(Topic ID: 192751)

High Speed issues after having playfield out.

By FMonk

6 years ago


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  • 30 posts
  • 5 Pinsiders participating
  • Latest reply 6 years ago by GRUMPY
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#1 6 years ago

Ok, so I had the playfield out to work on the ramp diverter and relocate the stoplight, and it's good news, bad news. I figured out why the diverter kept sticking, a C-clamp had come off and was letting the bat slide further up than it should, which was causing it to get caught on the ramp. The stoplight looks great in the back left of the cabinet, and I don't have to worry about an airball knocking the case off any longer.

Unfortunately, now I've got a bunch of stuff that won't respond. The wiring didn't get kinked or squashed during the process, I was very careful about that. GI and flippers work in diagnostic modes, but a few switches seem to be affected, since the ball trough doesn't register (this causes the game to fire all coils to try and dislodge the ball, but the saucer is the only one that actually goes). I did run through the edge and switch tests, but IIRC, almost all of them worked. None of the coils/flashers affected share a transistor, am I right to be looking at the big plastic playfield connectors first? Until now, I had never disconnected any of them, and I'm wondering if they're not making good contact. I've tried reseating all connectors in the backbox and to the playfield to no avail. Everything was working great before this, and I feel like once I get this issue sorted and clean up the shooter lane, it'll be ready to bring in the house from the garage.

Thanks to the test mode, here's the list of what's not firing with their part numbers and corresponding transistor:

Outhole 1P11-1 8P3-1 Q33
Ball Release 1P11-3 8P3-2 Q25
Flasher 1 1P11-9 8P3-9 Q17
Flasher 2 1P11-6 8P3-5 Q31
Flasher 3 1P11-7 8P3-6 Q23
Left Hideout 1P11-8 8P3-7 Q30
Right Hideout 1P11-9 8P3-8 Q22
Ramp Gates 1P12-6 8P3-13 Q15
Kickback 1P12-7 8P3-14 Q7
Right kicker 1P19-4 8P3-18 Q71

#2 6 years ago

It looks like those have two connectors in common.

Take a look at them to see if they came loose or got unplugged.

#3 6 years ago

Thanks, that made me go back and look a little closer at everything. The common point for all of the affected components is the large connector as I suspected. They come from three different connectors at the CPU board level (IJ11, IJ12, and IJ19), but they all go through this monster 36-pin connector en route to the playfield. Specifically, all the affected components are on the same end of the connector making me think that it's just worn out and pulling it apart (it was difficult to get apart when I pulled the playfield) caused the contacts to no longer make a connection. I tried putting some contact cleaner on the ends and scrubbing them a bit with a toothbrush, but no dice. I suppose it could be something at the CPU board, but that seems less likely to me? I guess the next step is to jumper across this thing to see if they fire, but it's too damn hot and humid in my garage to work on this any more tonight :p

playfield_connector (resized).jpgplayfield_connector (resized).jpg

#4 6 years ago

You need to push the connector together all the way, it usually requires using a channel lock pliers on each side a little at a time until fully seated.

#5 6 years ago
Quoted from GRUMPY:

You need to push the connector together all the way, it usually requires using a channel lock pliers on each side a little at a time until fully seated.

I just tried that (it's cooler in the garage now), and while I got the connector tighter than in the picture, it didn't change anything.

#6 6 years ago

How about another pic of the connector.

#7 6 years ago

If you look closely, the two sides are slightly tighter than in the previous image, and it's not going to get any tighter. None of the male pins are bent or flattened, and as best I can tell, none of the female connectors have anything bent or jammed in them. It's the gray and brown wires on the one end that are the ones running to the affected components.

playfield_connector3 (resized).jpgplayfield_connector3 (resized).jpg

playfield_Connector2 (resized).jpgplayfield_Connector2 (resized).jpg

#8 6 years ago

Just for curiosity did you check for power on some of the coils.

#9 6 years ago

No, but that's something else for me to check. One thing I noticed last night is that in the test mode, the right kicker/slingshot doesn't fire, but if I manually trigger it with my hand or a ball, it does fire off, so at least some of the parts are getting power. I assume there's a disconnect between the test mode and the actual switch-to-coil reaction because (as I understand it) the kickers were designed to fire without CPU intervention for faster response time.

