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Is anyone from Lomas Data Products on-forum?

RichCini

RichCini

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Aug 7, 2005
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Long Island, NY
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For a few months, I've been working on a replica of the Lomas Color Magic video board so I can use it with my Gazelle. Since I couldn't find one of my own, I decided to build a replica, and I borrowed a board from a friend so I could try to read the PALs. These PALs have the security fuses are blown, so I can't read them in the normal way. I've resorted to various direct methods used in the pinball preservation world, but none seem to work. I would really like to be able to make new PALs for my board, but to my knowledge none of the manuals ever had the equations. Does anyone know anyone who worked at Lomas that can maybe share the equations or JED files?

Thanks!
Rich
 
Yes, there's actually something to report on this. After many weeks of not getting the PALs read, I returned the board to the owner, who sent it to someone with better tools. He was able to decode all of the PALs and create working replicas. Based on this, I ordered a few prototype boards from China. Once I have one built, I'll report back.

But, yes, much progress.

Rich
 
RichCini said:
Yes, there's actually something to report on this. After many weeks of not getting the PALs read, I returned the board to the owner, who sent it to someone with better tools. He was able to decode all of the PALs and create working replicas. Based on this, I ordered a few prototype boards from China. Once I have one built, I'll report back.

But, yes, much progress.

Rich
Click to expand...
Excellent update! Please let me/us know if the board works as intended. I've got a Z120 all in one that I would love to bring closer to the PC MS-DOS world. Is there a potential for more of those replicas to be produced for the few of us left in the world who could put it to use?
 
I’m not producing ready-to-run boards but the design files and PAL/ROMs are posted on my GitHub. I may have a limited blank board run made since 4-layer boards are costly to make in low quantities.

But, let’s make sure it works first :)
 
No. I used a single chip with A13. I’m hoping that actually works. Design-wise that’s the only thing different.
 
RichCini said:
No. I used a single chip with A13. I’m hoping that actually works. Design-wise that’s the only thing different.
Click to expand...
I should note that I replaced the LM338K and LM317 adjustable regulators with the fixed equivalents and the associated resistors removed. The TO-3 was also upgraded to an EzSBC switching replacement.

As I'm building the board I noticed I used the wrong footprints for the resistors. So, I downgraded them to 1/8w and kept the 1/2w in the power supply section. Grrr. Also, the footprint for the LM7812 is backwards. Oops.
 
There are some problems with the boards so I have to scrap them. Since I have to re-do the boards, I’m going over the schematic redraw again and the versions of the scanned schematics that are on-line are not the best – there’s highlighting on it, and some signal names are obscured. Does anyone have a physical copy of the schematics that they can re-scan? It would be greatly appreciated.

Thanks!
 
To conclude, the 3rd prototype board works just fine. It's taken another seven months to bring it over the finish line, but it works. My Github has been updates with the final files and other details. Lomas has a companion 80186 board for which I have the schematics. That's a very tight board too and uses stacked DRAM chips and a weird TMS4500 DRAM controller. I might give that a try too.
 
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