Pole Position II PSU repair..

desiv

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OK, here's my sordid story..
Please don't be too harsh, as I didn't realize how dumb I was at the time.. ;-(

I picked up a PP II cab several years ago..
It worked when I got it...
But very soon (a week or so) after I got it, I noticed that sometimes when I powered it up, it wouldn't come all the way up.
Freezes, graphics glitches, etc..

I googled around (and as I said, I'm not an electronics guy) and found a thread that mentioned bypassing the power wires to the board and using an ATX power supply.

Well, that I can do..

So I did that..
And of course (I didn't research enough at all.. ) when I plugged it in, I popped the resistors on my ARIIs.

Then I did some more research and realized how stupid I had been.... ;-(

So, then I figured I'd probably convert it to a multi-driving MAME type machine...

Life got in the way, and it sat.. But while it was sitting, a few things happened.
1, a relative came over and tried to turn it on.
I had taken out the ATX PSU, so no power went to the board, but he left the switch on, so it was powered up for a bit. Not sure if that made any difference..
2, I realized, every time I saw it, that I couldn't convert it... So I decided to fix my damage..

I found a good deal on some ARII boards, so I got a pair.
Plugged them in, and.. nothing.. Hmm.. Not even the problems I had before...
Nothing..

So I finally got my soldering iron out and ordered some parts.
I fixed my old ARII, and did the sense mod at the same time.
Plugged that in, and ... nothing..
Then I noticed no lights on the board.. I tested voltage..
No 5v going to the board, no matter which ARII..

So, there's something wrong with my PSU...
Yes, I checked the fuses.. That's also within my technical level. ;-)

I've got the PSU board, and it has a big blue CAP (I think) on it, but I can't see any wires going to it (must be underneath), and then there's some wires that go from the PSU to a standalone big blue CAP, with wires on the top.
I've heard of the "Big Blue CAP" but I'm not sure which one is which..
(See, I'm really new at this..)

Anyway, I'm considering ordering the ATX PSU mod that is being talked about in a thread here, but I'm also considering another run at fixing this thing...

I'll take and post some pics if needed..

But I have a question to start...

Can I take the PSU out of the cabinet to work on/test??

I have heard people talking about things needed to be tested under load?
(And I want to be MUCH MUCH more cautious than when I first started working on this thing)

I am very confident that I can do the basic voltage tests in places and I can swap out some parts...
I just did a composite video mod on my Atari 7800, which was some of the tightest soldering I've ever done, so I'm feeling decent about my basic soldering abilities right now. ;-)
(Although I've heard the word "ripple" and I think think that's probably beyond me and my equipment, although I don't really know what it is..)

And I have a very (overly) healthy respect for CAPs, so I might take hours on something that should take minutes, but I don't think I'll shock myself..

So, any initial thoughts, pointers, or warnings to my wife to buy extra life insurance now? ;-)

Thanx in advance..

desiv
p.s. The battery is still there, but I checked and it looks good still.. If I get this thing working, I'll probably try relocating it to off the board...
p.p.s. Another funny side story about my newb-ness... When I got the replacement ARII boards, I saw this orange-ish gunky stuff below the largish caps, and thought I'd gotten boards with leaky CAPs. So I removed them and replaced them. But as I was cleaning the gunky stuff off of the boards, it hit me.. This stuff is really hard to clean.. Hmm. so sticky... Is this actually some type of glue to hold the CAPs down and not leaking stuff after all... :-( :-( Well, it looks prettier with the new shiny CAPs.. <sigh>
 
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Okay, a lot to cover here.

I found a good deal on some ARII boards, so I got a pair.
Plugged them in, and.. nothing.. Hmm.. Not even the problems I had before...
Nothing..

So I finally got my soldering iron out and ordered some parts.
I fixed my old ARII, and did the sense mod at the same time.
Plugged that in, and ... nothing..
Then I noticed no lights on the board.. I tested voltage..
No 5v going to the board, no matter which ARII..

