SE/30 won't boot with TwinSpark adapter

[pcamen]

Some very strange stuff going on with my SE/30.  I've been trying to get an SE/30 Pivot card working.  I had a monitor plugged in which showed the background and the Radius logo. But in the Monitors control panel, it doesn't show the display.  So I start peeling things back, take off the Pivot card, same thing.  Take off the Turbo040, same thing.  Take off the TwinSpark adapter, it boots fine.  Put the TwinSpark adapter back on, no boot. 

When I say no boot, I sometimes get a startup tone, but usually not.  Then it shows a mangled screen (see picture). 

I had an identical TwinSpark adapter I got from Bolle earlier this year and it does the same thing, so I don't think it is a bad adapter (and there isn't much on those anyways). 

Anyone have any ideas why it might be doing this?  Could the failure to recognize the video card (with 2.6 ROM from 1992) be a clue? 

I also swapped out the motherboard for another.  Both were recapped by UniServer a few years back.  This system was booting fine all yesterday and this morning and now I have this behavior.

 

[Bolle]

The adapter disables the onboard CPU. If you don’t have an accelerator connected but just the adapter you won’t get a working Mac.

On top of that some logicboard just seem to refuse to work with certain card combinations.

I have exactly one logicboard that works with MacCon+Turbo040+Radius Pivot for example.

All other boards refuse to work if I add the IIsi Pivot into the mix.

The problem with having two PDS cards and an accelerator seems to be that its running on the edge of what’s possible. Initially the slot was designed to take one card, we are running three cards now at once in that slot.

The Turbo040 especially is really pushing things even further as it seems to have very aggressive timing on the external bus cycles to gain a maximum of performance. This throws off a lot of PDS cards especially if you stack them and all of those cards have their own buffers that add more latency to everything happening on the bus.

 

[pcamen]

Hmm.  So it if was doing that with the Turbo040 installed, could mean that went bad or wasn't fully pressed in I'm guessing. 

I'm just trying one PDS and the accelerator at this point BTW.  Just the TwinSpark, Turbo040, and Radius card.