#10 6 years ago

Ok, feel free to treat me like the dummy I am since this is my first pin, I don't necessarily know how to work on these completely yet :p

If I test one of the nonworking coils for voltage, say the right kicker, I put a lead on each of the two legs and get zero VDC (even though I know it works because it fires if I trigger it manually). But if I test a known-working coil like the knocker, I also get zero VDC unless it's actively firing. If I put the game in test mode and have the knocker fire continuously, I get spikes of voltage every time it fires, which is what I expected to see. How can I test the voltage of any of these coils or lights if they aren't getting a signal to fire? Regardless, bad coils wouldn't explain why only three of the six flashers are working.

Someone did a hack job on one of the power board connectors soldering directly to the pins, but that's only for the GI power. I doubt that's the issue, but I have considered getting one of the modern replacements anyway to avoid potential power issues in the future.

Edit: I mean, I understand if this is just a troubleshooting diagnostic to see if the power is getting there but the coils are bad, I just want to make sure I'm not missing anything about how to measure voltage in pins.

#11 6 years ago

When checking for DC voltage you always reference to ground. So place the black lead under the ground braid. Now use the red lead to do the testing. If you check the red wire on the coil you should see a positive voltage. Then you can check the other wire for voltage and this will tell you if the coil is good or not.

#12 6 years ago

Yeah, ok, I guess my question was more that I shouldn't be seeing any voltage unless the CPU is telling something to fire, correct? When the game is in coil test mode and it fires the left kicker, I see voltage when it's active, but nothing when it's off. On the right kicker, which does not fire in test mode, I see nothing. However, if I trigger the right kicker with my hand, it goes off and I see voltage. This is normal, right (aside from it not firing when the CPU tells it too)?

Edit: I guess this is all still making me think that the big connector is to blame, but I want to avoid cutting into the wiring harness if I can help it. I suppose I could disconnect the plug at the CPU board and jumper each pin with alligator clips directly to the component and run the test mode to see if that causes it to work.

#13 6 years ago
Quoted from FMonk:

but I want to avoid cutting into the wiring harness if I can help it.

No one wants you to do this yet.

Quoted from FMonk:

When the game is in coil test mode and it fires the left kicker, I see voltage when it's active

When you place both test leads on the coil at the same time you will read the voltage that the coil itself is using when it is turned on. This is why you have no voltage reading when its not activated, because its not using any voltage. The is always power to the coils when the power switch is on unless you have a burnt fuse or a bad connecting. But you can't see the voltage until you use a ground reference for your meter. This is why you put the black lead under the ground braid. So far you have described a couple of different problems at the same time and you need to certain on how you are testing things.

Quoted from FMonk:

On the right kicker, which does not fire in test mode, I see nothing. However, if I trigger the right kicker with my hand, it goes off and I see voltage.

What you are describing here is a CPU board problem and not a connector problem.

#14 6 years ago

Did you remove the CPU during the PF swap?

#15 6 years ago

Duh, I just realized what you were saying, I was testing at the coil lugs, not on the grounding braid. Like I said, dummy who's only worked on vids before this :p Testing again and the coils that are still working have just under 30V, the ones that don't fire do not have power. No, I have not removed the CPU board, but I have reseated the connectors after it started acting up.

Other (probably?) unrelated things: One, I have a loose grounding strap in the head, it looks like it should be grounding the police light (not something I would expect anyone to touch during normal operation, but I want to make sure this is connected properly). And two, I just noticed that when the door to the head is closed, there's a humming noise, but not that loud. I didn't think anything of it until just now when I realized that it doesn't make the noise when the door is open. The displays and lighting all work either way, but when it's closed, there's a hum. I assume something is just picking up interference from the proximity to the rest of the wiring?

ground (resized).jpgground (resized).jpg

#16 6 years ago

You should use the chart or the manual to determine which fuse is responsible for the solenoids that have no power. Remove the fuse from the fuse holder and check the fuse with a meter, not a visual inspection.

As for your suspected connector problem, that should be easy to test. Machine powered OFF, With meter set to ohms, put one lead on the circuit on one side of the connector and the other lead on the other side of the connector. If you have zero ohms then the connector is fine. You can individually test the color wires you suspect are not connecting.

One more note on checking for power on a coil. You should have voltage from the ground braid to both coil lugs. Voltage is always present on both coil lugs and the coil is fired by the circuit taking one side to ground. That is why a shorted transistor will cause a coil to lock on as soon as the game is powered on.

#17 6 years ago

Oh yeah, I already tested all the fuses with my meter, they're all good.

#18 6 years ago

Then the next thing I would ck to see if there is voltage present on the test points on the board. Look for either a test post or a test loop that will be labeled with the +DCV you are looking for.

#19 6 years ago

I would check to see if you have power on the power supply J3 connector, check the red and the red/white wires on this connector to see if one of them doesn't have power.

