Mega ST2 and booster

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Darklord
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Re: Mega ST2 and booster

Post by Darklord »

exxos wrote: Thu Jul 15, 2021 7:50 pm @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.
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HigashiJun
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Re: Mega ST2 and booster

Post by HigashiJun »

Darklord wrote: Fri Jul 16, 2021 4:19 pm
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.
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Re: Mega ST2 and booster

Post by exxos »

HigashiJun wrote: Sat Jul 17, 2021 2:32 am 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
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viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
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Darklord
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Re: Mega ST2 and booster

Post by Darklord »

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.
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HigashiJun
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Re: Mega ST2 and booster

Post by HigashiJun »

exxos wrote: Sat Jul 17, 2021 5:04 am
HigashiJun wrote: Sat Jul 17, 2021 2:32 am 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. :)
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HigashiJun
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Re: Mega ST2 and booster

Post by HigashiJun »

Darklord wrote: Sat Jul 17, 2021 5:20 am 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 !
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HigashiJun
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Re: Mega ST2 and booster

Post by HigashiJun »

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
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Darklord
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Re: Mega ST2 and booster

Post by Darklord »

HigashiJun wrote: Sat Jul 17, 2021 2:32 am
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. :)

P1010002.JPG
P1010002.JPG (321.2 KiB) Viewed 2060 times
P1010005.JPG
P1010005.JPG (393.61 KiB) Viewed 2060 times
P1010007.JPG
P1010007.JPG (357.18 KiB) Viewed 2060 times
P1010012.JPG
P1010012.JPG (345.53 KiB) Viewed 2060 times
P1010014.JPG
P1010014.JPG (374.25 KiB) Viewed 2060 times
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HigashiJun
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Re: Mega ST2 and booster

Post by HigashiJun »

Darklord wrote: Tue Oct 26, 2021 5:30 am 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.
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Darklord
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Re: Mega ST2 and booster

Post by Darklord »

HigashiJun wrote: Tue Oct 26, 2021 9:09 am

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...
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