Tech: Gottlieb 80b A1J5 woes

[examiner]

Arena that I have been trying to fix. Had random boot problems, so had
the CPU out since I suspected daughterboard problems. (Important to
note that when it did boot, it played fine and I've been able to play
several games over the past few weeks without incident, other than an
occasional freeze in mid-game) Game is in the garage, I left the board
on the floor for a short while and to make a long story short, my wife
ran over it with her motorcycle.

So bit the bullet and bought a "new" reconditioned board. Thought I'd
be prudent so I followed the recommended start up procedures. 5v is
fine, both at the PS output and across the cap on the motherboard. So I
connect the display connector. Displays come up with the expected "slam
switch open" message and all zeros on the bottom display. This means
the board is booting OK, correct?

I then proceed to connect A1J5 and that's where things go strange.
Won't boot into attract mode..still get zeros on everything, except the
last digit of the player 4 display now shows a "3". Disconnect A1J5,
returns to all zeros.

It's not a slam switch issue. If I power the machine on while holding
open the slam switch on the coin door, I get the expected "slam switch
open" message. If I power the machine on while holding the ball roll
tilt closed, I get a "tilt closed" message. I have repinned the
connecter at A1J5.

So I have some communication between the coin door and the CPU, but the
test switch, etc. won't work and it won't boot into attract mode. I am
unable to find any shorts on the coin door wiring. The fact that
everything worked a week ago leads me to believe I have a switch matrix
problem on the "new, reconditioned" CPU and not a wiring short (also
checked the diode board in the cabinet, all tested out fine). But I
don't have a logic probe. Is there anyway else to check this? Or is
there something else I'm overlooking?

I just want to make sure I explore all options before I talk to the
retailer/seller of the board. If there's a board problem, I suspect
I'll get accused of causing the damage, but again, I have not connected
the driver board or the playfield connector to the new CPU, just the
display and coin door switches.

Sorry for writing so much, and thanks for any suggestions.

Greg


--
examiner
This USENET post sent from http://rgparchive.com

[Dan Beck]

Hi Greg,

I believe the first thing you do is to contact the seller and inform him/her of your troubles. The seller may have some suggestions for you to try. There are things we could suggest for you to try, but those tests may void your "warranty", if you will, so I do not wish to suggest anything, just yet. Please get back to the group after you have contacted the seller, and I know at least I could suggest something or two...

Regards,
Dan

[examiner]

Thanks Dan. I just a few minutes ago sent a support request to the
seller and referred them to my thread here for any ideas. I have no
reason to think they won't stand behind their product, but I also know
many of these things are attributable to the box and not the board so
didn't want to cry wolf. Will update when I hear back from them,mthanks
again for taking the time to reply.

[examiner]

oK. the professional ARCADE company that sold me this replied as
follows:

This is our procedure for reconditioned cpu. We set the board up for the
game we use for testing, in this case it would be a Raven. We install
the cpu, verify that it boots into attract mode, add credits, run the
solenoid test, switch test, lamp test. We play a few games to verify it
runs under normal game stress conditions. Power it off, check for reboot
with memory. Leave the board in the machine running and use it like any
other game here until the board is purchased and shipped. The cpu you
bought was then set up for Arena with the exception of the game option
switches which you should set up using your original cpu settings or a
manual. Coin door slam switch should be closed, not open. Driver board
has to be connected in order for the cpu to boot properly. Connect
everything except for the small reset board, make sure the slam switch
in the coin door is normally closed, set your game option switches and
try again.
If the game still does not work you should find a tech to check the
machine.

So it's obviously one of those "tough shit don't bother us" moments.

I do have all of the dip switches set exactly like the remains of my old
board. Slam switch is obviously closed which I thought I made clear.
After I plugged this board in with the original connector (and got this
behavior) I rebuilt the connector and am seeing the same behavior.

I have not done the ground mod to this board since I didn't want to
scrape the solder mask off a board "under warranty". I guess that was a
stupid thought so I will try that this morning. I'm 99% confident
there's nothing toasted on the playfield, so I might as well progress to
plugging that and the driver board in and see what happens.

Care to share your ideas Dan? I obviously have nothing to lose.
Thanks.

