exxos's Atari, Amiga & retro forum

Yes and about 10 percent faster nec made the v20 8088
And the v30 8086 they made dos move fast

Tom

Hmm... I'm not sure how this would interact with the video sub-system on the Apricot as it is more akin to the way that the ST operates than an IBM PC with the video sub-system sharing main memory. There's quite a bit of CPU interlock with drawing to the screen memory.

Interesting I have used the v20 in atari pc1 successfully and I'm still looking for a pc1 because I sold the last one

Tom

Well, you see the Apricot may run a version of MSDOS (modified to fit the different system) and have an Intel 16 bit CPU but it's most definitely not a PC compatible. It's a very different architecture.

Seeing that I don't have any electronic parts to fix the motherboard I've focused upon the case and floppy drive.

Lots of epoxying later and the number of case parts has reduced markedly and it's in a state where it can be put back together in a reasonable manner.

The floppy itself has had the upper head re-glued with tiny drops of epoxy resin where the double sided tape used originally was. Both heads have been cleaned and they look fine. The disc transport and eject mechanism worked fine but I re-greased that, along with the worm gear which moved the heads. I had to clean quite a bit of gunk off that.

So, after all of this the drive looks half decent again.


I can't do any more testing on it but previously it has moved the heads back and forward during the system POST so I'm at least half confident that it may work.

Just to remind you, this is what the drive looked like initially.


Finally this evening, after the epoxy had fully set I did a test rebuild of the machine to make sure that the case still went together.


This is after quite a bit of cleaning with both soap and water and IPA, though it'll need more IPA to get rid of the marker pen on the top. It's definitely going to need a spray after I've built a replacement for the missing bit of case on the front. (Oh, and you may have noticed that I forgot to fit the floppy eject button, which I do have.

Looking so much better than before.

And broken computers do make some odd but interesting crash screens :D

PhilC wrote: 10 May 2021 22:29 Looking so much better than before.

And broken computers do make some odd but interesting crash screens :D

Technically it's not even a crash screen as the processor hasn't actually got around to running any instructions. :-)

The replacement CPU arrived today. I swapped them over and no change. So the next thing to do is replace the CPU, ROM and bus arbitration EPROM sockets so as to rule them out.

stephen_usher wrote: 11 May 2021 13:54 The replacement CPU arrived today. I swapped them over and no change. So the next thing to do is replace the CPU, ROM and bus arbitration EPROM sockets so as to rule them out.

Kinda know how you feel, I've swapped out the system 6522 and CPU in my Beeb and no change, swapped out the ROM sockets, and started on swapping out the sockets for those two. Still nada, at least you have a crash screen :)

Yeah. At least I know that the video sub-system and memory are OK.