(Topic ID: 322525)

F-14 Tomcat scoring points from left flipper. Not the switches.

By johnboy1313

4 days ago


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  • Latest reply 21 hours ago by johnboy1313
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#1 4 days ago

Hi everyone. I’m having an issue on my F14 Tomcat where, during gameplay, switch 55 (General Yakov) and sometimes (not as often as switch 55) also switch 47 are being triggered just by hitting the left flipper, switch 63. During gameplay, it happens very often. Sometimes every time you hit the left flipper. In test mode, it doesn’t happen at all for some reason. Ive tried for days to get it to happen in test mode. All three switches are on the same row in the matrix.

I originally suspected an incorrectly gapped switch that was making intermittent contact from vibration. I pulled switch 55 off of the bottom of the table and gapped it properly. The problem remains. I even disassembled the switch stack. There was absolutely no way that the switch could be making contact.

Even with the switch hanging from the table with an inch between the blades, the problem persists. Like I said above, in test mode, it doesn’t show that any other switches are being activated. I’ve tried test 5, switch levels, and test 6, switch edges. Once you start a game, it’s immediately obvious that something isn’t right. The first four or five times I hit the left flipper, it starts scoring points as if those other switches are being closed too. The sounds are activated and in the case of switch 55 for Gen Yakov, the kicker solenoid is activated too. After the first four or five flipper strokes, it happens every handful of times the flipper button is pressed. It seems to be connected to the lower flipper, not the upper flipper. If I push the flipper button gently enough to activate the lower flipper but not the upper flipper, the problem happens. If I hold the left flipper button in and let it out slowly so that the upper flipper is cycled but the lower flipper is held, the problem doesn’t happen.

I have a logic probe, a DMM, and a small o-scope. I tried looking at voltage through connector 1J8 pins 7, 8 and 9 with my meter. Pin 9 is the column with the left flipper. Pin 8 is for the column with the Gen Yakov switch. With my meter on C53 in the flipper circuit, the voltage is steady when the flipper activates and the General Yakov switch doesn’t. When the flipper is pushed and the general also activates, the voltage on the flipper circuit jumps a bit and then settles down after the General Yakov sounds are done playing. It does this when the general switch is physically closed and also when the intermittent issue is happening. I’m not near the machine right now so I can’t give any specific voltage numbers off the top of my head. I also tried my logic probe on U38 and U40 to see if I could see anything going high when it wasn’t supposed to. Unfortunately, every pin I checked stayed low while cycling the left flipper.

The fact that this is so intermittent is my issue. If it was a mechanical issue or a shorted transistor, I could find it and fix it.

I don’t think this is related to switches or the harness but I’m going to build a switch matrix tester to rule those out.

Do any of you have any other ideas? Ive attached a pic of the MPU schematic I’m working with and a link to the manual.

https://www.ipdb.org/files/804/Williams_1987_F_14_Tomcat_Schematic_Diagrams_manual_pages_51a_to_60a.pdf

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#2 4 days ago

Have a look at the lane change switch on the left flipper. Is that switch on the same column or row? Also diodes on those specific switches getting flaky?

#3 4 days ago
Quoted from chad:

Have a look at the lane change switch on the left flipper. Is that switch on the same column or row? Also diodes on those specific switches getting flaky?

I’m not sure what you mean by “lane change switch”. I went through every switch in test mode and made sure I found every one listed on the matrix chart. I checked the diode on switch 55 but no others. I will check the others in that row and those columns this afternoon.

Thank you.

#4 4 days ago

The lane change switches are listed in the switch matrix as "flipper EOS" - they don't mean the high powered end of stroke switches, there is a secondary switch on each flipper used for entering your initials if you get a high score. Make sure the outer low power switches on the stacks are not shorting to the high voltage end of stroke they should be isolated either with fishpaper insulator or a plastic piece.

Switch level test will never show intermittent/quick switches, it shows every switch currently closed in a loop. Switch edges would detect switches but it's really quick, and if it truly is 2 switch at the same exact time (relatively speaking) it will only show one.

There are some RC networks on system 11 boards in the switch matrix that sometimes go bad, worth a look. Seek out posts from DumbAss and GRUMPY they talk about this a bit.

