(Topic ID: 261429)

Tom Callahan Pin Logic MPU game ROM's


By tomdrum

3 months ago



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  • 22 posts
  • 3 Pinsiders participating
  • Latest reply 3 months ago by tomdrum
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#1 3 months ago

I have an older Tom Callahan "Mutha MPU". It has worked well in various games I've owned over the years. It came with multiple game ROM's and various chips for the U6. Most recently it was in a Bally Eight Ball and worked well. I'm trying to move it a Bally Playboy. It came with game specific U2 chips. However the U6 chips have me confused. My choices are:

1) 720-35 U6-2732 installed- will not boot
2) 720-28 U6-33FE
3) 720-2132 U6-2732
4) 720-30 U6-2732

Rather than swap in the other 3, does anybody know which U6 chip is correct for a Playboy?

#2 3 months ago
Quoted from tomdrum:

However the U6 chips have me confused. My choices are:

Playboy requires system ROM "720-30" at U6, so go with option 4)

#3 3 months ago
Quoted from Quench:

Playboy requires system ROM "720-30" at U6, so go with option 4)

Quench as usual fixed my game! Installed that chip and game fired up. One thing I did notice with this "Mutha MPU", when the game is 1st powered up I get zero flashes on the LED. If I turn it back off and the on again, game boots as normal. It was doing this when last installed in an Eight Ball. Not a big deal as I got used to the double power up. But I'm considering selling this game with this MPU in it since my board repair guy has had 2 MPU's trying to get one OE ready for this game for 3 months.

#4 3 months ago
Quoted from tomdrum:

when the game is 1st powered up I get zero flashes on the LED.

By zero flashes do you mean the LED is locked on?

jlbintn had a similar problem with his Callahan Mutha MPU board - anyway might be a common issue with these boards.
https://pinside.com/pinball/forum/topic/fireball-ii-club-members-only/page/10#post-5328538

First of all, what voltage do you measure at TP2 (12 volts test point) on the MPU board?
And what voltages do you measure at each leg of the zener diode (VR1) on the MPU board - should be in the reset area.

One thing to note about the Mutha board is it uses a different CPU (a 6802) vs Bally that used a 6800. A key difference between the CPUs is the external clock circuitry. The 6802 uses a crystal that takes longer on power up for the clock signal to stabilise (compared to Ballys setup) meanwhile the Mutha board still uses Ballys reset circuitry that has a short time to release and let the CPU start.
The specification for the 6802 is that it takes 100 milliseconds on powerup for the crystal to start oscillating to provide the clock signal.
From previous tech support threads measuring Ballys /RESET signal release is about 4 - 10 milliseconds on power up.
In the case of this board, the CPU is coming out of reset *before* the CPU clock signal has started oscillating where best practice is that it should happen *after*. So this is potentially a problem.

What might be worth trying is delaying the /RESET signal release on powerup.

If by chance you have a 22uF capacitor, try connecting it between ground and the base leg of transistor Q1 (base leg is the middle leg) on the MPU board to further delay the reset.

Hope I'm making some sense.

#5 3 months ago
Quoted from Quench:

By zero flashes do you mean the LED is locked on?
jlbintn had a similar problem with his Callahan Mutha MPU board - anyway might be a common issue with these boards.
https://pinside.com/pinball/forum/topic/fireball-ii-club-members-only/page/10#post-5328538
First of all, what voltage do you measure at TP2 (12 volts test point) on the MPU board?
And what voltages do you measure at each leg of the zener diode (VR1) on the MPU board - should be in the reset area.
One thing to note about the Mutha board is it uses a different CPU (a 6802) vs Bally that used a 6800. A key difference between the CPUs is the external clock circuitry. The 6802 uses a crystal that takes longer on power up for the clock signal to stabilise (compared to Ballys setup) meanwhile the Mutha board still uses Ballys reset circuitry that has a short time to release and let the CPU start.
The specification for the 6802 is that it takes 100 milliseconds on powerup for the crystal to start oscillating to provide the clock signal.
From previous tech support threads measuring Ballys /RESET signal release is about 4 - 10 milliseconds on power up.
In the case of this board, the CPU is coming out of reset *before* the CPU clock signal has started oscillating where best practice is that it should happen *after*. So this is potentially a problem.
What might be worth trying is delaying the /RESET signal release on powerup.
If by chance you have a 22uF capacitor, try connecting it between ground and the base leg of transistor Q1 (base leg is the middle leg) on the MPU board to further delay the reset.
Hope I'm making some sense.

