Monday, March 19, 2012

A4000: Modding and testing an ATI Radeon on GREX

Hey peepz.

Some time ago I ordered an ATI Radeon 9200 (256MB RAM) in order to give it a test on the GREX :)
Yep I know that official CGX drivers don't exist for GREX but no worries... Ratte has something up his sleeve :)

So... the main problem with the Radeon is that it requires also a 3.3V line to operate which the Amiga PSU doesn't deliver.
Every problem though has it's solution so there are a couple of ways to bypass this:
  1. Putting an ATX Power Supply into the Amiga, and then feeding Radeon with the 3.3V line from the ATX PSU that Amiga doesn't use.
  2. Using an LM1084 3.3 regulator that you can feed with a max voltage of 27V as input (5V from Amiga are just fine to produce less heat) and ouput the required 3.3V.
I decided to use the second approach just because it seemed easier and more good looking :)

So... this is the ATI Radeon of mine in which I have marked the spots on the PCB where you can get the Input (5V), Output (3.3V) and GND lines.



The LM1084 has the following easy pinout as well...


Since regulator is getting a bit hot, I decided not to let it stay naked but instead I thought of putting a dedicated transistor heatsink.



Since my regulator was a PCB version without a hole for a screw, and because the heatsink was a bit big for my taste, I dremeled it and attached the regulator using a thermal paste glue!



Result was nice for my taste :) After soldering the wires to both the regulator and Radeon and gluing the heatsink on Radeon... this is how it looks like...





Not bad at all!!! The height is same as the GPU heatsink so it doesn't interfere anywhere else :)

This is how it looks in my Amiga's last available PCI slot (Slot 0).



After checking out PCI Info from CSPPC's screen, card was recognised!!! Time to log OS3.9 and check PCITool and OpenPCIInfo applications...



Presto! Both applications recognize the board just fine. You can check both logs from the links bellow:
I hope I'll have more news about this experiment in the following days :)

Stay tuned.


6 comments:

JetSetSkippy said...

Well done! Very clever indeed - Regards.

VincentGR said...

Very good job my friend, i couldnt setup mine on Mediator although it was recognised in pciinfo.
Μπράβο.

Edro Ferreira said...

excuse my ignorance, but why a 3.3V regulator?, if you put a shunt on b95 you get the same

Ratte said...

Will send you a new beta-driver ... should work this time ;-)

Anonymous said...

Thanx Mate
Bought same Card modded it like you showed works perfect with the full 256mb.

Great thread.

Nobby

Johan said...

Maybe a stupid question but how do I know where to put the voltage regulator on a different 9250 card?