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Reply 20 of 21, by Jo22

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Jo22 wrote on 2019-05-18, 15:53:
I see. Looking at some photos, it sadly wouldn't be possible, anyway. For some reason, the designers decided it was a good idea […]
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dr.zeissler wrote:

I will not modify the A2286/8 it will be like it is...I only update/change the ISA-Cards.

I see. Looking at some photos, it sadly wouldn't be possible, anyway.
For some reason, the designers decided it was a good idea to place the daughterboard directlly atop the 80286 and
the socket for the (hot) numeric processor (optional).. 😢

Hi Doc, how's it going? Did you find a solution/workaround in the mean time?
Speaking of.. Sorry for the necro. I just remembered this thread for no apparent reason.
I guess my subconscious was still working somehow on that problem.

If you haven't found a solution yet, I have an idea.

a) You could make an adapter, or rather an extension cable that goes to the CPU underneath the daughterboard (encircled in white colour).
However, where to get an PLCC "socket" from that fits inside the 286 socket?

That way, no real modifications are needed.
The clock frequency is low enough to alow for an extension cord of ~10cm or less, I think.
You could use a ribbon cable and use a carpet knife to slice it into stripes of ~5 cables or so.
In needed, it could also be folded carefully, too.

b) You can widen the standoff between the bridgeboard and the daughterboard by installing two or three pin stripes on top of each other.
Then you will have enough room in between to install some of those 386/486 upgrade chips. I mean, a few centimeters extra won't cause problems, electrically speaking.

"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

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Reply 21 of 21, by dr.zeissler

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Thx for the advice Jo22 but I'll stick to the A2286 like it is. I downgraded from E4000 1MB to QuadramEGA 256KB. Now I will recheck Games with MT32 support for the SB-MIDI interface. I am not sure, but I think cloudschatze already mentioned that some will work right ootb, some don't but it's possible to patch games with MT32 support in order to make them work on SB-Midi. I already came across some weird glitches that were not present while using VGA (ET4000). I noticed a BIG slowdown on the music on DoubleDragen when scrolling the screen in the intro. Some apogee EGA Games to use egal PAL but are coded to 70hz instead of 60hz EGA so there is stuttering.

Now I will go to my MT32 supported games catalog in order to try the EGA capable games with MT32 support. If someone has already patches, please let me know.

Retro-Gamer 😀 ...on different machines