exxos's Atari, Amiga & retro forum

exxos wrote: 15 Jul 2021 19:50 @Darklord All machines have their own quirks, as to how severe they are or not.. But all the boosters were tested on my H4 H5 boards and work fine. Is just these mega machines have the most faults over the entire ST range from my experience. Is why only generally recommend the 70789 style boards upgrading as I know what's are on those generally, and they are less problematical than all the other revisions of motherboards.

Understood. I guess I just got a decent machine and was lucky that the AdSpeed
works well with it.

Thanks.

Darklord wrote: 16 Jul 2021 16:19
Understood. I guess I just got a decent machine and was lucky that the AdSpeed
works well with it.

Thanks.

Could you tell which Mega ST is it, and what brand your chips are ?

I have found an interesting document from Atari (in French) saying that IMP chips were troublesome. It seems that C100167-001 REV.B motherboards cope well with these chips, but it does not mean at 16 Mhz.

I checked continuity in my machine and everything seems fine.

I ordered some chips (GLUE in Exxos store, with no confirmation mail :cry: ) and two other (MMU and Shifter) on Evilbay to do some tests. I would like to get a DMA chip (C398739-001) but there is no availability at this moment.

HigashiJun wrote: 17 Jul 2021 02:32 I have found an interesting document from Atari (in French) saying that IMP chips were troublesome. It seems that C100167-001 REV.B motherboards cope well with these chips, but it does not mean at 16 Mhz.

But this is already known https://www.exxosforum.co.uk/forum/viewt ... =20#p67441

Well, was thinking about taking that machine apart (again!) for a couple of
adjustments/changes so when I do I'll see what info I can grab for ya.

exxos wrote: 17 Jul 2021 05:04

HigashiJun wrote: 17 Jul 2021 02:32 I have found an interesting document from Atari (in French) saying that IMP chips were troublesome. It seems that C100167-001 REV.B motherboards cope well with these chips, but it does not mean at 16 Mhz.

But this is already known https://www.exxosforum.co.uk/forum/viewt ... =20#p67441

Yes, your article and own findings resumed it clearly. :)

Darklord wrote: 17 Jul 2021 05:20 Well, was thinking about taking that machine apart (again!) for a couple of
adjustments/changes so when I do I'll see what info I can grab for ya.

Thank you !

Ok, so after having tried different chips (Shifter, MMU and GLUE) instead the IMP branded ones, the booster still does not function as it should.

The best result I could obtain was finally with the original IMP chips.

I will not investigate more due to lack of time, but I certainly do not regret my trials.

:D

HigashiJun wrote: 17 Jul 2021 02:32
Could you tell which Mega ST is it, and what brand your chips are ?

I have found an interesting document from Atari (in French) saying that IMP chips were troublesome. It seems that C100167-001 REV.B motherboards cope well with these chips, but it does not mean at 16 Mhz.

Finally got around to opening my Mega ST4 back up. Took a few pictures. See if this gives you
the information you need. I'll have it open for a while longer if there is something specific you
want me to try to photograph.

HTH's. :)

Darklord wrote: 26 Oct 2021 05:30 Finally got around to opening my Mega ST4 back up. Took a few pictures. See if this gives you
the information you need. I'll have it open for a while longer if there is something specific you
want me to try to photograph.

HTH's. :)

Thank you Darklord !

I think all your chips, except your DMA, are IMP brand ones, but it is hard to see on the pictures.

Never got my hands on a ICD AdSpeed, but it pretty looks like Exxos' last 16Mhz booster.

HigashiJun wrote: 26 Oct 2021 09:09

Thank you Darklord !

I think all your chips, except your DMA, are IMP brand ones, but it is hard to see on the pictures.

Never got my hands on a ICD AdSpeed, but it pretty looks like Exxos' last 16Mhz booster.

You're very welcome. :)

Just glanced over them - I think you are right.

One thing I wasn't sure about was "revision B"? My motherboard says "revision 5.0". Not sure
how that equates?

The AdSpeed's are good accelerator boards, solidly built and well designed. I was lucky to
get my hands on one...