Sorry, I cant really offer any suggestions here as Ive never owned an ACA card. It does sound like more of an ordeal than it should be. Ive never owned an accelerator that didnt just work when plugged in. Not to speak ill of efforts for new classic amiga hardware, but yours isnt the 1st problem Ive heard of for the ACA '030 cards. Having said that though Ive heard plenty of good reports too.
The timing problem is not specific to ACA acclerators, but also effects 040 and 060 accelerator. I think it may be more common with Apollos.
Anyway, the timing mod affects STABILITY. From everything I have read the timing mod is not necessary for card to be recognized...
I would suggest the following:
Remove the top of the 1200 and loosen all screws that hold the motherboard to the bottom of the case (including the ones by the floppy).
This is completely optional but now would be a good opportunity to CHECK (not remove) surface mount components E123C and E125C to see if they are populated. You will have to remove the bottom RF shielding which requires removing all the little screws by the ports. Hopefully you have a suitable tool for that. I used a small socket. FYI: My NOS 1B.4 (From Amigakit) came with the correct configuration requiring no mod.
Bend the portion of the RF shielding over the trapdoor expansion up.
Clean A1200 contacts and inspect for damaged traces on the ACA. Look for any surface mount components that may be missing.
Insert the ACA and make sure it sits flush and not at an angle. My Typhoon sits at a slight angle still but adjusting the motherboard did make it much better.
Power the machine on and check with showconfig if the CPU says 030.
if so, Re-tighten the screws to the motheroard.
Power the machine on and check with showconfig if the CPU still says 030.
Finally, assemble the working A1200.
Good Luck.