#20 6 years ago

Also there is a single fuse holder in the back box under the flipper power supply for the L/R hideouts coils, did you check this?

#21 6 years ago

Power connector J3 has just under 30VDC on all the correct wires (all the 30VDC points I've tested have been around 29.7). The 5V test loop on the MPU is at 4.75, and the +/-12 at the power supply test points is +11.6 & -14.4. The -14.4 seems a bit to far out to me, but I don't know if that would cause major issues.

All the fuses in the head have tested good.

I'm thinking it's probably not a bad idea to get a cap/HV kit from Great Plains Electronics for the power supply regardless of anything else, since I don't think the previous owner did any work on it. Edited once more: except that appears to be out of stock...

#22 6 years ago

4.75 volts is too low and can cause CPU resets. Recapping the power supply may help with this. For now you still need to get power to the coils that are not working. Somewhere the power wire is broken, either the break is at the connector that you disconnected or you may have knocked a wire off when the pf was out.

#23 6 years ago
Quoted from GRUMPY:

4.75 volts is too low and can cause CPU resets. Recapping the power supply may help with this. For now you still need to get power to the coils that are not working. Somewhere the power wire is broken, either the break is at the connector that you disconnected or you may have knocked a wire off when the pf was out.

Those were my basic thoughts, cap the power supply and start the exciting process of tracing the wiring to look for breaks.

Also, the MPU isn't attached with as many screws as it should be, and I suspect this might be part of the hum I mentioned earlier. Is there a standard size for mounting hardware, or should I just take one of the screws down to the local hardware store to match?

#24 6 years ago
Quoted from FMonk:

I just take one of the screws down to the local hardware store to match?

http://www.pinballlife.com/index.php?p=product&id=237

Quoted from FMonk:tracing the wiring to look for breaks.

2 coils are on the purple/yellow wire, the rest I think are on a red wire. I would check P-4 connector to see if it is connected tight as you would have disconnected this too when you pulled the p/f.

1 week later
#25 6 years ago

Ok, I should have seen this coming. When I had the playfield out, I had disconnected the coil that runs the ramp diverter in order to work on that assembly. I forgot to reconnect it. Soldered that back together and everything works! This is always thing that screws me up, whether it's pinball, arcade, or computer repair... *sigh*

In my first test game, I lost all displays. I powered down, checked all display connectors and they came back. Alright, I was wiggling a lot of connectors while trying to troubleshoot this, so that was probably just a loose connection.

I also now have ghosting on some of the lamps that are LEDs, some faint, others pretty bright. For example, on the lower left stoplight bank, the red light almost always on, but not quite as bright as if it was 'on'. The 'Drive Again' between the flippers pulses along with the Freeway Scores bonus lights just above the flippers. A few other lights seem to be doing the same, but I haven't done a full inventory yet. This is a new behavior that wasn't present before all this started, and it doesn't happen in the attract mode. Some of the LEDs in the machine have always had a tiny amount of ghosting (like some of the indicators like ball in play or match in the backglass), but this is much more prominent.

I do have a bunch of parts on order to rebuild the power supply board (including the HV portion) to take care of those out of spec voltages.

#26 6 years ago
Quoted from FMonk:

I forgot to reconnect it.

Good find.

#27 6 years ago

That'll teach you to try and fix your pin!

I want to thank you for posting all your attempts and findings so well, it is really helping me to problem solve my machine! And of course all those that are responding

#28 6 years ago
Quoted from RonSS:

That'll teach you to try and fix your pin!
I want to thank you for posting all your attempts and findings so well, it is really helping me to problem solve my machine! And of course all those that are responding

No problem! It always drives me nuts when people fix something but don't post what the issue was, so I always try to explain what I did and how it went so people in the future won't have that issue :p

I just got a box full of caps, resistors, transistors, etc. in the mail, but who knows when I'll have time to get to that...

#29 6 years ago

So I forced myself to sit down yesterday and recap the power supply. I also replaced most of the HV components. Popped the board in today and everything is working fine, but my voltages at the test points haven't really changed. The 5V on the CPU board is now 4.8 instead of 4.75. The test points on the power supply board didn't really move either, but all game behavior seems to be working fine, so I'm not going to stress over it.

The ghosting LEDs stopped ghosting before I worked on the power supply board, and I did nothing to address that, so who knows. It has been hot af in my garage, so I'm wondering if that might have had something to do with it. All I have left is to clean up the shooter lane and I'll be bringing it in the house with AC, so that should help

#30 6 years ago

4.8 volts under load. What is it with the CPU disconnected?

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