What do I have here?

[ianoid]

I opened up my ST to find this mess. What is this upgrade with connector from Zubair interfaces? I have no experience with ST upgrades. The shielding is very bent up and there is electrical tape to prevent shorts here and there. Should I make sure I keep all the shielding in place or can I leave some out when I reassemble?

 

I wanted to see if it was a 6 chip ROM since I have a ROM 1.4 upgrade for that, but it’s a 2 chip. I believe I tested it when it was whole as ROM 1.0 or some other ROM too low rev to work with my UltraSATAN. While I have it open, what is the best upgrade for compatibility and easy of use? I understand that there are some sacrifices with every version. And any suggestions where I should buy said upgrade? I’d like something that autoboots without a floppy in the built in drive.

 

Or is it a moot point to worry about the UltraSATAN when I just got one of those new ST Disk adapters from Spain?

 

And FINALLY, should I recap the PS while I’m in here? Heard it’s a good idea. The caps on the motherboard look ok and are refreshingly through hole, while I was expecting to have to surface mount recap. I am planning to leave those alone. 

 

Oh but wait! I just noticed it’s a 1040ST motherboard here! I did test it to have 1mb RAM when it was whole but I just figured it was an upgraded 520ST.

 

Thanks ST people!

[ParanoidLittleMan]

That Zubair thing seems as RAM upgrade + something else, probably. I would not say that it is mess. But that insulation band over chips is good only to make chips warmer and that we can not see what chips are there.

You can search online about Zubair upgrade. Or remove that bands and make closer sharp photo, so can see what chips are there.

You can put it on shield if it is too tight.

ROM upgrade should be not hard with 6 chips: need 4 28 pin sockets, some soldering - what includes soldering pads - remove from 1M markings, solder on 256K ones - should be 3 of them.

Edited November 28, 2021 by ParanoidLittleMan

[derSammler]

It's one of those RAM upgrades that kill the PLCC socket. Also, these normally required mods to the mainboard, so it would not be a good idea to remove it unless you have the manual to know which mods to reverse and also be able to replace the PLCC socket, as chances are very high it will no longer make good contact to the chip once the adapter has been removed.

[Zogging Hell]

1 hour ago, derSammler said:

Also, these normally required mods to the mainboard, so it would not be a good idea to remove it unless you have the manual to know which mods to reverse and also be able to replace the PLCC socket, as chances are very high it will no longer make good contact to the chip once the adapter has been removed.

Totally agree, taking it out might open a can of worms with the MMU socket pins.

 

Ianoid, you could try and bend them back out if there is a contact problem, but if it ain't broke and so on...  

 

[Zogging Hell]

2 hours ago, ianoid said:

I wanted to see if it was a 6 chip ROM since I have a ROM 1.4 upgrade for that, but it’s a 2 chip. I believe I tested it when it was whole as ROM 1.0 or some other ROM too low rev to work with my UltraSATAN. While I have it open, what is the best upgrade for compatibility and easy of use? I understand that there are some sacrifices with every version. And any suggestions where I should buy said upgrade? I’d like something that autoboots without a floppy in the built in drive.

 

And FINALLY, should I recap the PS while I’m in here? Heard it’s a good idea.

I would definitely go with the 1.04 (it is definitely the best all rounder) and as you have that, makes sense. TOS 1.02 can be ok with some patches (say Fatspeed, Pinhead), and personally I've always found it the most compatible with original floppy based games (I haven't found anything I can't run with it in my 900+ originals, whereas TOS 1.04 has tripped up a couple of times), but I don't think it is that great a fit for an Ultrasatan and adapted games. TOS 1.0 is a pig's dinner for hard disks and a bit of a buggy mess in general.  TOS 2.06 has some game compatibility issues - if they haven't been patched, and is trickier to get installed, although if you want to explore the ST's 'serious' side then it is a good deal better for that. Ultrasatan is proven stuff and works with most/ all? hard disk drivers and is a fairly safe bet, but there are others though that work just as well, I probably wouldn't worry about which particular type of storage solution you get, more about who to get it from and whether they will be around in five months time.

 

PS recap, if you can, then yes you should

[ianoid]

Thanks to everyone for their helpful responses.

 

Thinking about it, shouldn't this ST have 1mb standard, and then this modification should bring it to 2mb or more than 1mb at least?

 

I'll pull the electrical tape and post some more pictures. 

[ParanoidLittleMan]

Nope. Obviously factory RAM is 0.5 MB. It would be 1MB if other 16 places for RAM were populated. There are no traces that there were chips soldered, and there are no capacitors too. Board is good for 512 ST, 1040 ST. And in case of 520 it meant easier RAM upgrade to 1MB.

Earlier 512 STs had no place for other RAM bank - those with separated floppy drive.  And to add, later models had 4 RAM chips instead 16 for 512 KB RAM .

Now, this upgrade can be +512 KB or +2 MB . ST(E) can have max 2 RAM banks, so if it is 1MB that means 2 banks. If want to upgrade such machine, need to remove or deactivate second bank.  Possible RAM sizes are: 512 KB and 2 MB with 1 bank. 1 MB, 2.5 MB and 4 MB with 2 banks.

There is literature where can see details about all it.  For instance:  https://docs.dev-docs.org/

 

[eightbit]

That looks like a Z-RAM 3D/4MB board. I can't find the manual for it. Here's the manual for the Mega 2 version of the product however which might help a little as it is more or less the same upgrade (attached).

 

I would expect anywhere from 2.5-4MB installed on that board. 

