Tech: Installed FPU in E-matrix and A1200 no longer boots

[save2600]

Sigh. Here we go. Received a known working FPU today, along with its crystal and its socket. Did a fine job soldering and made sure there were no shorts. My E-matrix board seems to be "special" in that it was either missing components or had too many. Comparing my board with one from BBOAH, I have rectified those scenarios. To the best of my ability anyway. Not sure if I have the exact value needed for the surface mounted diode above and to the right of the FPU's crystal, but I tried 3 and they all produced the same results.

Long and short of it: computer does not want to boot with the FPU installed. Only components missing from my board compared to the BBOAH's board is the circuitry for the SCSI side of it. I don't care about SCSI right now, just want this board to work happily with the FPU.

Anyone know what gives? I've attached 2 pics. The BBOAH's board will be on top and my board below. FPU I received is labeled: XC68882RC50A. My CPU reads: MC68030RC40B. They are both clocked at 40mhz. There wouldn't be an incompatibility here, would there??

[save2600]

What towel?  :-)

Again folks - the system boots perfectly fine without that frickin' FPU  :-(  

Card will probably be more stable now that I've touched up the cold solder joints on the connectors.

[save2600]

@ ideal:

JP1-JP3 are jumpers under that cap. The diode to the left is what was missing.

I've soldered a diode and desoldered it to no avail. I've traced the connection of that diode back to the SCSI circuit. Should not affect the FPU, but I installed on there anyway. Same goes for the cap.

@ wolfchild:

I've added three tantalum caps to no avail. Might not have been the incorrect values, but I tried three. Polarity was observed, so nothing blew up! lol  Even moved the tantalum cap to the lower left of the board to the place in question. Nada. Added a diode to the place in question as well to no avail. The pic from BBOAH looked like a diode to me. Upon testing it, it sure does not test like a diode. SO... lesson learned here. Why they'd make a  surface mounted tantalum cap look like a diode is beyond me (black w/ grey band). Course, didn't see the typical 1N00X markings, but...  

Maybe I should try spraying it down with WD-40 next?   LOL!

I'm totally out of ideas here. Either that FPU is blown and is causing the computer NOT to boot or something else is wrong here.

Card still works without the FPU of course. I'm not sloppy with an iron and I'm not in the habit of zapping out I.C.'s.

Thanks to all for the productive suggestions.