(Topic ID: 242425)

Repairing a Lucky Seven pin


By denoument

41 days ago



Topic Stats

  • 9 posts
  • 3 Pinsiders participating
  • Latest reply 33 days ago by denoument
  • Topic is favorited by 2 Pinsiders

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#1 41 days ago

Continuing from another topic:

Quoted from denoument:

I'm working on a project pin and these roms are helping out a lot. I think the blanking.txt calls out the wrong pins. Instead of "IC7 pin 6" it should be "IC7 pin 8". Instead of "IC12 Pin12" it should be "IC23 pin 12".
What frequency signal should I be getting at IC7 pin 8 with the blanking rom installed? My wavelength is 0.118ms (~847hz). It is on 50% of the time. When I look at IC23 pin 8 the signal is high for 73% of the wave. So it is only draining Q5 for 26% of the cycle. I have two head scratchers as well...when I put my logic probe on the Q5 trigger (IC23 pinthe blanking signal goes high(TP4 goes high)...also if I replace C32 with a smaller capacitor the blanking signal works (TP4 goes high).
I can't get the blanking signal to go high (TP4) with this rom. I am able to pass the leds, displays, cmos, and ram tests no problem. I have a meter, logic probe, and a logic analyzer to work with and from what I can tell pin 8 on IC7 (the Q5 trigger) is pulsing but IC23 pin 12 (the blanking threshold) stays high around 3.6V. I've replaced Q5, C31, C32, and IC23. Basically all the components that relate to the blanking signal.

Quoted from pincoder:

Thanks for the detailed information and positive feedback!
Before I can give you any detailed answers I'll need to know which game and system board are you running this on, and which schematics you are looking at.
To get you started in the right direction, the blanking signal should be showing up on PIA1 (PIA at address 2800) pin PA2 and waits for 3 clock cycles before toggling the pin.

Williams Lucky Seven 1978 Solid State
System 4 board

I am using the Lucky Seven schematics from ipdb.org as well as the Stellar Wars 1979 schematics on ipdb.org, the Lucky Seven schematic is drawn by hand so isn't the cleanest to look at so I'm using the Stellar Wars Schematic as well.

The clock on IC1 pin 37 toggles at 888.9kHz. The clock toggles for 0.3seconds before the PA2 signal starts to toggle. PA2 toggles at 8.949kHz, so one hundred times slower than the clock. PA2 starts about two and a half 8.949kHz cycles (0.3ms) after the RESET signal goes high (IC5 pin 14).

#2 40 days ago

No worries about hijacking a thread.. its meant for support just like this. We can work here regardless.

All of the numbers you stated seem reasonable to me (Save for the IC23 pin 8 IC7 pin 8 fiasco). The 8.9Khz PA2 toggle rate I'd have to verify with a scope on a good board. I can do that tomorrow sometime but I would think that rate would be more than enough to keep the blanking circuit from panicking. Have you followed the signal through to the 556 timer (IC23) and all that?

If C31, C32, R22, R23, or Q5 are not functioning properly it could be triggering premature panic. Variations in functioning values of the resistors and capacitors will have a direct effect on the length of time before a "timeout" occurs. Of course, IC23 could be suspect as well, as could IC7.

To start, I'd check IC7 pin 8 for the same toggle rate as what you're seeing on PIA1 PA2. If its the same then look toward the above. If its substantially different then look at IC7 or the path back to PIA1

Looking back at your original post I see you have already replaced most of the blanking circuit parts. It's worth checking the resistors just to be sure. Also, are the sockets okay on the related ICs? What about solder joints, flux remaining on board etc.

I'm curious about what rate you'd see on PIA1 PA2 when using the Williams ROMs. Can you verify? I'll check my Gorgar (system 6) and see what it comes in at.

Also, I'm pretty sure touching something with the logic probe shouldn't cause the blanking to go high. You also said the 05-displays test runs fine too? what about the tests that follow (lamps, switches, solenoids etc). Does the blanking circuit still behave normally there too? What did the blanking circuit do in the 01a-leds test? It's supposed to stay low during that test.

Lastly, what's happening on IC23 pin 12?

#3 40 days ago
Quoted from pincoder:

No worries about hijacking a thread.. its meant for support just like this. We can work here regardless.
All of the numbers you stated seem reasonable to me. However the 8.9Khz PA2 toggle rate I'd have to verify with a scope on a good board. I can do that tomorrow sometime but I would think that rate would be more than enough to keep the blanking circuit from panicking. Have you followed the signal through to the 556 timer (IC23) and all that?
If C31, C32, R22, R23, or Q5 are not functioning properly it could be triggering premature panic. Variations in functioning values of the resistors and capacitors will have a direct effect on the length of time before a "timeout" occurs. Of course, IC23 could be suspect as well, as could IC7.
To start, I'd check IC7 pin 8 for the same toggle rate as what you're seeing on PIA1 PA2. If its the same then look toward the above. If its substantially different then look at IC7 or the path back to PIA1
Let me know how it goes

Edit: Looking back at your original post I see that you have replaced most of the parts in the timing circuit. I doubt that the resistors have gone bad, but perhaps they should be checked. Also, is the 556 socketed? Perhaps somethings not right with it (solder joints, flux remaining on board, etc).

If everything looks good I can send you an updated 02-blanking ROM with an increased toggle rate. It would be interesting to see if that helps.

Also, it would be good to know what the rate would be with the original Williams ROMs in there. Are you able to verify? I'll see what rate my Gorgar (system 6) comes in at with the test ROMs and the Williams ROMs.

Lastly, What's happening on IC23 pin 12?

