(Topic ID: 218717)

F-14 Tomcat Power and Switch issues


By atrainn

1 year ago



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  • 42 posts
  • 5 Pinsiders participating
  • Latest reply 1 year ago by atrainn
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#1 1 year ago

Hey guys,

I'm relatively new to system 11 as this is my first one so sorry if these are dumb questions! I'm having a couple of issues with my F-14 Tomcat that I can't seem to figure out, I was hoping to get some ideas here.

1. I get occasional resets where the LEDs dim and the game will reset and come back to life. I've tested 12v on the main board on the "12v Unreg" point and actually get anywhere from 7-10 v off of it, so I'm assuming something is wrong with the psu board. I've ordered a cap kit because of this and hopefully it'll fix it, but cannot find the high voltage kit that Great Plains sells and has had out of stock for months. Any ideas on where to find that?

2. A couple of my switches are being very lazy (though I'm not sure if there's a better term for it). Basically the right center switch the ball drops into (pictured below) after being launched will sometimes just sit for 5-10 seconds before actually doing anything. Could this be power related, or something else? The switch works and I have tested it. I tried replacing the CPU epromms for the hell of it just to see if it was something weird with the cpu.

3. The other switch doing this is the gutter switch, the ball will just sit in the gutter sometimes for 5-10 seconds before moving onto the next ball. I have also verified this switch works.

4. The final thing I've noticed is that one of the ceramic resistors has fallen off of one of the lamp driver boards. Do I even need to fix this if I've switched to LEDs?

Thanks for any help!

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#2 1 year ago

1) What other switches are being lazy? Identifying this could help isolate the problem by using the cross matrix diagram.
2) What resistor fell off and on what lamp board? Pic would help. Not sure if you are describing a warming resistor. If it's warming resistor and you replaced your 89s (FLASHERS) with LEDS then no, you dont have to put it back. In fact, you are suppose to remove them all if you run LED'S in your flashers or else they will not function properly.
3) What do you mean it resets itself? Do you mean its "tilting"?

#1 & #3 sounds like you have a bad diode on a switch somewhere under the playfield allowing current to run back onto the "tilt" circuit.

#3 1 year ago
Quoted from RetroToys:

1) What other switches are being lazy? Identifying this could help isolate the problem by using the cross matrix diagram.
2) What resistor fell off and on what lamp board? Pic would help. Not sure if you are describing a warming resistor. If it's warming resistor and you replaced your 89s (FLASHERS) with LEDS then no, you dont have to put it back. In fact, you are suppose to remove them all if you run LED'S in your flashers or else they will not function properly.
3) What do you mean it resets itself? Do you mean its "tilting"?
#1 & #3 sounds like you have a bad diode on a switch somewhere under the playfield allowing current to run back onto the "tilt" circuit.

1. It's just these two switches.

2. The attached photo is the board that had the resistor fall off. It was a 10w 330ohm ceramic resistor (the same one on the bottom of the board in the pic). The actual location of this board on the playfield is the right side of the playfield, about midway up, but I can get more info if need be after I get home tonight. I wasn't aware I needed to remove all of these when I moved over to LEDs, so I can take care of that this weekend. It sounds like after my Googling that the one I need to remove from all the boards is actually the one that fell off.

3. I don't think it's a tilt reset as all the lights dim when it resets, but I can play with it some more tonight and test it out. Basically I'll be playing and the audio will stop and the lights will dim, then a second later it'll go back through the startup and go back to normal operation.
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#4 1 year ago

1)That is a warming resistor that fell off. You only have to remove the two outside ones on each board. These resistors warm up the incandescent bulbs for the flashers so that they can flash on and off quickly. However with LEDs, the resistor being on there will cause flashers to stay on or act funny because its supplying small current to it and LEDs dont need much current to illuminate, so they need to be removed. You can always desolder one leg if you want. But you definitly dont have to put it back if theres and LED there.

#3 definitely sounds like a tilt. Play it tonight. Pull the glass off and try holding down both flipper buttons and touch every target on game and every wire switch including any ball gates. Put your hip one flipper button and hand on the other and hit every switch/target on the playflied. Its a easy way to load test it and isolate the problem. if it resets, you have a bad diode under the playfield tripping the tilt circuit causing this "reset".

#5 1 year ago

Mine did the same thing and it was a bad diode on the flipper switch. See pic

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#6 1 year ago

Ah thanks guys. I'll test out all the switches and see if I can track down a bad diode. I found another post that references src6 as a failure point that can cause resets, so I'll look into that as well. Looks like I need this guy to do that fix: https://www.digikey.com/product-detail/en/4610X-101-102LF/4610X-1-102LF-ND/1089168

As for my 12v levels, that does seem very low, right? Is there a better area to probe for values instead of the 12vunreg point on the main board?

#7 1 year ago

ahhh, I see now. Says it right in the schematics, cant go below 10.5v or you get intermittent reset ...

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#8 1 year ago
Quoted from RetroToys:

ahhh, I see now. Says it right in the schematics, cant go below 10.5v or you get intermittent reset ...