[seymour.shabow]

examiner wrote:
> oK. the professional ARCADE company that sold me this replied as
> follows:
>
> This is our procedure for reconditioned cpu. We set the board up for the
> game we use for testing, in this case it would be a Raven. We install
> the cpu, verify that it boots into attract mode, add credits, run the
> solenoid test, switch test, lamp test. We play a few games to verify it
> runs under normal game stress conditions. Power it off, check for reboot
> with memory. Leave the board in the machine running and use it like any
> other game here until the board is purchased and shipped. The cpu you
> bought was then set up for Arena with the exception of the game option
> switches which you should set up using your original cpu settings or a
> manual. Coin door slam switch should be closed, not open. Driver board
> has to be connected in order for the cpu to boot properly. Connect
> everything except for the small reset board, make sure the slam switch
> in the coin door is normally closed, set your game option switches and
> try again.
> If the game still does not work you should find a tech to check the
> machine.
>
> So it's obviously one of those "tough shit don't bother us" moments.
>

Not sure who they are but this is one of those many-variables-contribute
type of situation. If they tested it as you relayed, I'm not sure what
else would be expected of them..... if you send it back and it works in
their testbed, there wouldn't be anything for them to "fix".

They're recommendation seems to be that it was working when it left
them, and that the other variables outside their control (the rest of
your machine) needs to be checked out. I'd be surprised that any
company would actually warranty a used board like this at all, because
most of them get damaged from the rest of the machine. Just because
your original board booted, although with issues as you noted, doesn't
mean another example of the board should work. Individual parts'
tolerances could account for the differences. I'd start with checking
over your machine VERY carefully to ensure there's not some kind of
sneak voltage situation going on. Don't rely on what your old, sort of
working board did. Look around for any kind of hacks or breaks in the
harness, and you're probably going to have to be very very through in
the examination of this. Stray lamp voltage sneaking in on the switches
is what I'd look for first, as it is bedeviling to find and fix this
type of problem.

> I do have all of the dip switches set exactly like the remains of my old
> board. Slam switch is obviously closed which I thought I made clear.
> After I plugged this board in with the original connector (and got this
> behavior) I rebuilt the connector and am seeing the same behavior.
>
> I have not done the ground mod to this board since I didn't want to
> scrape the solder mask off a board "under warranty". I guess that was a
> stupid thought so I will try that this morning. I'm 99% confident
> there's nothing toasted on the playfield, so I might as well progress to
> plugging that and the driver board in and see what happens.
>

Well, they did tell you that as well (plug the driver board in). One
thing I don't see if you did or not, did you replace the filter cap in
your game with a higher capacitance new one? Going back to your
original issue with the cpu that got ran over - it's not working fine if
the game freezes up occasionally. (Even if it boots).

> Care to share your ideas Dan? I obviously have nothing to lose.

You could send it to a different board repairer than wherever you got it
from - Chris Hibler and Jim Palson (Gott Lieb?) would be able to test
the board out if they're currently taking on more work.

IIRC the gottlieb power supplies are adjustable, measure the voltage at
the mpu board, sometimes you have to bump it up slightly.

[examiner]

seymour.shabow;2004020 Wrote:
> examiner wrote:[color=blue]

> If they tested it as you relayed, I'm not sure what
> else would be expected of them..... if you send it back and it works in
>
> their testbed, there wouldn't be anything for them to "fix".
>

I know and I sure the board is probably fine. It's just kind of
frustrating to go backwards at such a rapid rate.

As it relates to stray voltages, since I"m just dealing with the coin
door connector at this point, I assume that's the only wiring I need to
concern myself with up front?

Hadn't thought about the tolerance issue. I do have about 5.10 volts at
the CPU, so I hesitate to crank it up any higher. I have not replaced
the filter cap in the bottom of the cab. It's not one of the infamous
orange ones, and it tested OK per the "repair guide", but no harm in
that and I will do that today also. Thanks for the tips.

[Gott Lieb?]

Jot down all of your dipswitch settings on the board. Then, turn all of
the dipswitches off, and see if there is any change.

Now, onto the other things I always ask. Has the header pins on the 5v
power supply been reflowed and the pot replaced? Have the grounds been
secured at the transformer at a minimum, and at the circuit boards too?

Jim

Gott Lieb?

[examiner]

Tried the dipswitch trick yesterday (I think I've researched every
comment you guys have ever made about 80b) but no change.

The grounds at the transformer have the inline molex style connectors,
not the 9 pin square ones. Regardless, no I have not tied them all
together yet. I did remove the small boards they plug in to and
reflowed/added solder to the back of the boards. I can/will tie them
together today.

