Questions about an Atari STFM I recently purchased

[tlgrooms]

I recently purchased an Atari STFM off of ebay that looked to be in excellent condition.  I am an ST newbie as I was always a Commodore/Amiga guy back in the day.  I have a couple of questions about the hardware if anyone can help.  I'll post some pictures to see if anyone recognizes it.

 

Inside it looks to have a memory expansion board, I'm guessing 2mb as Taz reports it has 2.5mb of memory inside (see pic).

 

Does anyone recognize this board?  Is that all it is, memory expansion?

 

Also, barely noticeable in the pic is a cut in the case just in front of where the 68000 chip is located along the front edge where the top and bottom of the case comes together.  Looks like where maybe a ribbon cable once was I'm guessing?  It's about the right size for one.

 

Also, if it is a memory expansion, is there something that must be done to activate it so it can be used?  I have tried running Freeze Dried Terminal and it comes up and says it needs 1mb of memory.  It continues to load but if I try to enter the settings it says not enough memory and exits.

 

It has TOS 1.0 roms in it so I'm guessing at one time it had newer roms but were switched back when it was put up for auction.

Edited February 23, 2023 by tlgrooms
Better explain location of the cut in the case.

[Zogging Hell]

It is indeed a memory exansion, as it sits on the MMU and runs into the shifter chip which is a fairly standard way of doing it. Memory should 'just work', although there may be a problem with an application not liking a certain amount of memory (Although with GEM apps that is not common, games more so). So either that version of Freeze Dried doesn't like 2.5mb or there is some fault in the memory. Presuming Taz is reporting the correct amount of RAM I would suggest using a RAM test program to check the upgrade is ok as the next step, and then maybe looking into any issues Freeze has with memory. I ran an ST with 2.5mb of RAM for years and I don't remember having a single problem (less that with 4mb actually).

 

There doesn't look like there has been anything on top of the CPU like a accelerator, so it's possible the slot at the front was for some other upgrade like a Marpet memory board, that needs to sit on top of the shielding, and the ribbon cable was fed out there (or may be a not very useful user CPU 'cooling' hole/ vent!). Without seeing it, it is a little hard to say..

 

What makes you think the TOS 1.0 is not original? It has problems with hard disks and has a few glaring bugs but if you are running from floppy it would probably have been fairly serviceable with a few software patches (much more so than the early Workbench versions). No reason to upgrade it back in the day unless you were a 'power user' of that era and could afford a hard disk. Nowadays, yes, pull it out and put 1.04 in there instead, especially if you want to run HD adapted games.

[TGB1718]

Don't know what RAM upgrade that is, but just a guess that there's a gap of 512KB between the lower RAM (BANK 0)

and the expansion, maybe newer TOS versions don't care and compensate (unlikely, but sure someone will correct me).

[tlgrooms]

I was able to finally run sysinfo on the system and it is only showing 512k available system memory and not showing the expansion memory.

 

Taz still shows as the picture above as if there is 2.5mb available.

 

Edited February 27, 2023 by tlgrooms

[Zogging Hell]

Might be a seating issue where it sticks in between the MMU and its socket (assuming it is a socketed MMU - if it is not there was usually a socket on the memory board, and these were terrible for working loose). You may want to try and reseat it (try pressing down on it, not too hard as you don't want to damage anything), particularly if it has been in transit. The MMU is somewhere under the main board, not the bit that goes to the shifter chip in the metal box - although you may want to check that is still properly seated as well. You may also want to check the ground wire (black wire attached to motherboard from memory upgrade)

[TZJB]

I haven't seen this particular upgrade before. It seems to have a battery on the board too perhaps for a clock? It would seem to only be populated with 2MB of DRAM in Bank 1 with unpopulated spaces for another 2MB for Bank 0. As the populated bank is labelled Bank 1, Bank 0 would be the original 512KB of DRAM on the motherboard.

 

As TAZ is seeing all of the available RAM I think you may need to try an actual memory tester such as YAART. Also the Marpet Xtra-ram tester should work too.

 

Please see attached. Unzip on to a 720K PC formatted floppy disk and run on the Atari ST.

