power issues again

[amiga4001]

As my A4000 couldn't get it going any more I replaced it with a antec SP-350-Sp so smartpower 350W.

With nothing attached to mobo accept cyberstormppc it boots and the voltage of the +5V rail is about 4.92V.
As soon as I add the mediator it drops to 3.86V and if I place in my kickflash it comes to about 3.80 V.

I made the connection between the antec and the mobo as short as possible and soldered a original A4000 plug directly to the wires of the antec to it.

Needless to say if the voltages reaches 4.80 V it won't boot anymore and if it does there are things missing(keyboard/zorrocards).

What is going on here thought antec where quality psu's?
Payed 62 euro for this psu!

[patrik]

@amiga4001:

Sounds like something is fishy, a modern psu should have no problems powering an A4000 almost disregarding what expansions you throw at it.

I seem to recall you posted about this before.. was it so that the only powersupply that could make it boot with all expansions except the drives was the stock A4000 psu?


/Patrik

[amiga4001]

Yes that was me but don't believe something is wrong.
Did try another mobo same results and cyberstorm just takes a little bit of drain as the rest of the hardware.
I was thinking that maybe the mediator needed some extra juice as the tower model has an powerplug?
Maybe the traces to the mediator have to much resistance?
I'll try an other mobo with this antec and a 3640 and some zorro card see how that goes for voltage.

[Zac67]

If all (possible) wires are connected to the mainboard and the  voltage is that low, there's something wrong with the PSU - should still be under warranty.

BTW: 350W is way oversized for an Amiga, should be more like 200/250W. An oversized PSU runs in low efficiency, thus wasting electricity and producing unnecessary heat/noise.

[Framiga]

Theres definitely a problem with the mediator.

Take a look "carefully" to the 6 pins molex female socket soldered to the mobo (with a magnifier lens).

Mine for example, has the 5 volt female pin, a little bit faked(?) and btw i have to replace it.

Consider that those kind of connector has a avg. lifespan of 50 insertion !?! . . . go figure!

[orange]

I'd say its connector problem, too. touch the +5V wire at it to check if it gets hot. Use some contact cleaner and bend 'pins' for better grip.

[mechy]

The mediator needs power to it directly as well as the motherboard,otherwise you will be trying to pull ridiculous amperage thru the zorro connector,and eventually it may burn it up(if you havent already). pull he slotboard out and check the contacts in it,i bet you will see some that carry the 5v are discolored.It will probabaly still work tho.

the mediator and cards draw a good few amount of amps on the 5v side,so the mediator definately needs power directly to its connector. most good bus boards work this way.

Mike

[amiga4001]

I can boot her up now with the antec if I do a very fast doubleswitching of the powerswitch.
I removed the pin off the powerconnector and rubbed it clean(little brownish) and made the pin a little wider.
I also soldered a few wires to the zorro connector(+5V and a gnd).
Still there is no more then 4.87V which isn,t enough to keep the delfina going or warpos.

Best would be to solder the wires of an other connector on the underside of the mobo directly?
Could use some thick wires and a few AMP connectors.

Would the mediator be happy with only +5V and a GND or should it also need a 12V line?

Still strange that I have to doublestart to boot(only with the ppc not with "normal" processorcard.

Hoping to find the cure for this!