Z-RAM Mega 2 to 4 manual.pdf

Edited November 29, 2021 by eightbit

[ianoid]

When I change this ST from 2 chip to 6 chip, do I simply need to add the sockets and chips or are there any other necessary modifications?

 

Thanks!

[ParanoidLittleMan]

9 hours ago, ianoid said:

When I change this ST from 2 chip to 6 chip, do I simply need to add the sockets and chips or are there any other necessary modifications?

 

Thanks!

It is already written here, in this thread.  Quoting myself: "ROM upgrade should be not hard with 6 chips: need 4 28 pin sockets, some soldering - what includes soldering pads - remove from 1M markings, solder on 256K ones - should be 3 of them. "

And above that post is your (?) photo where can see those soldering pads.

And should DL schematic of your ST revision - also written where can find it.

[ianoid]

@ParanoidLittleMan Ah, had no idea what you meant until I had the motherboard laid bare and the sockets already soldered in. Thanks again!

 

[ianoid]

Thanks to everyone for their helpful responses. This has been my first dive into an ST as far as the hardware goes. Although it was a little confusing to get how the shielding works and how to get it all taken apart, it has been a fun computer to work on. 

 

I managed to add 4 sockets, convert to 6 chip TOS 1.04,  and connect the 3 pads (unfortunately one of the 1mb pads came off in desoldering so this modification to 6 chip is irreversible without a surface mount repair). The system works great with my UltraSATAN. Also successfully recapped the PS, although the largest 220V 200uF cap was slightly taller than the original and barely fits in the case. I left out the PS shielding for that reason. It should have better ventilation that way anyway. 

 

The main thing left to do is to get the STDisk I just picked up working. It seems to be finicky about the 5V PS and SD card so that is probably the issue. 

 

I did notice that the Atari diagnostic cart I have does not recognize TOS 1.04 as a valid ROM. It also doesn't recognize the RAM above 1MB as it is installed, but I think the UltraSATAN boot sequence said something about an additional 2.5MB. I'll try to document it. 

[tjlazer]

I would seek out a 2 chip TOS 1.04 for it to not mess with any more work.  B&C Computer Visions or Best Elec.  might have them in stock.   

 

On eBay:
https://www.ebay.com/itm/133230528296

Edited December 15, 2021 by tjlazer

[+DarkLord]

Joining this topic late so I if I missed the answer I apologize, but...

 

Why change from the original 2 chip TOS set to 6 chips? Why not

just replace the original 2 chip set with a 2 chip set of TOS v1.4

ROMs?

 

Thanks (just trying to understand)...

 

[ianoid]

@DarkLord I had a 6 chip set already that I'd picked up in a parts lot. And I already added the sockets and it works great! 

[+DarkLord]

4 hours ago, ianoid said:

@DarkLord I had a 6 chip set already that I'd picked up in a parts lot. And I already added the sockets and it works great! 

 

Ah, okay. Otherwise I was going to say I don't get it...

 

Glad it's working - make sure you get some mass storage and if you want to add TOS v2.06, extra memory (TT), and

USB as well as IDE support, check out the Lightning ST, STorm ST and Cloudy combination. Good stuff.

 

https://wiki.newtosworld.de/index.php?title=Cloudy

 

https://wiki.newtosworld.de/index.php?title=Storm_ST

 

https://wiki.newtosworld.de/index.php?title=Lightning_ST

 

Er, well...I scrolled back upwards. I see that you've got a couple of upgrades already...

 

[OldScot]

I have the same board in a used 520ST I bought 25+(?) years ago.

The 520 has a 1040 motherboard with 512K of ram.

The Ram expansion adds 2MB for a total of 2.5MB.

The machine also has a daughter board bodge on one of the Roms, with one 1.4 ROM on the motherboard and the other in a cabled daughterboard. (No idea why.)

I just opened up the machine to have a look as it is extremely flaky talking to an UltraSatan I just attached.

Sometimes it works for a short time, sometimes it simply bombs on boot. It doesn't work long enough to be useful.

I'm going to start by recapping the power supply as it looks like it needs it. (This is the first time I've run across an obviously failing cap.)

I'll see if the situation improves any after that.

I'd like to recap the motherboard as well as a there is one cap under the memory expansion and I'd prefer not to try removing it.

The memory expansion is wild, two circuit boards back to back on LONG pins going to a shifter socket.

Memory testing shows the 2.5 MB is working fine.

 

[Paul Westphal]

This looks like a good place to post this. My buddy found a 1040 that's badged 520. It has a double sided floppy and TOS1.0. He has not picked it up yet.

 

I'm assuming it only has 512k ram... was this a common thing Atari did? I think it's a pretty rare machine..

 

Maybe they stopped manufacturing the 520 and just sold 512k 1040's....

 

Any info on this machine would be appreciated!

[monzamess]

3 hours ago, Paul Westphal said:

This looks like a good place to post this. My buddy found a 1040 that's badged 520. It has a double sided floppy and TOS1.0. He has not picked it up yet.

 

I'm assuming it only has 512k ram... was this a common thing Atari did? I think it's a pretty rare machine..

 

Maybe they stopped manufacturing the 520 and just sold 512k 1040's....

 

Any info on this machine would be appreciated!

 

That looks like a standard 520STfm: http://www.computinghistory.org.uk/det/2578/Atari-520-STFM/

 

It replaced the original 520ST.

 

It was my first ST BITD. By my understanding it was basically a 1040ST with half the RAM, single-sided drive, and with the RF modulator. I had mine upgraded to 1MB and double-sided drive. The 520STfm is pretty common and I don't think it would be too unusual to encounter an upgraded example "in the wild" making the situation even more confusing.