Part III: TRS-80 Model 4 Network 3 Auto-Boot ROM Upgrade

[@GenXCoder]

Great job keeping TRS-80s alive and kicking! I remember in 1983 sitting in my middle school library before school and during lunch typing in BASIC programs then playing around and making my own modifications. This really brings back memories!

[@TJBChris]

Sounds a lot like my time in school, with lunches and free time spent on the computer writing something in BASIC or messing with other people’s programs. Seems like it was the 80’s way for those of us who were computer-inclined. Fun times for sure! Thanks for watching!

[@geekwithsocialskills]

Very cool! You have such an amazing TRS-80 model 3 and 4 collection!

[@TJBChris]

Thanks! I have a problem when it comes to the III and 4, in that I just can’t resist them! I’ve finally stoped buying them…I just have to hope a 4D or 4P doesn’t land in my lap, because I probably wouldn’t say no!

[@RetroGamingNook]

Great series this year... Pretty cool demonstrations. I always enjoy seeing some real-world video capturing, especially if you can see the graphics or text just fine. It feels more like really being in the environment.

[@TJBChris]

Thanks! It’s been a fun series to make. Overall, I prefer capturing the screens, even if it can be tricky, because it does feel more real.

[@idahofur]

Oh very cool and I still love the Trash-80 4. I don't need another retro computer. But, If I ran across a 4d local for a good price. Would follow me home. Also I try not to do computer stuff before work. Might not make it to work in time. :)

[@TJBChris]

I almost didn’t make it to work on time. It was a photo finish for sure! If you find a 4D, I’d definitely recommend making space for it. Thanks for watching!

[@wdatkinson69]

Any chance I could convince you to make me a set of M4 ROM's, plus the replacement C for the FreHD? I'd be happy to cover any and all costs. If no, I completely understand. Any pointers to a set stateside would be appreciated. The only burner I have is the TL866IIPro, which will not do the 24VDC IC's. This is how I killed my FreHD ROM. After I show my 1000HX this weekend at our club meeting for SepTandy, you've motivated me to re-bench my M4.

[@TJBChris]

Unfortunately I'm not really in a spot to make ROMs for folks at the moment. As it goes, I had to re-use EPROMs from other projects for this to work; so I don't really have the parts floating around. That said, for the Model 4, a 2364->27256 adapter will work on the A ROM, and I found 28C16 EEPROMs for the C ROM (not sure what B is...), and the TL866II should be able to manage those. 28C16s can be a bit tricky to find sometimes - I bought three last time, and only two worked. :) For your FreHD project, just finding a 28C16 for the C ROM should do the trick. If you have a working disk system with either real disks or a floppy drive emulator, I made a boot disk that lets you use the FreHD menu without modifying your system; it's what I do on my Gate Array 4. Check it out here: github.com/TJBChris/FreHDDisk Hope that helps some!

[@wdatkinson69]

@@TJBChris Understood and I thank you none-the-less. It's tougher troubleshooting without a similar model to be able to compare test results. That's held up my A500 project too.

[@BollingHolt]

PXE boot before PXE boot was a thing LOL.