Leako Talk

[barbeque]

Hi There!

This is the Discussions forum for the Leako ColecoVision-compatible game console project.

Some ideas for this area:

• Ask technical questions about the assembly process and seek help with board bring-up;
• Brainstorm additions, derivatives, and improvements to the Leako board;
• See who has the best high score on Frenzy

I hope you enjoy yourself, and please be nice to one another. We're all weird nerds here.

[Stanton54]

I am almost done the Leako.

The last thing I have to do is program the BIOS and the HELLO WORLD.

I am working with a T48 programmer with xgecu as software with a bios file from a coleco I had.

I checked my soldering and all seems well but I am a bit of a noob with the software end.

I have TMS9918ANL as my video processor and M27C512 as my BIOS chip.

How do I finish up the programming? I have tried a few times different ways and only get static sound and some light lines across the screen.

I have included pictures of my board as well.

Thanks!

[barbeque]

Looks good! I would skip writing the "hello world" program as it's not needed. For a 27C512 (which is 512/8 = 64k) I would duplicate the COLECO.ROM BIOS eight times and write it to the 27C512 EPROM.

Please also check for bridges and bad joints near U6/U7/U8 (the latches for the video SRAM) as that is where most of my problems were with video.

Speaker hum makes me think that the CPU is not initializing, so it could be BIOS ROM.

Please also make sure that only one of the -5V or GND jumpers is soldered, not both. It controls which value the controller will be pulled down to: it probably won't keep it from booting, but it won't work properly.

[Stanton54]

That's perfect,

I was able to upload the 8x bios so at least I know that's not the problem.

It must be something I soldered so I will check everything over:)

When I booted it up it did the same thing. Small horizontal white lines and electrical noise.