#5 4 days ago
Quoted from johnboy1313:

I’m not sure what you mean by “lane change switch”. I went through every switch in test mode and made sure I found every one listed on the matrix chart. I checked the diode on switch 55 but no others. I will check the others in that row and those columns this afternoon.
Thank you.

You're right, there are no lane change switches on the flipper assembly. Just checked my spare playfield.

#6 4 days ago

They must be in the cabinet then.

#7 4 days ago

Your problem is probably a loose connection if it is intermediate problem. I had points scoring on my Mata Hari from a loose diode wire solder into a hole of a target switch. Solder was solid looking would not pull out or come off but the diode wire had separated from inside the solder. Finally found this problem when I had left the machine on most of the day then went to play it so you can consider the machine was pretty warm. The ghost scoring started when the pop target switch was closed and every time flipper was used scoring started. Pulled glass back and hit playfield and scoring would start. I hit the pop target housing and scoring would start this went on and could repeat it on demand for about a minute or two then it stopped. I started pushing on diodes when target switches were closed and it started scoring. Just a loose diode connection. This loose connection was so slight moving you would of needed a flashlight to see it move. I resolder the diode and problem stopped.

#8 4 days ago
Quoted from CircuitRich:

Your problem is probably a loose connection if it is intermediate problem. I had points scoring on my Mata Hari from a loose diode wire solder into a hole of a target switch. Solder was solid looking would not pull out or come off but the diode wire had separated from inside the solder. Finally found this problem when I had left the machine on most of the day then went to play it so you can consider the machine was pretty warm. The ghost scoring started when the pop target switch was closed and every time flipper was used scoring started. Pulled glass back and hit playfield and scoring would start. I hit the pop target housing and scoring would start this went on and could repeat it on demand for about a minute or two then it stopped. I started pushing on diodes when target switches were closed and it started scoring. Just a loose diode connection. This loose connection was so slight moving you would of needed a flashlight to see it move. I resolder the diode and problem stopped.

Thank you. I will check the diodes this afternoon. I appreciate your help.

#9 3 days ago

Well I’m unable to find any loose diodes on any switches from those three columns. I did find a broken 2.2k 250vdc capacitor on the left flipper. It looks like it’s just to limit the spark on the EOS switch. Hitting the table doesn’t ever activate the switches. It only happens when the game is in play and you hit the flipper button.

Is it possible that the PIA has an intermittent short internally?

#10 3 days ago

Scoring comes from a closed circuit which is sent to the mpu. I studied your schematics. Try this pull glass off and start a game with some points. Then lift up your right flipper with your hand and hold all the way up and then hit right flipper button and tell me if it scores points. I am going to try my best to help you. Be easier if I had hands on your machine but not possible.

#11 3 days ago

Then try it this with your left flipper.

#12 3 days ago
Quoted from CircuitRich:

Then try it this with your left flipper.

Thank you. The right flipper scores no points when holding it up with my hand and hitting the button or when I hit the right flipper button any time. The left flipper button does NOT score any points at all when holding the flipper up with my hand and pushing the button. As soon as I let it go and the coil takes over it starts scoring points almost immediately.

I just found the flipper section on the schematic. I’m going to look it over and see if I can come up with anything else to check out.

Thanks again.

#13 3 days ago

Now we’re getting somewhere And let’s stay focus on around the left side of under playfield. Before I like direct pics so when your holding up the left flipper up with hand pressing the flipper button does the flipper fall when you let go or does the the flipper twitch because coil is holding it up and scoring starts? Does it score any certain amount of Points or is it random number and keeps going when flipper is up?

#14 2 days ago
Quoted from CircuitRich:

Now we’re getting somewhere And let’s stay focus on around the left side of under playfield. Before I like direct pics so when your holding up the left flipper up with hand pressing the flipper button does the flipper fall when you let go or does the the flipper twitch because coil is holding it up and scoring starts? Does it score any certain amount of Points or is it random number and keeps going when flipper is up?

With the flipper held up with my hand and the flipper button pressed, the flipper holds firm when I let the flipper go but hold the button and scores NO points. If I let the button go and hit it again without holding the flipper, it scores 50,000 points when switch 55 is triggered and 1000 points when switch 47 is triggered. It doesn’t score points every time, but it happens more often than it doesn't.

