Firepower will refuse to start a game, or work correctly without all 3 ball trough switches closed AND seen by the Driver Board / MPU. Very confusing when troubleshooting the game, but that’s how the code was written. I would also suspect your switch matrix if you confirm the physical switches are closed with a working board set.

Also check that the ball return switch isn’t stuck closed and that the diode on that switch and the switches that are chained together have good diodes. In my experience, sometimes swapping the switch matrix PIA will fix weird problems like you have. Also check pinwiki - I wrote much of the system 6/7 content years ago. For diagrams of all the boards, circuit diagrams check: www.firepowerpinball.com

No probs. I do some tech support & drew many of the circuit diagrams for the firepowerpinball site.
some other board repair info at www.firepower.2ya.com - if you can’t repair your original boards, give me a shout and I can sort it out for you. If you have sockets labelled SCANBE- they must be replaced. Usually they’re ROM sockets on the CPU board. PIAs on the Driver board were soldered in place from factory on all original boards I’ve seen.

So- I’m assuming now it’s not the boards. I’m still thinking you have a short in your switch matrix.

The strange thing is the diagnostic switches (on the coin door) are *not* part of the switch matrix. The coin door switches wire directly to the CPU at connector 1J4. They are very simple and don’t use diodes. They ground pin inputs and talk directly to the MPU. Check the wires there for continuity and that the coin door switches will work through to the 1J4 connecter with 1J4 unplugged using an ohm meter. Check also where the coin door switch wires can be crimped and shorting on the coin door hinge. To see how the coin door (diag) switches are wired up, see: http://www.firepowerpinball.com/downloads/CabinetWiring.pdf
I would start there.

The switch matrix is separate, the switches ‘daisy-chain’ in rows and cols with diodes on each switch. They talk through the switch matrix PIA which is scanned by the MPU. That is the next step after you have the coin door (diag) switches working.

If you can get into the switch matrix test, only three switches 51,58,57 (L,C,R of trough) are closed with 3 balls seen in the trough. No other switches should be indicated as closed unless you active them, such as by pressing a target or rollover. Manually removing the 3 balls, no switches should be shown on the display (as closed). If you can’t get that to work, you won’t get a game start. Start checking the switch matrix rows/cols. Chasing the color coded wires between switches and testing diodes is.a.pain.in.the...

The diagram http://www.firepowerpinball.com/downloads/SwitchWiring.pdf should help if it's the switch matrix, as will the Instruction Booklet.

Let me clarify a statement I made which was a simplification. Two modes will let firepower start a game:
1. Credits are available AND 3 balls are seen in the through.
2. It’s set to ‘freeplay’ and AND 3 balls are seen in the through (51,58,57 closed)
or two in trough and one in the shooter lane (51,58,46 closed).

To set freeplay, you set function 18 (Max credits) to 0 and save. But you have to get the coin door switches to work.

Hope that helps. Apologies in advance if this is information you already know. -Richard

Good progress. Just check that the diag button Advance up/down button or switch will have continuity to gnd (cabinet braid wire will do) in one position, and open in the other. The momentary (usually red) right diag button should only have continuity to gnd while being pressed. That’s it for 1J4. Note you check them at 1J4 first and if that fails, check directly on the switch with 1J4 unplugged to show that the switch itself is working. Do any continuity measurements and diode checks with the game switched OFF.

The start button *is* part of the switch matrix, and is shown as ‘credit button” at col1 row3. That may be messing up the game (switch matrix, confusing the PiA) if it was wired incorrectly. You need the band on the diode pointing towards the col wire. Row wire (white/orange) —>| col wire (green brown). I’m not sure why you say green/red- maybe that’s the green brown. There *may* be multiple wires on the switches, which need to be there as that’s how they are ‘daisy-chained’ to the next switch. But the wire traces on the *same* col side of the switches would be the same color code. You would need to trace that wire to see if it goes to another switch in col1. If it’s the last switch, it has 1 wire only. I would check all 8 red/brown are connected together as shown in the Cabinet Wiring Diagram (col1). You can do this quickly with a continuity checker moving between switches in that Column. An finally from one of the switches to the correct pin on the MPU or driver board. Same for the Rows too, really. But each game’s harness is different. I can’t give exact routing. The logical order in the circuit diagrams and the physical harness order on the playfield and cabinet aren’t always the same due to game layout- if that makes sense. WMS would save wire by using shortest paths, usually... but not always.

