Re: TECH: Totally bizarre system 80b Arena problems

On Apr 5, 6:26 pm, Hunty <luvcr...@xxxxxxxxx> wrote:
On Apr 5, 4:43 pm, biscuitbe...@xxxxxxxxxxxx wrote:



On Apr 5, 3:30 pm, Hunty <luvcr...@xxxxxxxxx> wrote:

(I'm breaking this off into a new thread because some people were
having trouble posting in the old one. The old one is athttp://groups..google.com/group/rec.games.pinball/tree/browse_frm/thre...
)

On Apr 5, 3:49 pm, biscuitbe...@xxxxxxxxxxxx wrote:

On Apr 5, 1:12 pm, Hunty <luvcr...@xxxxxxxxx> wrote:
OK, I'm bringing this problem to the group to get more input, and also
to save it for posterity when I (hopefully) finally figure it out and
get it fixed.

To recap what I've written elsewhere in this thread, I picked up a
Gottlieb Arena a couple months ago. It wouldn't play, and the
diagnostic mode would freeze at the lamp test. Someone suggested
turning off all the dip switches, which I did, and at that point it
would run the diagnostics, but it said that the switches in the 0
column were all closed. This told me that chip z13 and possibly chip
z14 were bad on the mpu board, so I replaced them, and then it would
finally play, but it wouldn't detect switch matrix rows x4 and x5.. I
tried swapping the RIOT chips at U4 and U5 to try to diagnose the
problem, but I didn't do a very good job of soldering them, and when I
put the board back in the machine it wouldn't boot.

So, at that point I sent to board to Chris Hibler for repairs. He
diagnosed that one of the RIOT chips was indeed bad, and replaced it,
and also put in nice machine pin sockets for U4 and U5, and tested it
in his Victory (another System 80b game) to make sure that it worked.
He sent it back, I put it back in my machine, and it still wouldn't
boot. :(

Playing around with it, I DID get it to do something once (and only
once) by holding in the test button as I powered it on; it showed all
zeros on the display, and played the startup tune, but wouldn't do
anything else. We thought that maybe this indicated bad proms, so I
got some known-good replacement proms, but it still wouldn't boot.. I
stripped it down to just the power and display connected to the MPU
board, but still nothing. Then I connected everything back to the MPU
board to see if it would do SOMETHING, but it still wouldn't.

I left it on while I scoured Clay's guide for ideas on what to do
next, and after it was on for a few minutes it started beeping,
playing random sound effects, firing random solenoids, and displaying
garbage on the screen. I turned it off and back on, and every time it
would do one or more of these things after being on for about 30
seconds. If I stripped it back down to just the power connector and
the display connector, it would do nothing again, but with other
things added it would do random things. At that point I gave up on it
for the night.

So, just now, I went back to trying to diagnose it, and on a lark I
decided to connect everything EXCEPT the display. In THAT
configuration, it would play the first second of the startup tune over
and over again, and it would do this reliably every time I started it
up. I disconnected the reset board, and then it would play either the
first second of the startup tune and then beep and go silent, or play
the whole startup tune and then go silent. It would not register
credits in either of these configurations, and without a display I
couldn't run the diagnostics.

So, here's what I've got at this point:

Before I tried to swap the U4 and U5 RIOT chips, everything was
working correctly except for two rows of switches.
The MPU board tests good in another system 80b machine.
The proms have been replaced with known-good proms.
The MPU board and the driver board have the ground mod.
The power supply puts out a steady 5.2vdc.
Starting with just the power and display connected produces no
results.
Starting with everything connected produces no results for about 30
seconds to two minutes, and then random behavior after that.
Starting with everything except the display connected produces the
first second of the startup sound looped.
Starting with everything except the display and reset board connected
produces either the first second of the startup sound followed by a
beep, or the full startup sound.

So, what should I do next? At this point I'm starting to suspect that
I somehow destroyed every single board in the machine when I swapped
those RIOT chips, and now that I've repaired the MPU board I'm going
to have to follow it up by repairing or replacing every single other
board. :(

Hello,

a few thoughts...

First of all, until that cpu boots correctly and you are able to
complete a
four player game, that reset board should NOT be connected in any way
to
your board, ever.  The reset board has been shown to be a confounder
to
System 80 diagnosis over and over again in RGP postings, and it is
NOT
necessary for the game to function perfectly, especially in the home
setting.  My experiences with it confirm the RGP opinion.

One of Steve Charland's dictums involves the operation of turning off
all
the dip switches.  My modest understanding of it leads me to believe
if you
perform this operation, and it makes a flaky board less flaky, then
perhaps
Z15 is at fault.  That Chris Hibler was able to use your board in his
game
puts holes in this idea, but still with System 80 you never know...

Getting back to Chris using the board successfully in his game...
Another
variable that perhaps you have not accounted for is the driver board.
I am
presuming Chris's driver board is working 100%, and the one in your
game is
flaky...

A game that spontaneously fires solenoids, plays random sounds, and
the like
certainly could implicate the U6 RIOT.  After all, it is this RIOT,
and its
TTL chips downstream, that controls such things.  Plenty of culprits
there.
Again, why this was not picked up when Chris had it puts holes in this
idea
as well...

Another dictum:  Connectors, connectors, connectors, and grounds,
grounds,
grounds...

I have never heard of an 80B score display having a leaky ground
causing
trouble, but I guess it is not beyond the realm of possibility...

Simply in terms of keeping this topic available for the rest of us to
ponder...  You may want to start an entirely new thread, with a link
to the
old thread.  Unfortunately I have to post this through google, rather
than my newsreader.  My guess is my newsreader does not like how old
the original thread is.

Regards,
Dan

Is it possible that one of the other boards in my Arena has something
wrong with it that fried the MPU board when I put it back in?
Unfortunately I don't know anyone else local with a system 80b
machine, and I'd hate to ship it all the way back to Chris to test it
again after he had it working before to see if it's broken again. :(

Also, all the dip switches on this board are off, as they have been
since I turned them all off to diagnose a bad z13 chip before this
mess with the RIOT chips.

I have considered that the driver board is bad, but even when it's
disconnected nothing comes up on the display at boot. Unfortunately, I
sold my MGOW last week, so I can't try swapping driver boards with it
to see if it changes anything. I'll note that the driver board DID
appear to be working after I replaced z13 and z14 and before I messed
with the RIOT chips.- Hide quoted text -

- Show quoted text -

Hmmm,

this is a far-fetched idea, but here it goes...

Set the dip switches as you would to set up the game in your game
room, e.g. attract sounds on, extra ball/replay, etc.  Maybe the game
is "confused" because all the dip switches are off...

Please check to make sure your 5 VDC does not sag under load.

Regards,
Dan

Nope, that didn't make any difference.

BUT!! I've finally found something that doesn't test right! Display
board pins 1 and 2, which are supposed to get 6.5vac, only get 1.5vac!
The schematic says that those two lines are on fuses 9 and 9a on the
transformer board, but there are only 8 fuses on the transformer
board! (And the transformer board is the only thing for which there is
no sketch in the instructions.)

Where are those two fuses?

AHA!!!! The fuse list cover thingy was floating around the bottom of
the cabinet, but I found it and used it to find the two fuses, and my
fuse 9 is bad!!! So, now I'm off to Radio Shack for a 1amp fuse! Wish
me luck!

I'm sure this won't fix everything, but I hope it will at least help!
.

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