Pinball Machine Repair

Discussion in 'The Projects Forum' started by nickorossa, Jul 31, 2010.

  1. nickorossa

    Thread Starter Active Member

    Jun 28, 2010
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    Hi

    I've been given a broken pinball machine which I thought may be repairable.

    The machine is a Saitek F1 Super Challenge.
    Pinball Machine.jpg

    The machine seems to function, with the exception of counting up a score. One the game is started the display shows "P161" (possibly an error code???). Music plays, the lights on the pinball table light, the motors spin.

    Needless to say I have opened up the unit :eek:

    The base unit consists of two circuit boards. One appears to mainly control the lights on the table section. This seems to be working fine as all the lights "randomly" flash etc.

    Base Unit Light Circuit.jpg

    The second circuit on the base unit feeds the light circuit; but also seems to have all the wires running to the switches, contacts and motors. I've checked for voltages across some of the switches and there is 3.2v across them.
    Base Unit Circuit Top.jpg
    Base Unit Circuit Bottom.jpg

    The head unit which takes a 9v input from a power adapter has the buttons, speakers, switches and counter display. There are two circuits in the head unit.
    Head Unit Circuit 1.jpg
    Head Unit Circuit 2.jpg

    The second circuit in the head unit has 3 COB chips on it, so if those are the likely issue, I guess I'm stuck.

    I'm guessing that something on one of the head circuits is the cause of the issue as the functions on the base circuits appear to be working. Any ideas on what to do to find the cause of the issue and fix?

    I don't mind putting in the time and effort to fix; but only if its something that is likely to be fixable.

    Thanks for your help.

    Nick.
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Have you gone to the manufacturer to see what the error code is all about? There is nothing to go on without that guidance. Wiring diagrams might be nice, too.
     
  3. bertus

    Administrator

    Apr 5, 2008
    15,645
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    Hello,

    I wonder if the manufacturer is still available, as the machine is from the 1990's.
    There are some standard cmos chips used.
    On the last picture there is a setup board(the green thing).
    Can you make a picture of the other side of this one?

    Bertus
     
  4. nickorossa

    Thread Starter Active Member

    Jun 28, 2010
    54
    0
    I did go to their web site, but it seems to be all PC related items like flight yokes etc. Absolutely nothing about pinball machines etc. I wasn't convinced I had the correct web site.

    I'm only guessing that the display is showing an error code.

    Experience tells me that manufacturers don't usually want to know once something is out of warranty and this table may be a few years old. I'll call them in the week, but I don't expect any help.

    Nick.
     
  5. nickorossa

    Thread Starter Active Member

    Jun 28, 2010
    54
    0
    Hi

    Thats the circuit with the COB chips. Picture attached.
    Head Unit COB Circuit.jpg

    Nick.
     
  6. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    There you could have a problem.
    When there is someting wrong with the chip under the blob, there is no way of repairing it.

    Try to get hold of a schemetic, to have some straws to hold on to.

    Bertus
     
  7. tom66

    Senior Member

    May 9, 2009
    2,613
    213
    P161 is obviously some kind of fault code.

    But if the main chip is fried (say from too many volts), it will usually not output anything... right? Also, a manufacturer would usually not bother about including extra circuitry to detect the failure of the main chip. So I think you can rule out the COB.

    My suspicions would point towards the memory. If it remembers high scores, then maybe it's got battery backed memory (NVRAM), and the battery is dead. Look for battery cells. You could also be dealing with integrated circuits with built in batteries.

    EDIT: It could also be an identifier, like bulb "P161" is faulty, replace to continue(?) You said the bulbs were lighting up but were all of them working?
     
  8. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Is the powersupply stable?
    Sometimes a bad capacitor can have strange effects on the processor.
    Does the P161 come on the display at startup or afther some time?
    Are some parts getting warm / hot?

    Bertus
     
  9. nickorossa

    Thread Starter Active Member

    Jun 28, 2010
    54
    0
    Hi

    Yeah, I was sort of expecting that; in part because the board is soldered in seperately; meaning it could be "replaced" easily.

    It just seems a bit weird that so much of it is working if those chips are at fault.

    Nick.
     
  10. nickorossa

    Thread Starter Active Member

    Jun 28, 2010
    54
    0
    Hi

    I've not gone round and checked each bulb, but watched them and I thought I'd seen each one light up. I'll make a list and check them.

    I haven't seen a battery, but the board at the back of the head unit I haven't looked underneath.

    The machine powers up and you can select number of players, turn music on/off; change tilt setting. Once you start a game, it just shows the P161 and doesn't register touches on the switches/sensors.

    I'll have a good look around and see if I can see a 161 that may relate to a faulty part its trying to tell me about.

    Nick.
     
  11. tom66

    Senior Member

    May 9, 2009
    2,613
    213
    It's quite likely that they've (Saitek) gone for one chip to control the lights, and one chip to handle the game logic and scoring. This reduces the number of IO they have to have on the controller chip.
     
  12. nickorossa

    Thread Starter Active Member

    Jun 28, 2010
    54
    0
    Picture of the underneath of the head unit board. Not much there.

    The chips on that board are:
    4 x CD74HCT373E
    2 x A 102J (in middle of one LED digit block

    Nick.
     
  13. tom66

    Senior Member

    May 9, 2009
    2,613
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    Can you post us pictures of some of the ICs on the other boards? (Close up pictures please... we want to see the IC numbers) I'd be interested to see if there is some NVRAM on there, or a battery.
     
    Last edited: Jul 31, 2010
  14. nickorossa

    Thread Starter Active Member

    Jun 28, 2010
    54
    0
    Hi Tom,

    The chips on the other side are the CD74HCT373E's.

    The picture is this one.
    Head Unit Circuit 1.jpg

    I can't see anything that suggests NVRAM or a battery on any of the circuits.

    When the high score button is pushed a number does get displayed. I'd have to power it up to check what i was though.

    Nick.
     
  15. bertus

    Administrator

    Apr 5, 2008
    15,645
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    Hello,

    Perhaps the blob-chip has a nvram part in it.
    Then you will not find a seperate chip.
    I see to power parts on the board.
    Are they voltage regulators?
    Are the output voltages of them as they must be (inside spec)?

    Bertus
     
  16. nickorossa

    Thread Starter Active Member

    Jun 28, 2010
    54
    0
    Tom,

    The circuit board that has the switches/detectors linked to it has the following.
    2 x CD4532BE
    2 x A472J

    Bertus,

    There are two voltage regulators; both are L7805CV's. I'll test the voltages on them shortly.

    Nick.
     
  17. nickorossa

    Thread Starter Active Member

    Jun 28, 2010
    54
    0
    Hi

    Voltages. The machine seems to use 3 voltages.
    +3 = 3.19 steady
    +5 = 4.97 steady
    +9 = 11.46 - 11.69

    The power supply in is 9v; so I'm not sure if the 9v reading is likely to be causing issues.

    The attached picture shows how the boards connect to each other.
    pinball.jpg

    Nick.
     
  18. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Can you see if there is a voltage regulator for this 9 Volts?
    It can be that it is unregulated for relays.

    Bertus
     
  19. nickorossa

    Thread Starter Active Member

    Jun 28, 2010
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    0
    Hi Bertus,

    I couldn't see a regulator for 9v assuming it looks like the 5v ones.

    Nick.
     
  20. nickorossa

    Thread Starter Active Member

    Jun 28, 2010
    54
    0
    Hi Bertus,

    The 9v goes straight through to the lighting board via the other boards. It is not used in the other boards.

    Nick.
     
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