Pole Position - Top Half Screen Garbled / Mirrored

drbogger

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Hi Everyone,

I am new to the forums and arcade games, however, I've been working on circuit boards and electronics for over 5 Years, so I have good experience with PCB's and soldering.

Okay, on to my problem:

I recently picked up a Pole Position, it worked good, and was in good condition until I took out the PCB to do the Edge Connector Bypass Fix, and clean up some left over flux on the board from a previous repair that must have been done before I bought it.

I then go to put the PCB Back in the cabinet, and this is I got:

1. The top half of the screen is Garbled / Mirrored from the bottom. (Ex. The Car is displayed twice, kinda like a mirror).
2. When I first turn it on from a cold start, it works fine for maybe 30 seconds, then it slowly starts to display the garbled display. (Like it happens once it starts to heat up)

Look at the photo below to see what I mean.

Has anyone ever seen this? Any idea how to fix it?
 

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reseat the interconnect board...its finnicky

I did 3 times, but I'll mess around with it more when I get home.
I'm out getting my car inspected right now, and there's a 3 hour wait >_<

In the mean time, any other ideas on what it could be?
I'd like a gather a list of possible causes, so I can check everything out at one time.
 
Okay, just got home and I messed around with the interconnect board, and it doesn't help at all.

I posted some additional images of whats happening.

More Notes:
1. The problem only occurs when on the actual racetrack.
2. The problem does NOT happen when on the credits screen, or the splash screen.
3. Once in a great while, i'll see a flicker or a flash while on the credits screen or the splash screen. They are so quick I cannot get it on camera.

***EDIT***

New Symptoms:

1. The game froze on the splash screen, and it flickering between the two different images that are posted below.
 

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Things seem to be getting worse...

I adjusted the voltage on both AR2 Boards to 5.10v (Before, One was at 5.0v, the other was at 4.90v)... The result seems to make things worse.. Now the main racetrack is black, and all the colors are really messed up...

Any ideas anybody?
 

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Here's a video of the problem:
http://www.youtube.com/watch?v=p4K_FEO5Fc8

Does anybody have any ideas?

That really looks like a bad connection to a chip. You could try some component cooler and see if that changes anything. It is freeze spray that you just spray on the ic chips to find bad parts and connections. A hair dryer is used some times but I don't use them much.

Just to be sure, measure the voltage on the chips and maybe drop it down to something like 4.95 and see if it gets better or not.

Did you have this problem before you adjusted the power supply?
 
It happened before adjusting the power supply, that was the reason I adjusted it to begin with.

For the freeze spray, I heard that using canned air upside down will work as a freeze spray, is that true?
If not, where would I purchase it?
Also, I would spray it on the IC while the game is on, and watch and see if the problem is corrected or changes, correct?
 
Given this happened after removing the board set, it is most likely a mechanical issue (solder joint that has gotten flaky due to movement or broken pin that is intermittent). Pole Position generates alphanumeric, playfield, roadway, etc as separate components then composites them together. In your case, it looks like the roadway is being displayed at the wrong time. Take a look at the LS157 located at 4H on the video board. It uses 128V to switch the top/bottom of the screen. Am guessing that if it switched as the wrong time, you might get weirdness like this.
 
Clean the board edge connector foil fingers.

Clean the legs of all the socketed chips.

Remove the nicad battery from the board.
 
It definitely seems like a bad connection somewhere, because I layed the board down on a table and ran it that way, and the problem went away, but as soon as I put it back in the cage, it started going haywire again..

I am actually waiting on a Pole Position II Upgrade for the PCB which should be here today sometime, and once it gets here, I will see if it works after upgrading.

Clean the board edge connector foil fingers.
I already tried this.

Clean the legs of all the socketed chips.
I will try this sometime tomorrow.

Remove the nicad battery from the board.
The battery is actually still working, believe it or not! However, I am planning on replacing it with a new battery at some point.

Any recommendations on the best way to do this?
Could I just wire up a external battery holder, and use 3 x Ni-CD AA Batteries?
Will the charging circuit be able to charge Ni-CD AA Batteries?
 
It definitely seems like a bad connection somewhere, because I layed the board down on a table and ran it that way, and the problem went away, but as soon as I put it back in the cage, it started going haywire again..

I am actually waiting on a Pole Position II Upgrade for the PCB which should be here today sometime, and once it gets here, I will see if it works after upgrading.


I already tried this.


I will try this sometime tomorrow.


The battery is actually still working, believe it or not! However, I am planning on replacing it with a new battery at some point.

