A while ago, I got a 520ST from exxos, knowing full well it wasn't quite right, and prepared to have a go at bringing it back to life. It seemed the right thing to do, because cosmetically it was in very good order.
So first off I resolved the problem of no PSU by building one (https://www.exxosforum.co.uk/forum/viewt ... &hilit=PSU), then resolved the problems with RAM. There was track damage due to a piggyback expansion, and in the end I felt it was simpler to remove all the RAM and fit a SIMM adapter to the MMU and Shifter, so having done that the machine was finally booting to desktop.
That left two problems:
1. The floppy drive didn't work,and any attempt to access a disk crashed the machine.
2. The TOS was version 1.00.
I'm happy to say the day is finally here where there are no problems left
I thought I'd tackle the FDD problem first, since I knew the machine was working upto getting a desktop.
That's where the diag cart came in, and on running a floppy test, this was the result:
Having already tried swapping the DMA, FDC and YM chips for known good items, they were ruled out, leaving the GLUE and MMU. Since the MMU had a memory adaptor plugged in, it had to be GLUE first, and lo and behold, with a replacement GLUE installed, the FDD sprang back into life I'll test the GLUE on another machine, but it certainly looks like it's had it's day.
The TOS upgrade was simple. I sourced some PROMS from evilbay, and split a TOS 1.04 image using ROMSPLIT on Hatari to get the 6 ROM images I needed and burned them.
Once swapped out,everything worked like a charm.
And I'm very happy to have this lovely machine back in the land of the living. I'll get it back in the case, hopefully tomorrow, but I think I'd better have a dig for some 1MB SIMMs and see how it likes 4MB first
I guess it might also be worthwhile seeing how it likes SMonson's DVI adapter whilst the lids off too.
520ST fully working and upgraded
- rubber_jonnie
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520ST fully working and upgraded
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
Re: 520ST fully working and upgraded
Nice work @rubber_jonnie ..
Re: 520ST fully working and upgraded
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
Re: 520ST fully working and upgraded
Well done @rubber_jonnie . Always fancied one myself too. Will keep a look out I guess.
If it ain't broke, test it to Destruction.
- rubber_jonnie
- Site Admin
- Posts: 10472
- Joined: Thu Aug 17, 2017 7:40 pm
- Location: Essex
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Re: 520ST fully working and upgraded
@PhilC They are lovely machines
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
Re: 520ST fully working and upgraded
A bit more of a challenge to upgrade but that's part of the fun.
If it ain't broke, test it to Destruction.
- rubber_jonnie
- Site Admin
- Posts: 10472
- Joined: Thu Aug 17, 2017 7:40 pm
- Location: Essex
- Contact:
Re: 520ST fully working and upgraded
And here we are back together and playing nicely
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...