Hi everyone,

I just got an Evel Knievel and am not quite sure what to do next in trying to get it to work. I've looked through a lot of other pinside posts that seem to address some of these issues, but really, I'm not really sure what to do next. This is the first game I've gotten that didn't work when I got it, and I'm a bit of a beginner at fixing things of this nature.

The previous owner (less experience fixing machines than even me) had it for 10 years and he never got it to boot up, although he tried. He noticed corrosion on the MPU board from the battery that was there, so he replaced it with a new alltek board, and that's about it. When he turned it on for me, the red 5V LED light on the board stayed on. I repinned some of the J4 connectors after I brought it home, and it booted.

Then I did something stupid: I saw a stray wire next to a chime coil and assumed it cracked off in transport to my house. I hooked it on and booted up the game and got to play! It was 30 seconds of awesome: everything seemed to work fine, but I can't be sure. The game just stopped, and I realized that (a) I shouldn't have connected that wire (I later found the coil to be bad), and (b) Fuse F4 blew. So I unhooked that wire, put a chime coil in my shopping cart, and replaced F4. There is also a new black charred area on the solenoid board that seems to be limited to just stuff very close to the R10 resistor (I am not skilled at reading schematics, but this seems to feed one of the chime coils, so this at least makes sense to me).

Currently, the game boots, I can start a game (only the faulty chime coil unhooked. One other chime coil is disconnected, but the third chime coil is connected), but no solenoids work: not the chimes or flippers or pops or anything). During a game, you can manually touch targets and activate switches and the score will keep track of it. When I do the solenoid test, no solenoids fire. The switch test passes as well.

I made the following measurements at the following test points. I thought I had done these before my stupidity and that all of the measurements were what they were supposed to be, but I can't be sure of what it was before. I realize now I should have been more deliberate about keeping track of stuff like that, but like I said, I'm a bit new at this:

Test Point measurements at (original) rectifier board with all plugs in:

TP1 5.9
TP2 can't get a reading, possibly due to corrosion on the test point itself
TP3 14.2
TP4 6.4
TP5 44.5

Test points at (original) Solenoid board (that has the charred resistor) with all plugs in (except one chime wire pulled out):

TP1 5.1
TP3 5.1
TP5 14.4
TP6 5.1
TP7 5.1

While I've been trying to solve this problem, I've been doing an LED conversion, which I just completed today (I put in a new alltek board along with the LED bulbs). There are some lamp sockets that appear to need to be replaced, but I can't see how this relates.

From what I can tell, these are some things I could do:

--Identify all components on the solenoid board that fried and replace them. Or just replace the board. I've never soldered anything before--maybe I could try replacing stuff and if it goes badly, then panic and get a new board.

--I've read of a playfield solenoid fuse on Ballys that some (all?) EK were produced without. I can't locate this fuse, but all other fuses are intact, even the one on the solenoid board near the high voltage area.

--I don't think the measurements on the rectifier board are correct. I'm not sure how to test individual components on that (or any) board with certainty. Still, I could just replace that board too. Or, I'm wrong and those readings are fine.

--I'll get some practice soldering when the new chime coil arrives. All other coils tested fine.

My questions for you all are:

(1) I don't understand what the confluence of these problems mean. That is, do you experts out there see something about these symptoms that points to just one problem, or many unrelated issues? I get the sense that (with exception to the disconnected coils), that if I could just restore power to one wire feeding the solenoids, the game would work fine. (I've read posts describing a daisy-chaining of the solenoids, and I think I've found that wire, but don't know how to test it.

(2) If you were in my shoes, what would you do to try to solve the problem? I'm willing to solder components, but if you think this is too big a job for someone with my lack of experience, would you just replace the board(s) if you were me? Given these symptoms, am I likely to damage a new board unless I address some other issue?

(3) Is there something I clearly don't understand about diagnosing this that I need to learn?

So I appreciate all of your help, and I apologize for my lack of experience. I don't think I'm an idiot, but I know I have a lot to learn. Thanks for any suggestions.

PS--On a personal note, the posts that I've read on pinside are, for the most part, extremely helpful. This community of people is really (a) knowledgeable, (b) helpful, and (c) very, very kind! I'm very thankful that you all take the time to help others. I also recognize that this post asks about things that already appear in other posts. I started a new topic because I just didn't know if those posts related to these issues. Thanks again for any help.

Hi, thanks so much for the help. I'm attaching some pics. The first one is the solenoid board, complete with black charred area. Note that transistor Q5 appears newer than the others: I think tomdrum was right that this chime was disconnected purposefully. The coil probably failed, and someone figured out that they could still play if they replaced F4 and disconnected the chime. The next pic is the chime assembly. I believe the lower chime is bad (zero resistance between the lugs, and that's the one I hooked the wire I'm holding on to. In fact, I believe the wire I'm holding belongs on the middle coil.

