Post this to the JJP forum.

Whaat you all have identified is what us engineers know as a "dirty litle secret". Now that it has seen the light of day, it will be interesting to see JJP's reaction. They will either be proactive, or deny it's a problem until the insurance company goes after them. Perhaps the board is contained enough that there will never be a fire claim. I guess that's the best case for all parties.

BTW, what does that replacement board cost if you just want to order one?

Sounds like $350 (spendy little bugger)

Just did.

yup, and this throw away society needs to fucking go...like yesterday. That's the real issue that's going to destroy our planet. The amount of garbage we make is astronomical. Government says they are taking steps to change this, but if anything, I see the disposable aspect becoming more and more increased. Due to laziness or companies wanting to cash out. Nobody seems to give a shit about the environment anymore. That's one of the main reasons, products like the Keurig coffee makers piss me the hell off. I mean how lazy do you have to be not to be able to make a damn cup of coffee without having to throw more plastic bullshit into the trash. We are so screwed.

A Bourns 2301 is show in one of the photo's. The 2301 inductor is a 10uH, high current inductor which appears to be the proper one for a 12V supply per TI datasheet. But I guess it depends on what max current value is spec'd at.
I think the high and low side transistors look to be woefully undersized and actually causing this fiasco. These appear to be about 50% of the physical size of the ones recommended in the TI datasheet. One fails and puts the switching regulator into discontinuous mode trying to keep the voltage up - hunka chunka current going through that bugger and all hell would break loose.

I don't know what is actually used on these boards but TI recommends a pair of FETs that are about 5mm Wide by 6mm long. For comparison -- that LM5117 controller is ~6.5mm long so the switching transistors should be nearly as wide as the controller is long. Looking the photos - the two switching transistors are about half the length of the controller so they appear to be far smaller than the recommended parts.

They may be sized to handled the voltage and current but based on their physical size, I'll bet their heat dissipation is horrible especially taking into consideration the small amount of copper surrounding the device that is supposedly acting as the SMD heat sink. I would love to see how hot those two transistors are running at.

That is why I always maintain that for these supplies, NOTHING beats a bigass thru-hole MOSFET or catch diode tied to a REAL heat sink.

Is there anything that could be added as a heatsink?

That's one of the upgraded boards. Mine is much smaller.

According to the manual, they are using Alpha & Omega AON7244:
http://www.aosmd.com/pdfs/datasheet/AON7244.pdf

The TI LM5117 eval board uses NXP PSMN5R5-60YS, and they claim the eval board can deliver 9A. Here's the datasheet for the NXP FETs.
http://www.nxp.com/documents/data_sheet/PSMN5R5-60YS.pdf

Rds for the two transistors is nearly the same, so the JJP design should not generate much more heat than the suggested design. The AO FETs, however, are much smaller, like you say, and will not dissipate the heat as well. I would agree that it would have been better to go with something with a little more margin than the AO FETs. FWIW, they did not seem to be getting hot in my game, while the inductor was blazing.

It seems like they may have underestimated the amount of current that would be drawn from the 12V source, but then oversized the fuse and set the current sense on the LM5117 higher than the parts can really handle.

Any heatsink would probably help as long as you could transfer heat from the inductor in the sink. Because of the irregular surface, it would be difficult without something like a thermal transfer pad.

Edit: Reading again, it sounds like you actually meant the FETs. The same answer applies, though. It's going to be tough to get a sink to stay on them and transfer the heat from the FETs into the sink. Normally, you need to have big areas of copper on the PCB as Ed mentions.

OK, I had to make a good number of assumptions to narrow down to these, but here is a comparison of likely inductors that could be used. I used the 10uH criteria from the one known 2301-V-RC, approximate size, RoHS compliance, physical appearance, etc. to narrow to these parts. It should be of no surprise that they all ended up being Bourns inductors like the one known part, and they are all similar other than being different physical sizes and having different current capabilities.

I do not know if any of these are actually being used other than Tom's board that has the part number shown.

1-Fixed Inductors Inductors, Coils, Chokes DigiKey - Google Chrome 11102015 94609 AM.jpg

Looking at the pictures, I would estimate that the 0.860" diameter part (2101-V-RC) is likely similar to the smaller inductor. That would put it around 11A current rating, and just over half the capability of the larger inductor on Tom's board. The peak current in the inductor will be higher than the output current, but I haven't done the calculations.

So now we have to entertain the idea of the inductor failing under normal conditions, regardless of the two switching regulators. On every photo of catastrophic failure I've seen at least one of the regulators as literally fried or exploded. Did the heat from the coil cause this, or vice-versa? I don't fully understand the conditions if one regulator fails, but I would assume it would be working quite a bit overtime to compensate?

Q20 and Q21 are the hi and lo side FETs, not two regulators. Judging by the heat damage on the board, my theory is that it is the inductor is generating the bulk of the heat, and it's getting hot enough to desolder the transistors. The transistors do not look to me like they are all that damaged, and the board doesn't look as bad on the side of the transistors that is opposite the inductor. I can try to get back in there and measure the transistor temps tonight. I'm also curious about how much current is typically being pulled from the 12V source.