I have reflowed the pins on the 5v power supply. I have not changed the
pot but it does not appear original. (it's not one of the blue dial
ones). I've got it adjusted up to about 5.15v leaving the power supply
and I'm losing about .05 volts through the connectors (haven't repinned
them yet). I have what appears to be rock solid 5.10v across the cap on
the MPU.

Unlike other 80b's I've seen (not that many), this machine does have
what appears to be a silver metal ground plane behind all of the boards.
I have continuity from this silver plane to the transformer. The power
supply is bolted directed to that (no standoffs like all the other
boards). I've added a ground line from pin 2 to one of the power supply
frame bolts. Ground mods added to driver board (still not plugged in)
and just finished adding a ground wire from the negative lead of the MPU
capacitor (no change when I added that). I have continuity between all
of these grounding points on the various boards. I have not added a
ground to the soundboard or the aux power supply yet as I haven't added
it into the equation yet (although it worked fine with the old MPU).

I guess my major question now is - based on what I am seeing, can I be
certain the MPU is booting (for instance the "slam switch open" message
when I have AIJ5 disconnected or if connected, when I power on with the
switch manually held open at the coin door)?

When I plug that A1J5 in, what would cause the "3" to appear in the last
digit of player 4 display? Is that the electrical noise that Seymour
alluded to?

thanks again everybody.


--
examiner

[Gott Lieb?]

If you see the slam switch message, the CPU is booting.

Try this. I assume that you haven't repinned A1J5. Remove all of the
connector pins from A1J5, and repin the slam switch first, or just
temporarily jump the slam switch return to ground on the CPU. Replace
each pin one at a time on A1J5. In between replacing each pin, turn the
game on to see if it boots. When it stops booting with the last pin
replaced, you've at least found part of the problem. Report back what
connector this is, and hopefully one of us can hone in.

Jim

Gott Lieb?

[Dan Beck]

Hi Greg, Scott offers good advice. Your game was at best flaky with the original board, before that board suffered its unusual demise. The 5 VDC power has to be solid, replacing the filter cap is necessary, as well as testing/replacing the power supply pot, and maybe also the big transistor on the power supply. Ground mods in the cabinet need to be done, also.

On the pin wiki website there is a "general" heading. There is an outlined procedure for testing ICs using the diode test on your DMM, under that heading. I would suggest testing the switch matrix ICs; if you are lucky they will be already socketed.

With the A1J5 connector disconnected are you able to get into bookkeeping? If not, let me know and I can outline a possible work around.

A System 80 control (CPU) board will boot into attract mode just fine without the driver board connected. I have done that many, many times on my workbench with my computer power supply and my oscilloscope. That line from the retailer is a pile of bunk, in my opinion. I view the driver board as a "passive" receiving instructions from both the control board, and playfield.

Regards,
Dan

[Dan Beck]

Nevermind on the A1J5 bookkeeping thing. You need that connected. I did not have my head in the game on that one...

Dan

[examiner]

I started w/ Jim's tips first. Thanks Dan, I was gonna ask how to do
that!

Disconnected A1J5. Had a brand new connector laying around, so snipped
off pin 10 (top one on the 80b sideways configuration which if I read
the schematics correctly is the slam switch line) and crimped a new pin
on. Replaced pin and connector, powered up with only that pin
connected. I am getting the same behavior. All 0's on top display, all
0's except the last digit on player 4 on bottom display (last digit
still shows a 3). With AIJ5 disconnected, I get "slam switch open"
message on top and all zeros on bottom display.

Keeping only that one pin connector hooked up, I manually held the slam
switch open at the coin door and re-powered. I got the "slam switch
open" message on display 1. For what it's worth, I tested continuity
from the slam switch leafs to ground in the NC position, and I have
that. If I manually separate the switches, I lose continuity. I would
assume that is expected behavior.

So it's as if the CPU recognizes when the slam switch is open (i get the
message) and when it's closed (i don't get the message) but something in
the circuit is buggered up and that's where I get lost. I thought the
only purpose was to provide a ground, which it appears to be doing.

Still haven't replaced the filter cap or tied the cabinet grounds
together, but this is solid repeatable behavior so I wouldn't think they
would contribute.

