Which 1040 STF is this?

[32bitminus]

Looks like I got one of the resistors backwards, should be:

ST Location, Part, STF Location

Resistors (Need to follow traces to STF Location first):
R129, 10k, R49 (Brown, Black, Orange, Gold)
R130, 100, R50 (Brown, Green, Brown, Gold)
R131, 150, R51 (Brown, Black, Brown, Gold)


Transistor:
Q10, 2N3904, Q8

Diodes:
CR9, IN914, CR10
CR10, IN914, CR11

Will still verify before I put it all together next week.

Thanks this is perfect!

Looks like I need...

ST Location, Part, STF Location

Resistors (Need to follow traces to STF Location first):
R129, 10k, R49 (Brown, Black, Orange, Gold)
R130, 150, R50 (Brown, Black, Brown, Gold)
R131, 100, R51 (Brown, Green, Brown, Gold)


Transistor:
Q10, 2N3904, Q8

Diodes:
CR9, IN914, CR10
CR10, IN914, CR11

I have not studied electronics in ages, so thanks for the patience

Its only a simple transistor buffer type circuit which merges V & H.


1.jpg


NOTE that is from a "ST" so part numbers are likely different on your board, but the circuit will be the same.

[Atarian Computing]

Being an STF, it's missing the modulator circuitry intentionally. Otherwise it would be an STFM. You can still get video out from the 13-pin DIN connector. The modulator involves more than the few apparent components. I wouldn't bother with that in this day and age anyway.

Thanks, I was not talking about Composite Video, but Composite Sync. The circuit takes the H and V lines from the board and makes the appropriate sync signal for VGA spec monitors. Atari's monitor can take separate H and V sync with the RGB and does not need this.

From what I read around, on an STFM pin 2 is Composite Video, on an STF it is either NC or Composite Sync, the ones that have composite sync look like this:

Screen Shot 2019-02-21 at 3.09.48 PM.png

Mine is missing those 6 components for the Composite Sync. I don't have easy access to an Atari or other monitor that can deal with seperate sync signals. Finding a parts list has been troublesome so far.

Ah, yes. I had noticed that composite sync in schematics before. What is CSYNC used for again?

[32bitminus]

I am no expert, but it is just a combines horizontal and vertical sync, just a standard I suppose.

[rubber_jonnie]

If the machine powers on, then personally I wouldn't touch the CPU, just leave it with the socket soldered on top. In the past it may have had some sort of accelerator board, or something like a Vortex ATOnce style of PC emulator board, there were all sorts of upgrades that clipped on top like that.

I'd also suggest binning the top metal shield for two reasons. 1) It isn't really necessary 2) It's a bit stabby and slicey after all that chopping!

The mods are quite possibly factor fixes or later owner applied patches, so I wouldn't be overly worried about them if the machine is functioning as expected.

If you have a 15Khz capable LED/LCD display, then get an UBESwitch from here https://www.exxosforum.co.uk/atari/store2/#0107 and you'll be able to use all resolutions.

If you don't have a 15Khz capable display, then you can still use these switches with any modern VGA display, but only in Hi Res, which is better than nothing.

Regarding the composite sync etc, there is an interesting post here that may be of help: https://www.facebook.com/groups/1331613 ... 024924214/

Be interesting to see what sysinfo makes of that version of TOS.

Also, PSU looks like an SR98, which is pretty easy to recap. I'd recommend you do so.

[32bitminus]

If the machine powers on, then personally I wouldn't touch the CPU, just leave it with the socket soldered on top. In the past it may have had some sort of accelerator board, or something like a Vortex ATOnce style of PC emulator board, there were all sorts of upgrades that clipped on top like that.

I'd also suggest binning the top metal shield for two reasons. 1) It isn't really necessary 2) It's a bit stabby and slicey after all that chopping!

The mods are quite possibly factor fixes or later owner applied patches, so I wouldn't be overly worried about them if the machine is functioning as expected.

If you have a 15Khz capable LED/LCD display, then get an UBESwitch from here https://www.exxosforum.co.uk/atari/store2/#0107 and you'll be able to use all resolutions.

If you don't have a 15Khz capable display, then you can still use these switches with any modern VGA display, but only in Hi Res, which is better than nothing.

Regarding the composite sync etc, there is an interesting post here that may be of help: https://www.facebook.com/groups/1331613 ... 024924214/

Be interesting to see what sysinfo makes of that version of TOS.

Also, PSU looks like an SR98, which is pretty easy to recap. I'd recommend you do so.

Thanks! I have indeed ordered the UBESwitch, and will be waiting for that.

I was thinking of cutting the shield a bit nicer, it is quite ragged. The other clue to the mod, not that it matters is because I am just curious, is the case has a hole in the back, I assume for a toggle switch.

I will either leave it or think of some other mod to make it complete

I see that on some sites tos 1.2 (1.02) is listed as mega tos, so maybe this was just an upgrade from 1.0 to 1.02 on this, as it seems maybe this system might have shipped with 1.0.

[rubber_jonnie]

I see that on some sites tos 1.2 (1.02) is listed as mega tos, so maybe this was just an upgrade from 1.0 to 1.02 on this, as it seems maybe this system might have shipped with 1.0.

Sysinfo will tell you PDQ just what is going on with TOS

[32bitminus]

I see that on some sites tos 1.2 (1.02) is listed as mega tos, so maybe this was just an upgrade from 1.0 to 1.02 on this, as it seems maybe this system might have shipped with 1.0.

Sysinfo will tell you PDQ just what is going on with TOS

Thanks, should get this up in a week or so, barring any problems. Guess I will start cleaning the keyboard and case while I wait for parts to come in!

[32bitminus]

Thought I would add a couple more photos. Case has been cleaned up, unfortunatly there is some minimal damage, the sticky tape was so hard and crusty on there, heating the water up too much did loosen things a bit but caused the paint on the badge to start softening, and I got most of the glue stuff off the badge so it is a compromise. Will still retrobrite the whole thing and the keys as well at some point, after I get the electrical all sorted for VGA color.

So I can see this is not TOS 1.0 by the 86 87, so so 1.02/1.2? This is from a bench test, still cleaning and going over the floppy drive.

IMG_20190228_172852.jpg (394.5 KiB) Viewed 5600 times

signal-2019-02-27-191710.jpg (264.12 KiB) Viewed 5600 times

[Maximilian]

Always nice to see someone taking the time to clean an old machine up.
I'm a bit of a ST noob but is this a 8 or 16Mhz 68000?
Also where are you located.
(if I may ask)

[tzok]

I can see P8 at the end, so 8MHz.