TECH: TZ Clock Problems Continue

[Eric]

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

I am still having trouble with clock on Twilight Zone.

Description of Problem:
The clock will start up ok during power-up and go forward 2 hours and back
to 12 o'clock with no problems. I can start up a game and go into a door
panel mode that utilizes the clock. It seems sometimes after the mode has
completed, the clock will try to return to 12 o'clock but get "lost" and
stop at some random time and not move the rest of the game. It doesn't
always break after a panel mode though. When a new player starts a game or
I cycle power, the clock works fine. During the test mode, the forward
function always works, but sometimes the reverse won't work, or works slower
during the test mode. The optos always seem to register fine.

Repair Attempts so far:
I replaced the original boards with a new set of boards from PBliz (the LED
version). I also replaced the IDC connectors at the base of the clock with
crimp-ons. I also put crimp-on trifurcon connectors on the motor driver
board and reflowed the solder connections on the motor driver board.

At this time, I'm just stumped. Any advice would be appreciated.
thanks,
Eric

 

[martin]

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

If the clock doesn't run properly in reverse, then the software will
likely have a problem. First, I would try reversing the wires to the
motor. If the forward motion is now erratic, it is the driver board or
back. If the reverse ode is still erratic, then it is the motor and
geartrain. If it looks mechanical, I would pull the click out, and see
if you can't get the mechanism running smoothly.

 

[otto]

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

Are the hands bent properly so that they consistently interupt the optos?


Otto

CARGPB11

My web page: http://home.bellsouth.net/p/PWP-Ottoslanding

"Eric" <estrangeway@NOcharter.SPAMMERSnet> wrote in message
news:da7Te.28196$1g2.16577@fe05.lga...
>I am still having trouble with clock on Twilight Zone.

 

[Eric]

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

The hands of the clock are ok. During the test mode when I run the clock
forward, the optos are perfect. It just seems to lock up after a door panel
mode and then is ok when a new game is started or power is cycled.

Eric
"Otto" <ottondebremove&%$*@bellsouth.net> wrote in message
news:FP7Te.11095$VU6.4076@bignews5.bellsouth.net...
> Are the hands bent properly so that they consistently interupt the optos?
>
>
> Otto
>
> CARGPB11
>
> My web page: http://home.bellsouth.net/p/PWP-Ottoslanding
>
> "Eric" <estrangeway@NOcharter.SPAMMERSnet> wrote in message
> news:da7Te.28196$1g2.16577@fe05.lga...
> >I am still having trouble with clock on Twilight Zone.
>
>

 

[otto]

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

You may also want to give Joel(@ Pinliz) a buzz on the phone during normal
business hours.

He provides excellent tech support for his customers.


Otto

CARGPB11

My web page: http://home.bellsouth.net/p/PWP-Ottoslanding

"Eric" <estrangeway@NOcharter.SPAMMERSnet> wrote in message
news:da7Te.28196$1g2.16577@fe05.lga...
>I am still having trouble with clock on Twilight Zone.

 

[Guest]

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

Excellent advice, but JC may be out of pocket
for the moment.

Try emailing to see when it is best to contact, first.

It sounds like the electric motor itself may have a
problem to me. (As Martin also suggests.)

--
Fred
TX
CARGPB#8
******************


"Otto" <ottondebremove&%$*@bellsouth.net> wrote

> You may also want to give Joel(@ Pinliz) a buzz on the phone during normal
> business hours.
>
> He provides excellent tech support for his customers.

 

[martin]

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

Yes, you really need to do that reverse wire test to eliminate the
control electronics. At this point, the clock boards are not suspect.

