Hi all

When I power up for the first time after it being off for more than say an hour or two, I get a few error codes:
1. Row 2 gnd short
2. Row 3 gnd short
3. Idol lock

The interesting thing is that the error self clears after about 15 or so seconds. After I power up I can immediately go into switch edges and see that row 2 and 3 are lit up, but you can actually watch it go away on its own. When this happens all the switches trigger and the row returns to normal status. The same is true with the idol lock... it doesn’t lock and skips over many stop points and then just starts working after you run the T14 diag test once or twice immediately after startup.

Then, once the machine is running you can power it off and as long as you power it back up within an hour or so, there are no errors thrown.

I’ve recently changed the mpu board, the POA optic board (there was a real problem with that) and even swapped out the power driver board and 8-board with no change.

I am thinking this is some type of power or transformer issue,perhaps there’s insufficient voltage somewhere that takes time to build up(perhaps a bad cap) and stabilize?

Any tips or troubleshooting advice? Thanks!

Does your issue also reappear only at cold start up, meaning that after the game warms up a bit everything is fine?

I don’t feel its a specific switch issue because it’s two rows and the idol... something isn’t either getting the right voltage or there’s a logic fault somewhere.

Wow, same issue indeed.
I think mine started when I changed the Mpu board. I am wondering if it is the cpu as suggested above. I did reuse the old cpu from the old Mpu board, I wonder if I should change it. Do you still have the original cpu?

Hi,

I have a ColorDMD (which I believe uses less power) and one led mod and I added a motor to the airplane prop...otherwise it’s stock.

I also will explore the power supply. To me it seems like it’s starved for power at startup. But I think the power driver board is only part of it, I guess the rest is the transformer.

I still also think it could be the cpu, but I don’t have a spare one.

Hi

I have a fresh Mpu board so I’m confident in those headers and I checked the connections. It’s really weird that it self corrects, I can actually go into switch edges and watch the two rows magically return to normal in a few seconds.

It can’t be a hard fault, i just don’t know what’s going on. The idol and is misbehaving because the optis are on one of the flaky rows.

Thanks.
The problem did start right after I changed the MPU board and re-used my old CPU (as I had reason to believe that the board itself was damaged due to corrosion issues from the battery... this was true, it was damaged).

Does anyone else have any ideas? I still have yet to try pulling out the J connectors from the bottom of the MPU board to see if the issue goes away. I did, however, clean the connectors up and made sure everything was tight and re-seated things a few times. It just doesn't make sense, as I can power the machine on and immediately go into switch edge test mode and see rows 2 and 3 lit up and then they start flickering off and on and eventually, after something like 5 to 20 seconds or so, they return to normal and the machine behaves fine. I wonder if I need to scope the power supply... but why only 2 specific rows if that's the case?

Hi all,

Ok, so I let it sit for a whole day. It's definitely true that the longer it sits, the longer it takes to "recover" to normal operation during first start-up. When I let it sit for a day, it took about 45 seconds to recover. If I let it sit for a few hours, it either always work at first startup or recovers in just a few seconds. When I go into Test 1 (switch edges), here's what happens:

1. rows2 and 3 are lit up (except for the flippers).
2. after a period of time that's a function, it seems, of how long it has been powered up, the following starts happening:
3. the various switches start flickering off and on, eventually settling down to expected. This takes anywhere from a few seconds to maybe 45 or so seconds
4. once they are settled down, they stay that way while it's powered up.

I did verify that if I pull out J209, the rows are clean, this seems to further the idea that it's not the CPU and it's power related. If the optos don't get enough voltage or power, would they read as triggered? If not, then my theory is dead.

I don't think this is the CPU, I would expect that a CPU issue would be more determinstic both in terms of when it happens and how long it takes to resolve. It feels like a power supply that's weak at startup, like a cap that's not charging or holding a charge. The longer it sits, the less available power there is due to a bad cap(s). Rows2 and 3 are probably just the most influenced for whatever reason. That theory doesn't seem solid, I would expect to eventually see problems on other rows/columns, but I can't think of anything else.

The thing is, I changed the power driver and 8-opto boards. What's left? The transformer?
I really need a scope.

Hi all,

I learned that there's a thermistor inside the power box, its job is to limit the voltage to the transformer at startup. It takes a bit for the game to "warm up" until it becomes a zero-ohm resistor and doesn't limit the transformer. This could exactly explain my problem... when the box is cold, the voltage is limited and things get starved for power and act flaky. To make this theory work, I am assuming that a low-voltage (somewhere) could cause flaky switch behavior.

This is where I will investigate next.

