Simple upgrades for a Mega-STE

[SpacedCowboy]

So I just took delivery of a brand-spanking new (well, old, but you know what I mean) Mega-STE that spent about 2 weeks in "Customs" before miraculously appearing on my doorstep. DHL tracking is weird...

Anyway, the insides look nice and clean:

Screen Shot 2023-11-04 at 4.13.15 PM.png (3.28 MiB) Viewed 2578 times

... and since I neglected to buy a video->VGA adaptor in the last order, it's going to stay switched-off until I get one of Exxos' ST2VGA adaptors... Together with a 15kHz-capable monitor, I think that'll do unless I ever get a Mach64 card for it. This isn't likely, the TT will probably get the high-end stuff, and the STE can be stock for compatibility.

So in the meantime, I wondered, is there any other simple upgrades I could get...

Questions

1) Can I just plug in the US TOS 2.06 that I bought on eBay a while back in anticipation of getting one of these ? There's no jumpers, or anything to do with that mysterious red dip-switch or anything like that ?

2) Can I get one of the 16MHz 68882's on Exxos' site. There's no point in getting anything faster (not that he has any) because the machine is 8 or 16MHz anyway, right ? I don't intend to overclock the STe (see compatibility above) so 16MHz seems sufficient. I did read that I might need a GAL change though... I do appear to have the header next to the socket so hopefully no track-patching/cutting needed.

Grateful for any advice on the above 2

[Bikerbob]

OH you should grab one of those DELL SE2722H monitors!!! it does all 3 resolutions.

Congrats!! I love the MegaSTE - that and my TT are my favorites.. LOVE my home setup with them. Everything else I have is on a shelf or in project mode.. THOSE two are my play toys.. Yours looks very nice!

I did the FPU and yes you need to change a GAL as well.. I did not need to change anything but there is a version of the board where you might have to run one bodge wire to fix up the circuit.. but its very easy.. no upgrade get in the way.. you might have to remove the LH VME cable connection to get at what you want.. but then you just plug it right back in.

OH the FAN!! you will want to upgrade the fan to a Noctua... IT is whisper quiet, the stock one will start to bother you quickly

James

[SpacedCowboy]

I'm seriously thinking about getting one of the SE2722H monitors - especially since they're down to $99 at Dell right now. Thing is I have about a dozen VGA monitors just lying around the place, so buying another without trying one of the existing ones "just to see" isn't sitting well with the wife ...

I've already put a Noctua into the TT, and yeah, it makes a difference. I think that's a definite change. The SCSI disk to a bluescsi "disk" / wifi seems like a reasonable update as well. These things can get pretty quiet when you change the fan and disk, and I seem to have become a lot less tolerant of whining machines as I age - Apple have spoilt me

Good to know about the GAL, because I don't think Exxos has it.

Anyone know about the TOS-swap ? I'm hoping it's just remove-the-old and replace-with-the-new, but blowing up the machine before I ever got to use it doesn't really appeal - I'd rather look stupid and ask than be stupid and .... boom!

Cheers
Simon

[Bikerbob]

Good to know about the GAL, because I don't think Exxos has it.

Anyone know about the TOS-swap ? I'm hoping it's just remove-the-old and replace-with-the-new, but blowing up the machine before I ever got to use it doesn't really appeal - I'd rather look stupid and ask than be stupid and .... boom!

Cheers
Simon

Jedek for the GAL is public - I can program GALs, other around can as well ( Im in Canada) What TOS swap you thinking?? or you mean a multi TOS?? to run say 2.06 and EMUtos or something?? OR you have 2.05 right now?? again easy to program.

[SpacedCowboy]

Thanks for the offer My ebay-fu might have been too quick for me today though, I've just ordered a 68882/GAL combo from Italy, which they actually test in a Mega-STE so I figured that'd be a decent punt.

It's a "straight swap" for the TOS roms - going from 2.06 German to 2.06 US. I bought the US ones some time ago because I'd had my eye on a MSTE, and there's a lot more choice out there if you're willing to shop world-wide.

I'm kind of expecting it to be "take the old ones out and put the new ones in" but in case there's also a jumper to set (those red dip-switches are pulling my eye, I ought to read up on exactly what they *do* do....

[rubber_jonnie]

Have a look here: FPU Stuff

Fitting the FPU isn't 100% straightforward as you might think, and there are differences between mainboards, so you need to review the docs linked to on this page first.

