Bally -35 "Heathkit" like board from Homepin.com

[dasvis]

Bally -35 "Heathkit" like board from Homepin.com

http://www.homepin.com/bally35.html

Bare board, with components, you assemble.
Has anyone tried this yet? Looks interesting.

 

[Homepin]

Hi. This kit is brand new and only a handful have been sold into Australia at this stage. We released it just 2 weeks ago.

We built up six of them in-house in various configurations prior to release.

There are 4 battery backup choices - a choice of micro used (6800 or 6802) and extra test points for ease of testing on the bench.

We have made numerous smaller mods to improve things that are known problems with this board such as beefing up the 82R resistor (R11) and including brass standoff eyelets to space it away from the PCB. Improved earth connections, allowance for modern electro caps and many many other things.

We also provide the small daughter board kit to replace the very rare 9602 chip used as an oscillator.

Our aim was to keep the board as original as possible whilst making it more robust and improving the known issues.

The latest revision of the assembly manual is available on the website now for those who would like to see exactly what is involved in the construction.

Cheers,

Mike Kalinowski (Australia)

 

[KenLayton]

How about a replacement board for the electronic HOME model Bally pinball machines?

 

[Sprout]

That would be a feat, but is there much of a market for those? Also, since that processor has a ROM built into it, that complicates matters. Not sure the code from the ROMs was ever dumped, and even if it was, if there was an easy way to design a replacement...

I'm all for helping keep those pin's alive - just don't know if there's much money in it to motivate somebody to bother...

Like the flexibility of the Homepin board (read about it a few days ago after the link was posted here) - seems like a nice product! Nice that it can cover the Stern -200 boards as well.

 

[HHaase]

The hitch is all in that Mostek 3870 processor. If you can find those, and a way to program them, the rest of the board is simple and easy. But without that processor, you'd have to design a whole new board using a different processor family. Not impossible, but worth the effort?

Same with the power supplys, easy stuff. Particularly that series II design. Those wouldn't be a problem at all, though I'd say you would end up with a much different looking board as there's no way I'd intentionally build a single sided board like that.

-Hans

 

[KenLayton]

There are still plenty of 3870's out there, just not programmed. If someone could program them then we could get these machines running again.

That's why I thought if someone could make a small plug-in retrofit board with an eprom and new processor that would plug into the original CPU socket much like a high score save kit would.

 

[Lindsey]

That's why I thought if someone could make a small plug-in retrofit board with an eprom and new processor that would plug into the original CPU socket much like a high score save kit would.

That wouldn't be difficult but it would be time consuming. Just replace the original processor with a microcontroller programmable by USB. I did basically the same thing for the 6800 series processors for grins. The main issue is that the demand is relatively low and there would be a lot of time required to re-write all of the game rules. A complete replacement board on new hardware would be a better option if it would actually sell.

The other issue is that the original processor is soldered to the board (IIRC) and a CPU replacement daughter board would only fix games with bad original processors. Seems like an extremely limited market.

The -35 replacement board is a cool idea. I don't see a large market for it though, unfortunately.

 

[HHaase]

Hmmm, found a POSSIBLE viable option for that Bally home board. The Mostek 38P70 processor. Basically a 3870, but with an external EPROM socket on the back of the processor chip. That makes it possible to program it now.

If homepin wants to go ahead with the project, I'll defer to them at this point. But if they don't, I'll start looking more seriously into it. Though if I could sell 20 of the boards, I'd be shocked.

-Hans

 

[Homepin]

"The -35 replacement board is a cool idea. I don't see a large market for it though, unfortunately. "

Actually I disagree. There are more and more containers of early SS machines coming to Australia every week and a lot of these have been in storage for many years = a lot of the MPU boards have been destroyed by the backup battery.

Many hobbyists and collectors want some reliability and it is getting harder to make a 30 year old, battery eaten board reliable.

I see a market for these for many years, slow for sure but that is what a "hobby business" is all about. As this board suits many tens of thousands of games it could make the difference between saving a machine or parting it out.

We never got any of the Bally home machines in Australia that I know about so there isn't much point persuing those from our perspective.

 

[KenLayton]

Hmmm, found a POSSIBLE viable option for that Bally home board. The Mostek 38P70 processor. Basically a 3870, but with an external EPROM socket on the back of the processor chip. That makes it possible to program it now.

If homepin wants to go ahead with the project, I'll defer to them at this point. But if they don't, I'll start looking more seriously into it. Though if I could sell 20 of the boards, I'd be shocked.

-Hans

This document describes the MK38P70 with the on-board eprom socket:

http://nice.kaze.com/MK3870.pdf

There's a lot of these "home" Bally pinball machines out there. IPDB mentions a production run of 10,000 Fireball machines (total of Series 1 and Series 2). All of the Series 2 gameboards had socketed 3870 CPU chips. I can't vouch for the Series 1 boards since I have never encountered any.

Attached are pictures of the eprom socketed version (38P70).

 

[Lindsey]

Actually I disagree. There are more and more containers of early SS machines coming to Australia every week and a lot of these have been in storage for many years = a lot of the MPU boards have been destroyed by the backup battery.