Mutha MPU looks like they have a crystal across p39 and p38 of the CPU chip. I could not get Motorola or STMicro 6802 chips to work reliably with a 2mhz crystal in this setup even with a long reset from a MCP130. 3.58mhz crystals worked and Hitachi CPUs did work fine at 2mhz tho. The moto cpu and 2mhz crystal would just not reliably start oscillating. Power cycling usually got a good boot. Looking at the datasheets Hitachi has slightly different requirements for p38 and p39 and i figure thats the reason Hitachi would work.

Going to a complete external oscillator then then Motorola chips would run at 2mhz divided by four.

If you have a hitachi cpu laying around, try it. HD6802P is the part number.

#6 3 months ago
Quoted from Quench:

By zero flashes do you mean the LED is locked on?

The Callahan board has 2 red LED's, one showing 5V and the other 12V. Also has a green test LED. When it doesn't boot, just the red LED's light, nothing from the green. The problem is intermittent, today I had the game powered on for almost an hour. Now after sitting off for a hour it boots right up. I've started it 4 times since and it will boot normally.

#7 3 months ago
Quoted from tomdrum:

The Callahan board has 2 red LED's, one showing 5V and the other 12V. Also has a green test LED. When it doesn't boot, just the red LED's light, nothing from the green. The problem is intermittent, today I had the game powered on for almost an hour. Now after sitting off for a hour it boots right up. I've started it 4 times since and it will boot normally.

Sounds like just a connector issue than. If the 5v is lit the 12v most be good at least at the driver board, so i'd expect the problem to be connector pin at MPU J4. Or maybe on the other side of that 12v wire.

#8 3 months ago
Quoted from barakandl:

Sounds like just a connector issue than. If the 5v is lit the 12v most be good at least at the driver board, so i'd expect the problem to be connector pin at MPU J4. Or maybe on the other side of that 12v wire.

It was doing the same thing when it was installed in a different game. In both games the MPU J4 connector was re-pinned.

#9 3 months ago
Quoted from tomdrum:

It was doing the same thing when it was installed in a different game. In both games the MPU J4 connector was re-pinned.

maybe it is the male pin then?

I am assuming the 12v LED is just across 12v and ground with a series resistor. It being out would mean no 12v. No 12v board likely stuck in reset.

Maybe that is a bad assumption.

#10 3 months ago
Quoted from tomdrum:

The Callahan board has 2 red LED's, one showing 5V and the other 12V. Also has a green test LED. When it doesn't boot, just the red LED's light, nothing from the green.

You mean when it doesn't boot, you don't even get the initial power-on flicker on the green test LED?

#11 3 months ago
Quoted from Quench:

You mean when it doesn't boot, you don't even get the initial power-on flicker on the green test LED?

It did it last night again. All 3 light and stay lit. The green LED stays solid. Just powered it up this AM and it booted normally.

#12 3 months ago
Quoted from tomdrum:

It did it last night again. All 3 light and stay lit. The green LED stays solid. Just powered it up this AM and it booted normally.

If u9 is a MC6802, EF6802, F6802 or S6802 try changing it to a HD6802. If crystal start up is the problem the hitachi HD6802 CPU should work better.

#13 3 months ago
Quoted from barakandl:

If u9 is a MC6802, EF6802, F6802 or S6802 try changing it to a HD6802. If crystal start up is the problem the hitachi HD6802 CPU should work better.

It is a MC6802. Who sell the hitachi HD6802?

#14 3 months ago

If you don't have easy access to a hd6802p to try you can check to see if the cyrstal start up really is the problem. With a scope or maybe even logic probe or DMM on frequency test you can watch the "E" pin #34 of the 6802. As soon as the reset lets go "E" pin should pulse around 0.5mhz. If it is slow to start up or way out of time on the failed boots that is probably the issue.

