Isn’t the Grand Slam MPU just an -35 MPU but with a diode in place of a resistor? I’ve had to make that mod to use a -35 in Grand Slam and Goldball. If the same mod is done to LISY then it should work in those games.

What exactly is going wrong with the current implementation?

I haven't looked at the game code, but I presume (guesstimate):
6821 is programmed for normal falling edge trigger which happens on the rising phase A.
Phase A crosses zero upwards and rises causing an interrupt to trigger.
Interrupt is serviced then 6821 is changed to sense a rising edge trigger (falling phase A).
Phase A falls and generates an interrupt trigger about 0.3ms *before* it has crossed zero.
Interrupt is taken but flagged to service phase B about 0.6ms later when phase B has become active.
0.6ms later phase B lamps are refreshed and 6821 is reprogrammed back to normal falling edge trigger for next rising phase A.

Or am I totally off base?

Top Tip: when installing your LED blocks in the LISY 80 displays, do not install them upside down.

Then the center segment becomes the dot and vice versa.

Whoops.

(sorry no pic.... I already desoldered it and flipped it over to the proper direction).

My presumption in this regard was based on the Zero Crossing being AC, but I forgot it was only 10 volts. It means the trigger times I mentioned (0.3ms and 0.6ms) are too short and in reality need to be longer because of the slower rise/fall in 10 volts wave.

See below wave snapshot showing the traditional relationship of the Zero Crossing detector output going into the 6821 against the 43VDC solenoid voltage. You can see the Z.C detector only changes state while the ripple is positive - actually it never "crosses zero" volts on traditional systems using DC.
When the Zero Crossing detector input is AC, it cannot detect and change state while the input is negative voltage. So this is the reason I presume you need to alternate the edge direction detection on the 6821 CB1 input and then wait some time after phase A falls and triggers near zero and then goes negative voltage (where phase B is now positive).
The Zero Crossing pulse length in the oscilloscope snapshot below is approximately 0.6ms (but again it's based on the steep rise/fall of 43 volts, not 10 volts).
The diagram below it hopefully explains my theory. Does it sound reasonable?

IMG_0052c.jpg
DC_Ripple1.png

Uhoh - I let the magic smoke(s) out....

History.... got machine (jacks to open) and one original display not working, and one p2/p4 digit locked on. Rottendog replacement mpu, Gulf pinball PS. Get the locked digits going and got a replacement display from a pinsider, which initially worked ok. Went to keep shopping and the new display craps out, figure it was just its time, etc. - disconnect and keep going. Then, all displays out, gulf pinball display section smoked, no schematics available, not paying $80 for another. It was blowing fuse F3 as well.

Go for the LISY design and the new PS/displays - had to repin a couple of the display harness connectors, visible sparking on the input voltage pin on 2x displays, so repinned both of those. Working fine up until a couple days ago, turned it on and display is incorrect on the credit display and other displays are really dim/off. It had blown F3 again.

Disconnected all displays and PS, tested input voltage for displays 60vac ok, hooked up PS, test voltages, all ok. (+5 is 4.9 where it was 5.1 when I first installed PS, but likely not important). Reconnected only credit display, still has bad info on display but lit. (power off between all connect/disconnect of course) - I did do the 10ohm mod for the displays on the PS when I built it (I ordered enough parts to build 10 boards, still have 4-5 to build up) Hooked up the p1 display and smoked what I think is the power regulator, and the 10 ohm current limited resistor blew as well, and F3 blew again as well.

I know it's never the transformer.... but do you think it could be the transformer? It doesn't blow F3 without anything hooked up to it, didn't blow it without the displays connected, but did blow (see pictures) when I hooked up the display. There was a big spark at the connector similar to what I noticed when the connector needed to be repinned.

I do have one spare display board that I can move the LED digits over to but I'd like to nail this down if I can before hand so I don't just blow them all up. I did turn up the brightness on all the displays as they were too dim - possibly the current just isn't enough to run all the displays so caused an undue load?

Any other thoughts?

20210812_101353 (resized).jpg

20210812_101417 (resized).jpg

20210812_101427 (resized).jpg

Ralf, finally got around to building a 35 board. I get random numbers on the displays. When hooked up to the hotspot lisy thinks it’s pink panther even tho S2 is set to on on rest off (eight all)

All Roms are on the Sd for Bally none for gottlieb

That’s the funny part this is a lisy35 board,

5F893EF8-256A-4315-B2BE-7C42F482DD4B (resized).png

Great to hear!

BTW, the display interrupt generator runs at:
Around 430Hz on Bally 7 digit display games
Around 320Hz on Bally 6 digit display games and Stern MPU-100 games
Around 400Hz on Stern MPU-200 games

I think you are running the display interrupt generator at 400Hz based on your diagrams? Because your approach will be more precise there is the opportunity that its interrupt could happen at the same time in sync with a 100Hz zero crossing. I think it would be safer to run the display interrupt generator a little higher speed say 410Hz to minimise this occurrence.