 

[Eric]

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

I will try the motor test tonite.
thanks,
Eric

"martin" <martin.reynolds@gmail.com> wrote in message
news:1125995761.639562.58400@g44g2000cwa.googlegroups.com...
> Yes, you really need to do that reverse wire test to eliminate the
> control electronics. At this point, the clock boards are not suspect.
>

 

[Eric]

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

An email has been sent to Joel. I emailed him a few weeks ago but I think
he was taking an extended vacation.
Eric
"Fred Kemper" <pbgarage@davlin.net> wrote in message
news:dfjam60kbm@enews3.newsguy.com...
> Excellent advice, but JC may be out of pocket
> for the moment.
>
> Try emailing to see when it is best to contact, first.
>
> It sounds like the electric motor itself may have a
> problem to me. (As Martin also suggests.)
>
> --
> Fred
> TX
> CARGPB#8
> ******************
>
>
> "Otto" <ottondebremove&%$*@bellsouth.net> wrote
>
> > You may also want to give Joel(@ Pinliz) a buzz on the phone during
normal
> > business hours.
> >
> > He provides excellent tech support for his customers.
>
>
>

 

[Eric]

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

I reversed the two motor wires as you suggested and now the forward doesn't
work and reverse is fine. Therefore, I am narrowing my search to the motor
driver board. I have already replaced both of the IDC connectors with
crimp-ons. I also reflowed the solder joints.

Anyone have any suggestion on common problems with the TZ clock motor driver
board? Possibly an inductor gone bad? Could the problem be further up the
chain?

I'll take the board out again tomorrow and start examing components and
testing the voltages in the different modes.

Thanks again everyone for the help so far.
Eric

"martin" <martin.reynolds@gmail.com> wrote in message
news:1125974251.495805.96860@f14g2000cwb.googlegroups.com...
> If the clock doesn't run properly in reverse, then the software will
> likely have a problem. First, I would try reversing the wires to the
> motor. If the forward motion is now erratic, it is the driver board or
> back. If the reverse ode is still erratic, then it is the motor and
> geartrain. If it looks mechanical, I would pull the click out, and see
> if you can't get the mechanism running smoothly.
>

 

[Guest]

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

I can't help you, but keep posting on it. I have a TZ with a fully
working, but old and original and will eventually fail, clock I am
going to rebuild soon. I'm following this intently to learn more about
the clock.

Thanks, man.

 

[Guest]

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

Eric,

Are you familiar with H-bridges? That's how you get a motor to run
forwards and backwards. Sounds like the H-bridge or interface on the
motor drive board is suspect. Also, do not assume your clock hands are
OK. My TZ worked fine in test mode and usually OK during the game, but
it would always get lost sooner or later while playing as game. Turns
out the minute hand was very slightly warped and would miss the 12 and
3 o'clock optos every so often depending on game vibration and other
playfields events. The minute hand passed through the slot just a
little high and didn't break the beam enough. That causes an
immediate clock fail mode in the software, and it stops working for a
while until it tries another test. I heated my minute hand in hot
water and bent it slightly to run deeper in the slots and it works fine
now.

K2

 

[Eric]

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

I am not familiar with H-Bridges (I assume its between the G-bridge and
I-bridge? j/k). Are you referring to L6203 dual driver chip on the clock
motor driver board? I'm going to take a look at it tonite and report my
findings.

Eric
<kenny_iik@yahoo.com> wrote in message
news:1126102607.776041.64140@g44g2000cwa.googlegroups.com...
> Eric,
>
> Are you familiar with H-bridges? That's how you get a motor to run
> forwards and backwards. Sounds like the H-bridge or interface on the
> motor drive board is suspect. Also, do not assume your clock hands are
> OK. My TZ worked fine in test mode and usually OK during the game, but
> it would always get lost sooner or later while playing as game. Turns
> out the minute hand was very slightly warped and would miss the 12 and
> 3 o'clock optos every so often depending on game vibration and other
> playfields events. The minute hand passed through the slot just a
> little high and didn't break the beam enough. That causes an
> immediate clock fail mode in the software, and it stops working for a
> while until it tries another test. I heated my minute hand in hot
> water and bent it slightly to run deeper in the slots and it works fine
> now.
>
> K2
>

 

[martin]

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

Eric, the motor test is the most important thing to do right now. If
the problem changes to the forward direction, then the clock is OK and
we have to debug the board. If the problem stays with the reverse
direction, then the problem is in the clock geartrain and mechanicals.

In fast, the voltages should (I think) be DC. To get the slow speeds,
it will be pulsed for sure.

