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(Topic ID: 257799)

F-14 column 7 of the switch matrix is dead


By GoneFishinLvMsg

11 months ago



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  • 29 posts
  • 6 Pinsiders participating
  • Latest reply 39 days ago by Brewchap
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#1 11 months ago

This column is mostly the upper targets, and none of them work. When I pull connector 1J8 and measure voltage at the pin, I get only 3 volts. All of the other pins are at 4.8V, so something is obviously wrong with the board. Do I replace the transistor or something else?

#2 11 months ago

Open up the manual and go to the switch matrix chart and see if those switches your talking about are in the same row going across.This will help narrow down the problem.report back

#3 11 months ago

They are in the same column, which is Column 7. Collector of Q42 is at 3V relative to the Emitter (GND). The Base is also at 3V versus less than .2V for all of the column transistors, which makes me wonder if U40 could be bad.

#4 11 months ago

The board was professionally repaired and tested by CoinOp Cauldron, and it worked fine for a few months.

#5 11 months ago

I always just replace the small transistor first and see if that gets it. Don't start with an IC further upstream, always start with what's closest to the playfield... I.E. the most likely things to fail.

It's more likely a trace or smaller component rather than an IC.

#6 11 months ago

Ok switches have nothing to do with transistors.Lift up playfield and start with the first switch in that column.Look for a loose wire on those switches going upstream

#7 11 months ago
Quoted from pinmike:

Ok switches have nothing to do with transistors.Lift up playfield and start with the first switch in that column.Look for a loose wire on those switches going upstream

100% wrong. The small transistors for each row and each column are listed in every system 11's switch matrix (manual). DE boards are of an identical design.

#8 11 months ago
Quoted from snyper2099:

I always just replace the small transistor first and see if that gets it. Don't start with an IC further upstream, start with what's closest to the playfield.

I will do that. I have spare transistors and 74LS244 chips. I just wanted to get some opinions before tearing into it.

#9 11 months ago

Dude, re-read my first post. I unplugged the connector. Playfield is not connected.

I'm going to go replace Q42 and will report back.

#10 11 months ago
Quoted from snyper2099:

100% wrong. The small transistor for each row and each column is listed in every system 11's switch matrix (manual).

Shit I keep getting WPC and system 11 mixed up

#11 11 months ago
Quoted from pinmike:

Shit I keep getting WPC and system 11 mixed up

Hey, everyone was there at some point. I still learn new things every day on Pinside. It beats getting into the drama of the other nonsense threads.

Also, this game is fresh on my front burner since I am gathering parts to build one, starting with just a populated playfield.

I always feel weird about projects like that... feels like I am cheating on the day I add it to the "my collection" page.

#12 11 months ago
Quoted from snyper2099:

Hey, everyone was there at some point. I still learn new things every day on Pinside. It beats getting into the drama of the other nonsense threads.

Ha? It’s weird every time I see the words “switch matrix” WPC always comes to mind

#13 11 months ago
Quoted from GoneFishinLvMsg:

I'm going to go replace Q42 and will report back.

The times that this has come up for me, this resolves it around 75% of the time. Hell, sometimes you pull the board and see that a leg just broke... out it comes anyway and I always just put a new one in there. Part is less than $1.

#14 11 months ago
Quoted from snyper2099:

The times that this has come up for me, this resolves it around 75% of the time. Hell, sometimes you pull the board and see that a leg just broke... out it comes anyway and I always just put a new one in there. Part is less than $1.

I thought I had some, but apparently not. I wish the rat shack down the street was still open. I'm going to look at some of the other miscellaneous boards I have laying around to see if I can steal one from somewhere. I parted out a GL a while back and have a lot of System 11 stuff from that.

#15 11 months ago

Replaced the transistor, powered it up and the switches worked, but they were activating the whole row. Checked the transistor and had very low resistance between both the base and emitter and the base and collector. Should be around 6-7k from what I could tell on the other ones. So I changed the transistor again. I got almost a full game in before the same thing happened. Something is causing that transistor to pop. Could it be U40???

#16 11 months ago

Saw this in the System 11 Club thread. I guess I need to go through all the wiring and look for shorts.

Quoted from Tomass:
Ok, I see why I ended up with 2n5550's and not 2n3904's. The 11c board has the 2n5550 transistor on q42-q49 but the 11a has the 2n3904 transistor in that same spot. Seems like it is the same but higher rated voltage, but that is only from reading other posts. I would think it will work since it is in the 11c board and perhaps even an upgrade? Am I wrong?
Thanks for any input

Exactly. It's functionally the same transistor, but it doesn't blow up instantly if a higher-voltage wire accidentally touches its circuit due to a fault on the playfield. Just a little more robust, and a slight bit of insurance against ignorant folk working on the game with the power on.

#17 11 months ago
Quoted from GoneFishinLvMsg:

Something is causing that transistor to pop. Could it be U40???

Doubtful, more like the EOS switch shorting to the lane change switch.

#18 11 months ago
Quoted from GRUMPY:

Doubtful, more like the EOS switch shorting to the lane change switch.

EOS for the upper flippers? They look fine. I checked the entire length of the wire for column 7 and can't find any evidence of shorting.

#19 11 months ago
Quoted from GoneFishinLvMsg:

EOS for the upper flippers?

There are no lane change switches on the upper flippers. You need to look at the lower right flipper.

As a test you can remove the white wire from the right flipper lane change switch and insulate it. Replace the transistor and play some games.
sm (resized).PNG

#20 11 months ago
Quoted from GRUMPY:

There are no lane change switches on the upper flippers. You need to look at the lower right flipper.
As a test you can remove the green wire from the right flipper lane change switch and insulate it. Replace the transistor and play some games.[quoted image]

My problem is with Column 7 though, not Row 7. That's the upper pf "TOMCAT" switches, Line of Death, and Top Left loop. Nowhere near the lower right flipper.

#21 11 months ago
Quoted from GoneFishinLvMsg:

. Nowhere near the lower right flipper.

Your issue is on the green/blue wire, correct. Look on the right flipper lane change switch, is there a green/blue wire?

#22 11 months ago
Quoted from GRUMPY:

Your issue is on the green/blue wire, correct. Look on the right flipper lane change switch, is there a green/blue wire?

Green/Violet. Q42 is blowing. Column 7 is on pin 8 because of the key.

#23 11 months ago

I meant to say white/violet which then connects to the Top Right Loop switch which has the green/blue wire. Its passed my bed time.

#24 11 months ago

Still have this problem. Grumpy, are you saying that something is shorting to white/violet, which is wiping out Column 7 whenever the Line of Death switch is active? Why wouldn't this affect any of the other columns?

#25 11 months ago
Quoted from GoneFishinLvMsg:

Grumpy, are you saying that something is shorting to white/violet, which is wiping out Column 7 whenever the Line of Death switch is active?

Yes, I realize this seems very remote. But to pop Q-42 so many times there must be high voltage getting on column #7. The most common way for this to happen is the EOS switches.

Quoted from GoneFishinLvMsg:

Why wouldn't this affect any of the other columns?

Could be that your holding the left flipper up so the the line of death doesn't go SDTM when this switch is triggered.

Cut and insulate both white/violet wires from the EOS (lane change) switches, replace the transistor and test. It's worth a try!

#26 11 months ago

I disconnected white/violet from both flippers and got several games in, but alas, Q42 eventually blew.

#27 11 months ago

Well crap!! How about posting a pic of each of the switches in column #7.
Maybe something will jump out to everyone who watching.

9 months later
#28 54 days ago

Having some issue blowing Q42. Did you figure out what was blowing your Q42?

2 weeks later
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