exxos's Atari, Amiga & retro forum

Apologies if this is in the wrong section.

I'm new to the ATari ST systems, I just bought a 520 STFM with sm124 monochrome monitor, (the monitor has screen burn in, and i have no idea if there's an ST program that could run to try and remove it, like those you can with TV static on LCD's), and mouse. IT was used its entire life as a music machine, and has the 1990 dated Frontier Xtra-ram deluxe 4mb upgrade installed as shown in Exxo's manual scan.

It currently has TOS 1.02 on it, atleast from what i can identify, it only has the 1987, 88 on the GEM interface.

I've looked through the store and google itself but I only get mentions of STE series. Not the STFM series. And i do not know what version of ToS it's upgradable to. I think 1.62? I'm not an amazing soldering expert.

If there's any other upgrades for the system that I can do, I'd be grateful to know. It has also been UK PAT Passed.

It currently has a Mitsumi Elec PSU in it The big black capacitor with the big red warning on it is curved at the top, i dunno if that's by design, but there's no stress or bulge looking damage (include a picture).. A 720K DS-DD drive.

I thought about recapping the PSU, but I' don't wanna touch that big one.

STFM can have up to TOS104 without a lot of work. I don't really recommend installing anything higher than 104 in a STFM anyway.

STE are generally shipped with 1.06,1.62. Most fit dualtos so they can use 1.62 and 206.

As for caps, I do list re-cap kits in my store for the SR98.

Hi Atarifilox,

I would recap your PSU for starters as those capacitors have been going since the late 80s and need a rest. So have a look on exxos's store for a recap kit for that PSU. Its fairly easy to do but dont rush it. Failing that, get yourself an exxos psu.

You can put Tos1.04 into your machine by putting either a rom board or 6 roms into it but it will depend on how many roms you currently have etc, as to how to do it.

It might be worth you waiting for a short while as exxos and Icky have two interesting projects in the go that firstly let you run Tos2.06 or 1.04 and can give you either IDE interface or flash rom and a built in clock

The above options do mean having to carefully remove the cpu, fitting a socket in its place and then putting either of the boards into your STFM when its completed.

So for now, maybe have some fun with your ST, have a read of the things going on on the forum as the current projects are pretty cool. And when you are ready, jump in with the upgrades of your choice.

Good luck :D

Hey thanks to you both!

exxos wrote: 07 Aug 2019 18:43 STFM can have up to TOS104 without a lot of work. I don't really recommend installing anything higher than 104 in a STFM anyway.

STE are generally shipped with 1.06,1.62. Most fit dualtos so they can use 1.62 and 206.

As for caps, I do list re-cap kits in my store for the SR98.

No higher than 1.04? Hm alright. Is there some incompatibility with the higher TOS? I'll also have to check what type of chips i have. But i assume it's the older type 6 chip.

Do you have to replace that big capacitor too when you recap? And which caps am i looking to get? You have several versions.

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PhilC wrote: 07 Aug 2019 18:50 Hi Atarifilox,

I would recap your PSU for starters as those capacitors have been going since the late 80s and need a rest. So have a look on exxos's store for a recap kit for that PSU. Its fairly easy to do but dont rush it. Failing that, get yourself an exxos psu.

You can put Tos1.04 into your machine by putting either a rom board or 6 roms into it but it will depend on how many roms you currently have etc, as to how to do it.

It might be worth you waiting for a short while as exxos and Icky have two interesting projects in the go that firstly let you run Tos2.06 or 1.04 and can give you either IDE interface or flash rom and a built in clock

The above options do mean having to carefully remove the cpu, fitting a socket in its place and then putting either of the boards into your STFM when its completed.

So for now, maybe have some fun with your ST, have a read of the things going on on the forum as the current projects are pretty cool. And when you are ready, jump in with the upgrades of your choice.

Good luck :D

I'm gonna start using it yeah! I have an SM124 monitor, that has a burn in on it. I was hoping to be able to run an anti burn in program on the atari. I can find adapters that let you use other monitors on the atari, but not the Monitor on a modern pc set at a small resolution.

I only know the difference for the st and st-e is.. some specs and better hardware? I'd love to get an ST-e someday.

I'd love a RTC! Haha. I've no experiance with removing delicate components and i dont have a desolder gun :(

AtariFox wrote: 08 Aug 2019 21:22 No higher than 1.04? Hm alright. Is there some incompatibility with the higher TOS? I'll also have to check what type of chips i have. But i assume it's the older type 6 chip.

TOS206 isn't in the same place in the memory map as TOS104. So swapping the chip just won't work at all. You need a decoder circuit to use TOS206, currently on my V2.2 booster has the logic circuit required to do it.

But using TOS206 isn't great if you want to play games on a STFM as the TOS version breaks a lot of software. But its fine if generally you only want to use apps... but TOS206 is better on a STE IMHO.

STFM can only have TOS1.00, 1.02,1.04. and I recommend 1.04 on a STFM because of many bug fixes.

AtariFox wrote: 08 Aug 2019 21:22 Do you have to replace that big capacitor too when you recap?

You don't have to no, but placing 400V across a 30+ year old item isn't exactly a good idea. So you should change it. All the caps are in my SR98 re-cap kits anyway.

The other guys have pretty much said it all, but I would like to underline the fact that the PSU should really be recapped.

The recap kits exxos sells are excellent, and it really is a simple but worthwhile job.

Just take pictures beforehand so you have a reference for the capacitor polarities.

One word of warning when you are working around SR98, the aluminium heat sink is live when power is on!

rubber_jonnie wrote: 09 Aug 2019 10:45One word of warning when you are working around SR98, the aluminium heat sink is live when power is on!

Not necessarily true. In many countries schuko (and other standards) is used and therefore the live pin can alternate. But in UK you always know which is the live pin since it can't be attached the other way around. But treat the heat sink as live is a good rule so you don't get hurt.

But don't work on the PSU with power on for God sake!!

By the way. A solder sucker can be used when removing solder along side with a soldering iron of course. You don't have to have a soldering gun. You might need some more heat to get the solder to melt on the ground planes though.

I'm in the UK, so not able to speak about other standards, but having been bitten a few times over the years working on bare machines it's always something I consider. Not sure how it worked out, but nearly all my PSUs are SR98 models. I have since moved to a Meanwell PSU for general workbench Atari stuff now as it's fully enclosed. Mine are all recapped now, so less chance of being zapped!

rubber_jonnie wrote: 09 Aug 2019 10:45 One word of warning when you are working around SR98, the aluminium heat sink is live when power is on!

Three guesses how I found that out :shock:

Another thing you may want to consider is the dummy load resistors Exxos sells them in his store to test the PSU under load after recapping before putting into your machine. https://www.exxosforum.co.uk/atari/store2/

I always test with those after recapping with a meter on the 5v etc power rails and with the PSU connected via an extension lead so you can switch on and off from a far :)

Not your PSU but there is a great guide on recapping the MegaSTE PSU that explains how to use the dummy resistors. You can use this to do the same on the SR98. https://www.exxosforum.co.uk/forum/viewt ... =psu+black

Example of one of my SR98's under load test https://www.exxosforum.co.uk/forum/viewt ... =20#p13878