 

[Eric]

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

Okay, I took out the motor driver board and inspected it. I found no bad
solder joints and contnuity was ok. The inductors (aka chokes?) were intact
and each had a resistance of .25 Ohms. I also tested some of the components
(in-circuit) and found nothing out of the ordinary.

I plugged connector J1 back into the board and turned on the game and went
into test mode. While probing the board, I found that the +12V supply was
13.5V so that is ok.

I then wanted to find the voltage at connector J2 so using my trusy Fluke, I
put the red prob on pin 1 and the black probe on pin 4. I am guessing that
the output to the motor is pulsed and not continuous becuase my reading was
all over the place. To try and get a better idea of what was going on, I
used the Min/Max feature of the Fluke DMM to see what the voltages were
during the four test modes. Below are the results (remember, the Fluke
tries to average and find the RMS voltages so if this is a pulsed signal,
its values are a bit munged).

Reverse Fast = 8.54Vdc
Reverse Slow = 6.07Vdc
Forward Fast = -5.27Vdc
Forward Slow = -3.10Vdc

As you can see, the Forward voltages are significantly less than the Reverse
voltages. I then went and measured the voltage coming into the L6203 driver
chip. I placed the red lead on pin 5 of the chip (IN1) and the black lead
on pin 7 of the chip (IN2). Below are the voltages I measured using the
Min/Max function on the Fluke (again, remember averaging and RMS on the
meter).

Reverse Fast = 2.39Vdc
Reverse Slow = 2.146Vdc
Forward Fast = -4.78Vdc
Forward Slow = -4.83Vdc

I looked at the schematics in the manual and it looks like they flip-flop
forward/reverse notation after the L6203 so the measuremnts show me that the
incoming voltage for the inputs may be the source of my problems.

Can someone verify with me that the output to the motor driver board is a
pulsing DC voltage to the motor? I will try and get an oscilloscope this
weekend to examine the waveform. I will continue to work up the chain and
start looking at the solenoid driver board that drives the clock motor
driver board.

Also, I did get an email from Joel (who took time out of his vacation to
email me) so thanks to him and Fred.

Again, if anyone else has any insight into this problem, I'm all ears.

Thanks,
Eric

 

[Guest]

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

Eric,

Simply put, an H bridge swaps the + and - outputs to make a DC motor
run forwards or backwards. The inductors are intended as surge/spike
protection, and have no real effect on the drive voltages. It sounds
like the 6203 drive chip itself is bad. Without the motor hooked up,
the only load on the input is the chip itself. Change it out and see
what happens. Seems to me I bought these from Mouser before at about
$8.00 a year or so ago.

K2

 

[Eric]

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

Thanks for the info. I am going to use a scope to see what the pulses look
like. It seems one leg of the circuit isn't getting the right voltage.
Eric
<kenny_iik@yahoo.com> wrote in message
news:1126190722.608060.188920@o13g2000cwo.googlegroups.com...
> Eric,
>
> Simply put, an H bridge swaps the + and - outputs to make a DC motor
> run forwards or backwards. The inductors are intended as surge/spike
> protection, and have no real effect on the drive voltages. It sounds
> like the 6203 drive chip itself is bad. Without the motor hooked up,
> the only load on the input is the chip itself. Change it out and see
> what happens. Seems to me I bought these from Mouser before at about
> $8.00 a year or so ago.
>
> K2
>

 

[martin]

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

There are still a few issues with measuring the voltage. What you
really need to measure is ground to pin 1 and ground to pin 4. Then
you will be able to precisely identify where the offsets and peaks are.
These readings will let us diagnose each of the four drive transistors.

Also, you need to look at the input voltages on the 6203. There's some
optos between them and the conector.

And did you ever try reversing the motor connections?

 

[martin]

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

Great, so the problem is narrowed down to the board. When you get back
on it, you should also check pins 8 and 4, making sure that the pump
voltage is getting back to the chip. Without the pump voltage, the
transistors can't turn fully on.

I am leaning towards a bad 6203 here, but the H bridge measurements
will tell us for sure.

Could also try switching pins 1 and 2 on J1 to see if it is a 6203
input or output problem.

 

[Eric]

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

Well, I scoped out the motor driver board on my TZ clock and was suprised
with the results.