[examiner]

schematics show that line goes to Z26 Pin 13 (a 7404). I'm not very
good at schematics, but it looks like all that does is provide ground to
the 5 volts and then feeds into U5, which is the display control chip.
Then I get completely lost.

[examiner]

WTF?

Pulled the board to do some of the MM checks Dan suggested (can't find
any problems)

noticed a component that had obviously been replaced. R7. Schematics
call for a 4.7k ohm resistor.

The new board has a diode in that position. This can't possibly be an
"upgrade" of some type can it? If you are interested, here's some pics.
First pic is the new board I just paid good $ for, second pic is the
old board.

http://s236.photobucket.com/albums/ff285/examiner_01/Sys80b%20boards/

[examiner]

sorry, that's supposed to be a 62 ohm resistor, and that's what I
measure on the old board

[GPE]

It's a blocking diode that somebody installed.
Apparently, the previous person removed the trickle charge resistor (62
ohms) and replaced with a blocking diode. Must have decided not to replace
batteries with rechargeables. If you have a Nicad or memory on the board -
don't expect it to work.

Ed

"examiner" wrote in message news:examine...@rrgparchive.com...

[GPE]

Argh!
That should read "If you have a Nicad or 1F capacitor (memory cap) on the

board -
don't expect it to work."

Ed

"GPE" wrote in message
news:5aqdnW1ZMYCtAO3N...@giganews.com...

[Gott Lieb?]

My money is on a lithium replacement.

Jim

GPE;2004155 Wrote:
> It's a blocking diode that somebody installed.
> Apparently, the previous person removed the trickle charge resistor (62
>
> ohms) and replaced with a blocking diode. Must have decided not to
> replace
> batteries with rechargeables. If you have a Nicad or memory on the
> board -
> don't expect it to work.
>
> Ed
>

> "examiner" wrote in message news:examiner.5k15cl (AT) rrgparchive (DOT)

> com...
>
> sorry, that's supposed to be a 62 ohm resistor, and that's what I
> measure on the old board
>
> --
> examiner
> This USENET post sent from http://rgparchive.com

--
Gott Lieb?

[examiner]

OK, it does appear to be a lithium battery replacement. Didn't realize
that was part of the charging circuit.

Any more thoughts on my slam switch issue?

[Gott Lieb?]

Try booting the game with the display disconnected. You will be able to
see if it booted by viewing the strobing controlled lamps on the PF.

If it doesn't boot w/ the display disconnected, reconnect it, and
disconnect the sound board. Connect / reconnect with the power off
every time.

Jim

QUOTE=examiner;2004247]OK, it does appear to be a lithium battery

replacement. Didn't realize that was part of the charging circuit.

Any more thoughts on my slam switch issue?


--

Gott Lieb?

[examiner]

Thanks Jim.

Went ahead and hooked all connectors up for the first time. (never had
the driver board in the equation until just now)

In both scenarios you requested, machine flashes on briefly and then the
tilt relay engages and the machine freezes with a couple of the
controlled lights stuck on.

With the display hooked up but no soundboard, I can see it boots to all
zeros....in about a second I can hear the tilt relay engage (GI turns
off), the display flashes and I end up with the "3" digit in the last
position of the player 4 display.

With soundboard hooked up but no display, I get the brief start-up tune
before the tilt relay engages and shuts everything down.

Popped pin 10 out of A1J5, kept everything else hooked up. Boots into
the "slam switch open" display as would be expected.

That tell you anything? Thanks again. Debating defeating the slam
switch, but it still appears to be working appropriately, at least up to
the point it hits the MPU. Logic tells me if I defeat it at the board,
I'll just end up in the permanently frozen state.


--
examiner

[Gott Lieb?]

Try disconnecting driver board and jacking up 5v to about 5.2v (5.15v on
CPU board).

Jim

Gott Lieb?

[examiner]

done, driver board disconnected again. Getting 5.16 across the CPU
cap.

No change. Display briefly flashes 0's, then a second later it surges
and the 3 shows up again the P4 display.


--
examiner

[Steve Charland]

Is it possible that there could be a logic problem with the ROM's
or piggyback board solder issue at U2/3? Maybe a solder bridge?

Steve
System 80, not just a job, it's an adventure
(posting from an old account)

[Gott Lieb?]

The last thing I can think of is to check the game roms. Make certain
they are seated properly and a leg is not bent over or out of its
socket.