Hi all,

I measured the thermistor's resistance at "cold" (well, fairly cold... it has been a few hours since it was used) and it's 4.7 ohms... this is higher than the 2-3 ohms expected and would explain things I think. A high value means it's limiting the voltage to the xformer more and I'm still betting that a low voltage will cause flaky behavior. Mine must not be too bad, because I think if it's really bad it can cause game resets.

Next I will turn it on and check the AC voltage across it, but I am thinking this is a formality. The voltage across it should be < 1VAC during normal operation. I am guessing I will see higher. A higher voltage drop implies more limiting is being down to the xformer, which would cause the rectifiers to see less power which would cause the entire array of circuits to see less voltage... it may just be low enough that only certain things are affected.

I should also mention that when I start up at cold, I don't always see all three failures, sometimes i only see one:
1. row 2 gnd short
2. row 3 gnd short
3. idol lock (but I think this is because the optos are on one of the affected rows)

Furthering my theory is that it's summer here in Texas, and that means lower line voltages to start with due to the unofficial "brownout" that results from all the ACs going hard. We typically dip down to 110V in the summer (which itself is probably fine, but not with a bad thermistor) and stay at over 118V in the winter. So, in the winter, at least for me, the chances of seeing this are probably smaller, I am guessing.

I suppose I can jumper around it temporarily to be sure at the risk of pushing the rectifiers a bit, but I ordered some of these from mouser (unfortunately Frys doesn't sell anything like this):

https://www.mouser.com/ProductDetail/Amphenol-Advanced-Sensors/CL-30?qs=sGAEpiMZZMuqZeNK75brD%2frjMwDFP8g4kbJYciAX3hY%3d

Well, I just jumpered the thermistor and the problem remains. It may have been a bad thermistor, but that's not the only problem unfortunately.

I so wanted that to be the issue, and it made perfect sense.

I am now at a loss without a scope.

Hi,

I have a new rottendog power board, so I'm pretty sure everything's ok there.
If it's not 12v, hypothetically, what would you suspect?

Hi all,

Ok, but, quick question... the switches in rows 2 and 3 are, for the most part, not controlled by the 10-opto board. Would this board still be able to influence a boot-up issue with rows-2 and 3?

I will probe the regulated +12V on the power board tonight. If it's not 12V exactly, what else could be going on (or do youi think the 10-opto board can somehow influence this)?

HI all,

I checked TP3 with a meter. Immediately at bootup it was 11.97V and then went upto 12.06V after about half a second (actually, this is probably just the response time of the meter).... seems like it's 12V. Sounds like this is ok, correct?

Cool
Actually,Zaza may have led me in the right direction. I did unplug J3 (from the 10-opto board) and the problem went away, need to do it a few more times before concluding that though, as the problem is not 100% consistent. But, looks encouraging. I don't understand why that board could be the issue, however

Yes, I did unplug J3 from the 10-opto board. And, initially speaking here, it seems to help, but I will do some more checks. I was really surprised by this, and this was the last board I was going to look at. But a leaky cap makes sense, as the problem seems like it goes away as something charges up. If the cap is weak, this explains why the longer I wait to do a power-up, the longer it takes for the machine to return to normal.

Hi

So it seems I have two problems: thermistor...but this isn’t the real problem, and a bad 10 opto board.

I went from a stable machine to all these issues all within a month: mpu board (corrosion damage), poa opto board, thermistor, 10-opto board.
Crazy stuff

I ordered a new 10-opto board and will update when it’s installed. For now, I bypassed the thermistor until the new ones arrive.

The good news is that I now have spare a 8-driver board, 3-opto board, power driver board and poa motor board.

Hi all,

Yes, I am very appreciative of this and it would have taken me a lot longer to look at that board, as I didn't suspect it could be the root cause.

Anyway, the new 10-opto board is in order and I will update folks when it arrives. Maybe I can also try to replace the caps on the original board, but I just hate soldering PCBs.

I have been keeping the boards that I have swapped out: so far I've changed 2x flipper opto boards, the POA opto board, the POA motor control board, the MPU board, the power driver board. On Friday, I'll add the 10-opto board to the list. I've also "tried" new 8-driver and 3-opto boards, but put the old ones (which appear to be originals) back in since they didn't help. Actually I think I can put the old power driver board back in, as well... it's just a lot of connections to undo and redo.

Is there a market for these old boards that need to be fixed? Or is it best to just keep them (in their broken state) for the next owner so that they have the original parts?

Hi all

10 opto board installed. 4 boots with no issues! Also installed new thermistor, but that’s not the root cause of the problem.

Thanks!!

Thanks all for your help.
It’s really weird how so many things went south all at once, but oh well, it’s all working now.

All the work has also inspired me to get a pinsound+. As luck would have it, I have a spare subwoofer... so naturally I’ll be able to add that to the system too.