think bridge rectifiers are marked with just the + side on the part itself and the board. as long as you line those up that's all you need. opposite to the + is the - side, so you'll get +DC out the + side and -DC out the - side. the outer legs are the AC inputs, usually denoted with ~ (symbolized by the waveform for alternating current). if ever you look at a schematic symbol for a bridge rectifier, it'll make more sense.

I never knew that the AR2s take DC in, but now it makes a lot more sense to me. I've wondered for a couple years now what the purpose of 10.3V was :p
 
OK, got the old bridge rectifier out and it is testing bad.

It is labeled + and - and the other 2 points are unlabeled (I assume they're AC then).

The new bridge rectifier from the Bob Roberts kit has AC and + labels and the other two are unlabeled. It is #7 in the picture on his page: http://www.therealbobroberts.net/bridge.html.
Based on that picture the bottom left is labeled + and the upper left is labeled AC.

The + connection is easy. Based on the description on his site, I would then assume that the - is the bottom right. And then the AC ones are the upper left and upper right. Am I correct?

Apologies, I've not changed out a bridge rectifier before.

Did some testing of the new bridge rectifier with the multimeter to see which connections are what. The + is clearly labeled (bottom left). The upper left is labeled AC. Turns out the upper right is the - and the bottom right is the other AC. When I test upper left and bottom right together on the multimeter it doesn't matter which direction the leads are attached...I get no reading...which is expected as I understand it.

Glad I decided to test the new one so I know which terminal is which. Going to label the other 2 terminals on it. Don't know why manufacturers don't do that.
 
The + and - are on one diagonal, and the AC terminals are on the other diagonal.

Just remember to test the brick without the main harness plugged in. (You will need to plug the smaller connector in which has the power switch, in order to turn it on, but leave the main large output connector unplugged, and verify all of the output voltages.)

The 5V side of AR's takes in 10.3V DC (which is always closer to 14V, not sure why they called it 10.3), and puts out 5V DC.

The other side of the AR (for the other types that supply additional voltages) takes in 36VAC, and either outputs +22V and -22V DC (for -04's, which gets regulated down to other voltages on the game board), or for -02's regulates the +/-22V DC to +12V and -5V DC, on the AR, and sends those to the game board.

Also, an interesting side note, the two sides of AR's are completely independent (i.e., you could physically cut the right side off with a hack saw, and the two halves would still work.)

Also, remember to check the main 7A fuse, in the round black twist-off panel connector, which is easy to forget.
 
Also one other thing, it's a good idea to use thermal grease when mounting the rectifier on the brick. They can get hot, and good heatsinking will make them last longer.
 
yeah, has to be closer to 14. the legends of catastrophic 3055 failures on AR2s sound strikingly similar to when it happens with Williams power supplies. except in the AR2's case, you get 14V down the +5 line, vs. 27V down the +12 line -- which pretty much only tears up your ram on a Williams game. BIG DIFFERENCE.
 
The + and - are on one diagonal, and the AC terminals are on the other diagonal.

Just remember to test the brick without the main harness plugged in. (You will need to plug the smaller connector in which has the power switch, in order to turn it on, but leave the main large output connector unplugged, and verify all of the output voltages.)

The 5V side of AR's takes in 10.3V DC (which is always closer to 14V, not sure why they called it 10.3), and puts out 5V DC.

The other side of the AR (for the other types that supply additional voltages) takes in 36VAC, and either outputs +22V and -22V DC (for -04's, which gets regulated down to other voltages on the game board), or for -02's regulates the +/-22V DC to +12V and -5V DC, on the AR, and sends those to the game board.

Also, an interesting side note, the two sides of AR's are completely independent (i.e., you could physically cut the right side off with a hack saw, and the two halves would still work.)

Also, remember to check the main 7A fuse, in the round black twist-off panel connector, which is easy to forget.

Thanks a bunch! It looks like Bob has the pins labeled on the power brick so I know where to test. http://www.therealbobroberts.net/apsnotes.html.

That'll be the next task...to plug that in, but not to the main harness, and test voltages. Standby for that...

Thanks again!
 
the presence of the Big Blue makes more sense now. that's the filter cap for the rectified voltage! thank you Greg, this has been a mind-blowing experience.
 
Thanks a bunch! It looks like Bob has the pins labeled on the power brick so I know where to test. http://www.therealbobroberts.net/apsnotes.html.

That'll be the next task...to plug that in, but not to the main harness, and test voltages. Standby for that...

Thanks again!

Hmmm...wondering if the pins are different on the Star Wars power block than what is labeled on Bob's site. I'm not getting any readings using what he has.
 
Color vector bricks are different. (As are b/w vectors also.) Some pins are the same, but the monitor voltages are different. Here are my notes for a color vector brick.

Pins 1, 2, 3 to 4, 5: 10.3VDC
Pins 6 to 7: 36VAC
Pins 8 to 9: 6.3 VAC
Pins 10+13 to 11: 25VAC
Pin 10 to 13: 50VAC
 
Color vector bricks are different. (As are b/w vectors also.) Some pins are the same, but the monitor voltages are different. Here are my notes for a color vector brick.

Pins 1, 2, 3 to 4, 5: 10.3VDC
Pins 6 to 7: 36VAC
Pins 8 to 9: 6.3 VAC
Pins 10+13 to 11: 25VAC
Pin 10 to 13: 50VAC

Cool, thanks. I assume Pin 1 is lower left as looking at the power brick (grooved connection end). Are you just using the ground post on the power brick as the ground?
 
Pin 1 is closest to the fuse block. Read right to left, if looking down on the block, with the transformer on the right.

Pins 4 and 5 are DC ground, for the 10.3V. All of the other voltages are AC, so they are relative to the other pins mentioned in the list (i.e., 'to' means 'relative to' in what I provided.)
 
If you get confused (or if my info is not correct, which I don't think is the case, but I could be wrong), you can flip the brick over and look at the wires going into the connector from underneath, as the colors sort of give a clue as to what' s what.
 
Also most likely, those white plastic Molex connector housings have the pin numbers molded into them adjacent to the holes. Just grab a decent magnifying glass and a bright light and look at it very closely and you'll see the numbers.

I got the impression from reading this thread that gregbl is not referring to the schematic. Star Wars schematic sheet 3A clearly shows all of the power brick wiring completely with pin numbers, wire color indicators, the bridge diode arranges, all of it.

If you don't have the schematic, grab it here...
Star_Wars_SP-225_2nd_Printing.pdf

Bill B.
 
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