(Topic ID: 192112)

(Fixed) Bally -35 board switch issue.

By JT-Pinball

4 years ago

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  • 44 posts
  • 4 Pinsiders participating
  • Latest reply 4 years ago by Quench
  • Topic is favorited by 2 Pinsiders


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    #1 4 years ago

    Tonight I am working to bring an old Bally -35 back to life. I intended to just have this be a spare board to have for the next project, as it didn't look too tore up by alkaline damage.
    So here is my issue. When I have this board on bench it boots up fine. When I put board in game known good game it boots fine. But after it boots it dose not seem to function it attract. Stuff on game seems slow or just stops. I have had this issues on boards before with bad jumpers settings or a break in jumpers. I have checked and verified that is not issue. Other issue is that the it is causing solonoid Q9 to fire repeatedly. Seems to just fire in sync in one second pulses.

    So here is what I have done.
    Replaced all header pins
    Replaced U2 socket
    Installed NVRam
    Installed new PIA in U10 and U11
    Replaced bad diode at CR41
    Using know good game Roms at U2 and U6

    Guess the next step is to trace back that solenoid strobe to U10 and see if I have a resistive short??? Or just replace the socket?

    #3 4 years ago
    Quoted from jj44114:

    short some where. Mpu probably

    I think so too...

    #5 4 years ago

    Thanks for your reply Quench.

    Quoted from Quench:

    Have you made any progress with this?

    No. I have had a crazy last few days at work and not been able to focus on this.

    Quoted from Quench:

    Do you have a device to measure frequency?

    Yes. My DMM will do frequency. I will pull the board out of the game and put back on the bench and run the test above.

    Quoted from Quench:

    It's unlikely but possible that the solenoid Q9 transistor repeatedly activating could be related to the slowness issue you've got with timers being out of whack.
    What game are you testing it in?

    Hot Hand

    Quoted from Quench:

    Have you tried another 6800 CPU at U9?

    No. I swapped the PIAs for new ones. Once I got board to execute the program and pulse the test lead with the Leon's, I assumed I had a good U9.

    #7 4 years ago
    Quoted from Quench:

    You'll need to leave the board in the game to properly measure the Zero Crossing detection circuit because it's derived from the unregulated 43V DC solenoid supply line.


    Quoted from Quench:

    Ok, solenoid transistor Q9 continually activating tells me the MPU board is sensing the left side kicker switch as being stuck on. It's trying to eject a "stuck ball" from the kicker.

    I forgot to mention I have J2 and J3 unplugged from MPU.

    Quoted from Quench:

    I was helping a fellow pinsider repair a battery corroded board 6 months ago - he got the board booting to attract mode but it would stop at that point (displays working, but no lamp animation/switch response). Turned out to be his CPU causing it, which is why I mentioned it.

    I'll swap the CPU and see if that helps first.

    #8 4 years ago
    Quoted from Quench:

    Do you have a device to measure frequency?
    In terms of the attract mode slowness, make sure the following signals are in spec:
    Pin 18 of U10 should have a 120Hz signal (Zero Crossing Interrupt)
    Pin 40 of U11 should have a 317Hz - 320Hz signal (Display Interrupt)

    Pin 18 U10 is 119.6hz Pin 40 of U11 is 319hz

    #9 4 years ago

    Swapped the CPU. No change.

    #11 4 years ago

    I had it in test mode before I started switching things around. I will have to see when I get back to the game this afternoon. Thanks Quench.

    #13 4 years ago

    Will not enter test mode. After I changed U9 now it plays the into music over and over.

    #16 4 years ago

    I'll see if I can get in to factory test mode. The more I read thru other post with similar issues it looks like to me it is probably a socket issue with U9 or U10. They are the old flat black Augat. I took a short video of it but can't figure out how to post. I'll pull board later and take some pictures of it. At this point if I take it out again I may just replace sockets at U9 U10 and U11. Those sockets just suck to get off the board. Even when you have a Hakko FR300.

    #20 4 years ago

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    #21 4 years ago

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    #22 4 years ago

    Thank everyone. When I desoldered U9 I had 2 traces pop up on the board. They still tone out. I think I will solder them together at the pad and solder on the SIP socket. Then add some conformal coating to hold them.

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    #25 4 years ago

    Hey Quench hope all is well for you today!


    Quoted from Quench:To be honest, looking at your board pictures I rather doubt that U9 socket was your issue.

    I think we need to revisit this. When I check in emulation with the kicker switch stuck closed, the game runs dead slow in attract mode and activates the Q9 transistor for the kicker solenoid repeatedly once a second which sounds like your original issue.
    I can see someone has replaced diode CR41 on the MPU board which is on the switch return line signal that the kicker switch lives in the switch matrix.
    Repair those two lifted traces and install a new U9 socket then put the original 6800 CPU back in.
    I don't know if you saw this thread below but you're likely to have similar board issues. We should do some resistance measurements on the switch return signals on the MPU board.

    Yes. I am following this thread.

