tech:Stern problems

G

Guest

Guest
Archived from groups: rec.games.pinball (More info?)

HI everyone!

Got a flight 2000 for free recently and i decided to bring it back to
life. Now i have an mpu that doesn't run it's locked up with the led on
all the time. My uiestion would be that i heard that there's a rather
small amount of variation in the 5v line that these boards can cope
with. is 5.3-5.4 volts all right or is that too high? Another thing is
that when it's turned one of the displays has its leftmost segment
displaying a 0 periodaically. Basically it's flickering. Any ideas as
to what that could be?
 
G

Guest

Guest
Archived from groups: rec.games.pinball (More info?)

These boards are only as finicky as the most senstive component. All
TTL will run on a minimum of +/- 10% supply. I've had TTL run at 8
volts and 3.5 volts. 5.4 volts is fine, not the problem.

The displays are not diagnosable with a locked MPU. They get their
data from the MPU, so if it's not working right, no telling what the
displays will do. Get that going and then see if the displays are
still flaky.

K2
 
G

Guest

Guest
Archived from groups: rec.games.pinball (More info?)

I just read the Motorola MC6800 datasheet. Here are the numbers
Motorola gives:

Maximum supply voltage: 7 volts

Minimum logic high threshold: 2.0 volts. Any signal with more than 2
volts is guaranteed to be considered a logic high by the processor.

Maximum logic low threshold: 0.8 volts. Anything at .8 volts or below
is guaranteed to be considered a logic low by the microprocessor.

The 5101 RAM datasheet also lists 7.0V as an absolute max input
voltage, with a "typical" max of 5.25 volts. The threshold voltages
are a bit more sensitive, but the no man's land of uncertain voltage
is still .7v to 2.2v.

The 6821's and TTL chips are rated the same as the 6800, just to cover
my bases.

So if you have a part on a Bally/Stern MPU that read 3.6 volts as a
logic low and reset the device, then the chip was bad or there were
other issues. Having a large AC component on the supply voltage due
to a bad power supply cap or noise due to corrosion or bad/missing .01
uF caps are likely candidates.

In summary, the voltage thresholds that matter are .7 and 2.2 volts.
As long as you are within the max supply ratings of the devices, these
limits are acccurate. I can go into the internal comparator structure
of the chips if you want to know how they know what to do, but I think
that's too dull, even for me.... :)

I hope I don't come across as flaming, that is not my intent. I just
like to keep things accurate whan I can.
K2
 
G

Guest

Guest
Archived from groups: rec.games.pinball (More info?)

There are dozens of things that can cause the famous "LED stuck on" symptom.

I'd start by going over your power supply and solenoid/voltage regulator
board to make sure everything is healthy- worn/old parts and connectors are
replaced, that upgrade mods are done, and that everything is tip-top before
moving on to the MPU. We have some info on solenoid/regulator board mods
and associated things to check on our website at: www.actionpinball.com in
the Technical Articles section- recommended reading.

Beyond that, you may have a failed component on the MPU board that is in
need of qualified repair. This is where it gets tricky, and as mentioned-
dozens of possibilities- really more than can be typed/explained here. If
you get to the point where you may want to send the board out for
inspection/repair, check with some of the repair shops listed on our site
(URL above) in the Game Service & Repair section.

I wouldn't worry about the display digit flickering right now- get the MPU
to boot first then move on to what else is still present or pops up after
that. All one step at a time.

Great game- congrats- good luck!

Ray J.
--
Action Pinball & Amusement, LLC
Salt Lake City, Utah USA
Web: www.actionpinball.com

We're serious about pinball. Anything else is just for fun!



"EdHunTer<eddietheremovethised@walla.com>" <eddietheed@walla.com> wrote in
message news:1121622786.330647.124060@z14g2000cwz.googlegroups.com...
> HI everyone!
>
> Got a flight 2000 for free recently and i decided to bring it back to
> life. Now i have an mpu that doesn't run it's locked up with the led on
> all the time. My uiestion would be that i heard that there's a rather
> small amount of variation in the 5v line that these boards can cope
> with. is 5.3-5.4 volts all right or is that too high? Another thing is
> that when it's turned one of the displays has its leftmost segment
> displaying a 0 periodaically. Basically it's flickering. Any ideas as
> to what that could be?
>
 
G

Guest

Guest
Archived from groups: rec.games.pinball (More info?)

5.4 is a tad high. I've seen 5.2 and 5.3 on occasion in some Stern MPU-200
and Bally -35 games- and still running okay- but suspiciously high. Worth
giving the power supply/regulator a "once-over" to replace any old/bad parts
and many any necessary changes- the regulator should be putting out 5.0vdc-
most of these games I've worked on have had 5.0 to 5.1vdc- rarely anything
below or above that, so this is a bit out of the norm.

The 6800 CPU chip on the MPU will reset at 3.6vdc, and when you're getting
higher than 5.0-5.1vdc you're pushing the envelope and may get high enough
for the CPU chip to "jump track" and lock up or act erratically. The higher
voltage in this game could also be indicative of other problems like high
voltage having gone through the board due to a short or power surge and
maybe fried the ROM chips and/or 5101 CMOS RAM chips- the ROMs and RAM are
usually the first to go in a power spike or overvoltage situation.

Ray J.
--
Action Pinball & Amusement, LLC
Salt Lake City, Utah USA
Web: www.actionpinball.com

We're serious about pinball. Anything else is just for fun!



