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Transferring ROMPAC Basic Programs from CP/M to Tape

Posted on by Graham

Some of the basic games that have been stored as CP/M com files are missing from the sorcerer archives at Microbee Technologies (Alan Laughton is the curator) so i went through the process of transferring them back to audio files.

These were translated to wav files as follows:

  1. At monitor GO BC00 to boot up CP/M.
  2. Load the basic rompac (LDRAM).
  3. Reset – starts basic.
  4. Bye to return to monitor.
  5. SE T=1 to set 300 baud.
  6. GO BC00 to boot up CP/M.
  7. Load up the game eg A>LAIR to load up LAIR.  This starts up the ROMPAC basic.
  8. Load up Audigy on a PC.
  9. Set recording gain to max and the input to mono.
  10. Connect LINE IN on PC to AUX on Sorcerer.
  11. Start recording and enter CSAVE LAIR.
  12. When the sorcerer comes back with READY stop the recording and trim if necessary.
  13. Apply a good 20dB of gain to maxout and square up the waveform.
  14. Export the audio to a wav file.

Check as follows:

  1. Connect the PC LINE OUT to the input of the external amp.
  2. Connect the external amp output to the EAR input of the Sorcerer.
  3. Set Audigy playback volume to max. 
  4. Watch the EAR input with a scope and back off the Audigy volume until the waveform is clean and square.
  5. CLOAD LAIR.
  6. Hit play on Audigy.
  7. The title should be shown in less than 30 seconds.
  8. By the time the audio is complete, the sorcerer should say READY.
  9. RUN and enjoy.

If you want to do another then breakout with ^C, BYE to return to monitor and GO BC00 to boot CP/M.

Sorcerer ROMPAC Basic Games on CP/M

Posted on by Graham

There were a number of games on the Sorcerer disks that fired up fine, but there were a large number that did not.

I got some help from Alan Laughton (Microbee Technologies) to work out what was going on. He spotted that the files contained basic. They were com files – so quite different from the basic files that you would load into the disk basic.

Browsing through the manuals and other data, it became clear that the ROMPAC BASIC work area had been set up in such a way as to allow programs to be saved and loaded with CP/M.

The ROMPAC basic has a lot more memory available to it than the disk basic. It doesn’t waste space on the interpreter or the operating system.

The first entry in the com file is a jump to the warm start area of the basic ROMPAC. This failed on my machine because i had no ROMPAC.

What i did have, though, was a 8k S-100 RAM card (Solid State Music MB6) which i could locate at the same address as the ROMPAC at C000.

The card, predictably, failed the Sorcerer Monitor RAM test, but the offending IC was found and replaced.

I tested it out by using ddt to load the ROMPAC which was moved up into the RAM card. Following reset, the “RAMPAC” was found and basic fired up.

“bye” at the basic prompt returned to the Sorcerer monitor and GO BC00 started CP/M again. One of the previously failing com files was loaded and sure enough it ran!

After that, i wrote a very short program that replaced the ddt step. This allowed another 23 games to execute.

I’ve since created to couple more which load the development and word processor ROMPAC code into the RAMPAC.

The memory card had a facility to write protect the contents, so i added a switch to the expansion unit to enable it.

Spare Parts

Posted on by Graham

I have accumulated a quite a lot of pre-1990 spare microcomputer parts including a lot of LS TTL, transistors, diodes, LSI parts in the Z80, 8085, and 8088 ecosystems, seven segment displays, and various analog ICs.

I have no inclination to mail these out, but i can help hobbyists in the Adelaide area, particularly members of the Adelaide Retro Computing Group.

I’m probably not going to be able to help out with bulk RAM or recap projects. You’re on your own!

Buying & Selling etc

Posted on by Graham

I regularly buy and sell machines and peripherals. This is not a profit making activity for me; it’s just an important part of managing my hobby.

The temptation is to acquire an ever greater number of machines, but i only have so much space. I now sell/give as much as i buy/acquire. It’s not a profit making venture. I try to recover my costs, but that’s not always possible. In this hobby we have to accept that sometimes we pay for the entertainment value of constructing, restoring or embellishing a machine.

I will post items that are for sale on this site, but i would rather sell low than go through the hassle of postage. Typically, i prefer pickup either at my shed (Cockatoo Valley SA) or at a monthly ARC meet (Unley SA).

Apple II Europlus

Posted on by Graham

The Apple II computer is iconic. It was the first computer that i ever touched – one arrived at Unley High in 1981.

I’m sure there are original Apple II machines in Australia but the earliest i could expect to find was a Europlus which uses PAL video without the colour encoding from the factory. This one appears to have been manufactured in 1979 when i was still at school. It was owned by Flinders University.

This one was a gumtree purchase and came with two third party drives. It had a language card and a disk controller card.

The keyboard was missing a key, and the replacement i got was not for this particular keyboard – it’s easy to spot if you look in the pic. Perfection is not my goal.

The power supply looked fine other than the line filter caps, and the machine largely worked – most of the time. Often it would stop working, and then it would need a push or a prod on the motherboard to get it going again.

I don’t pull down stuff just for kicks, but i pulled all the chips, cleaned the board and the ICs – in some cases re-attached some legs that had broken – and put it all back together.

The controller card and drives were all faulty, so i suspect they came from a repair box at the university. The controller card needed one IC replaced. Both of the drives needed replacement Darlington drivers – one was cracked. I eventually replaced the third party drives with Apple units.

I like to fill slots, so i added:

  • Printer (Epson): Slot 1
  • Super serial: Slot 2
  • 80 column card (Videx clone): Slot 3
  • Z80 card (softcard clone): Slot 4
  • Booti: Slot 5
  • Disk Controller (clone): Slot 6
  • RGB card (Taxan): Slot 7

I can also swap in a PAL card in place of the RGB which has some advantages when swapping between operating systems. The RGB card does not work with CP/M.

With the Z80 card installed i could boot CP/M but i got some strange behaviour including calculation errors in MBasic. The silkscreen indicated that IC B1 should be a 74S, but it was a 74LS. When i changed to the S part, the calculation issue resolved.

I also found an issue where the 80 columns mode would not work with Wordstar. This seems to have been related to a known problem with the Softcard when a Videx card is installed. The solution was to add a capacitor between pins 10 and 11 on IC15. This resolved the issue.

The booti card does a great job of serving up disk images including Total Replay. Real floppy disks provide a more genuine experience, but there’s no doubt that they take more patience.

IPX CD-ROM, Ball Mouse, & Monitor

Posted on by Graham

Michael from the Adelaide Retro Computing Group had a Sun CDROM drive arrive for recycling. He kindly sent it my way. I think it’s probably one generation newer than the IPX but it will do.

Like the DEC CDROM, it was non-functional due to leaking capacitors. Once they were replaced, it made a great addion to the lunch box stack.

Michael also came up with a very weathered Sun CPD-1790AS monitor. It really needs a lot of work to clean up the interior metalwork. It is operational though.

The original optical mouse had always been a pain. While acquiring Sun Keyboards for my Ultra 5 project, i also gained several mice, including a Sun Compact 1 Ball Mouse which work much better than the optical mouse.