Hi all. So I bought pinbot in June (my first pin!). At the time of purchasing it, when you depressed the flipper buttons, the flippers would just flip up and down repeatedly, and the guy I bought it from said he thought a flipper rebuild would fix the issue. I also noticed that after a time the flippers would lose power altogether and he said it was probably an issue with the flipper power supply board.

Since I purchased the game, I've done a complete flipper rebuild on both flippers and also replaced the flipper power supply board. Since the flipper rebuild most of the time when I boot the game up, pinbot will play fine (flippers act normally and are powerful). The only thing thats odd is that the flippers will still flip between games when they should have no power. However, sometimes (and it has been doing this a lot more as of late) after playing for a little bit the flippers will start to randomly flip up and down, and after a short time will stop flipping altogether. Also, if you depress both flipper buttons down at the same time when it's doing this, then the flippers simultaneously flip up and down so the issue is linked to both flippers.

I'm a total novice when it comes to pinball repair, and have no background in electronics so any help is appreciated! I'm not even sure where to start honestly.

Thanks!

Oh ok thanks! No battery corrosion on the board as far as I can tell. I will try and follow the traces and let you know how it goes.

Update: every time I boot the game on now there is no power to the flippers between games (as it should be), but the flipper power goes in and out repeatedly almost right away. The reason it is losing power is because the relay (k1) is opening and closing constantly during the game when it should obviously remain closed during the game. This is whats been making the flippers go up and down. Thanks for pointing me in the right direction to that!

I have not yet taken the board out of the machine to check and see what it looks like on the back, but I did check the transistor right before the relay (Q67) because I read that goes bad fairly often. It tested good on the multimeter, but I also ready that transistors could "test" good but still be bad, so maybe that transistor is still the issue?

I also have not tested the relay itself yet to see if thats bad (need to do some research on how to do that). But I feel like I am slightly closer to figuring out the issue even though the game is working less now, haha.

Thanks for the suggestions guys! When I have some time I'm going to pull the board off and see what it looks like on the back/check those solder joints. I also might just replace that transistor and see if it fixes the issue, since I need to order another transistor to fix one of the pop bumpers anyways. Seems like an inexpensive way to check out that problem.

If that doesn't work I'll buy a logic probe/figure out how to use it and check the transistor as robertmee suggested.

Just want to post an update - since the last post, I pulled the board out and checked the solder joints (everything seemed good). I also replaced transistor Q7 and that did not fix the issue. I also recently purchased a logic probe so I can figure out if the relay is being told to pulse, and try and pinpoint the issue.

I read through the pinside topic regrading logic probes, and am still a bit confused on exactly how to use one. I know one end is hooked to ground, and the other end should be to somewhere getting voltage, then I can probe - but not sure exactly where you would attached either of the two points? Again I don't actually have any background in electronics and I don't want to cause any damage to the board, so I have been hesitant to actually hook it up and use it.

Any advice regarding the use of the logic probe would be helpful! (robertmee or anyone else) Also if anyone has any suggestions on if I should just start replacing certain items? I am open to any and all help.

Much appreciated.

Update - Working on probing upstream of the relay and noticed that on the schematic wiring diagram there is a U46, U47, and U48 chip, none of which I can actually locate on the board (they are also not shown on the CPU board diagram). See attached image. Does anyone know why they are not there, or what I should probe upstream?

Screen Shot 2019-11-16 at 9.24.51 AM (resized).png

Thanks for the info. We probed upstream, and what we found was that pin 10 u50 was fluctuating with the relay going open and closed but the inputs to u50 (pins 8 and 9 and 11 and 12) all seemed to test good (I have my brother in-law here helping me out with his oscilloscope). So it seemed like that would mean U50 was bad. U55 also did not fluctuate with the relay so that seemed good. However, we decided that before we replaced U50 we would check to make sure that was the issue by jumping from pin 13 to pin 10 on the U50 chip thinking that it should then make the relay work, however when we did that the relay just stayed open. The relay then started flickering after we disconnected the jump. Then we decided to jump from the 5 volt VDC to the left of the relay (we confirmed 5 volts with the multimeter) and then connected that directly to the base of the Q67 transistor right before the relay. When we did that the relay stayed open, and we had no power to the flippers at all.

