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My “first” Atari ST

Atari 1040STFM #1 Label

Well, it is certainly not new - and it is also not my first Atari.

But from today's retro collectors point of view, it's my "first". And since my last one was sold over 20 years ago, this one is my "new one" too. Bought for about EUR 20, - on eBay - complete with mouse and monochrome monitor SM124 - a bargain!

Atari 1040STFM #1
Atari 1040STFM #1 SM124

Technical Data

TypeSTFM
RAM1MB (2 banks, 512 kB each)
BoardC070789-001 Rev D
Serial NumberA102L4043932
FloppyEpson SMD-380 (DD)
TOS1.02 (original), 1.04 (aufgerüstet, 6 Chips)
Statea bit yelowed; small part of the case broken, but still existing. Glued in quite perfectly.
RemarksTOS in 1M Chips (2 pcs), other 4 spaces without sockets

Restoration

First, the device was completely disassembled and cleaned. All plastic parts were soaked in warm water with a little bit of dish soap and scrubbed with a not too hard brush. With the label on the bottom you have to be careful - do not soak too long and do not brush off too much.

Theoretically, you can also clean the motherboard in water - some even swear to clean motherboards in the dishwasher. Thorough drying then is of course necessary. I would do this only in exceptional cases (extremely dirty) - dust with a solid brush or possibly treat with some isopropyl alcohol should be sufficient in most cases.

During the cleaning of this computer, I noticed a small defect on the case (small plastic part had broken out). Probably during transport, because the plastic part was still there. Was able to put it back in place with superglue - almost invisible.

As described in the last article, the power supply was the first thing in terms of electronics repair. For this purpose, all electrolytic capacitors were replaced. I did not touch the bridge rectifier - sometimes it's required to replace it, too.

Before the next steps could take place, I needed a functional test first.

Power on, and he boots. Without a boot disk in the drive, the whole thing takes a little time - so be patient.

The familiar (and missed) GEM desktop greeted me. Quickly looked into the info dialog: TOS 1.02 - one of the first versions. So it was clear that the first extension would be a TOS 1.04.

Since the current TOS 1.02 was installed as a 2-chip version (1Mbit chips), but TOS 1.04 was only available on eBay as a 6-chip version (256kBit), I was not able to simply replace the two ROMs with two new EPROMS (containing TOS 1.04). So the 4 free ROM slots had to be equipped with 28-pin sockets. Furthermore, there are three solder pads on the board, each labeled with 256k or 1M, which need to be re-soldered accordingly.

Since the computer was already disassembled, a somewhat tricky task was added: put the 68000 processor into a socket. Many extensions need to go above (or under) the processor. Then is a socketed chip is quite handy.

Desoldering a 40-pin chip is not trivial: lots of flux and new solder make desoldering easier (sounds weird, but it's true). A good desoldering pump - in my case a soldering station with electric desoldering pump - increases the chances of success. Everything went well here: Processor successfully desoldered, board and chip stayed healthy, put the socket in, plugged the processor back - running.

Next will be a memory expansion to 4MB - but I have to first research which version it shall be (there are several variants available).

But this will be a different story.

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