Jim

examiner;2004368 Wrote:
> done, driver board disconnected again. Getting 5.16 across the CPU
> cap.
>
> No change. Display briefly flashes 0's, then a second later it surges
> and the 3 shows up again the P4 display.


--

Gott Lieb?

[Steve Charland]

Jim, I haven't worked with that many 80B's, which game did Gottlieb
start making the slam switch as open instead of closed? Is there also
a CPU board jumper associated with this? If so, perhaps it's in the
wrong via and was missed at the bench test? (works enough to show life
on the board but not be playable) Just shooting it the dark here.

-S (CARGPB1 posting from an old account)

[Steve Charland]

My thinking is a late 80B CPU board in an early 80B game.

[examiner]

Reseated both of the game proms with no change.

Then pulled out both of the proms from my busted board (one of the edge
connectors got busted, most of the board was in good shape).

Replaced Prom 1 on the daughterboard. No change.

Replaced Prom 2 - BINGO!! Fired right up into attract mode text.

Hooked the rest of the playfield up, and my attract lights are chugging
along just fine.

Kind of pisses me off the retailer shipped a bad rom then told me to
"hire a tech", but oh well. I guess it only cost me 2 days of pulling
out what little hair I have left.

Thank you so much to everybody for taking the time to stick through this
with me, I really appreciate all the help. Maybe someday I'll be able
to pass along what I've learned.

Greg


--
examiner

[Gott Lieb?]

Bad Girls was the first w/ a NO slam switch, IIRC. It was the last 4
games that had a NO slam.

Jim

Steve Charland;2004376 Wrote:
> Jim, I haven't worked with that many 80B's, which game did Gottlieb
> start making the slam switch as open instead of closed? Is there also
> a CPU board jumper associated with this? If so, perhaps it's in the
> wrong via and was missed at the bench test? (works enough to show life
> on the board but not be playable) Just shooting it the dark here.
>
> -S (CARGPB1 posting from an old account)
>

> On Oct 7, 7:06*am, Gott Lieb? <r... (AT) papinball (DOT) com> wrote:
> > The last thing I can think of is to check the game roms. *Make

> certain
> > they are seated properly and a leg is not bent over or out of its
> > socket.
> >
> > Jim
> >
> > examiner;2004368 Wrote:
> >

> > > done, driver board disconnected again. *Getting 5.16 across the CPU
> > > cap.
> >
> > > No change. *Display briefly flashes 0's, then a second later it

> surges
> > > and the 3 shows up again the P4 display.
> >
> > --
> > Gott Lieb?

> > This USENET post sent from *http://rgparchive.com

[Gott Lieb?]

Congrats! I would inspect the prom 2 that you removed, see if it is all
right physically, and try reinstalling it.

Jim

Gott Lieb?

[Steve Charland]

Sweet! Glad you got it working Greg. The other guy probably didn't
doublecheck check his work in a working game. ;)

Steve
System 80, not just a job, it's an adventure

(posting from an old account)

[Steve Charland]

One to jam into my memory banks ... last 4 80B games, got it. :)
Do you know if there are differing CPU jumper settings from the early
to later 80B's?

Steve
System 80, not just a job, it's an adventure

(posting from an old account)

On Oct 7, 7:44 am, Gott Lieb? <r...@papinball.com> wrote:
> Bad Girls was the first w/ a NO slam switch, IIRC.  It was the last 4
> games that had a NO slam.
>
> Jim

[Gott Lieb?]

You should check out this site on occasion - http://tinyurl.com/7xdupej.
I see that you have some things posted there too. ;)

Jim

Steve Charland;2004396 Wrote:
> One to jam into my memory banks ... last 4 80B games, got it. :)
> Do you know if there are differing CPU jumper settings from the early
> to later 80B's?
>
> Steve
> System 80, not just a job, it's an adventure
> (posting from an old account)
>

> On Oct 7, 7:44*am, Gott Lieb? <r... (AT) papinball (DOT) com> wrote:
> > Bad Girls was the first w/ a NO slam switch, IIRC. *It was the last 4

> > games that had a NO slam.
> >
> > Jim
> > --
> > Gott Lieb?

> > This USENET post sent from *http://rgparchive.com

[Steve Charland]

LOL, just snorted my coffee. Yeah, I should look there once in a
while, I see that you and Chris are doing an awesome job filling in
the blanks for everyone. Thanks for doing that go to you both.