Also HS reset is at col1 row8 (and confusingly) the left diag button on the coin door. Check that none of the other switches in col1 are stuck closed. Slam tilt, ball roll tilt and especially the coin-drop leaf switches short out on diode legs or get stuck closed in some other way, jammed on the white plastic wheels that the wireform moves when the coin passes by...

You save settings by pressing credit (start button) to change the stored value up/down and then use advance with the toggle set to UP TO advance all the way through the other settings past the last one. On most games it will go to ‘attract mode’ after it wraps around past the final setting. If it goes back to setting 01 (the audits I believe) then you can turn it off. Wait a couple of seconds, switch it back on and check that the setting is retained. If the game goes into setup mode 04 again when switched on, then its probably CMOS Ram on the MPU (IC15 I believe from memory haha) or batteries which is a whole other issue. Sometimes switching off/on quickly with firepower will get it into ‘attract mode’ and you can credit up with the coin-drop switches (if needed) and start a game.

Sorry for the long post, I didn’t start out intending to write a novel.

Best of luck. Firepower is a really fun game once everything is working. Steve Ritchie rules!

-Richard

OK so the start button is good.

Check the ball trough switches are closing when the balls are over them. You can use the switch matrix diag mode now and the closed switches will flash on the display with a beep for each switch closed. You need to figure out how to move between the display test/switch test/coil test etc.

As I said previously 51,58,57 (L,C,R) should be the only switches closed which is what the MPU should see in order to be able to game start. If the wiring is correct... and the switches are working, and no other switches in the cols 7 & 8 are stuck closed or wired up wrong. Diodes need to be in correct orientation and good. A complete PITA.

Sometimes the leaf switch needs adjusting very slightly - so it’s closed with ball there and open otherwise. You may need to prop up the playfield slightly on a wood block or some other non-metal support to achieve this.

Finally clean the switch contacts with a business card or folded paper... By placing it between the switch contacts, pressing the switch closed and pulling the card out. Crud on the paper shows you are cleaning the contacts. Never file switch contacts or use sandpaper, as that ruins the leaf switch for good.

Meaning they all indicate *individually* during the switch test? Except 57? Test them one a a time. That would rule out the Driver/MPU as the source of the fault. Then you have only the wiring to the PF. And diodes. That’s it as far as I can see.

Try this; Close the PF, Put one ball in the trough. Go to switch test, you should see only sw51 (Left) then without changing anything, flick another ball into the trough from the outlane. You should see 51 & 58.

If you don’t, check (and I would just replace) the diode for 57 (Right Trough switch). I know it sounds counter-intuitive, but if you look at the switch matrix, that is a ‘steering diode” and switch 57 is seen first, so would probably work to PIA anyway. They are the only 2 switches on col 8. One is on row1 other is row2. So you don’t have too many to go through.

Next logical switch diode to change is actually on *switch 50* -as that is just before the faulty one (58) on row 2. Its on the left side of the PF to the right and below the left ball lock. That’s just the way it works.

There is also a strange triangulation switch effect to the matrix (I dimly remember) which I would have to look up to know what to try next. But that has to do with multiple switches closed on different row/cols. And I don’t think that’s the prob here.

BTW- this is a decent explanation of how the switch matrix works:
https://www.flippers.be/basics/101_switch_matrix.html
This is good switch matrix info from pinwiki.com:
https://www.pinwiki.com/wiki/index.php?title=General#The_Switch_Matrix

This is a good video about the switch matrix, and explaining the ‘switch ghosting’ problem. Which I referred to as ‘switch triangulation’. This shouldn’t be your problem... it’s more often seen during gameplay where multiple switches are being closed all at the same time. Example: 3 are closed and a 4th ‘ghost switch’ also is seen as closed from a shorted diode. The faulty diode is on a diagonal in a rectangle from the ghost switch and the diode is usually shorted. See video.

Hopeful that you get there and firepower springs to life.

Try this: raise the playfield slightly pull it towards you and rest it on a wood block (or something plastic) so it is fairly level, but you can still get to the ball trough switches. Power on the game, with all 3 balls in the trough. Press the centre switch closed and press start. If the game starts, then the ball isn’t closing the center switch. You would need to bend the wire slightly up so the ball completely closes the switch, but it is open with no ball installed. Switch test will also tell you this- which is another way to tell. The switch matrix is very low voltage, but don’t touch anything metal or powered in the game when closing a switch. A plastic start button is ok.

