User avatar
leighb2282

Posted Tue Jan 09, 2018 7:28 pm

Hey Folks,

Currently my Amiga is running a GVP 3001 030 Accelerator which included a Motorola 68030 CPU + 68882 FPU co-processor both running at 28Mhz, I have seen online a 68030 and 68882 both running at 50Mhz.

My question is can I upgrade to the 50Mhz chips by just replacing those 2 28Mhz Chips or is there other things I have to consider?

Any thoughts guys n' gals?

Thanks,

Leigh

User avatar
intric8
Seattle, WA, USA
Website

Posted Tue Jan 09, 2018 10:07 pm

I would assume its the chips but have no idea to be honest. Do you have the original manual? Are the CPUs soldered onto the board?

User avatar
leighb2282

Posted Wed Jan 10, 2018 12:43 am

intric8 wrote:I would assume its the chips but have no idea to be honest. Do you have the original manual? Are the CPUs soldered onto the board?
They are actually in sockets, and looking at the 'adverts' that big big book of Amiga has in its database one of the selling points is that you can grow all the way to 50Mhz, I'm just unsure if all I need to do is replace the processor, or replace both the processor and the FPU.

http://www.bigbookofamigahardware.com/b ... _1_big.jpg

User avatar
intric8
Seattle, WA, USA
Website

Posted Wed Jan 10, 2018 7:46 am

I bet it’s just the CPU then.

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Zippy Zapp
CA, USA

Posted Wed Jan 10, 2018 9:15 am

It really depends on the board. I am putting this simple, because I am no electrical engineer. But anyway, the board might have a setting for higher frequency CPUs or you might have to replace the crystals. They usually came in 8 pin DIL package and there many times is a socketed spot on the board for this.

Amiga kit sells them as do many other electronics supply places, like Digi-Key, Jameco and mouser.

https://amigakit.amiga.store/catalog/index.php?cPath=45

IIRC, you had to match the crystal with the CPU. So if it is a 50mhz CPU you had to make sure your crystal was also 50mhz. Again, I may be wrong but this is what I remember doing back in the era.

User avatar
Bulletdust

Posted Wed Jan 10, 2018 1:27 pm

You can't just change the CPU for an increase in clock speed, the speed printed on a CPU is it's maximum rated speed, the actual speed is set by a crystal oscillator and various multipliers/dividers on the CPU card itself.

For instance, my own ACA1232 accelerator was equipped with a 25mhz 68030 when I bought it, that same 68030 is now running at 40mhz with a corresponding increase in memory speed as I changed the multiplier that determines the speed the CPU/memory is run at - This is called 'overclocking'.

I'm not too familiar with the GVP 3001, but you have to see if there's jumpers on the board or some modification that can be performed that will increase the speed the card runs the CPU at. If you were to fit a faster CPU it would simply run at the same speed as the CPU the card came with unless such modifications were performed.

User avatar
leighb2282

Posted Wed Jan 10, 2018 8:21 pm

All good information, thanks folks, there IS one crystal oscillator on the accelerator card, from what I read and remember about the board there is technically two spots for oscillators but stock there is only 1 that is being used for the timing of both the CPU and co-pro FPU chip.

Unfortunately from what I remember the oscillator on my particular card is soldered directly onto the board, so I would have to un-solder the oscillator and replace it with a socket so I could experiment with different speed oscillators.

User avatar
Bulletdust

Posted Wed Jan 10, 2018 11:17 pm

I tell you what Leigh, if you work it out let us all know! Because I find this stuff downright fascinating.

For all you know, the 68030 currently fitted to the card may well have a good additional 20mhz headroom if overclocked. I have a switch fitted to my ACA1232 and switch between 25mhz or 40mhz.

User avatar
golgotha

Posted Wed Mar 18, 2020 9:35 am

Hey leighb2282, did you ever get your board upgraded?

I have a GVP Impact 3001 with the RAM32 board and thinking of upgrading to 50MHz and 20MB of 32bit RAM on the RAM32 board. Did you manage to upgrade yours? If you could provide any details on how you switched out the crystal that would be great.

Cheers





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