Also, my MSTE had a 1.44MB FDD installed when I got it, so check to see if you have one installed. Atari offered a kit to upgrade from the 720KB FDD, and possibly installed the HD drives as standard later.

The kit contained a PAL (GAL works just fine) and the 1.44MB drive, and is an easy upgrade. Docs can be found here: Atari docs under the MSTE section.

Obviously the FDD is harder to find in HD these days but the JED file is available.

[Steve]

OH the FAN!! you will want to upgrade the fan to a Noctua... IT is whisper quiet, the stock one will start to bother you quickly

Please @SpacedCowboy for the love of all things sacred DO NOT run the Noctua in low speed mode. Run it at full speed. Take the lesson from me where a part blew in my PSU and sent 7v down the 5v rail in my TT almost destroying it. It is not worth risking your TT/MSTe over a bit of fan noise. (I'm not saying Bikerbob is running in low speed mode, but the words 'whisper quiet' make me worried)

@mikro I think, did a temperature test on the parts inside the TT/MSTe PSU, one particular MOSFET runs at 90 degrees C even when properly cooled. If you run the fan slower it will go over spec and blow.

[SpacedCowboy]

@Steve not to worry, I have the TT’s Noctua on “full bore” mode. It’s still “whisper quiet” compared to the banshee howl of the original

Thanks for the cautionary tale though. Always better to know what the risks are…

[SpacedCowboy]

Have a look here: FPU Stuff

Fitting the FPU isn't 100% straightforward as you might think, and there are differences between mainboards, so you need to review the docs linked to on this page first.

So I have the GAL on order along with the 68882. My MSTE seems to have the jumper, so hopefully a fairly straightforward upgrade.

Screenshot 2023-11-05 at 9.54.43 AM.png (137.81 KiB) Viewed 2470 times

Also, my MSTE had a 1.44MB FDD installed when I got it, so check to see if you have one installed. Atari offered a kit to upgrade from the 720KB FDD, and possibly installed the HD drives as standard later.

The kit contained a PAL (GAL works just fine) and the 1.44MB drive, and is an easy upgrade. Docs can be found here: Atari docs under the MSTE section.

Obviously the FDD is harder to find in HD these days but the JED file is available.

Yeah, it's not powered up yet, still wondering about the TOS ROM swap - I did check out the red dip switches, and I have sw7 enabled so I suspect I have a 1.44MB drive as well - which is kind of nice because the TT has one of those too

Screenshot 2023-11-05 at 9.53.40 AM.png (1.47 MiB) Viewed 2470 times

[SpacedCowboy]

I'm fuming with myself right now...

I decided to try out the MSTE because if there was something wrong with it, it looks better if it's reported faster. Took the SM124 out to the shed to link it up, looked carefully at the arrangement of HI/LO EEPROMs and the fact that the Atari sticker was upside down on my board as in the picture above.

I carefully duplicated all that, put the SCSI disk in a safe orientation to start, and switched on. Huh. Nothing on the monitor. Check everything looks ok ? Yep, so wait a few secs... Nope, ok switch off then.

It was at that point I realised that the labels were on the other way around, on my US TOS EEPROMs. I found that out by touching them, and almost burning my finger off. They ought (in fact) to have been placed like this:

Screenshot 2023-11-05 at 4.10.58 PM.png (1.07 MiB) Viewed 2435 times

... based on the position of pin-1. I replaced the German ones, and everything boots up just fine, so no lasting damage to the machine, but the US TOS EEPROMs are toast, as far as I can tell. I did check for W20{1,2,3} being a bad match to these EEPROMs, but they seem to be appropriately set.

I just can't believe I did that - I *always* check for pin-1, in fact I'm the butt of a bunch of jokes around work for doing that, again, and again every time I replace/insert an IC. So yeah, sitting here trying for some cathartic typing instead. At least I didn't bugger the machine. With the heat, I'm assuming that +5v was connected to GND when they were rotated...

The day wasn't a total loss, I inverted the Noctua fan so it's now blowing air out of the case, I'd put it in, in the "normal" way, but apparently the TT inverts the polarity of the fan supply. I'm guessing (with that PSU running so hot) that it's better to pull internal air and push it out than it is to push the hot air all around the internals of the case.

So I guess I need new US EEPROMs - Exxos has them, but his shipping is somewhat delayed due to post-office manning from what I read. I'll see where I can source them from.