Well shit...totally missed that! Recap it is haha. I'll still test the diodes tonight. Hopefully it isn't an issue with the transformer as that'll become a far more expensive fix....

#9 1 year ago

I went ahead and removed the warming resistors (well, removed the ground from all 7 boards), the lighting on the game is much different now haha, I hadn't realize some of the flashers were not supposed to be on when they were on.

I've tested a few diodes in regards to the lazy switches and haven't found any bad ones but i went ahead and replaced the diode on that specific switch and have not seen the issue yet, though it could be a coincidence so I'll keep trying it.

I've also started noticing an inconsistent issue where the first ball will have no audio, it's quite strange... I'm not sure what's going on there. Hopefully it's just a power thing and the cap kit will fix it. If not, maybe time for new sound epromms?

#10 1 year ago

So I feel like an idiot...the gutter lazy switch wasn't actually lazy. The spring pulling the kicker back actually was disconnected so the balls couldn't reliably hit the switch. I couldn't figure out where exactly it connects to, so I sort of rigged it. It works now, but does anyone have a picture of the gutter kicker assembly so I can see where the spring goes? I couldn't find anything when googling.

#11 1 year ago
Quoted from atrainn:

I've also started noticing an inconsistent issue where the first ball will have no audio, it's quite strange... I'm not sure what's going on there. Hopefully it's just a power thing and the cap kit will fix it. If not, maybe time for new sound epromms?

Is it the first game after power on? It is possible to start a game after power on but before the sound board has booted and given the 'bong' indication.

#12 1 year ago
Quoted from gutz:

Is it the first game after power on? It is possible to start a game after power on but before the sound board has booted and given the 'bong' indication.

Yes it is! Interesting, I didn't know about that.

1 week later
#13 1 year ago

So I recapped the PSU and then started seeing constant blowing of fuse F5. I broke out the manual to take a look and saw it's supposed to be a 7A fuse. The previous owner had put a 1/4a on that spot. So once I switched to a 7a it ran as expected. I haven't seen a random reset since doing this + the recap. So everything now appears to be working as intended!

2 months later
#14 1 year ago

Sorry to bump this...but I guess the recap didn't actually fix it and must have just been coincidental. I continued troubleshooting and just replaced the 2N6057 transistor and yet the resets keep happening. I managed to get a video of it happening, it happens right around 25 seconds:

The game reboots abruptly. Is there anything else I should be testing? At this point I may just order a rottendog psu.

#15 1 year ago
Quoted from atrainn:

The game reboots abruptly.

Check for broken diodes on the left flipper coil, or just replace them.

Quoted from atrainn:

Is there anything else I should be testing?

Voltmeter on the five volt signal test point on the cpu board, then play a multiball while keeping an eye on the meter. Does it drop below 4.85 volts?

Quoted from atrainn:

At this point I may just order a rottendog psu.

I wouldn't, not made to last as long as the original p/s.

#16 1 year ago

So I went ahead and replaced both of the diodes on the left flipper, I haven't seen a reset yet, so that's something. One thing I failed to mention in the last comment is that my +12v is still very low after replacing the transistor and doing a cap kit. It comes in at ~9.5v coming out of the connector on the power supply, this is what I think is causing my resets but I'm not sure what else on the PSU should be replaced to attempt a fix.

#17 1 year ago
Quoted from atrainn:

+12v is still very low after replacing the transistor

The transistor makes +5 volts, has nothing to do with the +12 volts.

Quoted from atrainn:

It comes in at ~9.5v coming out of the connector on the power supply

This is normal.

Quoted from atrainn:

I'm not sure what else on the PSU should be replaced to attempt a fix.

D1, D-5 and BR1.

You should measure the 5 volts signal and I can help you better.

#18 1 year ago
Quoted from GRUMPY:

The transistor makes +5 volts, has nothing to do with the +12 volts.

This is normal.

D1, D-5 and BR1.
You should measure the 5 volts signal and I can help you better.

5v is holding very steady at 5.1v and did not dip below while I was monitoring it.

#19 1 year ago
Quoted from atrainn:

A couple of my switches are being very lazy (though I'm not sure if there's a better term for it). Basically the right center switch the ball drops into (pictured below) after being launched will sometimes just sit for 5-10 seconds before actually doing anything.

Did you figure this out? My friends F-14 is doing the same thing. Seems it is taking a long time to register in the switch before it kicks it out into play.

#20 1 year ago
Quoted from heni1977:

Did you figure this out? My friends F-14 is doing the same thing. Seems it is taking a long time to register in the switch before it kicks it out into play.

For me the switch issue ended up being due to a bad diode on the switch, after replacing it I haven't had it happen since.

#21 1 year ago
Quoted from atrainn:

5v is holding very steady at 5.1v and did not dip below while I was monitoring it.

If the five volts is good then one diode inside of the bridge rectifier is most likely open causing the low 12 volts.

#22 1 year ago

I've gone ahead and ordered a replacement bridge rectifier (GBPC3504L), fingers crossed...

