Switches on column 4 fire all other switches on column 4

David_Vi

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A new issue with Black Rose....

I adjusted the leaf switches on the pop bumpers and as far as I remember it worked ok. Today the pops weren't firing.

In test report it says check switch 46 and switch 47, (both are jets/pops).

If i activate any switch on that column I get a bunch of other switches in that switches row activated on the matrix with a "gnd short row 1" (with it changing to whatever row that switch is on.
Only column 4 switches do this.


Considering the last thing I messed with was the leaf switches for the jets I thought it must be that area. Ive studied the wiring to each leaf and nothing appears to be shorting out.

What do I check next? It surely can't be a coincidence?
Could it be a diode, and if so can fiddling around cause a diode to fail?

Update :
Pin was fine with new chip for about two weeks... Then last night went again.
Had another spare chip, which fixed it and game worked for a few hours but today has gone again.

Any idea how to find what's happening? I know this only started happening after i removed and adjusted the pops. But nothing down there seems to be shorting!
 

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Pick Holder

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You must of shorted from the lamp or solenoid power into the switch matrix.

Need to replace the ULN2803A chip on the CPU board.

Todd Tuckey calls this the 'fuse' chip. It is not really a fuse but it does stop any damage to the rest of the CPU board.

It is the ULN2803A near the middle at the bottom of the PCB.

Think it is U20 but cant swear on it.

You may also notice this has previously been socketed (most have over the years).

You are not the first to do this - or the last!
 
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David_Vi

David_Vi

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You must of shorted from the lamp or solenoid power into the switch matrix.

Need to replace the ULN2803A chip on the CPU board.

Todd Tuckey calls this the 'fuse' chip. It is not really a fuse but it does stop any damage to the rest of the CPU board.

It is the ULN2803A near the middle at the bottom of the PCB.

Think it is U20 but cant swear on it.

You may also notice this has previously been socketed (most have over the years).

You are not the first to do this - or the last!


Yup.
I swapped the u20 with one from road show and its ok now.

Well another lesson learnt 😂
 
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David_Vi

David_Vi

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So cheap to replace. I spend more money on shipping these days. Frustrating.

90p for the chip. £3.95 shipping 😆
 

Spandangler

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David. Jim @myPinballs used to sell these. I bought a tube of about ten, together with some LM339’s (for optos) a lifetime supply for me really. Handy to have in stock
 
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David_Vi

David_Vi

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Pin was fine with new chip for about two weeks... Then last night went again.
Had another spare chip, which fixed it and game worked for a few hours but today has gone again.

Any idea how to find what's happening? I know this only started happening after i removed and adjusted the pops. But nothing down there seems to be shorting!
 
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David_Vi

David_Vi

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Failed diode on one of the switches in column 4 perhaps?
Would it cause u20 to blow?

Odd thing is I replace u20 and game works as intended for a while. Sometimes a week.
I bought 11 chips two weeks ago and currently on the 2nd of that batch and the pin is still ok.

I thought it must be something grounding? But it's so hard to find what it could be.
 

stumblor

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A higher voltage is reaching that chip somehow and causing it to blow. Check underneath the playfield for loose wires, coil terminals resting on mechs or switches, that sort of thing.
 
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David_Vi

David_Vi

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I saw that page earlier today 😁

It's infuriating because I've checked the pop bumper area multiple times as it was the last thing I messed with before this recurring issue.
I am struggling to see anything shorting at all.
Doing me nut!
 

stumblor

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I assume you've got the U20 socketed now?

Check the voltages with the chip out, ie

--
While you most assuredly have a switch problem you don't have to go through
ALL of the switches, just some of them. Pop the 2803, and turn the game
on. Then with the meter, see what the pins where the 2803 should go read.

Chances are, you're going to find +25V on one of those pins. Then you'll
at least know which row/column to start looking hard at! :)
--

Also verify the outputs of the upstream LS37 (U14)
 
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Ped

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I had a knotty switch matrix problem on my BSD , Diagnosed in a slightly different way to @stumblor but with the same goal. With the game off, I disconnected all the row /column plugs from the board then just checked for continuity between the switch and column wires to ground with a DMM. if you get a tone, there's a short and you know which row / column wire to follow. If not then it could be something else on the board, as @stumblor says, the LS374

The reason I mentioned diodes is that if one is broken then all the switches in that column / row can show as closed. There's a really good explanation of this HERE
 
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Fubar

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Since you suspect the pop bumpers, you could try disconnecting one/all of them to see if it helps. That might tell you which specific bumper is causing it (if any).