#4 40 days ago

So I've done a little blanking circuit testing with my system 6 board and a scope with two leads (connected to PIA1 PA2, and IC23 THR):

The toggle rate for PA2 using various ROMs is as follows:

Williams ROM:120Hz. THR ranges 720-800mV
05-displays: 200-230 Hz. THR ranges 208-230mV
02-blanking: 2500Hz. THR is constant at 1.7V

I then updated 02-blanking to match the Williams ROM:

Updated 02-blanking: 120Hz. THR ranges 720-800mV.

In all of the above cases I got the expected HIGH on TP4 a half second or so after power up.

I will put out a beta release today that contains the new 02-blanking ROM as well as an update for all of the ROMs that use displays (eliminated ghosting).

So, with the new 02-blanking you should be getting the same results as if the Williams ROM is being used (without all the other stuff going on in a Williams ROM). Try it out and see if it changes anything on your side.

#5 39 days ago

I had already replaced the 556 and added a socket for IC23. I just rechecked the solder job and it all looks good. Continuity on each pin checks out. Also checked continuity between adjacent pins and close traces and it all looks good.
I didn't replace any of the resistors in the blanking circuit because they all ohmed out to the proper resistance.

I flashed another rom with the beta 02-blanking that I downloaded today. PA2 stays high with this ROM. It says Version 2019.05.08.1449_beta..ROM NAME when I look at the bin file ASCII translation in my eprom programmer. I'll be able to do some more checking over the weekend. It could just be an issue with me testing in the wee hours of the night...

Here are some answers:

==========================================================
01-leds : CPU board bench testing without driver board
leds on MPU board blink alternating
blanking signal is low (0V)

==========================================================
02-blanking : Build 2018-09-26-2051 : CPU board bench testing without driver board

When logic analyzer connected to pin 8 of IC23:
I traced PA2 all the way to IC23
IC7 pin 8 is identical to PA2 signal
After C32 (IC23 PIN8) signal on ~70% of the time and off ~30%. of the time. Signal looks the same as PA2 but high for 70% instead of 50% for PA2.
IC23 PIN8 TRIGGER 2.8V
IC23 PIN12 THRESHOLD 1.4V

When logic analyzer disconnected from pin 8 of IC23:
IC7 pin 8 is identical to PA2 signal
IC23 PIN8 TRIGGER 4.9V
IC23 PIN12 THRESHOLD 3.6V

==========================================================
05-displays: CPU board bench testing with driver board
PA2 is 214hz
THR is 2V
blanking signal is high
I'm currently working on the driver board so I can't really do more than the displays test, I have to resolder some sockets and install some ICs on the left side of the board. But the displays do cycle between all the digits when I install the board in the pinball machine. I'm not to the point where I want to connect the playfield yet.

#6 39 days ago

Do you have the full schematics?
I have the full packet the game came with

#7 36 days ago

I just did some more testing, results below. I might just continue testing my driver board since it looks like my CPU board boots fine with the game rom in place.

pincoder Let me know if you have any more ideas and I can do whatever checks you like.

==========================================================
Lucky Seven GAME ROM : CPU board bench testing without driver board
IC7 PIN8 PA2 116hz
IC23 PIN8 TRIGGER 4.9V
IC23 PIN12 THRESHOLD 2.3V
TP4 BLANKING stays high

==========================================================
02-blanking : Build 2019.05.08.1449_beta : CPU board bench testing without driver board
**if CPU leds blink once on then turn off after power applied to board**
IC7 PIN8 PA2 stays low
IC23 PIN8 TRIGGER 4.9V
IC23 PIN12 THRESHOLD 3.8V
TP4 BLANKING stays low

==========================================================
02-blanking : Build 2019.05.08.1449_beta : CPU board bench testing without driver board
**if CPU leds stay on after power applied to board**
IC7 PIN8 PA2 stays high
IC23 PIN8 TRIGGER 4.9V
IC23 PIN12 THRESHOLD 3.8V
TP4 BLANKING stays low

embryonjohn feel free to send me what you have.

#8 35 days ago
Quoted from denoument:

I just did some more testing, results below. I might just continue testing my driver board since it looks like my CPU board boots fine with the game rom in place.
pincoder Let me know if you have any more ideas and I can do whatever checks you like.
==========================================================
Lucky Seven GAME ROM : CPU board bench testing without driver board
IC7 PIN8 PA2 116hz
IC23 PIN8 TRIGGER 4.9V
IC23 PIN12 THRESHOLD 2.3V
TP4 BLANKING stays high
==========================================================
02-blanking : Build 2019.05.08.1449_beta : CPU board bench testing without driver board
**if CPU leds blink once on then turn off after power applied to board**
IC7 PIN8 PA2 stays low
IC23 PIN8 TRIGGER 4.9V
IC23 PIN12 THRESHOLD 3.8V
TP4 BLANKING stays low
==========================================================
02-blanking : Build 2019.05.08.1449_beta : CPU board bench testing without driver board
**if CPU leds stay on after power applied to board**
IC7 PIN8 PA2 stays high
IC23 PIN8 TRIGGER 4.9V
IC23 PIN12 THRESHOLD 3.8V
TP4 BLANKING stays low
embryonjohn feel free to send me what you have.

Okay all looks good except your second test case. If the LEDs go out on the 02-blanking test then your board is crashing sometime after powerup. This needs to be investigated.

#9 33 days ago
Quoted from pincoder:

Okay all looks good except your second test case. If the LEDs go out on the 02-blanking test then your board is crashing sometime after powerup. This needs to be investigated.

Thanks, will investigate.

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