Noobie PCB solder screwup?

Started 2 years ago by Corny in forum TechTech: Generic.


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Noobie PCB solder screwup?


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  • Started 2 years ago by Corny
  • 8 Pinsiders participating in this thread.
  • Latest reply from pinmike

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    2 years ago
    #

    In my TZ, the lower left field had the GI lights out, I had investigated the GI connectors and found them to burnt so I got some replacement headers and connectors. Last night I got around to working on it and pulled out the board to replace the headers.

    After soldering the headers back in I checked the continuity along the trace from the pin, it wasn't great but the DMM did beep (It wasn't great because I would not instantly find a path, had to move it around a bit)

    I don't have any pictures of the solder job I did but it looked alright to me(I have no experience so my opinion here is worthless), I can post a picture later tonight if need be.

    So I put the board back in and just to make sure I didn't screw that step up I plugged everything back in without replacing the connectors first. I turned it on and everything lit up, including the part that was burnt out last time. Yay!

    Then the game ran its tests and I got the infamous: "Check fuses F115 and F116, J112 and Opto 12v power supply"

    It was getting pretty late at this point so I only tested the fuses(I pulled the fuses and checked the continuity, they were ok) and then went to bed, when I come at this problem tonight, what should be the first thing I do? Do I have to desolder the pins and re-do it?

    If diagnosing this problem requires anything more than checking a diode, please be descriptive in how I can do it, I am not very proficient with the DMM and have only used the continuity setting. In other words please talk to me like I am a 10 year old.

    I appreciate any help.


    2 years ago
    #

    With Those Errors I would check to make sure you plugged every thing back in correctly.

    When you started only issue was the GI right.. you didnt have the other errors?


    2 years ago
    #

    I had marked all the connectors so I knew where they go and double checked all of them to be sure they were seated properly. Only problem was the ground connector in the upper right, I had missed one pin when I seated it. This did not fix my problem but not sure if that caused any new ones : /.

    The only other problem with the game that I knew of before this was the Dead end switch was not being registered and caused the credit dot. I verified while playing a game that I hit this switch and it was not registering, I hadn't investigated this issue yet.


    BVM

    Retired Pinsider
    2 years ago
    #

    Any photos?


    examiner

    Pinball addict
    1,129,750 3
    2 years ago
    #

    The Pinwiki site has a detailed testing/debugging procedure for that error, so break out your multimeter and head over there for info.

    On the surface there shouldn't really be any connection between what you did and what you are now experiencing (unless maybe you bridged a solder joint on the back of the board). It's not unusual to have to "work" your probe around a little bit to get a good continuity signal, so I wouldn't worry about that. Just make sure you don't have continuity among adjacent pins.

    Other than that, hit the wiki site up and start testing. This error message is typically a sign of a problem in the switch matrix. Good luck.


    2 years ago
    #
    Corny said:

    back in without replacing the connectors first

    So you powered up the game without some connectors being plugged back in on the board?
    Go over your connections again and reseat them again.


    examiner

    Pinball addict
    1,129,750 3
    2 years ago
    #

    I read it as if he plugged everything back in and fired it up - but he didn't take the time to physically replace the burnt connector for the specific header that he replaced. Despite not replacing the connector, the GI worked so the header fix must've worked.

    The existence of that burnt connector wouldn't cause these problems, but ya - definately confirm everything is plugged in correctly.

    Despite the fact there shouldn't be a correlation between what you did and your current problem - history would suggest there probably is.


    2 years ago
    #
    pinmike said:

    Corny said:back in without replacing the connectors first
    So you powered up the game without some connectors being plugged back in on the board?
    Go over your connections again and reseat them again.

    examiner said:

    I read it as if he plugged everything back in and fired it up - but he didn't take the time to physically replace the burnt connector for the specific header that he replaced. Despite not replacing the connector, the GI worked so the header fix must've worked.

    Examiner is correct with his interpretation.

    I just found the pinwiki site, I was originally looking for Clay's repair guide that everyone talks about but all I could find was people asking where it was and others responding that they e-mailed it to them.

    No pics yet, I am at work and would like more confirmation before I determine that this could be caused by my solder job before I pull the board out again. I will most likely run through the steps on pinwiki first then pull the board if all else fails.

    Thanks.


    2 years ago
    #
    Corny said:

    Examiner is correct with his interpretation.

    I just found the pinwiki site, I was originally looking for Clay's repair guide that everyone talks about but all I could find was people asking where it was and others responding that they e-mailed it to them.

    No pics yet, I am at work and would like more confirmation before I determine that this could be caused by my solder job before I pull the board out again. I will most likely run through the steps on pinwiki first then pull the board if all else fails.

    Thanks.

    The reason I said go over and reseat your connectors again is because there are 3 or 4 connectors that can be very easily crossed on that board.


    2 years ago
    #
    pinmike said:

    The reason I said go over and reseat your connectors again is because there are 3 or 4 connectors that can be very easily crossed on that board.

    That makes sense and is a good suggestion, thanks. If you read one of my earlier comments I mentioned how I tried to ensure this mistake didn't happen by marking all my connectors with a sharpie where they go.

    Corny said:

    I had marked all the connectors so I knew where they go and double checked all of them to be sure they were seated properly. Only problem was the ground connector in the upper right, I had missed one pin when I seated it. This did not fix my problem but not sure if that caused any new ones : /.