The next pic is an oddity in the backbox I probably should have mentioned. The black and yellow wire I think is disconnected that relates to disconnecting the knocker. I don't know what the heck that other wire is. I've tried to track it down and think it comes from J3 on the solenoid. Judging by its length (and the black and yellow wire's length), I think it once was pinned into J1 on the MPU. I can't read schmatics well enough yet to know for sure, and I've learned from my experience of just plugging wires into places.

The next pic is the rectifier board, and the final pic is the displays. The displays are not LEDs (I don't think!), and there is indeed a fuse in every slot. The displays seem to work fine.

To provide more info from what was suggested:

--I still can't get a reading from TP2 on the rectifier board. I'm using a dmm with leads, and sometimes a number flashes briefly there... this number is about 190 (red lead to TP2, black to some ground). But from @rikoshay's suggestion, this sort of suggests that I just can't get a good reading.

--I finally found TP2 on the solenoid board, although I never found TP4 (where the heck is TP4???). The same sort of thing happened: the dmm didn't read anything most of the time, but there were brief flashes of about 196 or 198.

--When I push the power button I hear an immediate "click"--sometimes it's louder than others. But except for my 30 second fantasy game, the flippers haven't worked since, nor have any other coils of any sort.

So, @rikoshay, does this new information point to some sort of plan of action? As in: you believe that some components on the solenoid board are faulty that could cause this?

Finally, @tomdrum, I'm not sure how to test whether or not there is 43 VDC at any of the coils. I just went and turned on and started a game and put the leads of my dmm on the lugs of a random coil and nothing came up in any of the settings (except ohms: I got something larger than 3). I also understand that there is some trick where you ground a transistor briefly and this fires the corresponding coil, but I'm not sure how to do this.

I can safely say that nothing I typed above I knew anything about more than two weeks ago, and it's been fun to learn about it. I wouldn't have made it this far without great help, so thanks again.

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I see now that my pictures posted in an order I didn't intend, but the way it came out appears to be (1) backbox oddity, (2) rectifier board, (3) solenoid board, (4) chime assembly, and (5) the displays working okay. Sorry for the scrambled images.

Update to @tomdrum, I just tried the dmm with a black lead on a ground and the red lead on one of the lugs of a coil with the game on and measured 44.7 at every coil I tried. So maybe the issue is that there is not a connection from these to a ground?

Thanks @tomdrum, I had no concept that the knocker could be up there. Glad that isn't an issue here!

And I'll keep your rectifier board suggestion in mind, too. Thanks so much!

And it sounds like you're suggesting that a new SDB is in order... thanks for the suggestion!

@Rikoshay, you're right, the J4 connector is out right now. The 7th pin from the bottom goes to the bad coil, and instead of removing and leaving out that one wire, for now I just put it back and disconnect J4. I should say that I've pulled that one pin and put J4 back on and have had no change in what's happening. Do you think that this coil needs to be replaced and the J4 connector plugged in (with the now good coil wire attached) before something might change? Do you agree with tomdrum that the problem is in the SDB board somewhere and that just replacing the board will likely solve the problem (in addition to changing the coil)?

Thanks again.

Thanks to you both: It sounds like I'll have to decide if I want to bother replacing the transistor/diode/resistor in that area along with the bad coil, or just panic and replace the whole board (and coil). And, that the problem is likely to be resolved at that point. I guess I could give it a shot and then order a new one if it still doesn't work.

And @rikoshay, that link looks like some great reading, thanks!

Thanks, I'll try that as my first experience soldering anything (I find it hard to imagine me screwing it up too badly). While I trust the solution is a good one, I guess I still don't understand how this (replacing the SDB board) would allow all solenoids to work. My guess for why it would is that the damaged Q5 area is just keeping everything from leaving the board, so that grounding any solenoid is impossible, rather than it being possible to ground some (so they fire?) and not others?

Thanks for this, although I'm not sure that's where I traced the bad coil wire. I thought I had traced it to the J4 connection, 7th from the bottom (I'll have to go look at J2, maybe I traced it wrong. Although once I pulled the one in J4 it stopped shorting. I think your earlier suggestion is a good one: to leave that pin in and have all connectors attached, but disconnect it from the faulty coil. I'll be doing that anyway when I replace it, and it seems to eliminate an unnecessary confusion in trying to track down the issue.

I would hope so, too. My multimeter doesn't have a diode mode that I'm aware of, so that's something I'll have to go and get.

For what it's worth, from @tomdrum's comment about how the solenoids work in the first place up above, I discovered what I'm sure the whole world already knows and that is you just need to connect the solenoid circuit to a ground to get it to fire. So I connected each of the transistors to ground and found that a solenoid fired for all of them except for Q1, Q2, Q3, and Q5, Q6, and Q7. So I'm guessing that I'll need to replace (or at least be suspicious of) the diodes and resistors in that area in terms of what to replace.