I checked the signal coming on both inputs on the J1 connector and they
looked fine; a standard PWM signal. The cycle was 150ms. For the clock to
go fast, the duty cycle time was 25ms and for the clock to go slow the duty
cycle time was 10ms.

I then placed the probe on J2. I placed the probe on pin 1 and the ground
on pin 4. This is where things got interesting. For the reverse mode, the
voltage was positive and had a +4.0V dc offset and the pulse went up to
14Vdc. At the end of the pulse though, the voltage doesn't drop off
instantly, it decays almost like the capacitor discharge.

For the forward motor, the dc offset is +1.6V and the pulse goes down
to -3.8Vdc. When the pulse is completed, the voltage returns to the normal
level quickly as I would expect. What suprised me here was that there was
only a difference of 5 Vdc for the forward motion but the reverse motion has
a 10Vdc difference.

Well, I am really stumped now. I can email a spreadsheet that has charts of
each measurement. Just let me know if you want me to email it to you
(estrangeway@NOcharter.SPAMMERSnet)

If anyone has a clue, let me know.
thanks
Eric


<kenny_iik@yahoo.com> wrote in message
news:1126190722.608060.188920@o13g2000cwo.googlegroups.com...
> Eric,
>
> Simply put, an H bridge swaps the + and - outputs to make a DC motor
> run forwards or backwards. The inductors are intended as surge/spike
> protection, and have no real effect on the drive voltages. It sounds
> like the 6203 drive chip itself is bad. Without the motor hooked up,
> the only load on the input is the chip itself. Change it out and see
> what happens. Seems to me I bought these from Mouser before at about
> $8.00 a year or so ago.
>
> K2
>

 

[Eric]

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

Just a quick update. I wanted to look at the L6203 chip so I scoped out the
inputs and output. On IN1 to GND, the PWM signal was a normal 0 to 5V, very
clean. For IN2 to GND, the PWM signal was also clean, but only from 0V to
3.9V.

I then scoped the output (OUT1 to OUT2) and at that point, the funky
waveforms I measured before were there.


"Eric" <estrangeway@NOcharter.SPAMMERSnet> wrote in message
news:WIrUe.5502$O52.3807@fe06.lga...
> Well, I scoped out the motor driver board on my TZ clock and was suprised
> with the results.
>
> I checked the signal coming on both inputs on the J1 connector and they
> looked fine; a standard PWM signal. The cycle was 150ms. For the clock
to
> go fast, the duty cycle time was 25ms and for the clock to go slow the
duty
> cycle time was 10ms.
>
> I then placed the probe on J2. I placed the probe on pin 1 and the ground
> on pin 4. This is where things got interesting. For the reverse mode,
the
> voltage was positive and had a +4.0V dc offset and the pulse went up to
> 14Vdc. At the end of the pulse though, the voltage doesn't drop off
> instantly, it decays almost like the capacitor discharge.
>
> For the forward motor, the dc offset is +1.6V and the pulse goes down
> to -3.8Vdc. When the pulse is completed, the voltage returns to the
normal
> level quickly as I would expect. What suprised me here was that there was
> only a difference of 5 Vdc for the forward motion but the reverse motion
has
> a 10Vdc difference.
>
> Well, I am really stumped now. I can email a spreadsheet that has charts
of
> each measurement. Just let me know if you want me to email it to you
> (estrangeway@NOcharter.SPAMMERSnet)
>
> If anyone has a clue, let me know.
> thanks
> Eric
>
>
> <kenny_iik@yahoo.com> wrote in message
> news:1126190722.608060.188920@o13g2000cwo.googlegroups.com...
> > Eric,
> >
> > Simply put, an H bridge swaps the + and - outputs to make a DC motor
> > run forwards or backwards. The inductors are intended as surge/spike
> > protection, and have no real effect on the drive voltages. It sounds
> > like the 6203 drive chip itself is bad. Without the motor hooked up,
> > the only load on the input is the chip itself. Change it out and see
> > what happens. Seems to me I bought these from Mouser before at about
> > $8.00 a year or so ago.
> >
> > K2
> >
>
>

 

[Eric]

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

Hi Martin,
I will measure pin 1 to GND and pin 4 to GND tomorrow morning (I'm getting
pretty tired and with my luck I'd blow up something).

