Falcon FPU - who can help?

[mgi]

Hi,

I am trying to fit the FPU to my Falcon but while recognised by GemBench it is crashing with bombs when testing and DevPac says it’s not there.

I know some people had issues with socket etc. I also have Eagle Sonic 32 accelerator which I am not using but could this be a problem?

I am looking for someone in UK who could look into it, throw away this accelerator and run a general MOT on this Falcon with any fixes if needed.

Any takers? :)

[mikro]

I'm wondering where this "devpac mania" started as this is maybe third post when somebody is testing FPU presence by Devpac. Devpac is an assembler. You can assemble FPU code on a non-FPU machine, you can assemble 68000 code on a 68030 machine etc. It's controlled by flags, not by hardware.

As for your issues, try to seach this forum (or was it AF?) for a long thread with similar issues. TL;DR version is: always check whether a pin isn't bent or damaged *and* make sure you have a regular, working, FPU and not some of the eBay fakes. These days people tend to buy something for $5 incl. postage from China and get upset that it doesn't work! That's the reason why it's worth buying from Chris here, he's selling tested and working stuff.

[mgi]

Hi,

I have my FPU from Exxos so I have no doubts it is OK. I tested this with the same FPUTEST software I have and I run on my TT where it is working correctly. GemBench is also recognizing FPU but when it comes to FPU test it is crashing. The example with DevPac is also just another example - I set all the flags in the compiler.

I reviewed the posts and I know the problem was with the connection to socket. I looked very closely at those, cleaned the socket but still have the same issue so not sure what I can do more hence asking for help from somebody who knows this better than me.

[exxos]

I've not seen a eagle sonic, is it like nemesis etc ? Does it over clock the fpu ? Normally you can turn the things on and off ?

Have you run this https://www.exxosforum.co.uk/forum/viewt ... =25&t=1700

Looks like this guy had a similar problem and was contacts on the socket https://www.exxosforum.co.uk/forum/viewt ... =10#p74276

[mgi]

You can turn it on and off but it Is crashing when changing resolution so I am just not using it. It was in the Falcon when I bought it.

I was using the same test and the result is exactly the same. I inspected the soldering but it is all looking good to my untrained eye. I guess it would make sense to remove this accelerator and try without it?

BF0E82A5-21BF-4AB1-A1F4-355A56BFE08A.jpeg

[Badwolf]

If that's an external CPU (which it what it looks like) and it's not got a fly lead driving the FPU's data strobe line, then it won't work with an on-motherboard FPU.

The fact that it's recognised at all makes me think it must have some tentacles soldered onto the board somewhere, but I had to jump through a few hoops to make an external CPU see the internal FPU when I was playing with it.

Is an FPU actually supported when using this accelerator, I wonder?

BW.

[exxos]

Is an FPU actually supported when using this accelerator, I wonder?

That's a good point. TOS must have "seen" the FPU and I assume set the cookie so the system sees the FPU, but cannot actually use it. :shrug:

[mgi]

So is the solution just to remove it and cut/unsolder any cables from this accelerator?

[exxos]

So is the solution just to remove it and cut/unsolder any cables from this accelerator?

With the current assumptions yes. But it might be a good idea to look for the manual to see if any other mods were done when it was being fitted. Or at least post some clear images if the motherboard so we can see if anything looks amiss.

[mgi]

Hi,

To be fair I could not find the manual for this one but only for Mighty Sonic one. The most informative thread was on this forum: https://www.exxosforum.co.uk/forum/viewtopic.php?t=1152

rpineau:
'I think you need to lift 2 pins (I think it's BR and BG but not sure) as with all of the board they did (Mighty Sonic and AfterBurner 040) and wire it to GND or something like this (As my falcon no longer has a 68030 I don't have to worry about that with my AfterBurner).'

Based on this I may pass on removal if it means resoldering the CPU legs back and I may look for somebody who actually knows a bit more. I really don't want to mess up this Falcon.

Is there anyone on the forum with some time to look into my Falcon, remove this accelerator, fit the FPU and see if anything else needs doing?