Also, check the pops' coil tabs can't contact anything, especially when the pops are firing. Maybe post a few pictures?
 
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David_Vi

David_Vi

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I assume you've got the U20 socketed now?

Check the voltages with the chip out, ie

--
While you most assuredly have a switch problem you don't have to go through
ALL of the switches, just some of them. Pop the 2803, and turn the game
on. Then with the meter, see what the pins where the 2803 should go read.

Chances are, you're going to find +25V on one of those pins. Then you'll
at least know which row/column to start looking hard at! :)
--

Also verify the outputs of the upstream LS37 (U14)

Check the voltages in the socket where the chip sits?

You may have to use idiot language for the final info, I'm clueless

Could it be a board issue?
 
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David_Vi

David_Vi

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I had a knotty switch matrix problem on my BSD , Diagnosed in a slightly different way to @stumblor but with the same goal. With the game off, I disconnected all the row /column plugs from the board then just checked for continuity between the switch and column wires to ground with a DMM. if you get a tone, there's a short and you know which row / column wire to follow. If not then it could be something else on the board, as @stumblor says, the LS374

The reason I mentioned diodes is that if one is broken then all the switches in that column / row can show as closed. There's a really good explanation of this HERE
So you mean clip one end of the DMM to the pin for column 4 on J206 then probe each switch at the solder joints?

I don't think it's a diode or it wouldn't work correctly with a new chip in U20 correct?

Will check out the explanation now I'm home 👍🏻


Since you suspect the pop bumpers, you could try disconnecting one/all of them to see if it helps. That might tell you which specific bumper is causing it (if any).

Also, check the pops' coil tabs can't contact anything, especially when the pops are firing. Maybe post a few pictures?
When you say disconnect you mean the wires from the lugs? But keep them intact like the two purple orange ones in the photo?

Only issue is it jas never blown straight away and sometimes works fine for week. This is what's making diagnosing it a nightmare.


One picture, I've been out all day and hope to try suggestions tomorrow as I'm off work.
20201029_203528.jpg


Can I confirm that u20 blowing would cause each switch on column 4 to activate every switch in that row?
Could someone explain why that would be?
 
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Ped

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So you mean clip one end of the DMM to the pin for column 4 on J206 then probe each switch at the solder joints?

I don't think it's a diode or it wouldn't work correctly with a new chip in U20 correct?

Will check out the explanation now I'm home 👍🏻



When you say disconnect you mean the wires from the lugs? But keep them intact like the two purple orange ones in the photo?

Only issue is it jas never blown straight away and sometimes works fine for week. This is what's making diagnosing it a nightmare.


One picture, I've been out all day and hope to try suggestions tomorrow as I'm off work.
View attachment 123561


Can I confirm that u20 blowing would cause each switch on column 4 to activate every switch in that row?
Could someone explain why that would be?
Click to expand...
So you mean clip one end of the DMM to the pin for column 4 on J206 then probe each switch at the solder joints

Easier than that actually. Unplug the j206, Set the meter to check continuity, clip either wire to the gnd strap and prod the the other wire end into the female sockets on the j206 connector. If it beeps you've got a gnd short
 

Ped

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And you're right, if the switches work OK until the chip blows then it won't be the diodes. Do take a look at the pinwiki link above, there's a section on switch matrix issues that's really helpful
 

Moonraker

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What you're experiencing it typical lamp meets switch short, they're in very close proximity and vibrations from the game as it is being played is causing the short and blowing the chip. This can be anywhere under the playfield, not necessarily connected to the pop bumpers as it could be a result of lifting/lowering the playfield to access the pop bumper switches.