Is anything else on? Marquee or coin door lights? Are you actually getting AC into the cabinet? Is it possible that the power cord isn't fully plugged in?

So, there's something wrong with my PSU...
Yes, I checked the fuses.. That's also within my technical level. ;-)
Did you meter on the fuses or the holders?

I've got the PSU board, and it has a big blue CAP (I think) on it, but I can't see any wires going to it (must be underneath), and then there's some wires that go from the PSU to a standalone big blue CAP, with wires on the top.
I've heard of the "Big Blue CAP" but I'm not sure which one is which..
(See, I'm really new at this..)
Huh, I didn't know that PP had two big caps in the PS. Someone else will know better, but I suspect they're the same 27,000uf caps as Atari used in all their classic games. Yes, there are a pile of wires connected to screw terminals on the bottom of the capacitor.

Anyway, I'm considering ordering the ATX PSU mod that is being talked about in a thread here, but I'm also considering another run at fixing this thing...
I'd go with fixing what you have.

Can I take the PSU out of the cabinet to work on/test??
Yes. There are four screws holding the metal base to the bottom of the cabinet. You have to remove it to replace the Big Blue.

I have heard people talking about things needed to be tested under load?
(And I want to be MUCH MUCH more cautious than when I first started working on this thing)
Pretty sure you can just drop the test leads across whatever you want to test and be fine. Someone who has done more of this sort of work may know better.

I am very confident that I can do the basic voltage tests in places and I can swap out some parts...
I just did a composite video mod on my Atari 7800, which was some of the tightest soldering I've ever done, so I'm feeling decent about my basic soldering abilities right now. ;-)
(Although I've heard the word "ripple" and I think think that's probably beyond me and my equipment, although I don't really know what it is..)

Fixing Atari power supplies is a piece of cake compared to that.

And I have a very (overly) healthy respect for CAPs, so I might take hours on something that should take minutes, but I don't think I'll shock myself..
I've done a handful of these, never took any special precautions, never got shocked. Definitely don't be sloppy, but it's not like working on a monitor.

So, any initial thoughts, pointers, or warnings to my wife to buy extra life insurance now? ;-)
Find the schematics and read them.
 
Is anything else on? Marquee or coin door lights? Are you actually getting AC into the cabinet? Is it possible that the power cord isn't fully plugged in?
Thanx,
Yes, there's AC to the cab. Marquee and fans start.
And I saw some DC voltage off of the power supply, but I don't think it was all the terminals.
Did you meter on the fuses or the holders?
Both
I'd go with fixing what you have.
K, I'll give it a shot... ;-)
Yes. There are four screws holding the metal base to the bottom of the cabinet. You have to remove it to replace the Big Blue.
Great.. I have to admit, the more nerve rattling part in testing is knowing the monitor is over my head as I'm bent in with the meter.. ;-)
Pretty sure you can just drop the test leads across whatever you want to test and be fine. Someone who has done more of this sort of work may know better.
Sounds good..
Find the schematics and read them.
Will do...

I'll take out the power unit and test it this weekend....
I'm pretty sure that the "external" large cap didn't have any power going in or coming out, so I think the problem is that part of the power...
But I didn't do a really thorough test. Just few check with the meter and I was missing voltage in some places...

Thanx,

desiv
 
It is my understanding that that particular supply has to be under a load or it will smoke r29 but I have not had much experience with that supply. If you do need to load that up you can use a resistor or a 12v car break light bulb on the +5 line.

EDIT:

I found some useful info for you on that game and power supply, most of the info you might want to look at is at the end of page 1 and continues to page 2......

http://www.stickycarpet.com/pinx/poleposition2.html

found one more from a current thread....

http://www.brentradio.com/images/PolePosition/Docs/poleswitcher.pdf
 
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It is my understanding that that particular supply has to be under a load or it will smoke r29

I'm talking about the power supply that puts power into the ARII boards.
Not the ARII boards themselves.. (where R29 is)..

