Some people have been able to use the raspberry pie powered RGB to HDMI device to get video out of the lisa using it built-in RCA video Jack.
I was not so lucky. I tried many different configurations that other people said worked for them, but I could not get good video out of my lisa using that device.
Thanks to Rick on LISA List I found out about how to get high quality HDMI video for the LISA using a RGBtoHDMI – 6-bit TTL Edition.
The big difference in this method is instead of using the RCA video out port on the back of the lisa,. you connect to a chip on the Lisa's motherboard.
Initially, I was very squeamish about messing around with my motherboard...
I take my lisa to different Vintage computing and Security events. I expect the experience would really be enhanced if I could get good video projected or a large monitor screen..
Here are my rough steps:
1. Spare chip.
I ordered several different chips so I would not endanger the original motherboard chip with my poor soldering skills. The chip on my motherboard is a 74LS132N. Thankfully, this chip seems relatively available. I ordered two off of eBay and one from Amazon. The one from Amazon doesn't have the exact same part number, but they appear to be compatible. I now have some extra chips by the way if you'd like to buy one off of me at cost.
The Amazon chip comes in a selection of logic chips. There appears to be no difference if you use a 74LS132N or SN74LS132N.
2. Order connectors.
I'm not a fan of a lot of Bodge wires and I also wanted to make sure if I take the back panel off I don't bend or pull anything off the logic board.
The RGB2HDMI device uses a nine pin CGA style input. So I ordered two sets of connectors so that I could easily unplug it from the back of an open expansion slot.. I used 3-D printed expansion slot covers to make a DB nine sized hole that could hold a connector.
For the inside, I used some floating DuPont connectors. These allow me to easily route a disconnectable cable from the chip to the lisa expansion Bay.
3. Chip soldering
I used a chip puller to remove the chip from the motherboard and tested the Amazon chip. It booted up and seems to work just fine. I applied my horrendous soldering skills to attach solid core 28 gauge wire to the chip.
4. Testing connections.
I went back through with an om meter to make sure signals could actually make it from the chip to the end of the CGA connector.
5. Making it work.
The final stage was to plug in the CGA video cable I had created to the RGBTOHDMI device. I then plugged the device into a HDMI monitor.
At first, I tried a CGA profile and got a nasty looping green image of the lisa's video.. after getting some advice from Alex. I used the Lisa profile that's normally used for the external RCA port and I got a much better image, but still not quite right. After running an automatic sync config, the screen turned into a perfect representation of the LISA video output.
6 links and notes.
So now I have a relatively decent looking installation for video out for on the Lisa that works fantastic on my HDMI monitors. It's still a bit of a bodge job on the inside, but I think I've made it so it stays out of the way of everything and easily disconnects.
I'm open to any suggestions for bettering the design although I have to warn you my soldering skills are a work in progress.
At the time of this writing, these are the links that take you to the products I used.
Again, I have some spare chips that I don't need if you'd like to get one from me at about my cost.
https://texelec.com/product/rgbtohdmi-ttl/
https://a.co/d/dzW5baE
https://a.co/d/bae1QFp
https://a.co/d/alEhSwA
Please note the screenshots attached to this thread look terrible because of the reduction mechanism. They are perfectly clear and sharp on the screen..