NOTE: If you have any mods connected to the 12V source, they are making the situation worse.

If Q21 fails short, you basically end up with 24V on your 12V output. If it fails open, you have no 12V, like a fuse blowing.

If Q20 fails short, the current sense should kick and and use Q21 to shut things down. If it fails open, I think it would limp along in discontinuous mode, which would generate more heat due to inefficiency.

this all just seems scary. Hope jack does something about this.

I use the re-usable insert, takes a whole 30 seconds to wash it out. When I went to get a new Keurig with the ability to make multiple cups I found it does not have that option, when I spoke to customer service they said they had no plans for it and I said, then I have no plans to buy one.

Companies want a throw away world, instead of something lasting years and being repairable, you are forced to replace it every X years. For most things worth under $200 almost always cheaper to buy new then to have someone repair it.

I was trying to figure out the maker of the inductor shown in Danisme's Picture on page 1 of this thread. As was mentioned, it appears to have a dual conductor thereby not only sharing the current load through two separate windings but also providing 4 solder joints instead of just 2. If the 2301 is 10 amps with a single conductor, the dual winding should carry considerably more even though the inductor body also has to deal with dissipating the built up heat from both windings. It appears most if not all of the boards have dual through hole pads for this type of inductor.

I am still scratching my head as to why they abandoned the use of an off-the-shelf ATX power supply. There were certainly a number of high quality UL listed ones to choose from and they could have made sure they were ball bearing fan for long life expectancy. A 430 watt Thermaltake I have on the shelf has 12 volts at 18 amps. Along with 5V@30A. I believe most intel/amd motherboards use the 12V for the CPU core voltage regulators. IMO, other than the SSHD and case fans, they should not have used that 12V source anywhere else on the machines.

I don't drink coffee but I love our Keurig. Its better than my wife spening $5 a day on a cup of coffee from Starbucks.

Ahhhhh, that just went click in my head. My former game (Oct 13) didn't have the Unified Power board. I had looked at pics of my game and couldn't find exactly where that part was. So some WOZ games don't have the same issue. Does anyone know when they switched over to the Unified Power Source?

And I agree with others, this should be replaced proactively by JJP. Building pinball machines is harder than I ever thought.

Seems like these inductors still are not standardized. My game manufacture date is 11/6/2014, with rev 3 board with a date of 10/29/2014. The inductor is different than TomGWI's picture, he posted his game manufacture date is 2/5/15, board rev 3 date 11/26/2014. So here are 2 rev 3 boards with different inductors, so are they changing on the fly, or re-working boards or what? Mine has no sticker on it.

IMG_2616.JPG

472363.jpg

Is yours using both through holes in the PCB (dual wire)?

I couldn't find an off-the-shelf one wound like this either. The closest I came was a hobbyist website with instructions on how to wind your own. The fact that they had holes in the PCB says they had considered this type of inductor from the start, though. Maybe I'll ask our power supply guru at work.

I feel like I'm harping on the subject, but it has really struck a nerve with me. It's an issue that I feel is dangerous, JJP apparently knows about it, and they have decided to keep quiet about it. If the inductor is all that has changed, it's a $3 part and about 15 minute job to swap it.

Just sent a ticket in asking if there is a specific manufacture range or known issues. My board appears OK right now, but I wanted to know if there is a risk, and if so, are they replacing the boards.

Wish they did indeed keep the off the shelf power supply. Great for service as you can buy a replacement at your local PC shop.

I've got 2 Woz machines. My original with the atx style ps has been fantastic. My other woz with the multi ps has had considerable issues, but with the updated power supply it's been quite a bit more reliable now.

I'm even using an off the shelf monitor in one of my games as its on location. I find all commercial grade monitors lowsy for reliability, expensive and their warranties are short. For about $150 I installed an off the shelf PC monitor with a 3 year warranty. Can't complain about that.

The idea of having a machine that can go up in smoke at any moment is unsettling. I realize the box will contain the fire, but I can't stand the smell of electrical fire. The smoke permeates everything and takes a long time to go away. This game hardly gets any use at my house and this makes me want to turn it on even less. I really want to resolve this problem even if I have to install a properly sized choke myself.

As for the rev level, it appears that rev 2 and rev 3 are major revisions and minor revisions might have been captured in individual work orders. Hopefully JJP has a proper quality management system to be able to track exactly what parts were installed on what boards. Otherwise this will make a factory recall even more difficult.

In my mind JJP should be providing new boards to every affected game regardless of whether they are beyond warranty or not the first owner...

Here is mine. Looks like Rev 3 with a small coil.

20151110_141817-1.jpg

Yes.
image2 (2).JPG

I forgot to mention in the first post that I measured the temperature at 68C after 1 hour in attract mode with the cover on.

Another oddity that I noticed but never really thought about until this inductor talk, is that on the cover of my box, there is a label that says "L9 - Inductor". I've always seen it, assumed it was a label to reference to drawings. The fact that it says "inductor" wouldn't be correct to describe what's in the box, but I had no reason to think about it any further. Thinking now, maybe this indicates what type of inductor is inside? Maybe they were doing a test of different types? Pure speculation and a wild guess on my part, but I hadn't notice this label in other folks pictures. The label is not glossy coated, more like your hand-held labelmaker type.
image1 (2).JPG

Great observation louvnj. L9 is what danisme said in his thread.

