More power for a 1200 (and 4K)

[xaccrocheur]

I bumped into another readme regarding the fitting of an old AT PSU to a 1200.

this link

My question is : If I use a 3.5' HD in (or out of) the 1200, how can I power the drive THRU the MoBo, to avoid an additionnal cable to be dangling from the side ?

since it HAS a power plug, unlike the 2.5 HDs... Where should I plug this latter power plug on the MoBo ?

Thank you

pX

[GreggBz]

You could splice the floppy power supply, which is what I did.

Be carefull! Normally, the amiga power connecter uses yellow as +5V and red as +12V whereas a PC molex connector is usually reversed, yellow is +12V and red is +5V. Grounds are always in the middle. You should look at the pinouts for a molex connector and verify the voltage on the Amiga side with a multimeter before striping soldering and insulating.

Other than this operation, I don't really know of an eaiser way.

[Karlos]

Before getting a  tower, I used an old PC supply.
I was worried about the current levels that would pass through the standard A1200 power socket, so I fitted an additional one.
I used a standard male hard disk power connector (from maplins), fitted into the back of my A1200, having cut a wee hole with a hacksaw and used a bit of super glue. I then powered the floppy disk/hard disk from this socket, and later added an additional feed to the mainboard via the original floppy power connector (be careful of the pin arrangement else you'll pump 12VDC into the 5VDC line!)
The upshot was that I had 2 power leads going into my A1200, both of which needed to be pugged in else it wouldn't work ;-)
This worked perfectly as a temporary fix until I got a tower.

[xaccrocheur]

Karlos wrote:
Before getting a  tower, I used an old PC supply.
I was worried about the current levels that would pass through the standard A1200 power socket, so I fitted an additional one.
I used a standard male hard disk power connector (from maplins), fitted into the back of my A1200, having cut a wee hole with a hacksaw and used a bit of super glue. I then powered the floppy disk/hard disk from this socket, and later added an additional feed to the mainboard via the original floppy power connector (be careful of the pin arrangement else you'll pump 12VDC into the 5VDC line!)
The upshot was that I had 2 power leads going into my A1200, both of which needed to be pugged in else it wouldn't work ;-)
This worked perfectly as a temporary fix until I got a tower.

Sounds fine, that's what I envisioned in the 1st place. On the other hand GreggBz's solution is much more elegant : That way you only have 1 cable.

thanks for the options !

Now I'm wondering, this time on my 4000, can I plug *that* much items init ?

A4040 w/ orgiginal DaughterBoards
GVP HC+8 Ser.II Rev.II (has a PSU socket, drains it from the ZII port)
TEAC SCSI CD-ROM (x32 I guess)
Original HD FLoppy drive
Conner CP30540 520 Mg SCSI HD (came w/ the machine I guess, am I correct ?)
IBM DDRS-HG 4560Mg SCSI HD
Seagate Hawk ST15230N (the BIG one, server stuff, double the thickness and heavy metal case)

The two latter disks are not mounted yet, since I'm quite concerned about power issues. I don't want to be losing data by corruption or long stress-inducing revalidations...

pX

[whabang]

I've heard that one could feed extra power into the A1200 mobo by using the floppy connector.
Is this true? It sounds a little bit dangerous...

[miles]

I'm running the standard 135 Watt PSU on my 3000 and have 4 Zorro
cards, 2 HDDs, 1 cd rom, HD FDD, CS060 plugged in with no ill effect
on the power.  I have had 2 more HDDs and another cd and a cd-r
plugged into this system as well in the past, probably pushing the PSU
to the point I would not have added anything else :-)  You should not
have a problem with your PSU.

[xaccrocheur]

miles wrote:
I'm running the standard 135 Watt PSU on my 3000 and have 4 Zorro
cards, 2 HDDs, 1 cd rom, HD FDD, CS060 plugged in with no ill effect
on the power.  I have had 2 more HDDs and another cd and a cd-r
plugged into this system as well in the past, probably pushing the PSU
to the point I would not have added anything else :-)  You should not
have a problem with your PSU.

Wow, indeed, that's reassuring. But then again, you have a 3K (lucky bastard) because my A4K's PSU reads "Output : 45W" witch is scary : I have a 250W PSU in one of my LinBoxes, is it really 3 times more powerful ? Or does the notation of those voltage are as serious as, say, the size of the monitors ? :-P

pX

[Karlos]

whabang wrote:
I've heard that one could feed extra power into the A1200 mobo by using the floppy connector.
Is this true? It sounds a little bit dangerous...

Sure. I do that in my tower too. As long as your careful about not mixing up the lines.

In fact, if you have a greedy accelerator, ram, gfx card etc. (ie BlizzardPPC/BVisionPPC) its a must ;-)

[Karlos]

xaccrocheur wrote:

Sounds fine, that's what I envisioned in the 1st place. On the other hand GreggBz's solution is much more elegant : That way you only have 1 cable.

thanks for the options !

Well, as I thought I said the point of having two cables was to alleviate the current levels flowing through the standard A1200 power socket - I didn't want to overload the regulators on there (which happened to an older mainboard of mine).
Better to be safe than sorry. Also, since I used a spare A1200 power cable (from an old PSU) it didnt look untidy, it was just another cable into the back of the machine.

[whabang]

So in theory, I could connect an AT PSU to the miggy via the floppy connector?

[Karlos]

whabang wrote:
So in theory, I could connect an AT PSU to the miggy via the floppy connector?

You could, but I wouldnt reccomend it as a sole power feed. For example, you wouldn't get -12VDC in which case your sound would be screwed up and your serial port probably wont work properly. The 5VDC and 12VDC lines are the most loaded, esp 5V when you add a few extra tens of millions of transistors in the form of a bigger processor, more memory, gfx card, etc. etc.

If you want to jam the juice in, use both. Also (obviously) power all your drives / fans straight from the PSU.

[whabang]

@Karlos
Of course...
Thing is that the miggy hangs every now and then. The sound is corrupted etc. etc...
Conclusion: I don't think that ol PSU of mine is enought to power accelerator, HD, floppy, mobo...

[Karlos]

whabang wrote:
@Karlos
Conclusion: I don't think that ol PSU of mine is enought to power accelerator, HD, floppy, mobo...

What do you have? It's not a standard C= PSU is it?

[whabang]

Yes it is... A bog standard A500 PSU. ( The machine won't even boot with the A1200 PSU :-P )

[whabang]

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