Power supply question - plz help!

[Vulture]

Hi all!

quick question for someone who may have tried it and worked:

I have a Mediator 1200 and a 200W AT psu on it. Still, sometimes I get weird crashes even without startup-sequence or any pci cards inserted. I've pretty much tried everything (trust me, I have) to fix this except of messing with the power supply. I'm pretty sure 200w are (more than) ok for my setup, still it could be that some current is lost on its way to some parts due to the thin layers of the board acting like a resistor (or so I've read).

So, I've also read that if I take a floppy connector from the psu and plug it to the floppy power connector on the board, it'll make the current more stable. Is that true?

But most importantly, will this work in conjuction to the Mediator or will it blow something up? I've read of ppl doing that with the standard a1200 power connector, but I've not found a mediator/floppy combo. So, if anyone here has done it and it works, please, let me know.

Thanks!

[SteveSMS]

200W should be more than adequate IMHO.
Are you sure the PSU is OK?
Maybe there's a fault in the PSU causing current drops?
I had that once that's why i'm asking.

[hardlink]

Power problems are a good thing to rule out, but I don't know anything about the Mediator, so I can't speak to that. But, have you tried swapping in a different power supply? AT PSU's can often be found hiding in big tan metal boxes on the curb before trash day

[ChuckT]

As an Amiga 500 user, I bought a custom made power supply because I remember having to buy one to replace the power supply on my C-64 and I remember them saying stuff in the magazines about people plugging more than two disk drives into their computer and how the Amiga 500 power supply might not handle it.

The custom made power supply I have for the Amiga 500 is steppable which means that if you increase the load, the power supply will increase the supply.  It is one of the reasons I'm skeptical about the XT power supply because I don't know enough about it.

[Vulture]

Yes, I've tried another psu. It's how the current is shared inside. I have problems when I put mouse+keyboard on the switch to share with the pc for example (yes I've tried several switches, various types, it's not that - there are other problems too). It's quite obvious (to me, as I know wwhat problems I have exactly) that it's power related, but it's not the PSU. I've even tried 300w atx and the same things occur.

[rkauer]

 Easy steps:

 - Take out the Mediator, accelerator & passtrough. Put then back. With this act you will remove any oxidation from the contacts;

 - If above didn't do anything, put a power socket into the floppy power header on the motherboard. It will alleviate the current from the Mediator to motherboard.

 200W is more than enough, even in a very expanded 1200, but those 200W AT don't have this output (average is 130W!). So, if you have Voodoo, TV-card, Sound Blaster and net NIC plus a Blizzard PPC (with or without BVision), buy a stronger PSU (350W "declared" is OK).

[Vulture]

@rkauer

thx for the tip. any idea if there'll be any problem having the Mediator and the floppy powering the board together?
thx!

[ChuckT]

Sometimes using a pencil eraser carefully can remove (oxidation) buildup between terminals but you have to use a lot of patience because you don't want to damage the leads.

[rkauer]

Vulture wrote:
@rkauer

thx for the tip. any idea if there'll be any problem having the Mediator and the floppy powering the board together?
thx!

 In theory, someone can point you can't use two power supply points in one device (look the entire Amiga as one), but I did this and not a single problem at all. Since you use the same PSU to power everything, it's OK.

 Here are some hints:

 1- Check the voltage levels on different points on the computer. On power conector, original power connector, floppy power header, passtrough, accelerator (carefully, to not short anything who ruins your computer);

 2- Put the "extra" power floppy wires;

 3- Feed the accelerator fan directly from the PSU instead from the accelerator board (watch out! look the fan voltage first).

[swift240]

Why not get an ATX 300 watt PSU.

Mike.

[AMC258]

In theory, someone can point you can't use two power supply points in one device

Sure you can, no problem.  As long as there is no potential difference.  And, you won't encounter that.

Check the voltage levels on different points on the computer.

I expect if they are different enough to point out a problem, you have already burnt out some traces (or are VERY close to doing it)!

Does the Meditator 1200 have a power connector?  I know the A3000D and A4000T ones do.

[rkauer]

 AT or ATX, doesn't matter. But an ATX involves another hack or adaptor (or new wiring).