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Well the reference manual says to set it to a minimum of 500 and not to go beyond 640. I don’t know if that means the optimum pulse width would be right in the middle or not ?…

Sideburn wrote: ↑Tue May 14, 2024 10:25 pm

ronin47 wrote: ↑Tue May 14, 2024 10:13 pm

Sideburn wrote: ↑Tue May 14, 2024 8:41 pm Thats with the pot pretty much maxxed out. If I turn it all the way up then it gets just a tiny bit wider. So 500us is about as good as I can get.

Interesting, I can easily get up to near 600uS with mine.

And you are measuring the top of the waveform like I am?

If I max the POT out then i can get it goes to where the green arrow is (actually about half that far):

OH wait is that 600?

max.jpg

Looks like it might be 600...

bxdanny wrote: ↑Wed May 15, 2024 11:54 am If you want to increase that pulse width beyond 500 microseconds, would it not make sense to increase R53 from 10k to 12 or 15k?

I'm thinking 12k would give a maximum pulse width of 550 us, and 15k would give 625 us, since the series resistance of R57+R53 would be increased by 10 or 25 percent.

Do you mean with R57 maxed out? Need to check what it is on my Klyball, but I definitely can get to 600us easily, a bit over IIRC.

Sideburn wrote: ↑Wed May 15, 2024 12:13 pm Well the reference manual says to set it to a minimum of 500 and not to go beyond 640. I don’t know if that means the optimum pulse width would be right in the middle or not ?…

That's what I was working on, but it may depend on your machine. I suppose starting low and working up would be the way to do it.

I really want to 3D print one of these cases and the microcassette is a beautiful touch too... Also what is the bodge next to the character ROM? Extra video memory?

Yeah it has a 48 character mod and 2K video ram. Problem is I can't get any software or games to work right with those mods.

The story behind it is A friend gave me his superboard II.. It was his first computer as a kid and it was full of modifications and bodge wires all over the back of it. I didn't know where to begin and I had never even heard of the board. I am about 10 years behind him so by the time I got my first computer it was a trs-80 coco with color and sound and a case even!

It took me a while and a lot of help from the guys here to get it running and bxdanny on here had to make me a custom ROM to support the 48 columns.

There's a lot involved in the portable build. It took me a month off and on to design it. It takes over 100 hours of printing, the LCD display section is specifically designed for a particular LCD TV from the 90s and I had to strip the LCD PC board down as thin as possible. I made some incorrect measurements towards the end and the LCD didn't fit! in the end after shaving everything I could off the LCD board I still had to thin the back of the display lid down to 1MM. Just barely made it. and thickening up the display part would have been a MAJOR reworking of the entire thing. Then there was the building of the NIMH packs and power management circuit...

I plan on taking it to VCF Socal this year and I am brainstorming doing an Atari 8 bit "laptop" next...

** with some work, the display portion could be refactored to fit a different one as long is it can be whittled down to fit inside.

I found the perfect Microcassette tapes. The Maxell Ultra Dynamic's They are read and writing flawlessly. They must have been made for saving data!

Sideburn wrote: ↑Wed May 22, 2024 11:14 pm I found the perfect Microcassette tapes. The Maxell Ultra Dynamic's They are read and writing flawlessly. They must have been made for saving data!


s-l1600.jpg

Nice find!!!

Must get back to fixing my cassette in/out, but my 2012 MBP is currently taking up all the room on my workbench on account of having a dead keyboard.

Soon...

Wow, really cool!

I'm interested in how the LCD is connected. Is it composite or is there a conversion such as composite to HDMI or RGB2HDMI? I've always been impressed by RGB2HDMI for its ability to configure the screen. On one project I did I was able to take a 640x200 resolution screen plus borders, that had a 640x128 active display area and exactly position it to fill an ultra-wide LCD panel perfectly. I think it would work great for your portable machine.

I have had the idea to put my 600D reproduction board in a cool case, and yours is very cool. Are you planning to release the 3D design files?

Steve

It’s composite. And it was difficult to find an lcd that would sync.
Ended up using a 90s lcd tv. I just found out about the rgb2hdmi and will be using that on an Atari 8 bit to laptop conversion.

** the design would need some modifications done to it and the display portion refactored to fit a different lcd panel and circuit. You can send me a PM if you deside to take the plunge and I can help you get it sorted.