More power for a 1200 (and 4K)

[whabang]

BTW. Do the different revisions of A1200 motherboards have a different power usage?

[JurassicCamper]

I assume you have gotten to the point where you have chopped the lead of the AT Power supply and connected to the A1200 connector.

Now once you have done that you can either:-

Splice the floppy connector to power the hardrive.

 I would recommend this method as putting too much load on the floppy connector can lead to tracks burning out as they are very thin.

Take the motherboard out of the A1200 turn it over using a multimeter find out the voltage on the pads where the power connector is soldered.

For Hard Discs / CD-Roms you need +5v GND +12v

Cut one of the D-connects of your AT Power Supply with plenty of wire, as close as to the Power supply as possible.

Solder the Yellow (+12V) to the +12v Pad
Solder the Black (GND) to the GND Pad
Solder the Red (+5V) to the +12v Pad

Obviously verify the colours and voltages using the multimeter on the AT power supply first.

This way the load you require is not being drawn through the motherboard.

If you are feeling confident you can solder directly on the back of the Power Connector in the A1200.

[JurassicCamper]

Corrupt sound is usually a -12v problem

Middle Pin on the power connector, use a multimeter to see if -12V is coming out.

[tonyw]

Just an aside: the 4000 PSU is 145W, not 45. I think the number '1' has been rubbed off yours.

I was always unhappy about the PSU in my 4000 - the fans used to slow down whenever the CD spun up. Now that it's in a tower with a proper ATX supply, I'm much happier.

tony

[xaccrocheur]

Can somebody confirm that the A4K PSU is only 45W, whereas for example, that of the 3K is 135W, and that of a basic PC is at least 200W...

That would place the A4K PSU just above "the brick", the tiny toyesque A1200 PSU...

Anyway I'm very concerned that it could not cope with the amount of W needed to fully operate my 3 big SCSI drives...

How can I make this sure ? the Electric specs are not even stated on one of the drives, the BIG Seagate HAWK...

Well, if somebody has his 4000 as crowded as this, please drop me a line to reassure me ;-)

pX

[zipper]

Missing a "1" ?
145 W is perhaps nearer the right figure.

[Karlos]

whabang wrote:
BTW. Do the different revisions of A1200 motherboards have a different power usage?

Possibly, but they all use the same voltages which is the important issue. The thing is, any piece of electrical hardware will only draw the power it requires irrespective of how much the PSU can deliver. It's when the hardware needs to draw more power (ie higher current) than the PSU can deliver that you get problems.

Basically you can end up getting voltage drops (so drawing too much current from the 5V line can pull the voltage down) so that the hardware becomes unreliable. Worse still, the PSU can burn out and take the hardware with it :-o

Anyway, bear in mind that the mainboard voltage regulators  have a max current rating before they start to fry which is why I strongly advise a dual power input to the A1200 mainboard.

I know because this actually happened to me once when I had a dsektop 1200 using just the standard power connector with a 200W supply :-(

Luckily, I had an electrical engineer flat mate at the time who replaced the surface mount regs (in the lab at his workplace) so I got away with it ;-)

[Phoenix]

All wattage outputs quoted on power supplies is the MAXIMUM output not the continous sustainable output.



Cheers

Phoenix :-D

[duesi]

I never had Power problems in my 4000
(the only bad thing is the noisy fan)
I replaced it with silent one...

[z36ra]

I cannot confirm the 4k has a 45 Watt PSU but I can say that a standard PSU for a PC is not a standard thing. I pulled a 130Watt PSU out of a Compaq POS with k6-2 400MHZ just the other day. I have seen old Dell computers with 65Watt PSU and i286. Now when you're talkin Athlon and P3 you wont see anything less than 250watt. but the newer Athlons and P4 will have 350 to 400 watt.

I don't understand what these guys are saying about "pumping" too much power into the mobo if the Wattage of the PSU is larger. What that says to me is that if you cross the 5 and 12 V you get more smoke.

Also, Hook the damn drive up to the Floppy connector and use a bigger PSU...

Problem solved