saustrup, to random
@saustrup@mstdn.dk avatar

The repairs of my continue. It can run an old 32K ROM but not a newer 64K ROM. Also it fails the RAM test. Replaced the old soldered RAM chips with new socketed ones. Same result. Main suspect now is one or more of the address lines on the PCB. Unsure how to test it, as one of the ASICs does some clever memory banking, which probably means they're not directly attached to the CPU.

I'm way out of my comfort zone here, but I'm trying to diagnose and fix a 40 year old .

Enterprise PCB with ROM socket and Z80 CPU visible.
RAM test during Enterprise startup. First two banks succeed (FE and FD) - third reboots the computer (FC).

saustrup, to VintageOSes
@saustrup@mstdn.dk avatar

Firing up #PolyPascal on my 40 year old #Enterprise64 for the first time in probably 35 years. Actually, I'm not sure if I ever go PolyPascal running on it, or it was just the previous version, Compas Pascal. Glad to see an old #Dnaisg friend from the #CPM era again though. It's been too long.

#Enterprise128 #Enterprise #vintagecomputing #z80

saustrup, to 8bit
@saustrup@mstdn.dk avatar

Some 40 years ago, my dad took a leap and decided to import and resell the microcomputer from the United Kingdom. This was indeed the era of the "micro", and lots of options were available like the , , , and numerous others. Unfortunately competition was hard, and the Enterprise was delayed for almost a year. Eventually they went bankrupt and all stock was exported to Eastern Europe where it got a second life among some very hard core enthusiasts. Very few were actually sold in Denmark - I would assume less then a hundred - and today I managed to get my hands on the third one in my collection. Inherited from his dad, the seller had no idea what to use this for. It's very much a special item, and very far from the mainstream like the Commodore 64. It is nevertheless a fascinating machine, sporting a with support for up to 2MB RAM. The operating system also contained IS-BASIC, and was a bliss to work with.

Seller's image of the Enterprise 64: Visible is original box holding the system. I haven't had the original box for probably 30 years.

bread80, to random
@bread80@mstdn.social avatar

And I only just found this. I didn’t realise the Flan name actually made it into production.

This means it’s a revision 4 board, from the first production run. The run with bugs in the video chip and ROM.

bread80, to random
@bread80@mstdn.social avatar

The Enterprise keyboard layout is coming along nicely. The photos show a printout of the design under the matrix.

I had to redo the horizontal positioning when I realised they used the same size matrix for both dimensions and the keys are 19mm x 19mm. The error was only 1mm across the width of the board but that’s plenty enough to cause problems.

The function keys and joystick are the only things which aren’t on the matrix.

Closeup of the keyboard centre.
Closeup of the joystick area.

bread80, to keyboard
@bread80@mstdn.social avatar

I want to see if I can make my keyboard a bit less ‘squidgy’. I’ve bought a selection of the thinnest tactile switches I can find to experiment with. The switches here run from 0.8mm to 2.5mm.

bread80, to random
@bread80@mstdn.social avatar

Having a play with the video chip on the . This is a demo from the manual which creates a text video window in the centre of the screen. The original BASIC text window is still there ‘underneath’ it. Note that the central lines of the BASIC window are still there, just being masked out by the second window.

A video. A narrow window in the centre of the screen remains static. A larger window displays lines above and below it. The program listing scrolls up the larger window, unaffected by the smaller one.

bread80, to random
@bread80@mstdn.social avatar

I finally have the Flan wired up to the RGBToHDMI. Still some sparklies on screen but otherwise looking fantastic.

And having a little explore of the BASIC. Recursive function definitions is cool. The wordiness isn’t so great though. Feels a bit like interpreted COBOL.

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