#23 1 year ago

Well I got the replacement bridge rectifier tonight and uninstalled it. +12v still reads ~9.5 everywhere I test. I played for a bit and didn't have the random reboot happen, but even so shouldn't the 12v be higher? Even the manual states +12 being under 10.5v will cause issues. I'm not sure what else to try as at this point I've replaced every major part on the PSU.

#24 1 year ago
Quoted from atrainn:

I'm not sure what else to try

What do you get for AC voltage on TP3 and TP4?

#25 1 year ago
Quoted from GRUMPY:

What do you get for AC voltage on TP3 and TP4?

Not to sound like an idiot but where are TP3 and TP4? A few threads I've come across mention them yet I don't see them labled anywhere on my board nor mentioned in the manual.

#26 1 year ago

The only dumb question is the one nobody asks. On the power supply there 4 test points, 3 are grouped together just below the I'd label in my pic. These test points are labeled on the power supply schematic in the manual. Test point #2 is ground, #3 and #4 are + and - 12 volts.

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#27 1 year ago
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#28 1 year ago

Alright so:

Tp3: 9.11
Tp4: -14

#29 1 year ago
Quoted from atrainn:

Alright so:

Tp3: 9.11
Tp4: -14

Repeat test on AC setting.

#30 1 year ago
Quoted from GRUMPY:

Repeat test on AC setting.

Hm I can't seem to get a reading. It jumps all over the place, it might be because my multimeter is auto ranging without any sort of manual setting. Or I'm an idiot and testing it wrong. I can pick up a better one tomorrow to see if it's just my meter not adjusting properly.

#31 1 year ago
Quoted from atrainn:

I can pick up a better one tomorrow to see if it's just my meter not adjusting properly.

Give a different meter a try. Was it jumping around on both test points or just the +12 volts?

#32 1 year ago
Quoted from GRUMPY:

Give a different meter a try. Was it jumping around on both test points or just the +12 volts?

Both test points were doing it, I'm going to assume it's due to it not properly autoranging. I'll pick up a better one tomorrow and report back.

I also went ahead and ordered one of the Rotten Dog power supplies. If I still can't get this fixed soon then that'll at least tell me if it is the power supply causing the resets. At the very least it'll be able to serve as a backup once this one is fixed.

#33 1 year ago

Well this is strange, the new multimeter will briefly take an AC reading before dropping down to ~.2

TP3 = 12.2
TP4= -14.4

DC it also is getting a slightly higher reading on the 12v line at ~10.1. It also seems to be resetting more since replacing the bridge rectifier. I can't even get a full game in without a reset.

#34 1 year ago

This is ok. When you had the power supply out did you look for cracked header pins?
You can check the voltage at the CPU board to see if there is a voltage drop from the power supply to the CPU board. There can be cracked header pins on the CPU board too.

#35 1 year ago
Quoted from GRUMPY:

This is ok. When you had the power supply out did you look for cracked header pins?
You can check the voltage at the CPU board to see if there is a voltage drop from the power supply to the CPU board. There can be cracked header pins on the CPU board too.

Yeah, after seeing this AC fluctuation happen I'm wondering if it's the case. I'm going to replace all the solder on the connectors today and see how that goes. I'll order totally new headers as well and replace those if this fixes the issue, but for now I want to see if that's the problem so I'll at least reflow them.

On the plus side I've finally bought a True RMS DMM

#36 1 year ago

If there was a big AC signal on the 12 volt DC line this may indicate that the new cap you replaced is bad.

#37 1 year ago
Quoted from GRUMPY:

If there was a big AC signal on the 12 volt DC line this may indicate that the new cap you replaced is bad.

Thanks for the help so far. It's interesting that it has gotten worse after I replaced the BR as well. Either way I'll reflow all the headers today and see what happens. The Rotten Dog PSU should be here Monday so that'll tell me for sure if it's a psu issue, then once I fix the stock psu I can have the Rotten Dog psu serve as a backup.

Are there any parts on the CPU board that could be causing the reset, aside from a poor connection? If so, I can just proactively replace those as well.

#38 1 year ago

Well that's interesting, I replaced all the solder on the pin headers and now the voltage is sitting at 10.55 on +12 and -12.22 on -12. So that's better. So far no resets but I'll keep playing.

#39 1 year ago
Quoted from atrainn:

and now the voltage is sitting at 10.55 on +12

I thought you read 12.2 volts on TP#3. Where are you reading 10.55 at?

#40 1 year ago
Quoted from GRUMPY:

I thought you read 12.2 volts on TP#3. Where are you reading 10.55 at?

Sorry, this is DC voltage on TP3, AC voltage is unchanged. But now the CPU board 12v line is getting 10.5 as well, which is a huge change from the 9.1ish it was getting before.

#41 1 year ago

So with the new meter what do you read on TP3 for AC.

#42 1 year ago
Quoted from GRUMPY:

So with the new meter what do you read on TP3 for AC.

AC isn't any different with the new meter after reflowing the pin headers. There is an initial spike for less than a second, then the meter settles around .2 and -.3v respectively.

It does seem like a lot of the problem was due to a crappy connection, though I'm not sure if it's possible to get the +12v line closer to 12 rather than 10.5.

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