But yes, check diodes on switch 57 and then 50. Remember to test the diode in both directions by reversing the test leads. It should conduct in one direction only, and be ‘open’ with the test leads the opposite way around. Apologies if you understood this already, i’m adding it for completeness. Personally I would replace 57 and then 50 in that order and test each time for game start and diag switch test for further clues.

I edited this post so you may want to read it again.

Sounds like you may be reading resistance through the switch / diode with it open. Put a thin card between the switch blades and test again, just to take that out of the equation.

Are you sure switch 58 in row 2 isn’t shorting to the diode somehow? check the ends sicking out and that the sandwich insulation looks good and it’s not grounding to the trough plate. check the wiring to the switch is as the other trough switches. Leads from the diode can not cross, or even touch slightly. Band on the diode points AWAY from the white wire.

Yes, I would expect it to conduct 0.5-0.7 in one direction and be open the other way. Make sure you are on a diode setting on the meter looks like ->|. Doing it on ohms or a continuity setting may not properly check the blocking property, as it won’t bias the diode with enough voltage.

Did you do the same check on switch 50? Do you get the same reading there? What about others on that row: sw42, sw34... etc.

Then test diodes with the harness unplugged from header 2J2 & 2J3 on the Driver board. Stick your meter lead in the header for col 8 (green/gray) and the other lead into row 1 (white brown). To avoid harming the connector, I stick in paper clips and wrap them around the meter leads. Even easier to do if you have alligator clips. Press each switch in the row, moving the column lead back 1 position in the connector and pressing the appropriate switch.
So col8/row1 press sw57. col7/row1 press sw49.

I’m hoping you understand what I mean. You’re checking the diode all the way through the harness and switch. You will likely need help finding and pressing switches. It’s harder on your own for sure. Sorry this sucks, but it’s the only way I’m sure will isolate the problem. Look for differences in readings.

In one orientation of the leads, they all read 0.5-.07v approx. The other way around they should all be the same - open or no reading. I’ll leave it to you if you want to swap leads for each switch, or do them all and then swap leads and do them all in order again. I prefer the former.

Afterwards check each switch you got. funny reading on and the soldering and for stray wires for each lead. I just replace any diode I think may be bad, and move on. They cost pennies.

Sure, or put a paper card between the switch blades. Good catch.
I’m pretty sure that with coils, you have to unsolder one leg of the diode before testing. That’s what I do.

It’s going to be a faulty switch or diode somewhere.
You can try sw50.
Also go back to check sw01 to sw09 shown here on pg10 of this excelllent booklet:
http://www.firepowerpinball.com/2ya/downloads/InstructionBooklet.pdf

Use the diag switch test for each of these, make sure only sw1,2,3,.. is shown on the display as 01, -2, etc and *no other* switches show closed when you make those switches. Check wiring & diodes on any that close 2 switches. And around any ghost switch that closes with it.

Check diodes and wiring on the plumb bob tilt (shown as 7D1 on Cabinet Wiring diagram) which is on col1/row1. Take the plumb bob off, so we know it isn’t stuck closed. You can set if back up once the game is working.
Same for the ball roll tilt (shown as 7D2 on Cabinet Wiring diagram) which looks like a metal angle bracket with a slot it, near the plumb bob tilt. The little ball that rolled down to the switch if the front of the cab was lifted & dropped is usually missing. Make sure the metal switch at the end isn’t grounded out, and that the diode is good. It’s on col1/row2. Row2 is the row with the faulty switch (58). I don't want to ignore those just because they aren't on the playfield.

Also check the ‘slam tilt’ which is on the underside of the playfield and has a weighted switch the vibrates and closes if the game is slammed around, it should be marked ‘slam tilt’ and the same rules apply: not stuck closed - check for diode good & operation in switch test. It should only close 1 switch sw47 when tested.

Then I’d work my way up row 2, from ball roll tilt (sw47) to sw10, sw18, sw26, sw34, sw42, sw50...
Using the operation for diag switch test. Only one switch should be shown at a time as they are closed.
Then use the procedure above of checking the diodes and switches with the game off from the disconnected row/col headers all the way through the wires to the switch-diode you want to test. Connection on row 2 should be open, and then show one diode in one direction for each column and switch closed. They should show no reading with the test leads reversed.

I’m out of ideas.

Best Wishes.
-Richard

You need to figure out if the problem is the boards or the wiring/playfield.
Do the trick of removing 2J2 and 2J3 from the driver headers. Take a diode and a test lead or jumper wire.
With the game on and in switch test mode, nothing should register as nothing is connected. As above, diode band points towards the column (2J2). Touch the diode /wire between the pin for row1 and the pin for col1. That’s the plumb bob tilt,
Strangely both #1 drives are located on pin9 of the connector. Trap for the uninitiated.