That said, on the picture you've provided at that angle there is an illusion that the switch has 2 diodes connected (diode topside is the switch connecting green/yellow and white/purple). It hasn't but it shows that they're fairly close together and (I suspect) the second set of wires (plain red and white) that the diode is connected to (?) feeds the pop bumper light. They should be held apart but if the holding bracket or screw has worked loose then it could be the culprit.
 
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David_Vi

David_Vi

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So you mean clip one end of the DMM to the pin for column 4 on J206 then probe each switch at the solder joints

Easier than that actually. Unplug the j206, Set the meter to check continuity, clip either wire to the gnd strap and prod the the other wire end into the female sockets on the j206 connector. If it beeps you've got a gnd short

No beeps! It's not a constant short i don't think.



So I have a beep somewhere else, not sure if I'm doing the right thing but I was poking about and I get a continuity beep from the lamp on the red and gray wires bottom right.

Not sure what that means!

Early in the day, only just started diagnosing
 

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David_Vi

David_Vi

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Okkkk

So if i touch there when grounded I get a beep!

What next? 🤔
I get beeps on a lot of GI so maybe it's normal? 😂
 

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David_Vi

David_Vi

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I assume you've got the U20 socketed now?

Check the voltages with the chip out, ie

--
While you most assuredly have a switch problem you don't have to go through
ALL of the switches, just some of them. Pop the 2803, and turn the game
on. Then with the meter, see what the pins where the 2803 should go read.

Chances are, you're going to find +25V on one of those pins. Then you'll
at least know which row/column to start looking hard at! :)
--

Also verify the outputs of the upstream LS37 (U14)

Tried the socket, they all read 12v.

🤷🏻‍♂️
 

Ped

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Okkkk

So if i touch there when grounded I get a beep!

What next? 🤔
I get beeps on a lot of GI so maybe it's normal? 😂
Yep, normal on the GI there, but as @Moonraker says it could be intermittent when things are vibrating / moving about when the game is on.

Also found this:

"
Other things can cause U20 to fail too. If the game works for a few minutes and
then U20 fails, this could be caused by a bad U14/U23 chip on the CPU board. Or a
bad LM339 chip on one of the under playfield opto board(s). A simply way to tell is
to unplug all the CPU board's switch plugs and see if U20 fails after 15 minutes or
so. If it does not, the problem is on the playfield. If it does fail, suspect U14 (WPC)
or U23 (WPC-S/WPC-95) as the problem."
 
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David_Vi

David_Vi

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Yep, normal on the GI there, but as @Moonraker says it could be intermittent when things are vibrating / moving about when the game is on.

Also found this:

"
Other things can cause U20 to fail too. If the game works for a few minutes and
then U20 fails, this could be caused by a bad U14/U23 chip on the CPU board. Or a
bad LM339 chip on one of the under playfield opto board(s). A simply way to tell is
to unplug all the CPU board's switch plugs and see if U20 fails after 15 minutes or
so. If it does not, the problem is on the playfield. If it does fail, suspect U14 (WPC)
or U23 (WPC-S/WPC-95) as the problem."

I fiddled for a few hours, took a pop out and put it back.

Obviously the pin is working ok because it has a new U20 chip. I was tempted to leave the pin running for a while without the switch connectors plugged into the cpu.
Would that test if its the cpu blowing it?
 

Ped

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I fiddled for a few hours, took a pop out and put it back.

Obviously the pin is working ok because it has a new U20 chip. I was tempted to leave the pin running for a while without the switch connectors plugged into the cpu.
Would that test if its the cpu blowing it?
Yep, won't hurt, and will rule it out if nothing else
 
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David_Vi

David_Vi

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Any idea how long? I had it on an hour or so with J206 unplugged.
Played a game or two after all good.

It's so strange I'm sure I'll be lulled into a false sense of having fixed it (somehow?!) and tomorrow or a few days later I'll notice the switches not working correctly. 🤦🏻‍♂️
 
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David_Vi

David_Vi

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Ok so it went again...
I was having the most amazing game.

The only thing that seemed odd before I noticed certain switches not working was the bottom pop got hit and stuck on. I think the stick got lodged off off the pop bumper spoon and off the edge of the spoon so didn't push the ring back up... so the switch got stuck on.

Would that cause something to blow?!