 

yaart0231.zipXTRA-RAM.zip

Edited March 1, 2023 by TZJB

[tlgrooms]

I removed the shielding to get a better picture of the memory expansion and can now see the manufacturer name.  Can't find much of anything about them on google.

Does anyone have any info about this board?

 

[TZJB]

On 2/23/2023 at 5:29 PM, TGB1718 said:

Don't know what RAM upgrade that is, but just a guess that there's a gap of 512KB between the lower RAM (BANK 0)

and the expansion, maybe newer TOS versions don't care and compensate (unlikely, but sure someone will correct me).

No there is no missing memory. Memory in a 520STFM is 512KB and sits in Bank 0. If there were motherboard RAM in Bank 1 it would make it a 1040STFM and the memory upgrade would not work until the motherboard RAM Bank 1 is disabled. TOS 1.0 to 1.04 will recognise this asymmetrical arrangement.

 

On 2/23/2023 at 5:27 PM, Zogging Hell said:

It is indeed a memory exansion, as it sits on the MMU and runs into the shifter chip which is a fairly standard way of doing it. Memory should 'just work', although there may be a problem with an application not liking a certain amount of memory (Although with GEM apps that is not common, games more so). So either that version of Freeze Dried doesn't like 2.5mb or there is some fault in the memory. Presuming Taz is reporting the correct amount of RAM I would suggest using a RAM test program to check the upgrade is ok as the next step, and then maybe looking into any issues Freeze has with memory. I ran an ST with 2.5mb of RAM for years and I don't remember having a single problem (less that with 4mb actually).

I agree. This is essentially similar to the Marpet Xtra-RAM ST deluxe with SIMM memory upgrade for the Atari ST/F/M, with similar Shifter and MMU connections, and which supports 1MB, 2.5MB and 4MB total memory depending on SIMM arrangements.

 

5 hours ago, tlgrooms said:

I removed the shielding to get a better picture of the memory expansion and can now see the manufacturer name.  Can't find much of anything about them on google.

Does anyone have any info about this board?

I can't find any information on this memory upgrade board. What I can tell you is your ST motherboard is an early model so has TOS 1.0. The memory upgrade is motherboard specific so can't be installed in any other type of ST motherboard of which there are many. It also looks like an extra 2MB can be added to the memory upgrade board to replace the motherboard Bank 0 memory by adding extra chips of the same type as Bank 1. Also the clock chip has been omitted consequently so too has the battery.

Unfortunately the MMU connection is a common point of failure as the MMU connections are pins forced into the MMU socket which can break the socket. Certainly run a memory test and see whether it tests the full capacity. A TOS upgrade isn't necessary at this point but can be considered later.

Edited March 10, 2023 by TZJB

[tlgrooms]

I replaced the rom chips with tos 1.04 chips last Friday.  I carefully applied a little pressure to the pins that go into the MMU socket and the memory showed up in SYSINFO.  It is very touchy and soon quit working afterwards.  It appears to need some pressure applied to it to work.  The pins on the memory expansion board are very tiny, not sure if they were longer and are broken off or just tiny to start with.  I haven't removed the memory expansion all they way as the ground wires are keeping me from doing it.  May desolder one to see if I can tell what is going on.  It did have a piece of antistatic foam taped to the top of it where the pins go into the mmu connection as  you can see in the above picture.

Edited March 13, 2023 by tlgrooms

[TZJB]

On 3/13/2023 at 9:05 PM, tlgrooms said:

I replaced the rom chips with tos 1.04 chips last Friday.  I carefully applied a little pressure to the pins that go into the MMU socket and the memory showed up in SYSINFO.  It is very touchy and soon quit working afterwards.  It appears to need some pressure applied to it to work.  The pins on the memory expansion board are very tiny, not sure if they were longer and are broken off or just tiny to start with.  I haven't removed the memory expansion all they way as the ground wires are keeping me from doing it.  May desolder one to see if I can tell what is going on.  It did have a piece of antistatic foam taped to the top of it where the pins go into the mmu connection as  you can see in the above picture.

Good diagnosis. The antistatic foam was probably applying pressure on the expansion board against the top metal screening I would guess. Without the screening fitted it is floating loose and the MMU pins are not making reliable contact. As I previously said, this is a common point of failure, but if you can refit the top screening with the foam applying pressure to the board this may solve the reliability issue.