You should get one switch indicted closed in the diag. If all switches fire in the row, for any one ‘jumper touch’ the fault is on the MPU/driver. If only sw1 fires, that’s the correct result.

Just remember that on connectors 2J2 and 2J3 that pin1 is column or row8, and pin 9 is column or row1 (kind of opposite what you might expect). Also check the manual for the maximum switch number used in the game, some game switch diags won’t register switches beyond the max game switch. I think firepower will do the whole switch matrix. All modern games do the whole matrix and just say ‘not used’. But on early games the software was new-ish and there was very limited space to write code for the ‘flipper roms’ (system code).

While there, work backwards on the row pins on 2J3 and you should get 1 switch closure per touch. Then move to col2 and do every pin for the rows again. It’s easy to check the whole board switch-matrix this way.
You should *never* have more than 1 switch detected closed per pin-pair.

If you do- it’s a board fault. Maybe a 7406 or more likely the 4049 IC5. Or the PIA. I can’t be sure, but a logic probe would narrow it down, as would swapping PIAs.
Here’s a list I hope you don’t need:-
2J2 pins 1-3,5 (Columns 5-8 switch drives): IC18 (7406)
2J2 pins 9-6 (Columns 1-4 switch drives): IC17 (7406)
2J3 pins 1,3-5 (Rows 5-8 switch inputs): IC16 (4049)
2J3 pins 9-6 (Rows 1-4 switch inputs): IC15 (4049)

And we’re back to the beginning of the thread where you disconnect the switches at 2J2 and 2J3 and use a logic probe to work backwards and see whats’s happening.

So lets say the MPU/Driver switch test checks out 100%. Then we’re back to a fault only on the playfield/wiring. Which would be good, because it is possible to have both.

What can happen is you have a fault like a lane change switch (in the switch matrix) touching +50v for the coil. This is a very common firepower problem. It blows a chip on the driver board. You replace the boards and switch on the game, and it blows that new driver board too. You need to check there isn’t a voltage at the plumb bob tilt (ball roll tilt or credit button,etc..) any of the row1 switches with 2J2 and 2J3 *disconnected* and the game on, to avoid this situation.
If you do have a voltage something is mis-wired on row1 or a wire is pinched in the coin door to power.
Seeing some voltage with 2J2 and 2J3 connected and the game on is normal. But they all should be nominal and match in level for the most part. An abnormal voltage reading points to a problem for that row/col pin. With a logic probe that LED is way to bright compared to the others. But I prefer a DMM on a 20v setting for example as I don’t want to blow a logic probe. I usually only use a logic probe on the bench, where I know my MPU/Driver PSU only puts out 12v and 5v DC.
Actually I do have 2 cheap logic probes just in case. But be careful is all I’m saying.

You can just take out the plumb bob tilt / switch / diode from the game (for home use) and tape off the wires to get it working. And then figure out what it was, once you get the row working. I’m hoping it’s diodes and wiring. That’s cheap to fix, it just takes time. Board repair is a whole other subject.

Let’s hope its a row1 switch diode fault or ground fault (where a wire is pinched on a metal bracket that’s grounded to the ‘braid’). Note that the switch matrix wires (white with stripe/green with stripe) are *not* connected directly to ground. Or to a voltage coming from anywhere but the Driver board. Ever.Or you get this kind of result when the switch closes.
I found another excellent switch matrix article, and to avoid duplicating it here, I enclose the link:
http://homepinballrepair.com/index.php/pinball-switch-lamp-matrix-troubleshooting/#switches-closed

Fingers crossed. -Richard

More likely to be a diode folded over and legs touching near a leaf switch tab, or a wire that’s been trapped under a metal bracket somewhere and grounding... you also get switch matrix wires touching at lamp sockets and picking up a voltage. Suff like that. Good Luck on your tests.

No probs for the help.
That’s a relief, that the boards appear to be ok. It still could be the switch PIA or support chips, but it’s much less likely to ge the case.

So you know it’s likely to be the plumb bob tilt or other diode/wiring in the cabinet (likely).
I would start with the plumb bob. Just remove it from the circuit. Then go through each switch in Col 1 (mostly cabinet) switches. Especially the coin switches as they are so small and the diodes are close to the tiny flimsy switches. You don’t really need any switches in col1 except the start button (credit). You could just wire up credit on it’s own to col1.