Many hobbyists and collectors want some reliability and it is getting harder to make a 30 year old, battery eaten board reliable.

I won't disagree with any of that. There is definitely a market for a Bally/Stern MPU replacement. My point was that the market for this specific board is limited by cost, convenience and the fact that most people will choose an Ultimate MPU over something they have to assemble themselves for little savings. Not to mention other perceived advantages.

The fact that the classic Bally/Stern system was produced in such large numbers means that there are still lots of MPUs in the used market. Obviously they're not comparable to a new product but it's another option that will be there for some time to come.

Don't get me wrong. I wish you success with your project. I know exactly what it takes to make something like that happen and it's a big commitment of time and money. I have no doubt that there is a percentage of the overall market who will love this option. For those people you're offering an awesome product. If I could find a really cheap source for 6800 and 6821 I would even be considering a reproduction PCB myself because I know people want them. Even though there are already a bunch of options out there.

I see a market for these for many years, slow for sure but that is what a "hobby business" is all about. As this board suits many tens of thousands of games it could make the difference between saving a machine or parting it out.

We have to assume that there is already a pretty large demand for Bally/Stern MPUs given that there are several companies making reproductions. I'm sure that demand will continue over the years as more and more machines are restored. More and more machines will also inevitably be parted out as well. Again, my point was never that there is no market for Bally/Stern MPUs. Just that only a small percentage of that market is likely to choose this option (IMO). That's no comment on the quality of the boards. They look awesome.

 

[Lindsey]

Hmmm, found a POSSIBLE viable option for that Bally home board. The Mostek 38P70 processor. Basically a 3870, but with an external EPROM socket on the back of the processor chip. That makes it possible to program it now.

If homepin wants to go ahead with the project, I'll defer to them at this point. But if they don't, I'll start looking more seriously into it. Though if I could sell 20 of the boards, I'd be shocked.

-Hans

Has anyone ever dumped the ROM from the original games? You would need that first.

Something microcontroller based seems like the best option. The rules on those games were really simple so it wouldn't be that bad to write new game code.

Does anyone have a manual with a schematic of the MPU? I would like to get an idea of how difficult it would be to replace the processor.

 

[HHaase]

Has anyone ever dumped the ROM from the original games? You would need that first.

Something microcontroller based seems like the best option. The rules on those games were really simple so it wouldn't be that bad to write new game code.

Does anyone have a manual with a schematic of the MPU? I would like to get an idea of how difficult it would be to replace the processor.

Depends on which schematic, there's two generations. If possible, I'd say try to use the 2nd generation for all the available games, as it's much more simple since the 3870 integrated a few chips into a single IC. It's almost nothing on the board, since that Mostek CPU basically was an all-in-one module that combines the CPU, ROM, RAM and peripheral interface.

I forget where I found it, but I have a PDF of the repair manual that includes all the schematics. Shoot me a PM with your e-mail, and I can send it to you.

I was considering contacting Planetary Pinball to see if they might have the ROM images for it. It's not on the website, but that may be just because nobody has done anything silly like try to make new boards.

-Hans

 

[KenLayton]

Here's the Bally home pinball manual & schematics:

http://www.tinlin.net/jim/pinball/schematics.html

Steve Kulpa fixes the power supply boards:

http://stevekulpa.net/pinrepair/ballyh_rps1.htm

http://stevekulpa.net/pinrepair/ballyh_rps2.htm

 

[Lindsey]

Here's the Bally home pinball manual & schematics:

http://www.tinlin.net/jim/pinball/schematics.html

Thanks, Ken!

It's too bad that there are 2 versions of the hardware. Each one would require a different solution to replace the original CPU. In the case of Series I it doesn't really make sense because there are interfacing chips in addition to the CPU that could go bad.

Series II is a different story. Like HHaase mentioned, all of the processing and interfacing is contained in one IC making it a perfect candidate for replacement by a modern microcontroller because you can drive the whole game from one socket.

Now... if someone wanted to donate a Home version game with Series II hardware to me I could build something Seems unlikely but as microcontroller based embedded systems projects go, this one actually looks really simple.

 

[KenLayton]

The Series 1 board & power supply uses +5 volts and +12 volts to power the logic. None of the Series 1 power supply boards were fused nor did they have any over-voltage protection. Generally the +5 regulator crapped out and fried the chips on the gameboard.

The Series 2 board & power supply were simplified and only use +5 volts to power the logic. Bally/Midway did provide a ton of circuit breakers in this design, except for the most critical: the +5v regulator (18vac transformer winding). Again, if anything happened, the regulator went over-voltage and fried the chips.

It is strongly recommended that regardless of whether your machine has a Series 1 or Series 2 power supply board, to install a Peter Chou power supply to handle the +5 and +12 volts to the gameboard. That way you'll never have to worry about the chips getting fried. Naturally, you must leave the original power supply board operating the solenoid, general illumination, and switched illumination circuits.

 

[Homepin]

"Again, my point was never that there is no market for Bally/Stern MPUs. Just that only a small percentage of that market is likely to choose this option (IMO)."