For my testing, I wouldn't even have the ARII boards connected.

Thanx for the links!!
More info is good!! :)

desiv
 
With the PCB unplugged, current can't flow through R29. And he did the sense mod anyway, so it's not an issue in this case.
 
OK, I'm already lost...
I have this (sorry, blurry phone pic):
PP2psu.jpg


I know I have to measure the voltages coming off of that thing, but not sure where..
There are the points at the fuses, and then there is the block where the plugs go...
The smaller 3 wire plugs are 110V, and those are good..

I thought I had possibly measured across the ones where the fuses are (assuming they were DC), but it turns out my multimeter (analog) isn't working.
My digital is tho, and I realized that I have no idea what voltages are there....

My manual has no voltages, but I found this:
http://pdf.textfiles.com/manuals/AR...h Printing) [Schematic Package] [English].pdf

And page 3B has (I think) what I might need, but...

I'm totally lost looking at it and trying to compare it to my PSU...

I basically have no idea where I need to test and what voltages I'd be looking for...
:-(

desiv
 
You want to measure on the molex in the lower right of your photo. Just shove the test leads down there. Consult the schematics for the correct pinout so you can tell what is what.
 
You want to measure on the molex in the lower right of your photo. Just shove the test leads down there. Consult the schematics for the correct pinout so you can tell what is what.

The schematics don't show the pinout for the molex connector.
They show wires numbered 1-15..
They do list colors, so I suppose if those match, I can go by that..
At least for the DC voltages.

The AC's don't make as much sense.
They show 3 wires per AC, but it's not totally straight forward.
For instance, it shows:
ppIIpwr.jpg


What to I test for the AC? 3 wires per? What's the "KEY" part?
Is one of the wires ground?
(I don't see a common color for gnd for the AC..)

I'll keep looking, but it's not as straight forward as I'd hoped...
(Which maybe is part of the reason so many people fall back to the switcher mod, or (as in one of those links posted above) buying a replacement (or 2 as in the link above) on e-bay.)

desiv
 
The schematics don't show the pinout for the molex connector.
They show wires numbered 1-15..
They do list colors, so I suppose if those match, I can go by that..
At least for the DC voltages.

The AC's don't make as much sense.
They show 3 wires per AC, but it's not totally straight forward.
For instance, it shows:
ppIIpwr.jpg


What to I test for the AC? 3 wires per? What's the "KEY" part?
Is one of the wires ground?
(I don't see a common color for gnd for the AC..)

I'll keep looking, but it's not as straight forward as I'd hoped...
(Which maybe is part of the reason so many people fall back to the switcher mod, or (as in one of those links posted above) buying a replacement (or 2 as in the link above) on e-bay.)

desiv

Don't worry about the center wire as it is usually the center tap and has little or no voltage. The key here is to have the meter set to AC voltage and high enough to see the voltage.

Going by the drawing you posted here R to R which go to pins 6 and 7 of j5 should have 36 volts ac

Y to Y should have 6.1 vac pins 8 and 9 of J5

BN to BN/W should have 60 vac (volts ac) pins 10 and 12 of J5

BU to BU/W should have 60 vac pins 13 and 15 of J5

If you look at the top the thing with the pointers (diodes) that is the only part that has the DC voltages.
 
Don't worry about the center wire as it is usually the center tap and has little or no voltage. The key here is to have the meter set to AC voltage and high enough to see the voltage.

Will do, thanx..
Man.. "center tap"????
Adding that to the list of words/phrases involving electronics that I had never heard until recently ... ;-)
(along with "ripple".. ) :)

desiv
 
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Testing now..
Too bad my analog meter is dead..
Testing now and my digital (auto-ranging) multimeter is going REALLY SLOW..
Maybe the auto-ranging isn't working..
I started with the first DC measurement.
It started around 0 and started climbing up.
It should get to 10.6VDC.