    2 years ago
    #
    Corny said:

    That makes sense and is a good suggestion, thanks. If you read one of my earlier comments I mentioned how I tried to ensure this mistake didn't happen by marking all my connectors with a sharpie where they go.

    I know you said that and you did also mention you did miss a few pins...
    Mistakes like this can happen even if the connectors are marked.


    2 years ago
    #

    Ok, here are some pics of the two headers I resoldered for the GI.


    2 years ago
    #

    While I was looking at the back of my board since it was out I also noticed this, no idea what it is but it looks bad : /


    2 years ago
    #

    Looks like someone probably replaced a bridge in the past..hard to tell from the back of the board...whats on the other side?


    2 years ago
    #

    Update on my last test, TP3 is giving me 10v, supposedly I am supposed to have 12v here. All the LEDs are on EXCEPT for LED3, this one tries to turn on, really hard too, but alas it flickers out. It will eventually come on briefly before it flickers out again.

    Looks like someone probably replaced a bridge in the past..hard to tell from the back of the board...whats on the other side?

    Those pins belong to the heatsink in this picture.


    2 years ago
    #

    If you're talking about the brown stuff, I think it is just Flux from the Rosin Core solder.. You can just clean it up with alcohol and a toothbrush. You should do the solder side of your new header pins too. I've read that it should be done, but not sure why? I'm just a beginner also..

    Good Luck on your problem, Bill in Indiana


    2 years ago
    #

    yes the worrisome area is nothing to worry about just flux from a previous repair being done on the board. The 10v is an issue though


    2 years ago
    #

    I don't know how else to proceed with the voltage drop. #1-3 on the list below all check out then. I can rule out #4 as the fuse is not blown. That leaves #4.

    On step #4, I do not know how to test the 7812 voltage regulator.

    Diagnosing the problem

    Start by checking DC voltage at TP3. You should see about 12VDC. If not, follow these steps.
    1.Actually check fuses F114 and F115 using the procedure here. If a blown fuse is found, replace it. If F114 immediately blows again, then BR1 is probably shorted. Skip to the paragraph below to test the bridge.
    2.Check LED6. If not lit (indicating the absence of 18V at TP8), then suspect BR1 or the filter caps for BR1, C6 and C7. If BR1 had failed shorted or if C6 or C7 where shorted (rare) then you would expect to see F114 blown. BR1 can be tested using the procedure below.
    3.Check LED1. If not lit (indicating the absence of “digital” 12V at TP3, then test D1 and D2 (both 1N4004 diodes). If D1/D2 test good, then check continuity from pin 2 of the 7812 voltage regulator at Q2 to J114, pin 1. This verifies the path through F115.
    4.If this all checks out, yet 12VDC is still not at TP3, then suspect the 7812 voltage regulator at Q2. Q2 is in a TO-220 package (like a TIP-102) and has a small heat sink attached.
    5.There is one more way for the 12VDC power to be lost. A shorted IC on the MPU that uses 12VDC can cause F115 to blow. To help isolate the problem to the MPU, replace F115, disconnect power going to the MPU at J210, and turn power to the game on. If the fuse does not blow, the problem is almost definitely on the MPU board. Any of the LM339s (theoretically) or the ULN2803 (definitely) can fail and short 12V to ground, causing F115 to blow.


    2 years ago
    #

    Flux attracts moisture. Moisture on a board is bad. So, you remove flux when you do board repair.

    Have I ever seen a board shorted because someone left the flux on it? Nope.

    But, it's a generally accepted principle, just like wiping down your stove after you make dinner, because something splashed out of the skillet onto the stove It's just good housekeeping


    2 years ago
    #

    With the board removed from machine and no power I checked Q2, Black probe on the metal tab, Red probe on each leg. One outside leg was 1 (no change) the other outside leg was 1.5, center tab was a short(BUZZ).

    I checked other TIP-102 transistors on the board and got .5 for the two outside and short(BUZZ) for center. How do I know if the 7812 voltage regulator is bad?


    2 years ago
    #

    Q2 is a PNP not a NPN, so I had it wrong, its red probe on metal tab not black probe. Q2 is fine.

    I plugged everything back and put the board back in the machine to test out the voltage on the bridge and.... it works now. Fun.

    So after all that crap, mike was right all along. Probably a loose connection somewhere, would have been nice to know what it was but for now its working and I won't mess with it anymore after I replace the female connectors for the GI.

    Now to figure out the switch failure...


    2 years ago
    #
    Corny said:

    So after all that crap, mike was right all along. Probably a loose connection somewhere, would have been nice to know what it was but for now its working and I won't mess with it anymore after I replace the female connectors for the GI.

    Sounds great and I'm glad it's working again..

    Corny said:

    Now to figure out the switch failure...

    What switch are you having trouble with?


    2 years ago
    #

    Not having trouble diagnosing the switch yet, its switch 41, dead end. I just haven't looked into it, it just started to give me the credit dot and I have visually seen the ball go over the switch.

    I'll probably start looking into that one tonight.


    2 years ago
    #
    Corny said:

    I'll probably start looking into that one tonight.

    Ok,Just activate that switch during gameplay and the credit dot could be any switch that hasn't been activated in awhile.



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