exxos's Atari, Amiga & retro forum

@rubber_jonnie , wrong @PaulJ_2.0 mentioned. :coffee:

PaulJ wrote: 06 Feb 2020 15:08 @rubber_jonnie , wrong @PaulJ_2.0 mentioned. :coffee:

@PaulJ @PaulJ_2.0

Damn.....

Too many of you lurking about if you need version numbers.....

:dizzy:

rubber_jonnie wrote: 06 Feb 2020 16:13

PaulJ wrote: 06 Feb 2020 15:08 @rubber_jonnie , wrong @PaulJ_2.0 mentioned. :coffee:

@PaulJ @PaulJ_2.0

Damn.....

Too many of you lurking about if you need version numbers.....

Well your in luck RJ, I don't believe there will ever be a rubber_jonnie_2.0.... I think they broke the mold!!! :dizzy:

PaulJ wrote: 06 Feb 2020 16:22
Well your in luck RJ, I don't believe there will ever be a rubber_jonnie_2.0.... I think they broke the mold!!! :dizzy:

You may well be right there @PaulJ

Ah, the satisfaction:

Time to jot down a few things, at least that way I'll remember stuff later, provided I can find this post.

Project wise we're looking at the following:

1. Mega 1 needs to have SILs replaced, it's still sporting the originals. After that we'll see if the IDE interface, stable on the Mega 4 now, will improve.It's a bit hit and miss for now.
2. Mega 1 and Mega 4 probably need mandatory fixes doing, I'll work that out once I've done item 1.
3. Revisit the H4 and do the same sort of troubleshooting as on the Mega 4. I need to install an expansion socket and build a tool to pull down the address bus, /AS, /LDS & /UDS and see what the data bus is doing. Feels like no ROM so this will help decode whats what there.
4. Build a RAM tester. Although thenTL866 Pro I have will test RAM, 41256 and 4164 are not covered, so I'm going to build one of these http://forum.defence-force.org/viewtopi ... 3NlchvZsnM. I'll post my progress on here.

Guessing everyone esle is busy out in retro Atari land :)

Work started building the DRAMArduino RAM tester, more info here: http://forum.defence-force.org/viewtopi ... 3NlchvZsnM


I'll post up some more when I've completed the build and tested.

Also decided that the Mega ST 1 is going to stay more or less stock. It's a nice machine, FDD is good and the case is completely stock with no weird cuts/holes for mods etc.

Here she is before the lid went back on:


Minimum MODs done are:

SIL resistors swapped out for new 2.2k items.

2 chip German TOS 1.04 swapped out for 6 chip UK TOS 1.04, see more here: https://www.exxosforum.co.uk/forum/viewt ... =16&t=2565

Being a Mega ST 1, it had no CPU fan, but I've fitted one from @exxos

For now I've decided the IDE interface can wait until there is a newer version that is slightly smaller and doesn't get in the way of the case support leg.

Finished the DRAMArduino today as well as fixing the LS11 problem on the H4, so what with getting both Megas sorted last weekend, I've had a pretty good run lately :)

Here's the complete unit:


And here's the back side of the protoboard showing my lovely wiring :) Took quite a while I must admit.


Here's the link to the build details and Arduino sketch that makes it all go: http://forum.defence-force.org/viewtopi ... 3NlchvZsnM

Pop in a DRAM, 4164 (Jumper on for these) or 41256 (Jumper off for these)plug it into a power source and press reset. Then wait for a red or green for nay or yay. Simples

And yes, there is a big bit of fluff in the middle where I cleaned up after with IPA and a cotton bud! Now removed :)

Will try and build another as I have a second Arduino to hand and all the parts too. I reckon total cost including Arduino is £15-£20.

Ahh the never ending fun and games of retro ownership!

My test board has decided to have a floppy disk outage 😟

Known working FDDs just sitting there with the seek light on permanently and never reaching the desktop. Pull the FDD and desktop happily arrives.

Damn thing worked last time I used it and suddenly this.

Looks like I have another round of troubleshooting in my future.

Thank god for the desoldering gun, it'll certainly make rework a ton easier.