#15 2 days ago

Here is what your going to have to do is put a piece of thin cardboard or business card in between all your high score target switches on your playfield. Keeping the circuit open and not allowing any voltage pass through the switch contacts. Do you know if the switch contacts are close enough without touching current can pass. If doing this stops the ghost scoring then one at a time using the left flipper button to activate remove the blocked switch contact one at a time till you remove the one that is giving you the problem. I studied your schematics well and the flippers get there power directly from power supply. They do not emit any source of current to activate scoring.

#16 2 days ago

So you know what switches are scoring too many points?

#17 2 days ago
Quoted from CircuitRich:

So you know what switches are scoring too many points?

Yes, switch 55 and 47. 55 is the problem most of the time. The ghost scoring happens even with that switch hanging from the bottom of the table with the stack disassembled and the blades an inch apart or with a piece of tape in the switch.

#18 2 days ago

Did by any chance you test the switch diode or diodes when you had the leafs apart? The diode acts as a switch allows current to flow one way. Guess what happens on a score switch when diode goes bad? It either shorts completely out or can allow voltage pulses to flow both ways. Diodes can either protect say a coil flipper solenoid or allow voltage to flow only one way on like a score switch. If a score switch sends pulses quicker than a blink of a eye. Which you end up with pulses floating in that circuit. Scoring a lot of points! Also you need to replace that transistor you said was bad it almost works like a diode but with higher current. When it goes it blows! Not 100% sure this is your problem but worth betting on. Oh yeah diodes do go bad!

#19 1 day ago
Quoted from CircuitRich:

Did by any chance you test the switch diode or diodes when you had the leafs apart? The diode acts as a switch allows current to flow one way. Guess what happens on a score switch when diode goes bad? It either shorts completely out or can allow voltage pulses to flow both ways. Diodes can either protect say a coil flipper solenoid or allow voltage to flow only one way on like a score switch. If a score switch sends pulses quicker than a blink of a eye. Which you end up with pulses floating in that circuit. Scoring a lot of points! Also you need to replace that transistor you said was bad it almost works like a diode but with higher current. When it goes it blows! Not 100% sure this is your problem but worth betting on. Oh yeah diodes do go bad!

Yes, checked all diodes on every switch in those columns and that row.

It turns out switch 31 is also ghost scoring. It’s a micro switch rather than a stack of leaves. I attached a picture of it. I don’t see a diode on that switch but I don’t see one on any of those three switches and the other two aren’t ghost scoring. All of the ghosting switches are on the same row.

So far, the only thing I’ve found out of sorts is that 2.2k 250vdc capacitor on the left flipper.

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#20 1 day ago

I will look even further later. Out of town this weekend. Some of this don’t make sense to me because of lack of years of experience of searching this problem out but I usually find it it just takes a while. But it makes sense that it does this in a string of target switches. Just multiples the area to find the problem. Sometimes it will act up you just have to eliminate problems.if you have original boards makes problem solving a little longer. See transistors and other semiconductors have electrolyte in them and after many years they dry up. If it is a old machine it is not unusual to replace rectifier, mpu and solenoid board. This cuts down on down time and problem fixing. I am sure you know this.

#21 1 day ago

Did you check the diodes on the flipper coil(s)?
If they are broken they tend to send voltage spikes up the wires which can cause all kind of induced interference.
When in doubt, just replace them anyway (5 cent part).

#22 21 hours ago
Quoted from Inkochnito:

Did you check the diodes on the flipper coil(s)?
If they are broken they tend to send voltage spikes up the wires which can cause all kind of induced interference.
When in doubt, just replace them anyway (5 cent part).

Yes, I checked them both.

Also, I pulled the green-violet wire out of the connector. This is for the column that switch 55 is connected to. It still scores switch 55 when it’s not even plugged into the board.

#23 21 hours ago
Quoted from johnboy1313:

No I haven’t. I will check them next. Thanks.

Also, I pulled the green-violet wire out of the connector. This is for the column that switch 55 is connected to. It still scores switch 55 when it’s not even plugged into the board.

#24 21 hours ago
Quoted from Inkochnito:

Did you check the diodes on the flipper coil(s)?
If they are broken they tend to send voltage spikes up the wires which can cause all kind of induced interference.
When in doubt, just replace them anyway (5 cent part).

I haven’t checked those. I will next.

Last night I pulled the green/violet wire out of the connector on the board. This is the wire for the column that includes switch 55. Even with switch 55 disconnected from the board it’s still scores points when you hit the flipper.

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