Haven't seen a schematic for that MPU, but looking at pictures it appears the crystal setup is exactly what I tried and found to be unreliable at times with motorola CPUs so I can't expect that board to work any better.

If it turns out to be a crystal startup problem and you cant get a hd6802 you could also try changing the load capacitors, the CPU, and/or the crystal itself to see if you get more reliable boot. What value are the two capacitors in the pierce oscillator circuit near the crystal? You can try a range of about 27pF to 50pF. Fine tuning the load capacitors here may help. NPO/COG type capacitors are normally whats recommended to be used. The cheap ceramic caps drift big time with heat.

#15 3 months ago
Quoted from barakandl:

If you don't have easy access to a hd6802p to try you can check to see if the cyrstal start up really is the problem. With a scope or maybe even logic probe or DMM on frequency test you can watch the "E" pin #34 of the 6802. As soon as the reset lets go "E" pin should pulse around 0.5mhz. If it is slow to start up or way out of time on the failed boots that is probably the issue.
Haven't seen a schematic for that MPU, but looking at pictures it appears the crystal setup is exactly what I tried and found to be unreliable at times with motorola CPUs so I can't expect that board to work any better.
If it turns out to be a crystal startup problem and you cant get a hd6802 you could also try changing the load capacitors, the CPU, and/or the crystal itself to see if you get more reliable boot. What value are the two capacitors in the pierce oscillator circuit near the crystal? You can try a range of about 27pF to 50pF. Fine tuning the load capacitors here may help. NPO/COG type capacitors are normally whats recommended to be used. The cheap ceramic caps drift big time with heat.

Thanks but that went way over my head! Changing a socketed chip, sure I can handle that. I pay people to fix my boards or buy new ones. Speaking of which, when will assembled Bally rectifiers be available AS-2518-18?

#16 3 months ago

Lo and behold I found a hitachi HD6802p in a bunch of chips that I've had for years. I'll swap that in.

#17 3 months ago
Quoted from tomdrum:

Thanks but that went way over my head! Changing a socketed chip, sure I can handle that. I pay people to fix my boards or buy new ones. Speaking of which, when will assembled Bally rectifiers be available AS-2518-18?

My blank boards are manufactured in China. I have an order tied up hoping would get shipped before Chinese New Year and now the virus delay on top of that. Numerous items are going to go out of stock soon =(.

#18 3 months ago
Quoted from barakandl:

My blank boards are manufactured in China. I have an order tied up hoping would get shipped before Chinese New Year and now the virus delay on top of that. Numerous items are going to go out of stock soon =(.

Ouch. I see the blank boards are still on the website. Are the components also missing? I think I bought a dozen of them in the last 18 months.

#19 3 months ago
Quoted from tomdrum:

Ouch. I see the blank boards are still on the website. Are the components also missing? I think I bought a dozen of them in the last 18 months.

the design is changed slightly. I don't have enough parts for the older style but I have 3 blank boards left on hand.

#20 3 months ago
Quoted from barakandl:

If u9 is a MC6802, EF6802, F6802 or S6802 try changing it to a HD6802. If crystal start up is the problem the hitachi HD6802 CPU should work better.

Having minimal board experience, if I change out the U9 to the hitachi HD6802p, is that all I'll need to do? I don't want to hit a brick wall taking a working game and kill it by a chip change.

#21 3 months ago
Quoted from tomdrum:

Having minimal board experience, if I change out the U9 to the hitachi HD6802p, is that all I'll need to do? I don't want to hit a brick wall taking a working game and kill it by a chip change.

Yeah, just try swapping in the HD6802P and see if it boots up every time. Nothing else needs changed

The Hitachi part is much more forgiving about starting up the crystal at 2mhz than Motorola and other brands of 6802 in my XP

#22 3 months ago
Quoted from barakandl:

Yeah, just try swapping in the HD6802P and see if it boots up every time. Nothing else needs changed
The Hitachi part is much more forgiving about starting up the crystal at 2mhz than Motorola and other brands of 6802 in my XP

Swamped in the Hitachi and unfortunately it didn't fix it. About every 3rd start up it fails to boot. But always boots immediately on the 2nd try.

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