Then I’d work down row 1. Check left outside rollover r2c2 (inside rollover too r3c2) next. As I’ve said it can be an unrelated switch grounding out. I’ve has some weirdness that made little logical sense with the switch matrix. You will know once you recognize it. A strange looking diode, solder bridge on a switch, pinched or frayed wire.

Ouch. That’s not good. Do the whole pin test for at least all of Row1 and Row2 as described above without 2J2 2J3 installed. Write it all down in a matrix and then list the switch(es) that don’t work here. It won't be just sw58 when tested this way. I think that’s an impossible result. Do all of C1 and C2 as well and I’ll let you know what chip(s) are likely to be faulty.

Likely being the key word. You can’t just assume that. As I said- you could have both the boards and the PF now faulty. The fault on the PF can blow the chip, so you still need to be sure you don’t have voltages on Row or Column Harness pins coming from the PF. Otherwise you will blow up a repaired Driver switch matrix as soon as you plug 2J2 and 2J3 back in again. I’d assume that the wiring is still probably good on a new game, but not on an old firepower. Unless you know exactly what happened to blow the switch matrix (plumb bob connected to power) or (lane change switch shorted to solenoid power) or (pop bumper scoring switch shorted to power) Etc... those are typical firepower failure points.
Been there, seen that. Owned 3 firepowers and they all eventually had problems. Usually sound speech, but often driver boards. The original firepower boards are probably easier to repair yourself. Sorry.

You need to unplug 2J2 and 2J3 and then use the DMM to check if you have any voltage on the diode (or the other ‘open’ side) of the switch. There shouldn’t be any.

On the switch testing with a diode and wire... the results make no sense to me. How can r1c8 work and the r2c8 does not? Given that r2 works on every other switch? Input levels? Check voltage on all the column drives to ground on the 2J2 pins (with headers removed). Are the all the same? What about 2J3?

The reset (meaning the game reboots?) from pb tilt is def wrong. I’m fairly sure you have a fault on the plumbob switch wiring. As I suggested, take it out of the circuit. I would unsolder the ‘upstream connections to it, meaning the place where it connects to the next row1 col switch. If it’s the first one, you would leave the rest disconnected if you didnt join the wire from 2J3pin9 to the other switches. Note that you still need to maintain continuity to the 2J2 and 2J3 connectors, in this case only for the credit button on Or/white (row3) to start a game.

New Idea:
—————
Personally at this point, I would pull col1 (green/brown) from the header at 2J2 pin9 to isolate the column that’s causing problems. Sometimes you can release tension on the connector and pull it out so it can be reinserted, rater than cutting the wire or yanking the terminal out of the housing.

Then connect up the headers, put three balls in the game and switch it on. You should get attract mode. If it says ‘04’ ‘1497’ on the displays, switch it off & on quickly to get to attract mode.
Then simulate adding coins:
Simulate a drop of a few coins by jumpering 2J2pin9 to 2J3pin6 (yel/wht). Thats a good test. You won’t see any change if freeplay is set.
Try to start a game:
Simulate a press of the credit button by jumpering 2J2pin9 to 2J3pin7. You need to have a diode there as before with the band pointing towards Row3 at 2J3pin7 (Or/Wht).

If that starts a game you know you have a fault on col1 wiring between the backbox to the cabinet. It could even be the plumb bob tilt that’s caused the fault.

I suspect the driver board has a level fault too, maybe a blown cap at C37 or C50. Not sure yet. Could be the input 4049 chip. If you want to send me the old system 6 boards (both MPU and Driver), PM me. I have spare chips and a test rig to check them out.

Uh not just now. I love playing pinball, don’t mind adding mods. This type of fault, nahhh.

Is this your problem with the rottendog board? https://pinside.com/pinball/forum/topic/warning-to-rottendog-327-owners-check-it-now
Also see Pinwiki section 4.2.7 on this link: https://pinwiki.com/wiki/index.php?title=Williams_System_3_-_7

Right. And the pinwiki link above says that may have caused switch column IC at U17 to fail. But maybe not. Worth isolating that pin from the bracket & trying again.

Electrical tape probably isn’t any good. Once you tighten down the screw, it can just punch through and cause an intermittent fault. You should isolate the metal by doing some file or Dremel work on the bracket as shown.

