Model 4p owner saying hello

[Roach III]

Just wanted to say hello after just registering. There's a lot of good info here that I will pour through for a long time coming. Hope I will be able to contribute as well.

My dad bought the 4p shortly after they discontinued it. So he got it for a good price. I was 12 years old at the time. I spent every waking moment tinkering with that computer. Dad installed the 300 baud modem and the Grafyx Solution hi-res board. I loved messing around in Gbasic.

We also had quite a few operating system. TRSDOS 1.3, 6.2, LDOS, CP/M, and a few others I can't remember at this time. I used to rewrite BASIC games from 1.3 to work in 6.2 so I could get the 4mhz speed. I could run 1.3 in 4mhz with a poke command, but it would glitch and lock at times.

Super Utilities was my best friend. I used it to format my disks at 42 tracks instead of 40 to get the little extra space. I also used to punch an extra hole and a notch in the disks to make them double sided. I just flipped them over after loading the MODELA/III ROM.

Sorry for the long post. It's just exciting to see an actual active forum for this great machine. I've been looking for years.

 

[Agent Orange]

Welcome aboard from 1000SX land!

 

[leeb]

Greetings and Welcome!!!

Greetings and Welcome!!!

I got mine a few years ago off Ebay 'cause I had always wanted one but couldnt afford them new... and I wanted to run CP/M again without owning a Model 12... :shock:

FINALLY got a bootable CP/M disk and... waited another year to learn that the built-in diags were RIGHT when they told me that the RAM was defective... once I moved CP/M down below the bad ram it was up & running!!!

Dont have a modem or graphic card in mine but DID get an 8-bit IDE controller and (until yesterday) now it runs off IDE hard drive with a single 3.5" floppy as 'B:'...

Getting ready to swap the HUGE (8gb) drive being used right now for an old Conner 20mb laptop drive (as I have 'a few' at the moment....) and doing the requisite 'patching' to get that done!

Again, WELCOME!!! :mrgreen:

 

[Roach III]

Thanks!

I always wanted a hard drive for it. I believe around $1500 was the price of a new one. Might have been more expensive, but I don't remember for sure.

You put an IDE controller in it? Wow......that's amazing. How exactly did you get that to work? I have lot's of parts here. The 4p needs a new reset switch, though. Sorry to hear about your ram. Do you have the 64KB or 128KB? Dad never opted for that upgrade.

I used to know a lot about the operating systems. But much of that has faded. I remember (IIRC) the device command under TRSDOS 6.3 and 6.3. I would reroute all kinds of stuff. Keyboard to the printer, display to the printer, keyboard to the RS232 (which I connected a 286/16 to with a null modem cable). Clickgen, I believe that was it....made a clicky sound from the speaker when you typed. Even ran a BBS program for a bit. I think the modem has never worked from day 1. So, I used Teleterm on the 286 and connected through the serial port and could access it that way. Just a 14 yr old experimenting really. Yeah.......the wonder years.

Does anyone remember the 80Micro issue with the Cryptsys code? I typed for what seemed like hours to put that into basic. It was a really cool program. It would encrypt your documents with a key.

Sorry to ramble. Just excited to finally meet fellow TRS-80 owners. And, thanks for the welcome again!

 

[leeb]

The IDE controller came from a users group in Germany, I believe it is... KC85 IIRC....
There is a thread about it 'down below' somewhere... in the 'spiderweb section!'

It is known as a GIDE originally built by Tilmann Reh (sp?) and is a piggyback to the CPU socket. In 'our' case, it needs an 'extension cable' but seems to work just fine!

The nice thing about it is that it can be configured to the 4p's default location of 0C0h and is compatible enough to be possible to BOOT CP/M from the IDE. I ended up rewriting the boot-track code but that was the easy part!

It originally had only the 64k. When I found that it was defective I ordered a full bank of replacements (as the defect was spread across multiple chips) and put the 'broken' ones in the 2nd bank. So... I have a 'defective' ram drive that I never use.

Eventually I will replace them too... so that CPM-3 will be able to bank-select.... once I get CPM-3 that works.

NEVER-EVER did like TRSDOS... so I never did anything with it.
In fact that was part of the original problem, as TRSDOS would boot fine and ignore the area of RAM that was failing... Because I was adapting the 3.5" drive at the same time, I blamed the problem on my cable even tho TRSDOS worked...
Once I was certain that the floppy cable was not at fault I resolved to fix it. and did...

Unfortunately I have no suggestions about a replacement reset switch other than Digikey or Jameco...
Good luck on that one! Heaven help me if mine ever goes out! :shock:

EDIT:
Well, I thought I had made a thread about 'the dinosaur' here or in the CP/M section but it doesnt seem to exist. Oh well!

 

[Rick Ethridge]

I have a 4P I bought at an auction for $15. I updated the green-screen gate array to 128K. It's a neat little machine.