I had a look at the code:
- Zero Crossing interrupt occurs
- Alternate a RAM phase flag (actually it's just bit zero of a free running counter)
- Perform a delay around 1.10ms
- If RAM phase flag is set, service the phase ØA lamps, else service phase ØB lamps
- Perform all other Zero Crossing system services
- Alternate the edge detection on the 6821 Zero Crossing CB1 input
- Exit the Zero Crossing interrupt service routine

Looks around 1.3ms to me. Doesn't this seem too short to you considering the AC wave is 50% duty? With 20ms cycle (50Hz) I would expect the Zero Crossing Detector pulse to be around 12ms.
It doesn't look like you are getting Zero Crossing interrupts occurring every transition, only every second transition which doesn't seem right like Zero Crossing is serviced at 50Hz, not 100Hz and the phases are serviced at 25Hz. This is likely happening because that Zero Crossing Detector pulse is too short considering the 1.10ms delay in the zero crossing service routine causing the edge detection not being reprogrammed in time for the next transition - see below.

BallyFA_ZeroCrossing.png

Thanks for the help got that sorted now having issues were I’m getting no lamps, and solenoids not working cross detector is always lit

Can you explain how you're generating the zero crossing detector signal?
Is it controlled by the power signal coming from the rectifier board to the MPU board at J4 pin 15?
Or is it a timer implemented in your hardware?

An AC signal going into MPU J4 pin 15 will produce a zero crossing detector signal with a cycle time of 20ms (50Hz), but your snapshot shows the cycle time is 10ms.

This occurs on factory MPU boards too that the interrupts will occur at the same time every now and then.

And that's exactly what I've been expected too! Well done.

You mean full rectified DC signal? (not AC). If yes, then the cycle time is 10ms.

Yes, games with the dual phase lamp setup will be refreshed at half speed on each phase. The AC voltage is higher to compensate for this and in terms of incandescent lamps that have long persistence, the higher voltage makes them stay on longer so the slower rate of refresh will not be noticeable or cause flicker.

LEDs complicate matters since they have no persistence. 50Hz refresh will be enough to not produce flicker, the problem as we know is that with traditional single phase DC games the lamp refresh occurs early in the DC phase when there is not enough current draw from LEDs for the lamp driver boards SCRs to latch. The solution has been to add resistors across the LED circuits to increase the current draw that helps the SCRs latch. This still isn't perfect and I suspect flicker can still sometimes occur in part because of nested interrupts (display interrupts can interrupt the zero crossing service routine).

Why is this? The 6800 /IRQ input is level sensitive (not edge). The 6821 IRQ outputs are open drain and all tied together in an OR fashion meaning they could all request an interrupt at the same time. It is up to the game software (operating system) to prioritise IRQs and determine which IRQ source(s) is active.
In other words, interrupts are prioritised and dealt with in software and nesting should only occur to one level based on their frequencies.

Anyway, great work! and to get back to the original request, hopefully a Bally 6803 control board replacement will one day make it on your list

Thanks for the help, built this board over the course of a month, over a 9 months ago. Grabbed the wrong resistor, didn’t have the 1.5m ohm but had 2m and it solved all my issues

Does anyone have an extra LISY1 PCB? It looks like I could use one of them to revive a Buck Rogers. I think I have most of the parts to assemble it.

Yes, I have two extras of the LISY 1 and 1 extra of the LISY 80 board.

PM sent.

That's amazing.. will make a lot of sys80 people happy I'm sure!

Special awarded/no extra ball

LISY80
Chicago Cubs Triple Play (CCTP) 696
LISY game number 041

I finally got my System 80 board running. Everything seems to be working correctly expect from the extra ball. The game currently awards the special. I would prefer to have it reward an extra ball. There is not a dip.csv file for this game in the LISY files. I assume it is using the default file. The manual for CCTP shows that dip 22 controls whether the awards special or an extra ball. I examed several other dip files and they all had 22 as special/extra ball award. I thought I would clever and edit the default file by changing dip 22 from ON to OFF. Saved/exported as a CSV file and placed it in the LISY80 dip. When I reinstalled the SD card and powered up the machine it did not boot.

I assumed that the csv file could be edited. Can it?
Do you think perhaps the csv file was corrupted when I opened it? ( I did export from Numbers as an csv file).
Anyone have ideas that I could try to so the awarded extra balls?

Thanks,
Phil

Have you tried the LISY connect that let's you modify the virtual dip switches for that game?

Thanks Bontango,

I got the file edited in txt editor. Everything works great now. Thanks much.

Somethings I am more technologically impaired than I care to admit. Still trying to get connected my webbrowers for future work.

Phil

Question about LISY support for Haunted House. It looks like it supports the original ROM and one patched for 7-digit displays.

Is there support for any other alternate ROMs for Haunted House? Specifically the 669-3 and 669-4 and their variations to support the extra trap door sound or a game setup with a sound board modified for speech.

https://www.flipprojets.fr/PromHH_EN.php

If not those would be great additions to support. Would like to try a LISY80 on a Haunted House with speech but at the moment it doesn't seem to be supported.

bontango Thank you for the explanation I think this will help others as well that may need to try alternative versions of code for games. That version to support Speech is a big one for many Haunted House owners. I'll try this on Haunted House and see how it goes.

**EDIT: NEVERMIND I found it!***

I ordered a batch of LEDs a while ago, in green and blue - but red, yellow and orange weren't available.

Where does one go to find these LEDs - for the Bally display boards - these days?