I actually don’t know much about the MPU327, other than it combines the MPU and driver together removing the interconnection which can be problematic if not repinned correctly. The switch DIP switch settings and schematics don’t appear to be online in a quick search. I was assuming normal setup and original boards (completely compatible) in my posts. This board has multiple (and modified) game ROMs and appears to have made some changes to the original designs... although they may be improvements I can’t comment what effects they may have. It’s also worth noting that they originally claimed compatibility with system 7 games, but removed support for Sys7 - Black Knight, Alien Poker and similar later games.

I have always repaired and used original boards in firepower and my other games. I have done upgrades to help make them more reliable, but again on original boards. At a guess, as it’s concerning row1, col1: IC15 and IC17. I gave chip locations and types in this post above:

If the game is working correctly, it shouldn’t blow chips. Usually a few spare PIAs (general to switch, solenoid and lamp matrices) some 4049, 7406 chips for the switch matrix are enough.

Here is a list of components I made most of these are driver board.
EQUIVALENT COMPONENTS:
Transistors
TIP122 NPN Darlington = TIP102 (SE9302) or TIP120
2n4401 NPN Pre-Driver = 2n3904
2n6427 NPN Darlington = MPSA14 (NTE46)
2n6122 NPN Power = TIP41C or 2n5296
2n5060 SCR = 2n5061 (NTE5400)
ICs
MC14049 Invert. Hex Buffer = 4049
6820 PIA = xx6821, xx68A21, xx68B21, where xx can be MC (Motorola) or HD (Hitachi Data).
740x = 74LS0x, 74HCT0x. x is an even number like (2,4,8)

I have some spare PIAs - if they want like $20+ a chip (which is too much) let me know on PM and I’ll send you a good one for just my shipping cost.
Always willing to help get a firepower running given all the problems you have experienced.

I wouldn’t advise someone to swap in new boards into a game that glitched and stopped working. Not without testing the switch matrix, lamp matrix for shorts and testing and ‘beefing up’ the PSU with new caps and diodes, if needed. But that’s where we are... luckily it looks like the rottendog chips are socketed, so it should be an easy fix.

They’re separate fuses. Solenoids are F2, lamps are F3. No lamps, check headers are not swapped first, the check F3 fuse for continuity off the board. Sometimes fuses look good, and check as open.

Re: Solenoids
Sol 01 Ball release is hidden under the Apron. It’s the out-hole kicker on to the ball ramp.
Sol 08 Ramp thrower is under the Playfield with a hook shaped mech. It kicks the ball up into the shooter lane.
See the plyfield diagram in the lower LH corner here for locations:
http://www.firepowerpinball.com/downloads/SolenoidWiring.pdf

This chart my help. You use the coil wire colors to confirm the connection pin on the driver board. This gives you confidence of the driver transistors to check & replace for that coil. If you set the solenoid self test to fire that coil repeatedly *with the solenoid fuse removed* -the driver board pin (and the metal tab on the top of the correct Tip102) will go to ground each time the coil ‘fires’.

From memory moving from Advance auto/up to Manual/Down changes whether the self test goes through all coils in sequence(auto) or does one coil at a time (manual). You press credit/start to move to the next coil. Works the same way for lamp and display digits tests. A logic probe is the best way to see this happening with coils. If it grounds the pin/tab then *both* the pre-driver and Tip102 are likely to be good and don’t need replacing. You can quickly check all the solenoid transistors using this method, but you must remove the solenoid fuse to use a logic probe, which is easiest.

88246820-D8C9-43A2-B856-A78C0E465514 (resized).jpeg

You need to send out the boards, or learn to run the Leon Diagnostic built into the Rottendog board via dip switches. Please note: If you dip switch for Leon’s test Rom, You *must* remove the Lamp, Switch, Cabinet and solenoid headers. You can’t attach the playfield- power the board at *only* 1j2 connector & run diags. Leon’s diag rom “pulses” all the PIAs and you use a logic probe to trace back trough the circuits and see if the board is locking the coil OR if it’s still a fault on the PF/cabinet. Hey, you may have fixed the original coil/wiring problem and have blown two sets of Driver boards. It’s all in Pinwiki- or just google the procedures for Leon’s test rom. There’s a start to tracing with a logic probe way at the top of the thread. You may find it’s IC15 and/or IC17 for the switch inputs, failing that the PIAs on the driver board. If the board isn’t locking up the coil drive(s) (most likely it’s the board as you say) - then you still haven't found a fault on the PF.

So yes, that sounds like a chip fault on the Driver board rather than the playfield wiring to the coils.