A1200 Power Pinouts / ATX PSU / Molex Mod.

[delshay]

you must also remember not to plug the A1200 onto a *un-modifyed* PSU connector as you can short out the -12 when the standard amiga power plug is connected.

the project should work for most users.

better still if you are very good with a soldering iron,solder a wire ( as thick as possible ) from the 5v power point to the 5v rail on the floppy connector,do this on the underside of the motherboard. this will help to reduce  the voltage jrop at the trapdoor when a card is fitted.

[delshay]

Thanks for the responses guys.

Also, nice one on passing straight to the floppy, is it worth doing this on any other parts (HD, PCMCIA, 150-pin etc.) ?

doing the power point to floppy makes a difference but it all comes down to the load on the trapdoor connector. you can check this yourself but must have a card connected at the trapdoor. check the voltage at the input power in,then check it at the floppy connector,note the differences in voltage.

now most users claims they have 4.95v on the card,i say check again this time put the meter ground probe on the card and the positive probe on the card 5v connection now what is the real voltage on the card. the art to having a stable A1200 is to get the voltage near to 5v across the motherboard with no voltage jrop at the floppy connector. no matter what you do you will lose around .03 volts at the trapdoor if all extra powerfeed is done correctly.

here on my system it reads 5.01v on the PPC card this is **KEY** to why i have a 80Mhz bus speed with 256Mb ram with Bvision attatched. if the voltage jrops to 4.8v on the card it  starts to crash.

i also have improved the ground tracks on the trapdoor connector and now shows .02 voltage jrop across the trapdoor at full load.

so if my voltage input is 5.04,the floppy connector will also read 5.04. on the Blizzard card reads 5.02.

you be suprise how more stable your system becomes there is no need to add extra powerfeeds anywhere else if the floppy power wire is done correctly.

also note that the groung wire thickness is also important for desktop users,so if anyone is going to modify the power point i recommend removing the old amiga socket and replace it with a new type of socket attached to the motherboard so thicker wire can be used to reduce voltage jrop. ( experts only ).


****ALL MODIFCATION AT YOUR OWN RISK****