Any recommendations on the best way to do this?
Could I just wire up a external battery holder, and use 3 x Ni-CD AA Batteries?
Will the charging circuit be able to charge Ni-CD AA Batteries?

Here is a thread about just this

http://forums.arcade-museum.com/showthread.php?t=53000
 
Any recommendations on the best way to do this?
Could I just wire up a external battery holder, and use 3 x Ni-CD AA Batteries?
Will the charging circuit be able to charge Ni-CD AA Batteries?
I used a 1F 5.5 volt super-cap in my pole position. Won't maintain high scores for years powered off like NiCD battery alternatives, but has maintained for 3+ months fine. I soldered the super-cap positive lead to the original battery positive and then soldered a small jumper wire from the super-cap negative to a female spade connector and plugged it into the grounded spade terminal by the edge of the board. Could have just as easily soldered the super-cap negative to the original battery negative, but wanted to minimize board soldering in case a different solution was desired in future.
 
I used a 1F 5.5 volt super-cap in my pole position. Won't maintain high scores for years powered off like NiCD battery alternatives, but has maintained for 3+ months fine. I soldered the super-cap positive lead to the original battery positive and then soldered a small jumper wire from the super-cap negative to a female spade connector and plugged it into the grounded spade terminal by the edge of the board. Could have just as easily soldered the super-cap negative to the original battery negative, but wanted to minimize board soldering in case a different solution was desired in future.

Good idea! I think I have a couple of those laying around somewhere, so I may give it a try later.. I'm just waiting on more 28 Pin sockets to be delivered, I ran out while doing the pole position 2 upgrade. They should be here within the next day or two, then I can finish the upgrade, and test it out.
 
I just completed the Pole Position II Upgrade, and it all works great now!
My guess is the problem was related to one of the IC Chips, but all is well now!

I also replaced the battery with a 1F 5.5v Capacitor, and I will be putting that to test as time goes on!

I made an adapter board for the 1F Capacitor, to allow it to fit in the same battery solder pads.

I also hooked up my oscilloscope and check how much ripple / noise was in the power supply line, I get aprox. 0.7v Vpp (Volts Peak to Peak), so I'm going to assume that all the capacitors are fine.

One thing I did noticed, is every time I hooked up the Oscilloscope to the voltage leads, the game actually froze and displayed a garbled screen, to fix this I just switched the power off, then back on and it loaded fine.

Any ideas if this is normal? and what may be the cause of it?
 
For the freeze spray, I heard that using canned air upside down will work as a freeze spray, is that true?

Also, I would spray it on the IC while the game is on, and watch and see if the problem is corrected or changes, correct?

Yes and Yes. I have seen my father do this many times and it MAY give you an indication as to where the problem is or near to it. It works much better with intermittent problems that are very hard to track down.

I like the cap. idea instead of an acid bomb aka battery.

As for the scope on the power lines, it is probably just putting some noise down the line that the filter caps can't filter.
 
Here's a question for ya'll:

When I put the game in self-test mode, the engine revving sound plays immediately, and when i use the shifter to play other sounds, they play at the same time as the engine revving sound... like playing 2 sounds at once... The engine revving sound doesn't go away.

Is that normal? It never did that on Pole Position 1, but after the upgrade to PP2, I now get this...
 
When I put the game in self-test mode, the engine revving sound plays immediately, and when i use the shifter to play other sounds, they play at the same time as the engine revving sound... like playing 2 sounds at once... The engine revving sound doesn't go away.

As I recall, there is something quirky about the accelerator after the PP2 upgrade. My PP2 board set (upgraded from a PP1) has a mysterious jumper that ties the accelerator input to SB1. I soldered the jumper, but its been so long I cannot remember exactly why. My PP2 board set is not currently in a cabinet so cannot try self-test at the moment. Did you end up replacing all the EPROMs with your PP2 upgrade? I vaguely recollect that my issue might have been due to a partial upgrade.
 
Well my gas pedal is wired with a Switch (Somebody removed the Pot, and replaced it with a lever switch), and they wired it with 2 resistors.

I re-wired the resistors to pull-down the green wire, and that fixed the revving sound.

------------

I also have this problem after the upgrade:

90% of the time, when I switch into self-test mode, the game will freeze with everything scrambled on the screen, and I have to switch it off, then back on.

If I turn the self-test switch on before I switch on the power, the self-test loads fine.

Any ideas why this might be happening?

Other than this, the game runs fine, I just find this to be a odd issue.

------------

I'm also thinking about upgrading to a Switching Power Supply, and eliminating the AR-II Boards all together.
 
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