I did reverse the motor connections and that problem followed the swap (IE
originally, I had problems with reverse and the forward was ok. I then
swapped the wires and reverse was ok but forward was messed up).

Thanks,
Eric

"martin" <martin.reynolds@gmail.com> wrote in message
news:1126322529.158803.3930@g44g2000cwa.googlegroups.com...
> There are still a few issues with measuring the voltage. What you
> really need to measure is ground to pin 1 and ground to pin 4. Then
> you will be able to precisely identify where the offsets and peaks are.
> These readings will let us diagnose each of the four drive transistors.
>
> Also, you need to look at the input voltages on the 6203. There's some
> optos between them and the conector.
>
> And did you ever try reversing the motor connections?
>

 

[martin]

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

I assumed that you had a handheld scope. Sounds like you have a line
powered one, you are shorting the bridge output to ground which is why
you see the funny voltages.

The decay is not that much of an issue, but you should also see it on
the low side.

It sounds like your high voltage transistors are good. Can you look at
the low pin (i.e. pin 1) when in reverse mode? see what the voltage
there does?

It might be possible to do a simple patch to add a transistor to fix
the problem. You'll need a TIP122. Collector would go to the forward
pin on the L6203; emitter to ground; base to the approrpriate input on
the L6203.

 

[Eric]

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

Well, I think the culprit is the L6203 motor driver IC. I looked at a bunch
of stuff with the scope and kept coming back to output of L6203 being
screwed up. Just an FYI, when I use the terms forward and reverse, I am
referring to the mode that I have running in the test function.

I checked the Enable signal and both of the IN1 and IN2 signals and they
were ok. I checked the BOOT1 and BOOT2 pins and they were both about
+10Vdc. The Vs was at +12V.

I then wanted to check the ouptuts (OUT1 and OUT2) of the L6203. I hooked
up the scope from OUT1 to GND and then OUT2 to ground. Both of the signals
went up to about +12.5V, but the reverse (pin 3) had the goofy voltage
decay. (see graphs L6203 Output Forward/Reverse). I then went to the motor
connector J2 and measured each signal to GND (Pin 1 to GND and Pin 4 to
GND). The same thing was found (see the other two graphs).

On my previous graphs, it showed that the forward voltage was only swinging
about 5 or 6 volts when it was pulsing (instead of 12V). It turns out that
there is something screwy with the scope because when I switched the leads,
the voltage was fine (IE when swapped, the forward had the full 12V swing
and the reverse only had 5-6V swing).

I think the problem I am having is with the odd voltage decay for the
reverse direction pulse. I checked all of the components and connectors and
haven't found any other problems. I will probably order a new chip. I will
also check ebay for an motor driver board because it would be interesting to
to a side by side analysis of a good one vs. mine.

If anyone has a L6203 chip or an extra TZ clock motor driver board they want
to sell, please let me know. Also, if you want to see the excel
spreadsheet, just email me at estrangeway@NOcharter.SPAMMERSnet

thanks
Eric

"martin" <martin.reynolds@gmail.com> wrote in message
news:1126324676.015650.13430@z14g2000cwz.googlegroups.com...
> Great, so the problem is narrowed down to the board. When you get back
> on it, you should also check pins 8 and 4, making sure that the pump
> voltage is getting back to the chip. Without the pump voltage, the
> transistors can't turn fully on.
>
> I am leaning towards a bad 6203 here, but the H bridge measurements
> will tell us for sure.
>
> Could also try switching pins 1 and 2 on J1 to see if it is a 6203
> input or output problem.
>

 

[martin]

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

A little more thought...

Your symptoms are consistent with a shorted lower transistor in the
"reverse" side of the H bridge. If this is the case, your reverse
voltage will look like a 12V spike with a decay, but the decay should
start almost immediately. The 12V should be more of a spike than a
pulse. You should not see a full width pulse. The decay comes from the
overload protection kicking in. If this is the case, the TIP122 fix
won't work, but a new 6203 will fix the problem.