exxos's Atari, Amiga & retro forum

Hello! First time posting here. English is not my first language as you’ll find out. Really appreciate all your work Exxos!

All right so on to my problem. I have previously installed the Exxos PSU, the DAC noise reduction kit and replaced most of the STE’s motherboard capacitors. With this upgrade I first installed the TOS selector and tested it out before getting along with the booster, everything seemed fine. I could switch the TOS version and run programs from a Ultra Satan with no problem. After the booster was fitted I got some problems. The STE will only boot properly in TOS 2.06 and only when a floppy is inserted (no hard drive), in other cases I get bombs after the RAM test.


My machine does not have a socketed blitter so I should assume maybe that this has to do with the clock signal being off in relation to the booster?

So what I need to do for the internal blitter configuration is to make changes to C1 and R1. Reading a thread here I didn’t really understand what this meant. I’m really slow-witted and know very little about this kind of stuff so I made some images to illustrate the questions I have.

I’m waiting for a 68R resistor to arrive, which I’ll replace the SMD resistor marked R1 with. But how do I go about removing the C1? In the picture I saw at the other thread the arrow was pointing at the disc capacitor and not the MLCC near the actual C1 mark.
Do I need to remove both capacitors marked above with red and blue or just one of them?
Also, I am going to need to bridge some of these contact points afterwards, right?

Sorry for asking such stupid questions but I really don’t want to damage anything.

Nothing wrong with asking questions before potentially doing something dangerous :)

You just need to simply de-solder that disc capacitor (points C & D) and remove resistor "E" and replace with 68R. That's all you need to do.

I also assume you have read topics about parity Simms, the routing of the cable and making sure you have not got a "S" series buffer under the PSU etc ?

You will also likely need to do the mandatory DMA fixes. https://www.exxosforum.co.uk/forum/viewt ... =17&t=1585

Thanks a ton for such a quick reply! :-) All right, so I just remove the disc capacitor and don’t make any bridges.

I should have mentioned that I’m also using your RAM simms. :-) The IC at U407 is a 74F257. I’m not so sure about the routing of the cable to the buffer however, I made it short and it hangs at a height above the motherboard but it does pass some of the video components. The image looks pretty stable at least. I will do the video fix soon.

I have seen the topics about the DMA fixes and I planned on doing them. Haven’t got around doing it yet as things were working before.

Things will have to lay on the shelves for a time until I get the necessary components but I’ll let you know how everything goes. :-)

harbert wrote: 13 Aug 2020 19:42 The STE will only boot properly in TOS 2.06 and only when a floppy is inserted (no hard drive), in other cases I get bombs after the RAM test.

This is standard TOS 2.06 behaviour. If no floppy drive is found it will throw 4 bombs.

/Troed

Thanks for the info troed. Is that so? How come I’ve never realised after all this time. It also happened when the drive was powered on and present but without it containing a disk. That can’t be normal 2.06 behaviour too, can it? Am I losing my mind?

If the floppy drive isn't plugged in then TOS will bomb. I think that is what troed is referring to..

Simply not have a floppy in the drive will just mean you have a white screen for about 45 second until it hits desktop.

All right so the 68R resistor arrived in the mail today! Swapped out the existing SMD resistor on R1 and also removed the nearby disc capacitor.
Looks a bit stupid with a through hole resistor but It’ll do.

And with this being the only change I’ve made since my last post, everything just worked afterwards! :-) What a huge relief!
I can switch between TOS 1.62 and 2.06, boot without a disk and use the Ultrasatan again.
Testing out Stunt Car Racer in 32 MHz. :-) Very exciting to witness I gotta say! Played some Wings of Death and saw a noticeable boost in performance there as well.

I will still attempt the mandatory fixes you mentioned earlier Exxos but I thought I’d just let you guys know that the internal blitter mod did the trick on my STE.

harbert wrote: 17 Aug 2020 19:01 Testing out Stunt Car Racer in 32 MHz. :-) Very exciting to witness I gotta say! Played some Wings of Death and saw a noticeable boost in performance there as well.

I will still attempt the mandatory fixes you mentioned earlier Exxos but I thought I’d just let you guys know that the internal blitter mod did the trick on my STE.

:bravo: :goodpost: