Any info on Video Technology Laser 500 computer?

[Robbbert]

On 12/27/2018 at 12:27 AM, nippur72 said:

Thank you for the patches!

As for the wait states, in my emulator I have a per-instruction CPU emulation, so I simply add the number of memory reads/writes to total count of instruction's T-states.

Not sure if you're still around nippur72, but the wait-state issue has been fixed in MAME 0.224 which is available now.

[nippur72]

18 hours ago, Robbbert said:

Not sure if you're still around nippur72, but the wait-state issue has been fixed in MAME 0.224 which is available now.

oh thank you I'll check it ? I'll compare it to the browser emulator which is pretty solid.

BTW we have also an FPGA implementation for the MiST platform that is accurate as well, though it doesn't replicate the VLSI chip but emulates it at a functional level.


 

[evdberg]

On 6/18/2018 at 6:50 PM, nippur72 said:

My Laser 500 just arrived! I'm happy as a child . I haven't touched this machine since the late '80. WOW.

 

- the unit is in pretty good state, doesn't seem to have been used much

- I have the QWERTY model, with ANTENNA/TV connector in place of RGB. It is possible to choose between CH3 and CH3 via a little switch on the back (anyway I haven't tested it)

- no PSU included, but I've plugged to it a 9V DC positive central power supply (thank to the info on this thread). It works even with 0.5 mA but the power supply gets really hot. And by giving less than 9V the image flickers considerably.

- the keyboard is quite responsive, much more than I remembered

- image quality using composite video is rather BAD on my LCD screen. I am puzzled as it was crisp on my old TV. Now it's like there is a VIC20 attached (if you know how that machine looks). But if I switch to monochrome (via the switch on the back) it's very sharp (but alas, no color!).

<snip>

I just acquired a Laser 500 myself, the same version as you. And I also have very bad image using composite video on my plasma screen. However, in later posts from you I saw a screenshot of your screen and it looked pretty good. Did you manage to improve the image quality and if so, how?

 

Also, it seems that interest in this computer has died after 2019, or is the discussion moved to another location?

[carlsson]

There is a partially active FB group for these Laser computers. 50% English and 50% Italian.

[nippur72]

the discussion moved to the Facebook group (which I think you already subscribed, right?) but not much activity recently. The only noticeable perhaps is the release of a Tetris game for this machine.

 

[evdberg]

@nippur72,

Yes, I just subscribed to the Facebook group. Although it should be publicly visible, I could not find it through search on Facebook or Google. I found it through the link on your github page for the emulator.

 

Any ideas on the image quality through composite?

[nippur72]

can you post a picture (here or on the group) ? In my experience, composite output to CRT screen is fair; on LCD is not so good because modern TV use post-processing. On the contrary, output with the Peritel/Scart (which you don't have) is incredibly clean and sharp.

[evdberg]

It proved difficult to make decent pictures. The effect is very clear in real life, but difficult to capture. For instance I was unable to capture the jail bars in the border and background. I think the under exposed picture shows the problems the best. On the 3rd picture you can see the shadow next to the cursor and random black pixel (between a and r).

[nippur72]

this is very similar to what I get on my LG LCD TV; for some reason on the CRT it's better.