    #27 4 years ago
    Quoted from Quench:

    With the MPU board on the bench i.e. disconnected from game, set your multimeter in resistance mode (at the 200k ohms scale if your meter isn't auto-scaling) and measure the resistance between:
    My meter is auto scaling.

    a) J2 pin 8 and J2 pin 9 3.4M
    b) J2 pin 11 and J2 pin 12 115k
    c) J2 pin 14 and J2 pin 15 115k
    Now measure the resistance between these signals on the 6821 PIA chip at U10 between:
    d) pin 10 and pin 11 3.5M
    e) pin 13 and pin 14 112k
    f) pin 16 and pin 17. 102k
    Report all the readings.
    For reference, two of my boards on the bench measure around 95k-100k ohms at all these locations.

    Ok. So I glued down the traces with gorilla glue and then sealed them in conformal coating.

    I took readings and had a open line at U10 P13 I reseated U10 fixed open line and got above readings. For giggles I put board back in game, this seemed to fix sound problem. Game is also running faster. Still won't enter test mode. Q9 still pulsing and I can see it flashing as soon as it goes into attract. I have disconnected sdb but have connected my sdb output testers and can watch it flash. It pulses in rhythm as soon as mpu boots.

    So I am looking at the -35 schematics. Looks like I have a short somewhere between PB 0-1 and PA 0-4 or into the zero crossing signal coming into P18. Well this is my guess based on schematics. I think I should change U10 socket? No?

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    #28 4 years ago

    Thanks quench

    #30 4 years ago

    Open your quote

    #32 4 years ago
    Quoted from Quench:

    Oops, sorry I was in a rush. Lol! No worries.

    Quoted from Quench:

    The repair looks good. I presume you have solid connection between the top and bottom traces at those two pin holes at the U9 socket where the traces lifted?

    Thank you! It took a minute to fix that without jumpers. No room to try stick a solder stich in the socket. I had to tin the end of that trace under magnification, stick it to broken end or the plated hole under the socket. Smoothed it out, put a dot of flux there and soldered it from the back. I have good continuity between the socket and board. Board boots!

    Quoted from Quench:

    The switch return line shown on the schematic as "I1" is the PB1 signal (pin 11) of U10 and it goes to a 56K resistor (R45) which pulls the signal low. Your original symptoms and very high resistance readings at pins 10 to 11 on U10 tell me there is an open circuit on this PB1 signal to that resistor or the resistor itself is open circuit.
    See the picture below showing the location of this resistor. With your meter on resistance mode, do you read 56k ohm across that resistor?
    Pin 11 of U10 goes to the left side of that R45 resistor. Do you measure an open or short circuit between these two points? If it's open, follow the traces on top and bottom of the board between these locations to try and work out where it's open circuit.

    Let me get the schematics and I will look at that and follow thru and report back! Thanks Quench

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    #33 4 years ago

    Not sure why pictures reattached.

    #34 4 years ago

    Ok so resistant at R44 is 3.2M. Other are 56k.

    #35 4 years ago

    Bang! Changed R44 as you suggested. Game enters attract and plays as it should! Quench thank you!

    I will mark as fixed. So wonder what happened? Resistor blew for some reason caused diode to blow? I replaced diode but should have checked to make sure path to ground did not short?

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    #37 4 years ago

    I have started do most work under magnification. Helps see the detail. I didn't notice any physical difference in the resistor. Just the different resistance measurements.

    I had a display issue once on a stern MPU 200. One digit out on all displays randomly. It looked good. But in the game it pulled open just enough as barakandl said where the lead entered the resistor body. I traced the path back with schematic and was reflowing things. Low and behold the lead moved and fell out. New resistor and displays have been working since.

    #39 4 years ago
    Quoted from Quench:

    Great stuff!
    Is the test switch on the coin door working?

    Yes. Game functions as it should. Only one difference I noticed and maybe you Quench or barakandl can help me understand. I took my NVRam out of the stern MPU -100 I had in the game. I had played maybe 300 or so games on that MPU with the NVRam. But when I put it in the -35 the settings were erased? I guess I thought all the audits would stay. So my next question is is to put that NVRam back in the original MPU will the setting and audits return?

    Quoted from Quench:

    Trivia: Hot Hand has a secondary switch location within the matrix that spots the "Ace", but no switch on the playfield is assigned to it. Makes me wonder if that white standup target next to the spinner was originally put there to spot the Ace but was deemed too easy...

    I have had this game for a long time, and were looking at these schematic long before I had any understanding. But now that you point that out I see it instantly on the switch matrix. Lol! Thanks for the trivia Quench

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    #41 4 years ago
    Quoted from barakandl:

    The games probably use different parts of the memory for different things My test bed is a Black Pyramid a lot of times. When i throw different game ROMs in after being played as BP, usually a lot of the audits have ramdom crud in them. BP must use certain areas of memory for gameplay stuff while other games use that spot of memory for an audit.

    Ok. So it must be driven on the board. No? This -100 had my original game roms for Hot Hand the 9316A and this NVRam. I put the 9316A Roms and the NVRam in this -35 and back into Hot Hand. So the different board must address memory differently?

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