It's at 6.59 now, but has been REALLY SLOWLY climbing for 10 minutes or so...

It's at 6.72 now...
So it's still climbing...

Hopefully it will settle in around 10.x or so.. (stop climbing)
Looks like it might be time for a new multimeter.. ;-)

desiv
(6.83 now)
 
OK, I don't think it's my digital multimeter...

All the AC voltages tested out right..

I test a AA and I get 1.544.....

I go back to the DCs, and it goes to 12.45 and climbs really slowly....

So, as long as it's plugged in, the DC voltage starts too low and climbs really slowly, but it just keeps climbing....
So, I do some checking..

The V(iolet) wires go into the Big Blue, as do the OR(ange) wires (and the OR/W, which goes to a fuse first).
They also are attached to a square piece of electronics which I assume is a voltage rectifier.

So, next steps?
I'm thinking possibly get a new Big Blue?
I don't have a meter that can test a capacitor.
I might be able to borrow an analog meter I have at work and use this technique:
http://www.squidoo.com/how-to-check-capacitor
(Using the "multimeter" method, which requires an analog meter)

Or does anyone know if this is what I should expect with a Big Blue failure?
(Also, I have that other large blue cap in the bottom of the cab I probably need to test too...)

Thoughts?
(places to order Big Blue caps from?)

Thanx,

desiv
p.s. What would I be looking for? The cap (I haven't taken it out, so I can only read part of it) says 20V on it.
But in reading online quickly, I see "Big Blue" defined as 25V or 30V?? Does it matter???
(Or is it one of those things that needs to be "at least" 20V or something..?)
 
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Your problem is likely to be F3 and its associated wiring.
They always burn up the clips and melt the wires.
Go to a car audio store and pick up a 25 amp fuse and holder and wire it in.
(Yes, 25 AMP was recommended later on by Atari)
 
Your problem is likely to be F3 and its associated wiring.
They always burn up the clips and melt the wires.
I've tested the connectivity at all the fuses and it's good...

Could a problem with the F3 connection cause a multimeter to read voltages increasing like I was seeing???

desiv
 
Testing now..
Too bad my analog meter is dead..
Testing now and my digital (auto-ranging) multimeter is going REALLY SLOW..
Maybe the auto-ranging isn't working..
I started with the first DC measurement.
It started around 0 and started climbing up.
It should get to 10.6VDC.

It's at 6.59 now, but has been REALLY SLOWLY climbing for 10 minutes or so...

It's at 6.72 now...
So it's still climbing...

Hopefully it will settle in around 10.x or so.. (stop climbing)
Looks like it might be time for a new multimeter.. ;-)

desiv
(6.83 now)

I would check the batteries in the meters, it is a common problem that gets overlooked quite a bit.

Make sure you are measuring the DC and not AC with the meter. Replace the batteries and re test, report back.

EDIT:

The only dc voltages are pins 1,2,3 to ground all of the rest are AC.
 
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I would check the batteries in the meters, it is a common problem that gets overlooked quite a bit.
OK, although as I mentioned, it measured other batteries I have in the house properly...
And it seems to be working fine with the AC measurements.
Make sure you are measuring the DC and not AC with the meter. Replace the batteries and re test, report back.
It was measuring the AC lines properly.
It was just the DC where I was seeing those weird results.
All 3 DC spots...

desiv
 
OK, although as I mentioned, it measured other batteries I have in the house properly...
And it seems to be working fine with the AC measurements.

It was measuring the AC lines properly.
It was just the DC where I was seeing those weird results.
All 3 DC spots...

desiv

If it is not the meter, I still suspect a bad meter, then the diodes are probably bad but the readings are very strange. How does the meter do with ohms measurement?

The test is with power off.....


http://www.allaboutcircuits.com/vol_3/chpt_3/2.html

EDIT:

Plant the black lead to a ground and measure with the red lead to pins 1,2,3 on dc voltage at about 20 volts dc
 
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