-s (CARGPB1 posting from an old account)

On Oct 7, 8:22 am, Gott Lieb? <r...@papinball.com> wrote:
> You should check out this site on occasion -http://tinyurl.com/7xdupej.

> I see that you have some things posted there too. ;)
>
> Jim

[examiner]

Ya, already tried that for giggles. Prom 2 causes the problem for some
reason. No biggie, I know crap happens.

Just fired it up ran the tests (all OK) and played a game. Seems like I
only have one issue right now - end of ball logic causes the game to
freeze.

If I don't score on ball one, outhole/trough switch works and it kicks
out a pity ball like it should. If I get 3 ball multiball going, balls
one and two can drain, kick over and things continue as expected. But
when the 3rd ball drains, (i.e. end of ball) it locks up. Switches all
test out fine, which makes me think it's not a diode issue but that's
just a knee jerk thought.

Oh well, never expected it to be easy. I'll start digging on that.
Ordered a few things from Ed to button up some loose ends (finish
rebuilding the connectors on the driver board, new filter cap, new pot
for the PS just to be sure) and I'll tie the grounds together in the
cabinet.

Thanks again for the help. At this point at least I've got a machine
that will let me play a 1 ball game (albeit not keep a high score cuz it
freezes at the end).

greg


--
examiner

[Gott Lieb?]

With one ball in the outhole and the other two in the trough, put the
game into switch test. Are these the only two switches registering?

Jim

Gott Lieb?

[Dan Beck]

Hi Greg, congrats on the find! There is not much in the data base for 80B, so any contribution is great. As for the new findings, you will want to make sure your solenoid grounds are solid (sounds like they are already), and you may want to inspect/ maybe repin the control/ driver connector.

Regards,
Dan

[examiner]

Gott Lieb?;2004443 Wrote:
> With one ball in the outhole and the other two in the trough, put the
> game into switch test. Are these the only two switches registering?
>
> Jim

Ya, 20 & 66. Outhole and ball trough. The way the trough is set up
though, there shouldn't be any period of time when a ball is on both
switches. But I tried every combination...ball on each individually,
ball on both, ball on neither. Switch report shows everything as
expected.

Score no points on the first ball, and it will immediately serve another
one and the CPU keeps running fine. On 3 ball multi, balls 1 and 2 can
drain and both will immediately kick over to the trough and be ready to
be served and the CPU will keep chugging along. But whenever we get to
"end of ball", it freezes. Doesn't reboot. Requires a power off/on to
get it going again.

I'm 99% sure it's not a mechanical or physical issue, based on the fact
it works under certain scenarios. I backtracked and put all my dips
off, no change. Oh - seems as if the knocker was going off
simultaneously with the CPU freezing up. I disconnected the knocker,
but no change. I reset all the high scores to extremely high numbers
(thinking maybe I was "winning" a game since the memory was empty), but
no change there either.

After chasing this other issue for 2 days, I'm probably overlooking
something simple. Or maybe it's just a connector.


--
examiner

[examiner]

Probably should add this could be the same freezing behavior I was
seeing before I pulled the old board and it got run over. I was so
stinking mad at that point I don't remember..... As usual with these
80b's, I bought the game nonworking. I got it going by fiddling with
the daughterboard, adjusting 5v and changing out some fuses, and I know
I was able to play some complete games (entered initials, etc.) before
it started acting up on me again and got busted.

I just tried another cpu/driver board interconnect harness, and same
behavior.

I was running the "old" rom set, so I put the "new" rom1 into the
daughterboard. No change, but at least it works. Took yet another shot
with rom2, and went back to the old slam switch behavior so it's
definitely corrupt. So at this point I'm running one new rom and one
old rom. I really have no idea what rom2 does - any possibility that
could be an issue? I don't have the depth of experience you guys have,
but the fact it works under some scenarios and not under another
specific scenario makes me wonder if it isn't another CPU logic issue.

oh well, gonna watch the Cardinals beat the Nationals and jump over
periodically and watch the Bears get victory #4. Thanks again.

greg

[quattrohead]

I am suffering this exact issue with a Bad Girls, bought with a missing CPU.
I have a "should be working" CPU so I burned the 2764 rom 2 but could not get the burner to do a 2732, so I doubled the image and put it on a 2764, tied pins 26,27 and 28 together and hung the top 4 pins out of the top of the socket.
It will boot and show if the slam or tilt switches are not to its liking, but that is about it.