Right, I think I may have been responding to you and tomdrum at the same time, sorry if I was confusing. I think I understand your comment: make sure that the faulty part is out of the circuit loop one way or another. With that component either replaced or removed, I might have been confusing by wondering why none of the solenoids would fire if just some of the corresponding components on the solenoid board are damaged.

I did go take a few more pics of the chime coils in question, you can clearly see the one coil wrapper burned. I tested resistance between the lugs on all three, and only the burned one appeared shorted.

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My apologies for a delayed reply: I had to go to my "day job".

I managed to get the burned coil out of the chime assembly and disconnect it from the game (I'll have to do that anyway), so I could plug in J2 to test the transistors. I'm attaching a pic of the removed damaged coil and the multimeter I've been using (the coil sleeve is jammed/melted in there pretty well. One of the pics is the current state of that chime assembly until I get the replacement parts. I inferred from earlier that the green wires give power to the coils, and the others are grounds. So I capped all of the green wires together to ensure that power gets to the remaining coils, however, the ground is removed from the middle one, and that and the other ground I put a cap on only to keep from them shorting anything else until I get more taken care of. That leaves only one coil "hooked up" in that assembly, and the other single chime I didn't mess with and appears to be connected properly.

So I turned it on (with J2 plugged back into the solenoid board) and was relieved to not blow F4, with the same symptoms: I can start a game but no solenoids fire. I retested the transistors by grounding the tops of them:

Q1, Q2, Q3: nothing (this makes sense from what you wrote: Q2 and Q3 aren't used, and Q1 must be one of the two chimes I disconnected).

Q5: still doesn't work, this must be the other chime I disconnected.
Q6: nothing except a faint click somewhere.
Q7: A chime sounds!

I should note that there is no chime sound at startup, although that chime sound could be one of the disconnected ones.

All of this tells me that I have the following plan:

(1) Replace resistor (R10), transistor (Q5) and diode (CR5) near Q5 on the SDB, and be suspicious of those near Q6 (CR6, R12, Q6, and possibly also R9 and R11, see (3) below).
(2) Replace at least the burned chime I removed (I redid the resistance test with it disconnected and got about 1-2 ohms).
(3) Q6 not firing seems to suggest that at least one other chime coil is malfunctioning, or, the components near Q6 on the board are faulty. So I'll disconnect the last chime in that assembly and test its resistance. If bad: replace. If good: consider the issue to be somewhere on the SDB board.

I almost forgot:

(4) Send a fruit basket to Rikoshay for their continued help and interest: this conversation was profoundly helpful in many ways. Once again, up until a few weeks ago I had never even thought about what those circuit boards do, and have at best a C- understanding of electronics... let alone have any idea how to diagnose or even fix issues.

I have some parts ordered (although perhaps not all of them that I might need! Thanks for the links above) and it'll take a little while to arrive. When they do and I get through my plan above I'll report back with the results. At the very least I hope this post helps others with my skill/understanding of this stuff who are having similar issues.

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Hi all,

I wanted to report that I figured out the issue, and it's because I'm an idiot: At some point before I replaced the blown F4 fuse (but after I repinned the connector on the MPU) I disconnected and removed the solenoid board to inspect it. I always put it back and plugged everything back in. I did it again today to look more closely at the board, not really knowing what I should be looking for, and when I put it back I realized that the J4 plug had been hiding and I had never plugged that back in the last time I had completely removed it. My focus was on the other connector and it never occurred to me that I had forgotten to plug it back in. In fact, Rikoshay even mentioned this but the chime issue took my attention away from it:

Thus, the chime issue was really a distraction to this issue and was separate (except for the fuse blowing). It's embarassing to admit it, but at least it shows others who may be reading this that these things can happen. I plugged J4 in and the game booted (including the chime, which I had set to ON--except only two chimes were hooked up), and I could actually play!

(The "middle" chime tested at around 50 ohms, so I hooked it back up and it works fine: I think its ground wire did get knocked (or cut) off somehow as I thought, but I had hooked it to the wrong (shorted) coil, frying the corresponding components on the board, if they weren't faulty already damaging the coil... it doesn't really matter what damaged what though. But at least this explains the final mystery.)

There are a number of other minor issues with the game, but I feel well equipped to deal with them: some corroded lamp sockets, and generally inspecting the rest of the now working machinery. I even feel that I can replace the fried components on the solenoid board and install the new chime coil that is on its way.

So thanks to everyone for "talking" it out with me. Even though the solution ended up being simple, just reading input from you all taught me a lot about what to look for and how these things work.