<kenny_iik@yahoo.com> wrote in message
news:1121627761.231507.260000@g47g2000cwa.googlegroups.com...
> These boards are only as finicky as the most senstive component. All
> TTL will run on a minimum of +/- 10% supply. I've had TTL run at 8
> volts and 3.5 volts. 5.4 volts is fine, not the problem.
>
> The displays are not diagnosable with a locked MPU. They get their
> data from the MPU, so if it's not working right, no telling what the
> displays will do. Get that going and then see if the displays are
> still flaky.
>
> K2
>
 
G

Guest

Guest
Archived from groups: rec.games.pinball (More info?)

Ok let's put this another way...
logic power needs to be 4.9 vdc to 5.2 vdc as measure at the
MPU test points. there are more than just the 4 chips you listed
on the board. and they all like 4.9 to 5.2 volts. make sure it's
in that range. and make sure there is .200 volts AC in the 5 volt
DC rail.

kenny_iik@yahoo.com wrote:
> I just read the Motorola MC6800 datasheet. Here are the numbers
> Motorola gives:
>
> Maximum supply voltage: 7 volts
>
> Minimum logic high threshold: 2.0 volts. Any signal with more than 2
> volts is guaranteed to be considered a logic high by the processor.
>
> Maximum logic low threshold: 0.8 volts. Anything at .8 volts or below
> is guaranteed to be considered a logic low by the microprocessor.
>
> The 5101 RAM datasheet also lists 7.0V as an absolute max input
> voltage, with a "typical" max of 5.25 volts. The threshold voltages
> are a bit more sensitive, but the no man's land of uncertain voltage
> is still .7v to 2.2v.
>
> The 6821's and TTL chips are rated the same as the 6800, just to cover
> my bases.
>
> So if you have a part on a Bally/Stern MPU that read 3.6 volts as a
> logic low and reset the device, then the chip was bad or there were
> other issues. Having a large AC component on the supply voltage due
> to a bad power supply cap or noise due to corrosion or bad/missing .01
> uF caps are likely candidates.
>
> In summary, the voltage thresholds that matter are .7 and 2.2 volts.
> As long as you are within the max supply ratings of the devices, these
> limits are acccurate. I can go into the internal comparator structure
> of the chips if you want to know how they know what to do, but I think
> that's too dull, even for me.... :)
>
> I hope I don't come across as flaming, that is not my intent. I just
> like to keep things accurate whan I can.
> K2
 
G

Guest

Guest
Archived from groups: rec.games.pinball (More info?)

Ok let's put this another way...
logic power needs to be 4.9 vdc to 5.2 vdc as measure at the
MPU test points. there are more than just the 4 chips you listed
on the board. and they all like 4.9 to 5.2 volts. make sure it's
in that range. and make sure there is .200 volts AC or less in
the 5 volt DC rail.

kenny_iik@yahoo.com wrote:
> I just read the Motorola MC6800 datasheet. Here are the numbers
> Motorola gives:
>
> Maximum supply voltage: 7 volts
>
> Minimum logic high threshold: 2.0 volts. Any signal with more than 2
> volts is guaranteed to be considered a logic high by the processor.
>
> Maximum logic low threshold: 0.8 volts. Anything at .8 volts or below
> is guaranteed to be considered a logic low by the microprocessor.
>
> The 5101 RAM datasheet also lists 7.0V as an absolute max input
> voltage, with a "typical" max of 5.25 volts. The threshold voltages
> are a bit more sensitive, but the no man's land of uncertain voltage
> is still .7v to 2.2v.
>
> The 6821's and TTL chips are rated the same as the 6800, just to cover
> my bases.
>
> So if you have a part on a Bally/Stern MPU that read 3.6 volts as a
> logic low and reset the device, then the chip was bad or there were
> other issues. Having a large AC component on the supply voltage due
> to a bad power supply cap or noise due to corrosion or bad/missing .01
> uF caps are likely candidates.
>
> In summary, the voltage thresholds that matter are .7 and 2.2 volts.
> As long as you are within the max supply ratings of the devices, these
> limits are acccurate. I can go into the internal comparator structure
> of the chips if you want to know how they know what to do, but I think
> that's too dull, even for me.... :)
>
> I hope I don't come across as flaming, that is not my intent. I just
> like to keep things accurate whan I can.
> K2
 
G

Guest

Guest
Archived from groups: rec.games.pinball (More info?)

Okay i looked through most of the other internals. The rectifier board
has a lot of hackjobsbut it seems to be putting out more or less
accurate voltages. There are only .01-.02 differences. I also tried
putting it on my testbench (pc psu) problem is the psu doesn't put out
exact voltages (since pcs are more tolerant for voltage differences the
regulation isn't as exact) the 12 volts is somewhere around 15 if i
remember correctly and 5 volts is around 6. I measured the pins on u9
as per marvin3m.com and all are higher with at least 1 volts tho none
are over 7 volts. none of the data lines have a signal train(pulsing
signal)
If i reset the u9 cpu by shorting legs 40 and 39 the signal train
arrives on leg 5 but it stops after a while (at first it stayed on
after a reset but it is stuck high now) and stays high also i get no
clock signals on u9 pins: 3 36 37. Any ideas? i think that getting the
pulse on pin 5 will disqualify the opportunity of the u9 being bad. Any
thoughts suggestions?
 
G

Guest

Guest
Archived from groups: rec.games.pinball (More info?)

I forgot to ask am i correct in stating that r11 can be replaced aith a
resistor the same value but of higher wattage ?