exxos's Atari, Amiga & retro forum

PaulJ wrote: 17 Apr 2020 15:18

rubber_jonnie wrote: 17 Apr 2020 12:59 Happy days, bumper parcel opening today after they came out of quarantine!
Replacement soldering iron, H4 board no2, a bunch of 27C256 proms and a 44 pin IDE cable! Exciting stuff :)

Rj, don't understand how you have so many issues with your iron, you drop it, it burns you, you drop it, it commits suicide.. Ya know knifes and other dangerious weapons have a lanyard. I'll bet you could use a leather shoelace and make a lanyard for that pesky iron.. maybe wear a leather glove to minimize any injuries delivered in anger by your iron.

@PaulJ I blame the Mega4. I was moving it around on my insanely small workbench and the whole iron went over the back. Not just the iron, but the really heavy base unit too, which is what killed the iron. It actually works too now it's glued back together, but I expect it will have a limited lifespan. I guess it could be partly related to the amount of time working with one.

To be fair it is just the iron, the base survived unscathed, so it's equivalent to changing a damaged tip. Well, in my eyes at any rate.

I guess me and soldering irons are just not supposed to co-exist, but it was unfortunately inevitable.

Who knows? So far no recent burns though, and I have been using the desolder gun too.

Decided I needed some good news, so finished the Mega 1 off yesterday. I'd had it in bits again for testing the IDE boards I'd built. Pretty much all that was required was reassembly and install of the 3d printed 2.5" HDD cradle.

Initial install location was to be on top of the floppy:


But the cradle and HDD were just a smidge too tall for the tin lid to fit properly, so I changed the location to here:


And here all connected up:


The cradle is attached with servo tape designed for radio controlled models, so I doubt it's going to fall off any time soon!

Final spec is as follows:

1. TOS1.04 patched to give TOS details on boot (No of floppies, RAM and TOS version) and for IDE boot.
2. PPs Megabus IDE adapter.
3. 8GB laptop HDD.
4. HDDRIVER V11.
5. Vortex ATOnce 8Mhz/16Mhz 286 PC emulator

This is a very nice machine, and I've opted to keep the original floppy drive, since I can also connect my CosmosEx if I want to in order to transfer data, plus I expect to have an external Gotek up and running very soon, which will also allow for quick transfer of any data I ant to move to HDD.

@rubber_jonnie , out of curiosity why did you use a conventional drive vs a flash card? :coffee:

PaulJ wrote: 19 Apr 2020 14:55 @rubber_jonnie , out of curiosity why did you use a conventional drive vs a flash card? :coffee:

A couple of reasons. Firstly I have a few spare laptop hard drives, and I like to recycle, and secondly, all of my CF cards are in play elsewhere with exxos' V1.1C and Beta IDE interfaces.

I kind of like the old fashioned feel for this machine too, since it is very original externally, no Gotek here either.

Finally got round to fitting a Gotek into my external Datel enclosure:


Works lovely with the Mega1, but I still need to test with the 520ST, though I'm confident there won't be any problems.

Luckily the orginal drive from this enclosure had a D0/D1 jumper in plain view (Set to D0, so Gotek set to S0), and the drive had the pins in exactly the same alignment as the Gotek, so no flipping required.

I buzzed out the 14 Pin DIN to 34 Pin floppy connections whilst I was at it, just need to draw it up nicely now.

Another treat for myself arrived today:


Looking forward to having a close up look at the next thing in need of repair!


On another subject, now the Mega4 is working, I have one of exxos' 1/4MB RAM expansions coming, and I don't know what to do with it.

I'm considering two options:

1. Installing it in my Mega 1 so I have two 4 meg Megas.
2. Pulling the Marpet SIMM adapter out of my 520ST and installing it there, then dropping the Marpet into the Mega 1 where there is a bit more room, and upgrading to 4 meg that way.

Hmmmm, choices....

So, seeing a post by another forum member saying they were going to upgrade their 520 ST to 4MB with one of the adapters from Harry, it spurred me on to make the decision I would fit mine, originally intended for the Mega4, to my 520ST, since the Mega 4 was now running fine after problems with D2 & D4 were resolved.

Assembly of the Shifter adapter was done quickly, and no need to fit a socket to the 520, because it was already fitted with one having had a Marpet Simm adapter fitted with 1MB. I really had wanted to fit 4MB at the time I put in the Marpet, but it was never stable with 4MB fitted.

A quick review of the install instructions, and it was soon fitted:


So I booted up, to be greeted by a white screen. I removed the MMU adaptor and tweaked the contacts as per my post here: https://www.exxosforum.co.uk/forum/viewt ... hilit=plcc

When a MMU adaptor is plugged in a while and removed, it can upset the contacts in the socket. If you're doing this fresh then you probably won't hit this problem.

MMU adaptor refitted, I plugged in the Diag Cart and a serial cable over to my Win 2000 laptop running Hyperterm just in case. I needn't have worried, it came up just fine :)

Here is the Diag Cart RAM test pass shown at the ST and also at the other end in Hyperterm:

ST end:


Hyperterm end:


And I left it running the XTRA_RAM test:


It had got to around 5 passes last I looked, and no faults.


And finally reassembled:


With the external Gotek installed.


All told about an hour to install including teardown, reassembly and adaptor build, but it would have been a bit faster had I not had the initial white screen problem.

Not a bad Sunday morning project.

Well done @rubber_jonnie , that version of the ST looks the best in my opinion. I must get one at some point.

PhilC wrote: 03 May 2020 12:31 Well done @rubber_jonnie , that version of the ST looks the best in my opinion. I must get one at some point.

Yeah, they really are nice, get one if you can.

The only annoyances are the number of cables and the external power supplies. Otherwise, I agree, the ST/STM are more sleek and have the mouse and joystick ports in a sane location!

Oh, and when I got mine in '88 they were being sold of cheap as people preferred the all-in-one STFM by that point.
I see you had one of those generic external floppy drives too, though I see you've fitted a Gotek into it.

At some point I should think about replacing the unknown memory upgrade with an Exxos one and maybe removing the original RAM too. Then again, I guess it's part of the history of the machine. I had to send it off to Third Coast Technologies to get it fitted as I couldn't get it to work as a DIY job. From the look of things they merely soldered extra ground wires.