Now, when we boot the game up the relay stays open the whole time, and also all of the jet bumpers and slings do not work. I would have thought this would be the result of a blown fuse, but all of the fuses tested good with the continuity function on the multimeter. Any thoughts on what would cause the slings and bumpers to stop working?

Update: I replaced the U50 and U45 chips as well as the Q67 transistor. Also transistor Q9 tested bad, so I replaced that while the board was off. After plugging the board back in, nothing is different than before. Here are the list of issues, none of which were happening before I started trying to "fix" the board: Flippers will not move at all (relay is always open), the jet bumpers and slings will not fire, there is no music in the attract mode, the top row of lights below the visor are not on.

Anyone have any thoughts on this?

GRUMPY Sure- Here's a couple pictures of the board in the game. Appreciate your help! We're spinning our wheels here a little bit.
IMG_8366 (resized).JPGIMG_8367 (resized).JPGIMG_8368 (resized).JPG

Also, just a heads up, the wire with the wire nut in the middle of the image was there when I bought the game - it connects to a power time-delay device thats in the cabinet.

The time delay power device makes it so that when you turn the machine on there's a delay until it actually boots up (and a dial to adjust how long the delay is). Right now I have the dial set to no delay. This doesn't seem to cause any issues, just odd that it was installed to begin with. Also, the battery holder is definitely not factory, although it also has not seemed to cause any issues, but see picture below.

It's worth noting that after I did the flipper rebuild the game was working pretty well for a few weeks and the only thing odd about it was that there was power to the flipper between games. Other than that it played great and everything functioned as it should. After a little while though, it reverted to intermittent flipper power (which it was doing when I bought it)

Only just today did all of the other issues pop up (we must have screwed something up). Again, really appreciate you taking the time to help me out.

IMG_1793 (resized).jpg

Took the cover off the relay - contacts look clean, and continuity tested good. Think its an issue with the relay being given an incorrect signal to stay open.

Yeah, you're right - I'll place an order to buy stuff to fix these issues. As mentioned before this is my first pin, so it was hard to figure out where to start. My initial reaction was to try and get it functioning and then fix up the items mentioned above, but definitely seems like a good idea to fix them up front.

I've been relying on friends who have a lot of experience with soldering/board repair to help with the soldering on the boards. I would say I am ok at soldering but not a pro yet so I've been letting them handle that while showing me how it's done so I can learn.

For anyone interested, here's a picture of where I left off on Saturday trying to solve the problem of why the relay is acting up. You can see that out of game high voltage is going into the relay so it's staying open (which it should), but when you start a game, high voltage is also getting to the relay so it is also staying open (when it should be closed and allowing power to get to the flippers). When probing pin 5 on the U56 chip or pin 13 on U50 the logic probe kind of "freaks out" not going to low or high, so my best guess is that the U 56 chip may be bad, or the U 50. I will order a replacement chip when I also buy the parts to fix the problems that GRUMPY outlined above.

Still unsure of why the slings and pops are not working though, when they were working before I enlisted the help of my brother in-law with the diagnosis.

PinBot Scan (resized).jpg

I realized that image in my previous post didn't show up well. Here's a higher resolution one:

PinBot Scan1.pdf

Ah, well that makes a lot of sense. Are you talking about the signal specifically from pin 10 on U-50 that goes to the relay? Or the signal from pins 1 and 4 from U-50 shown above that on the circuit diagram (as well as the signals from U-45 in the same area)? I know I am getting a little bit ahead of myself, but just curious. I've been learning a lot since getting this game, so I want to make sure I understand exactly what's going on.

Ah yeah, I see where you're looking at. Then it definitely looks like both problems are stemming from the U50 pin 13/U56 pin 5 area.

Want to post an update in here, replaced chip U56 last night and we are back in business! Flippers and slings all fully operational. It took me a while to get the parts because I was trying to buy everything in one place to fix the flippers and the problems grumpy mentioned above. Thanks again GRUMPY and robertmee for the help.