Just a guess here but I am thinking that anyone that has that "L9 Inductor" decal on their metal box has the dual wound coil. An obvious way for JJP to identify units that have been modified/upgraded.

Not to bring up bad memories, but this probably goes double for you.

Dumb question: why didn't JJP use an off-the-shelf PC power supply? If the board really is $350, what's special about it? I did say it's a dumb question!!

There are some odd voltages in there like 7.5 that I don't think would be in a PC power supply. On the other hand L9 is in the 12v circuit, so it would not be too tough to put in a separate power supply and pull the fuse on this one. It's just hard to believe that JJP had trouble designing a 12v supply in this day and age. They really need to do something about this.

12v.jpg

$$$ and inventory. To bulk replace you gotta buy a big run of kit... and spend the time and $$ to do swap outs. Just like the LED boards.. its cheaper for them in the cash outlay department to deal with them as they come.. instead of spending a bunch of money up front.

my 75RR has the L9 inducer sticker also. the board is a rev 3 11/6/2013 and the sticker on the "donut" is 301-v-ro-1429
mine is also different than louvnj as it is soldered on opposite sides and is green and blue in color

i just re-read his post, mine would be a single wire as it has half as many windings

I can't keep track of this---how many different inductors were they using?

Another set of measurements I took this evening:

Q20 - 73C
Q21 - 64C
L9 - 126C

So, for a non-technically inclined pin enthusiast who is thinking about getting a standard WOZ sometime next year, do I need to worry about this, or are the ones they are manufacturing now coming with the larger part that doesn't get so hot? This thread alone is making me reconsider what's the next pin I should get.

I'm pretty sure all the new ones are fine.

Now that I think of it during the big LED craze JJP had technicians replace the LED power supplies on some games. If this board powers the new LEDs, maybe the design of the 12v circuit was a bit rushed.

Exactly. They had to have 7.5volts for the updated LED boards, so I guess the figured it made sense to go to this all in one p/s board.

As a side note, I just put in a trouble ticket at JJP and asked for instructions on trading my board in on a new one.

There are only 2 that have reported the smoking WOZ that I know of. Of course that's just from Pinside.

...so you're saying it's a fire hazard?

...and you shouldn't feel that way. I haven't went back to read your comments, but I don't remember you ever saying that there was a design mistake or that it was a hazard. I take that responsibility on myself.

I've read LTG's response on the other forum, and I understand his position. He doesn't say whether it's also the position of JJP. I have the utmost respect for Lloyd's experience, but in this case, I think he's making a mistake.

Is it likely that it will cause a house fire? Probably not. Is it a big design blunder? In my opinion, yes. The circuit is obviously overtaxed, and the protections (fuse, current monitor) are inadequate. As an Engineer, it bothers me to see this sort of problem, especially with a known solution, go unresolved.

Is it "super rare"? In this thread, we have identified 5 cases of failure. Without knowing real numbers, I'm going to estimate 500 machines with the small inductor based on the number of machines built during the time frame after the ATX supply and before the problem was identified. That's 1%, and I'm sure there are more. Further, I believe ALL of them are being run out of spec, and it only gets worse the longer they are run. There will be more failures.

I know of two other failures on games I've serviced (although not for this issue). They haven't been mentioned on Pinside.

Simple problems like a switch not scoring, coil stop falling off etc? Or, something more serious that could possibly negate a UL rating?

So would this type of a change, removing the atx power supply and going to a different single board design for power require new UL testing?

No, nothing else that was as serious as the inductor failing.

One is a location game, so typical stuff like switch adjustments, flipper issues, tweaks, LED issues. When the inductor failed on this one it was pretty spectacular. Took out the mobo, the display board, and monitor.

The other was a RRLE and I can't remember if the inductor failure took out anything else. Service work on it was just installing Cliffy protectors and a few tweaks such as the lockdown bar not latching, switch adjustments, etc.

Are you saying all of these things were destroyed as a result for the failure?? That's incredible! What probably happened was this:

All I know is the inductor failed. All the other components were replaced after that failure in order to get the game going again. They all worked before the failure.

Mentioned before I have 2 woz machines. The original one with the atx power supply also came equipped with 7.5v led boards. So I'm not sure how the atx handles them, but it does.

Maybe the new boards are backward compatible with 5v. I talked with one of the engineers a year or two back and they replaced the power supplies along with the new boards because IIRC 5v wasn't enough to activate some kind of voltage regulator in the new boards that would prevent failures.

This happened to my machine a few weeks ago. I called the distributor I purchased it from and they came out and replaced the power supply, the motherboard, and some part of the LED screen too, although it was working fine at that point. It was pretty disturbing to come home to that weird burning plastic smell (I'd left the machine on while I ran errands, since I don't like to turn it on and off multiple times in one day) and a dead machine, but at least the fix was easy.

That was the LCD controller which also runs on 12v.