We certainly understand this point - there are a lot of collectors who WILL want to built it and many who won't want to. Aside from some of the reported problems with other options - and also aside from the surface mounted components issues - this is the closest to a new, original board as you are likely to get and that in itself is a big attraction to some.

There is also nothing to stop us from assembling them for sale if they don't sell as kits.

 

[HHaase]

The Series 1 board & power supply uses +5 volts and +12 volts to power the logic. None of the Series 1 power supply boards were fused nor did they have any over-voltage protection. Generally the +5 regulator crapped out and fried the chips on the gameboard.

The Series 2 board & power supply were simplified and only use +5 volts to power the logic. Bally/Midway did provide a ton of circuit breakers in this design, except for the most critical: the +5v regulator (18vac transformer winding). Again, if anything happened, the regulator went over-voltage and fried the chips.

It is strongly recommended that regardless of whether your machine has a Series 1 or Series 2 power supply board, to install a Peter Chou power supply to handle the +5 and +12 volts to the gameboard. That way you'll never have to worry about the chips getting fried. Naturally, you must leave the original power supply board operating the solenoid, general illumination, and switched illumination circuits.

The solution that I'm looking at is a single CPU board design that replaces the series 1 and series 2 CPU. I Just haven't done much yet, but it looks like the only real changes on the series 2 CPU was using a 3870 instead of a 3850 and two 3851's.

Then a single-solution power supply as well, but with some filtering of the 5v, more robust parts, status LED's and test points, and board mounted fusing instead.

-Hans

 

[Lindsey]

The solution that I'm looking at is a single CPU board design that replaces the series 1 and series 2 CPU. I Just haven't done much yet, but it looks like the only real changes on the series 2 CPU was using a 3870 instead of a 3850 and two 3851's.

That's a fairly considerable difference if you look at the schematics. Both CPUs are 40 pins but that's about where the similarities end and the pinouts are totally different. That makes using 3870 (series II) CPUs in 3850 (series I) games impossible.

You could still build an "all in one" solution using a microcontroller but you would need a few jumpers and incorrectly setting the jumpers could cause damage. I would write the microcontroller operating system so you can write common game rules for either system but if I were designing it I would probably do a unique board for each version to provide a "drop in" replacement in both cases with no jumpers, etc... The microcontroller would still be programmed to work in either system. I would most likely use a PIC18f4550 microcontroller.

I couldn't find a datasheet for the 3851 PSUs but I didn't look too hard. You're definitely going to need that to figure out how to initialize and drive them. And here I thought the 6821 PIAs were a pain to figure out. I have a feeling these will be even more evil.

Then a single-solution power supply as well, but with some filtering of the 5v, more robust parts, status LED's and test points, and board mounted fusing instead.

-Hans

That is a great idea. Looks like the original power supply has connectors from the transformer and out to the game making a replacement easier to design than if it were soldered in. Making it cost effective could be tricky in small quantities.

 

[Lindsey]

We certainly understand this point - there are a lot of collectors who WILL want to built it and many who won't want to.

Agreed. I said basically the same thing.

Aside from some of the reported problems with other options

I would like to hear about some of these problems and how your MPU is a better option. I'm not being facetious. I'm genuinely curious. Beyond R11 which to me is a non-issue.

and also aside from the surface mounted components issues

Actual measurable issues or just people's perception? People tend to dislike surface mount with good reason but it's debatable whether they're less reliable. Surface mount definitely makes future repair more difficult but it can reduce cost and offer design options that you just can't do with through-hole. It's really a trade-off. Most collectors seem to favor through-hole construction but the questions is whether they're willing to pay more for it. Looks like Alltek are using surface mount NVRAM now which doesn't surprise me because the supply of DIP Ramtron FRAMs dried up. The cheap ones anyway (FM1608).

this is the closest to a new, original board as you are likely to get and that in itself is a big attraction to some.

There are at least 2 other companies making MPUs based on the original design. The most common example is the Two Bit Score "Dash35".

http://www.twobits.com/Dash35/

I think the Two Bit version is an exact -35 replica so it won't work in an MPU-200 based game out of the box. They're really expensive too. I have to wonder who actually buys them. I also wonder why they didn't at least so some basic upgrades like Dallas style reset circuit, Single EPROM (could use a ROM position that will never be used like U5), NVRAM, etc...

With the use of NVRAM and a Dallas reset circuit you could eliminate the +12VDC all together (and R11). Just power the LED with +5VDC. Jumper selectable RAM (MPU-200 or original) is also a nice option but that starts getting away from the original design more than you may like, though it can still be done without surface mount logic (look at the Alltek schematic).

There is also nothing to stop us from assembling them for sale if they don't sell as kits.

I think that would increase your sales options considerably. Assuming you can keep the assembly costs down. It's tough to compete with someone like Altek because they're probably having their assembly done by the board house who is making their boards. The problem there is you're looking at $10K plus minimum orders to make it happen.

Again I'll say that I think you're offering an awesome product and I fully appreciate what it takes to make a project like that happen. My only comment was that it's a limited market compared to other option.

EDIT: Looks like the "Dash35" does actually work in MPU-200 based Stern games. Assuming their game list is accurate.